Glossary
Aviation glossary
1,419 terms, acronyms and definitions reproduced from official FAA handbooks and the EASA EPAS acronym list — all on one page, searchable, with each entry tagged to its source document.
1,419 terms
#
- 100-hour inspection
- An inspection identical in scope to an annual inspection. Conducted every 100 hours of flight on aircraft of under 12,500 pounds that are used to carry passengers for hire.
- FAA PHAK
- 14 CFR
- See Title 14 of the Code of Federal Regulations.
- FAA PHAK
- 4G
- fourth generation of wireless mobile telecommunications technology
- EASA EPAS
A
- A.C
- Alternating current.
- FAA PHAK
- AAS
- Airspace Architecture Study — Proposal for the future architecture of the European airspace created by SESAR Joint Undertaking, 2019
- EASA EPAS
- Abeam Fix
- A fix, NAVAID, point, or object positioned approximately 90 degrees to the right or left of the aircraft track along a route of flight. Abeam indicates a general position rather than a precise point.
- FAA IPH
- ABs
- Advisory Bodies
- EASA EPAS
- Absolute accuracy
- The ability to determine present position in space independently, and is most often used by pilots.
- FAA PHAK
- Absolute altitude
- The actual distance between an aircraft and the terrain over which it is flying.
- FAA PHAK
- Absolute pressure
- Pressure measured from the reference of zero pressure, or a vacuum.
- FAA PHAK
- ACARE
- Advisory Council for Aviation Research and Innovation in Europe
- EASA EPAS
- ACAS
- airborne collision avoidance system
- EASA EPAS
- Accelerate-go distance
- The distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1, and continue the takeoff on the remaining engine(s). The runway required includes the distance required to climb to 35 feet by which time V2 speed must be attained.
- FAA PHAK
- Accelerate-stop distance
- The distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1, and abort the takeoff and bring the airplane to a stop using braking action only (use of thrust reversing is not considered).
- FAA PHAK
- Accelerate-Stop Distance Available (ASDA)
- The runway plus stopway length declared available and suitable for the acceleration and deceleration of an airplane aborting a takeoff.EASA definition
- FAA IPH
- Acceleration
- Force involved in overcoming inertia, and which may be defined as a change in velocity per unit of time.
- FAA PHAK
- Acceleration error
- A magnetic compass error apparent when the aircraft accelerates while flying on an easterly or westerly heading, causing the compass card to rotate toward North.
- FAA PHAK
- Accelerometer
- A part of an inertial navigation system (INS) that accurately measures the force of acceleration in one direction.
- FAA PHAK
- ACNS
- airborne communications, navigation and surveillance
- EASA EPAS
- AD
- Airworthiness Directive
- EASA EPAS
- ADC
- See air data computer.
- FAA PHAK
- ADF
- See automatic direction finder.
- FAA PHAK
- ADI
- See attitude director indicator.
- FAA PHAK
- Adiabatic cooling
- A process of cooling the air through expansion. For example, as air moves up slope it expands with the reduction of atmospheric pressure and cools as it expands.
- FAA PHAK
- Adiabatic heating
- A process of heating dry air through compression. For example, as air moves down a slope it is compressed, which results in an increase in temperature.
- FAA PHAK
- Adjustable stabilizer
- A stabilizer that can be adjusted in flight to trim the airplane, thereby allowing the airplane to fly hands-off at any given airspeed.
- FAA PHAK
- Adjustable-pitch propeller
- A propeller with blades whose pitch can be adjusted on the ground with the engine not running, but which cannot be adjusted in flight. Also referred to as a ground adjustable propeller. Sometimes also used to refer to constant-speed propellers that are adjustable in flight.
- FAA PHAK
- ADM
- See aeronautical decision-making.
- FAA PHAK
- ADR
- aerodromes
- EASA EPAS
- ADS-B
- automatic dependent surveillance - broadcast
- EASA EPAS
- ADS-C
- automatic dependent surveillance - contract
- EASA EPAS
- ADSP
- ATM data service provider
- EASA EPAS
- Advanced Surface Movement Guidance and Control System (A-SMGCS)
- A system providing routing, guidance and surveillance for the control of aircraft and vehicles, in order to maintain the declared surface movement rate under all weather conditions within the aerodrome visibility operational level (AVOL) while maintaining the required level of safety.
- FAA IPH
- Advection fog
- Fog resulting from the movement of warm, humid air over a cold surface.
- FAA PHAK
- Adverse yaw
- A condition of flight in which the nose of an airplane tends to yaw toward the outside of the turn. This is caused by the higher induced drag on the outside wing, which is also producing more lift. Induced drag is a by-product of the lift associated with the outside wing.
- FAA PHAK
- AeMC
- aero-medical centre
- EASA EPAS
- AEMS
- aeroplane emergency medical service
- EASA EPAS
- Aerodynamics
- The science of the action of air on an object, and with the motion of air on other gases. Aerodynamics deals with the production of lift by the aircraft, the relative wind, and the atmosphere.
- FAA PHAK
- Aeronautical chart
- A map used in air navigation containing all or part of the following: topographic features, hazards and obstructions, navigation aids, navigation routes, designated airspace, and airports.
- FAA PHAK
- Aeronautical decision-making (ADM)
- A systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances.
- FAA PHAK
- AFM
- aircraft flight manual
- EASA EPAS
- AFUA
- advanced flexible use of airspace
- EASA EPAS
- Agonic line
- An irregular imaginary line across the surface of the Earth along which the magnetic and geographic poles are in alignment, and along which there is no magnetic variation.
- FAA PHAK
- AI
- artificial intelligence
- EASA EPAS
- Ailerons
- Primary flight control surfaces mounted on the trailing edge of an airplane wing, near the tip. Ailerons control roll about the longitudinal axis.
- FAA PHAK
- Air data computer (ADC)
- An aircraft computer that receives and processes pitot pressure, static pressure, and temperature to calculate very precise altitude, indicated airspeed, true airspeed, and air temperature.
- FAA PHAK
- Air mass
- An extensive body of air having fairly uniform properties of temperature and moisture.
- FAA PHAK
- Air route surveillance radar (ARSR)
- Air route traffic control center (ARTCC) radar used primarily to detect and display an aircraft’s position while en route between terminal areas.
- FAA PHAK
- Air Route Traffic Control Center (ARTCC)
- A facility established to provide air traffic control service to aircraft operating on IFR flight plans within controlled airspace and principally during the en route phase of flight
- FAA IPH
- Air traffic control radar beacon system (ATCRBS)
- Sometimes called secondary surveillance radar (SSR), which utilizes a transponder in the aircraft. The ground equipment is an interrogating unit, in which the beacon antenna is mounted so it rotates with the surveillance antenna. The interrogating unit transmits a coded pulse sequence that actuates the aircraft transponder. The transponder answers the coded sequence by transmitting a preselected coded sequence back to the ground equipment, providing a strong return signal and positive aircraft identification, as well as other special data.
- FAA PHAK
- Air Traffic Service (ATS)
- Air traffic service is an ICAO generic term meaning variously, flight information service, alerting service, air traffic advisory service, air traffic control service (area control service, approach control service, or aerodrome control service).EASA definition
- FAA IPH
- Aircraft altitude
- The actual height above sea level at which the aircraft is flying.
- FAA PHAK
- Aircraft Approach Category
- A grouping of aircraft based on reference landing speed (VREF), if specified, or if VREF is not specified, 1.3 VSO (the stalling speed or minimum steady flight speed in the landing configuration) at the maximum certificated landing weight.
- FAA IPH
- Airfoil
- Any surface, such as a wing, propeller, rudder, or even a trim tab, which provides aerodynamic force when it interacts with a moving stream of air.
- FAA PHAK
- AIRMET
- Inflight weather advisory issued as an amendment to the area forecast, concerning weather phenomena of operational interest to all aircraft and that is potentially hazardous to aircraft with limited capability due to lack of equipment, instrumentation, or pilot qualifications.
- FAA PHAK
- Airplane
- An engine-driven, fixed-wing aircraft heavier than air that is supported in flight by the dynamic reaction of air against its wings.
- FAA PHAK
- Airplane Flight Manual (AFM)
- A document developed by the airplane manufacturer and approved by the Federal Aviation Administration (FAA). It is specific to a particular make and model airplane by serial number and it contains operating procedures and limitations.
- FAA PHAK
- Airplane Owner/Information Manual
- A document developed by the airplane manufacturer containing general information about the make and model of an airplane. The airplane owner’s manual is not FAA approved and is not specific to a particular serial numbered airplane. This manual is not kept current, and therefore cannot be substituted for the AFM/POH.
- FAA PHAK
- Airport Diagram
- A full-page depiction of the airport that includes the same features of the airport sketch plus additional details, such as taxiway identifiers, airport latitude and longitude, and building identification. Airport diagrams are located in the U.S. Terminal Procedures booklet following the instrument approach charts for a particular airport.
- FAA IPH
- Airport Sketch
- Depicts the runways and their length, width, and slope, the touchdown zone elevation, the lighting system installed on the end of the runway, and taxiways. Airport sketches are located on the lower left or right portion of the instrument approach chart.
- FAA IPH
- Airport surface detection equipment (ASDE)
- Radar equipment specifically designed to detect all principal features and traffic on the surface of an airport, presenting the entire image on the control tower console; used to augment visual observation by tower personnel of aircraft and/or vehicular movements on runways and taxiways.
- FAA PHAK
- Airport Surface Detection Equipment-Model X (ASDE-X)
- Enables air traffic controllers to detect potential runway conflicts by providing detailed coverage of movement on runways and taxiways. By collecting data from a variety of sources, ASDE-X is able to track vehicles and aircraft on the airport movement area and obtain identification information from aircraft transponders.
- FAA IPH
- Airport surveillance radar (ASR)
- Approach control radar used to detect and display an aircraft’s position in the terminal area.
- FAA PHAK
- Airport surveillance radar approach
- An instrument approach in which ATC issues instructions for pilot compliance based on aircraft position in relation to the final approach course and the distance from the end of the runway as displayed on the controller’s radar scope.
- FAA PHAK
- Airport/Facility Directory (A/FD)
- Section within the Chart Supplement regional booklets published by Aeronautical Information Services that provides information about all airports in the region. The A/FD section includes runway length and width, runway surface, load bearing capacity, runway slope, airport services, and hazards, such as birds and reduced visibility.
- FAA IPH
- airprox
- An airprox is a situation in which, in the opinion of a pilot or air traffic services personnel, the distance between aircraft as well as their relative positions and speed have been such that the safety of the aircraft involved may have been compromised. (ICAO Doc 4444: PANS-ATM).
- EASA EPAS
- Airspeed
- Rate of the aircraft’s progress through the air.
- FAA PHAK
- Airspeed indicator
- A differential pressure gauge that measures the dynamic pressure of the air through which the aircraft is flying. Displays the craft’s airspeed, typically in knots, to the pilot.
- FAA PHAK
- Airway
- An airway is based on a centerline that extends from one navigation aid or intersection to another navigation aid (or through several navigation aids or intersections); used to establish a known route for en route procedures between terminal areas.EASA definition
- FAA PHAK
- Airworthiness Certificate
- A certificate issued by the FAA to all aircraft that have been proven to meet the minimum standards set down by the Code of Federal Regulations.
- FAA PHAK
- Airworthiness Directive
- A regulatory notice sent out by the FAA to the registered owner of an aircraft informing the owner of a condition that prevents the aircraft from continuing to meet its conditions for airworthiness. Airworthiness Directives (AD notes) are to be complied with within the required time limit, and the fact of compliance, the date of compliance, and the method of compliance are recorded in the aircraft’s maintenance records.
- FAA PHAK
- AIS
- aeronautical information services
- EASA EPAS
- Alert area
- An area in which there is a high volume of pilot training or an unusual type of aeronautical activity.
- FAA PHAK
- Almanac data
- Information the global positioning system (GPS) receiver can obtain from one satellite which describes the approximate orbital positioning of all satellites in the constellation. This information is necessary for the GPS receiver to know what satellites to look for in the sky at a given time.
- FAA PHAK
- ALS
- See approach lighting system.
- FAA PHAK
- Alternate airport
- An airport designated in an IFR flight plan, providing a suitable destination if a landing at the intended airport becomes inadvisable.
- FAA PHAK
- Alternate static source valve
- A valve in the instrument static air system that supplies reference air pressure to the altimeter, airspeed indicator, and vertical speed indicator if the normal static pickup should become clogged or iced over.
- FAA PHAK
- Altimeter
- A flight instrument that indicates altitude by sensing pressure changes.
- FAA PHAK
- Altimeter setting
- Station pressure (the barometric pressure at the location the reading is taken) which has been corrected for the height of the station above sea level.
- FAA PHAK
- Altitude engine
- A reciprocating aircraft engine having a rated takeoff power that is producible from sea level to an established higher altitude.
- FAA PHAK
- AltMoC
- alternative means of compliance
- EASA EPAS
- Ambient pressure
- The pressure in the area immediately surrounding the aircraft.
- FAA PHAK
- Ambient temperature
- The temperature in the area immediately surrounding the aircraft.
- FAA PHAK
- AMC
- acceptable means of compliance
- EASA EPAS
- AMC-20
- general Acceptable Means of Compliance for airworthiness of products, parts and appliances
- EASA EPAS
- AME
- aero-medical examiner
- EASA EPAS
- Amendment status
- The circulation date and revision number of an instrument approach procedure, printed above the procedure identification.
- FAA PHAK
- AML
- aircraft maintenance licence
- EASA EPAS
- AMM
- aircraft maintenance manual
- EASA EPAS
- Ammeter
- An instrument installed in series with an electrical load used to measure the amount of current flowing through the load.
- FAA PHAK
- AMO
- approved maintenance organisation
- EASA EPAS
- AMOC
- alternative method of compliance
- EASA EPAS
- AMS
- apron management services
- EASA EPAS
- AMTO
- approved maintenance training organisation (Part-147)
- EASA EPAS
- ANAC
- Agência Nacional de Aviação Civil (Brazilian national aviation authority)
- EASA EPAS
- Aneroid
- The sensitive component in an altimeter or barometer that measures the absolute pressure of the air. It is a sealed, flat capsule made of thin disks of corrugated metal soldered together and evacuated by pumping all of the air out of it.
- FAA PHAK
- Aneroid barometer
- An instrument that measures the absolute pressure of the atmosphere by balancing the weight of the air above it against the spring action of the aneroid.
- FAA PHAK
- Angle of attack
- The angle of attack is the angle at which relative wind meets an airfoil. It is the angle that is formed by the chord of the airfoil and the direction of the relative wind or between the chord line and the flight path. The angle of attack changes during a flight as the pilot changes the direction of the aircraft and is related to the amount of lift being produced.
- FAA PHAK
- Angle of incidence
- The acute angle formed between the chord line of an airfoil and the longitudinal axis of the aircraft on which it is mounted.
- FAA PHAK
- Anhedral
- A downward slant from root to tip of an aircraft’s wing or horizontal tail surface.
- FAA PHAK
- Annual inspection
- A complete inspection of an aircraft and engine, required by the Code of Federal Regulations, to be accomplished every 12 calendar months on all certificated aircraft. Only an A&P technician holding an Inspection Authorization can conduct an annual inspection.
- FAA PHAK
- ANS
- air navigation services
- EASA EPAS
- ANSP
- air navigation service provider
- EASA EPAS
- Anti-ice
- Preventing the accumulation of ice on an aircraft structure via a system designed for that purpose.
- FAA PHAK
- Antiservo tab
- An adjustable tab attached to the trailing edge of a stabilator that moves in the same direction as the primary control. It is used to make the stabilator less sensitive.
- FAA PHAK
- AOC
- air operator certificate
- EASA EPAS
- AP
- Accelerated (rulemaking) procedure
- EASA EPAS
- Approach End of Runway (AER)
- The first portion of the runway available for landing. If the runway threshold is displaced, use the displaced threshold latitude/longitude as the AER.
- FAA IPH
- Approach Fix
- From a database coding standpoint, an approach fix is considered to be an identifiable point in space from the intermediate fix (IF) inbound. A fix located between the initial approach fix (IAF) and the IF is considered to be associated with the approach transition or feeder route.
- FAA IPH
- Approach Gate
- An imaginary point used by ATC to vector aircraft to the final approach course. The approach gate is established along the final approach course 1 NM from the final approach fix (FAF) on the side away from the airport and is located no closer than 5 NM from the landing threshold.
- FAA IPH
- Approach lighting system (ALS)
- Provides lights that will penetrate the atmosphere far enough from touchdown to give directional, distance, and glidepath information for safe transition from instrument to visual flight.
- FAA PHAK
- APU
- auxiliary power unit
- EASA EPAS
- ARA
- authority requirements (in the Aircrew Regulation)
- EASA EPAS
- ARAC
- Aviation Rulemaking Advisory Committee
- EASA EPAS
- Area chart
- Part of the low-altitude en route chart series, this chart furnishes terminal data at a larger scale for congested areas.
- FAA PHAK
- Area forecast (FA)
- A report that gives a picture of clouds, general weather conditions, and visual meteorological conditions (VMC) expected over a large area encompassing several states.
- FAA PHAK
- Arm
- See moment arm.
- FAA PHAK
- ARSR
- See air route surveillance radar.
- FAA PHAK
- ART
- Eurocontrol Agency Research Team
- EASA EPAS
- ARTCC
- See air route traffic control center.
- FAA PHAK
- ASAWG
- ARAC Airplane-level Safety Analysis Working Group
- EASA EPAS
- ASBUs
- Aviation System Block Upgrades
- EASA EPAS
- ASDE
- See airport surface detection equipment.
- FAA PHAK
- ASISP
- Aircraft Systems Information Security/Protection
- EASA EPAS
- ASOS
- See Automated Surface Observing System.
- FAA PHAK
- Aspect ratio
- Span of a wing divided by its average chord.
- FAA PHAK
- ASR
- annual safety review
- EASA EPAS
- Asymmetric thrust
- Also known as P-factor. A tendency for an aircraft to yaw to the left due to the descending propeller blade on the right producing more thrust than the ascending blade on the left. This occurs when the aircraft’s longitudinal axis is in a climbing attitude in relation to the relative wind. The P-factor would be to the right if the aircraft had a counterclockwise rotating propeller.
- FAA PHAK
- ATC
- air traffic control
- EASA EPAS
- ATCO
- air traffic controller
- EASA EPAS
- ATCRBS
- See air traffic control radar beacon system.
- FAA PHAK
- ATIS
- See automatic terminal information service.
- FAA PHAK
- Atmospheric propagation delay
- A bending of the electromagnetic (EM) wave from the satellite that creates an error in the GPS system.
- FAA PHAK
- ATO
- approved training organisation
- EASA EPAS
- ATPL
- air transport pilot licence
- EASA EPAS
- ATS
- air traffic services
- EASA EPAS
- ATSEP
- air traffic safety electronics personnel
- EASA EPAS
- Attitude
- A personal motivational predisposition to respond to persons, situations, or events in a given manner that can, nevertheless, be changed or modified through training as sort of a mental shortcut to decision-making.
- FAA PHAK
- Attitude and heading reference system (AHRS)
- A system composed of three-axis sensors that provide heading, attitude, and yaw information for aircraft. AHRS are designed to replace traditional mechanical gyroscopic flight instruments and provide superior reliability and accuracy.
- FAA PHAK
- Attitude director indicator (ADI)
- An aircraft attitude indicator that incorporates flight command bars to provide pitch and roll commands.
- FAA PHAK
- Attitude indicator
- The foundation for all instrument flight, this instrument reflects the airplane’s attitude in relation to the horizon.
- FAA PHAK
- Attitude instrument flying
- Controlling the aircraft by reference to the instruments rather than by outside visual cues.
- FAA PHAK
- Attitude management
- The ability to recognize hazardous attitudes in oneself and the willingness to modify them as necessary through the application of an appropriate antidote thought.
- FAA PHAK
- Autokinesis
- Nighttime visual illusion that a stationary light is moving, which becomes apparent after several seconds of staring at the light.
- FAA PHAK
- Automated Surface Observing System (ASOS)
- A weather observing system that provides minute-by minute weather observations, such as temperature, dew point, wind, altimeter setting, visibility, sky condition, and precipitation. Some ASOS stations include a precipitation discriminator that can differentiate between liquid and frozen precipitation.
- FAA IPH
- Automated Surface Observing System (ASOS)/Automated Weather Sensor System (AWSS)
- The ASOS/AWSS is the primary surface weather observing system of the U.S.
- FAA IPH
- Automated Weather Observing System (AWOS)
- A suite of sensors that measure, collect, and disseminate weather data. AWOS stations provide a minute-by-minute update of weather parameters, such as wind speed and direction, temperature and dew point, visibility, cloud heights and types, precipitation, and barometric pressure. A variety of AWOS system types are available (from AWOS 1 to AWOS 3), each of which includes a different sensor array.
- FAA IPH
- Automated Weather Sensor System (AWSS)
- The AWSS is part of the Aviation Surface Weather Observation Network suite of programs and provides pilots and other users with weather information through the Automated Surface Observing System. The AWSS sensor suite automatically collects, measures, processes, and broadcasts surface weather data.
- FAA IPH
- Automated Weather System
- Any of the automated weather sensor platforms that collect weather data at airports and disseminate the weather information via radio and/or landline. The systems currently consist of the Automated Surface Observing System (ASOS), Automated Weather Sensor System (AWSS), and Automated Weather Observation System (AWOS).
- FAA IPH
- Automatic Dependent Surveillance-Broadcast (ADS-B)
- A surveillance system that continuously broadcasts GPS position information, aircraft identification, altitude, velocity vector, and direction to all other aircraft and air traffic control facilities within a specific area. Automatic dependent surveillance-broadcast (ADS-B) information is displayed in the flight deck via a flight deck display of traffic information (CDTI) unit, providing the pilot with greater situational awareness. ADS-B transmissions also provides controllers with a more complete picture of traffic and updates that information more frequently than other surveillance equipment.
- FAA IPH
- Automatic dependent surveillance—broadcast (ADS–B)
- A function on an aircraft or vehicle that periodically broadcasts its state vector (i.e., horizontal and vertical position, horizontal and vertical velocity) and other information.
- FAA PHAK
- Automatic direction finder (ADF)
- Electronic navigation equipment that operates in the low- and medium-frequency bands. Used in conjunction with the ground-based nondirectional beacon (NDB), the instrument displays the number of degrees clockwise from the nose of the aircraft to the station being received.
- FAA PHAK
- Automatic Terminal Information Service (ATIS)
- A recorded broadcast available at most airports with an operating control tower that includes crucial information about runways and instrument approaches in use, specific outages, and current weather conditions, including visibility.EASA definition
- FAA IPH
- Autopilot
- An automatic flight control system which keeps an aircraft in level flight or on a set course. Automatic pilots can be directed by the pilot, or they may be coupled to a radio navigation signal.
- FAA PHAK
- Aviation medical examiner (AME)
- A physician with training in aviation medicine designated by the Civil Aerospace Medical Institute (CAMI).
- FAA PHAK
- Aviation Routine Weather Report (METAR)
- Observation of current surface weather reported in a standard international format.
- FAA PHAK
- AWOs
- all-weather operations
- EASA EPAS
- Axes of an aircraft
- Three imaginary lines that pass through an aircraft’s center of gravity. The axes can be considered as imaginary axles around which the aircraft rotates. The three axes pass through the center of gravity at 90° angles to each other. The axis from nose to tail is the longitudinal axis (pitch), the axis that passes from wingtip to wingtip is the lateral axis (roll), and the axis that passes vertically through the center of gravity is the vertical axis (yaw).
- FAA PHAK
- Axial flow compressor
- A type of compressor used in a turbine engine in which the airflow through the compressor is essentially linear. An axial-flow compressor is made up of several stages of alternate rotors and stators. The compressor ratio is determined by the decrease in area of the succeeding stages.
- FAA PHAK
- Azimuth card
- A card that may be set, gyroscopically controlled, or driven by a remote compass.
- FAA PHAK
B
- B777
- Boeing 777
- EASA EPAS
- Back course (BC)
- The reciprocal of the localizer course for an ILS. When flying a back-course approach, an aircraft approaches the instrument runway from the end at which the localizer antennas are installed.
- FAA PHAK
- Balance tab
- An auxiliary control mounted on a primary control surface, which automatically moves in the direction opposite the primary control to provide an aerodynamic assist in the movement of the control.
- FAA PHAK
- Baro-aiding
- A method of augmenting the GPS integrity solution by using a nonsatellite input source. To ensure that baro-aiding is available, the current altimeter setting must be entered as described in the operating manual.
- FAA PHAK
- Barometric scale
- A scale on the dial of an altimeter to which the pilot sets the barometric pressure level from which the altitude shown by the pointers is measured.
- FAA PHAK
- BASA
- Bilateral Aviation Safety Agreement
- EASA EPAS
- Basic empty weight (GAMA)
- Basic empty weight includes the standard empty weight plus optional and special equipment that has been installed.
- FAA PHAK
- BC
- See back course.
- FAA PHAK
- BEA
- Bureau d'Enquêtes et d'Analyses (French Safety Investigation Authority)
- EASA EPAS
- Bernoulli’s Principle
- A principle that explains how the pressure of a moving fluid varies with its speed of motion. An increase in the speed of movement causes a decrease in the fluid’s pressure.
- FAA PHAK
- Biplanes
- Airplanes with two sets of wings.
- FAA PHAK
- BIS
- Best Intervention Strategy
- EASA EPAS
- Block altitude
- A block of altitudes assigned by ATC to allow altitude deviations; for example, “Maintain block altitude 9 to 11 thousand.”
- FAA PHAK
- BPL
- balloon pilot licence
- EASA EPAS
- BVLOS
- beyond visual line of sight
- EASA EPAS
- Bypass ratio
- The ratio of the mass airflow in pounds per second through the fan section of a turbofan engine to the mass airflow that passes through the gas generator portion of the engine.
- FAA PHAK
C
- C-UAS
- Counter Unmanned Aircraft Systems
- EASA EPAS
- CA
- competent authority
- EASA EPAS
- CAA
- civil aviation authority
- EASA EPAS
- CABA
- Certification Authorities for Bilateral Agreements & Certification Procedures
- EASA EPAS
- Cabin altitude
- Cabin pressure in terms of equivalent altitude above sea level.
- FAA PHAK
- CAE
- Continued Aviation Education
- EASA EPAS
- CAEP
- Committee on Aviation Environmental Protection (ICAO)
- EASA EPAS
- CAEP/10
- tenth meeting of the committee on Aviation Environmental Protection
- EASA EPAS
- CAEP/11
- eleventh meeting of the committee on Aviation Environmental Protection
- EASA EPAS
- CAG
- Collaborative Analysis Group
- EASA EPAS
- Cage
- The black markings on the ball instrument indicating its neutral position.
- FAA PHAK
- Calibrated
- The instrument indication compared with a standard value to determine the accuracy of the instrument.
- FAA PHAK
- Calibrated airspeed
- The speed at which the aircraft is moving through the air, found by correcting IAS for instrument and position errors.
- FAA PHAK
- Calibrated orifice
- A hole of specific diameter used to delay the pressure change in the case of a vertical speed indicator.
- FAA PHAK
- Camber
- The camber of an airfoil is the characteristic curve of its upper and lower surfaces. The upper camber is more pronounced, while the lower camber is comparatively flat. This causes the velocity of the airflow immediately above the wing to be much higher than that below the wing.
- FAA PHAK
- CAMO
- continuing airworthiness management organisation
- EASA EPAS
- Canard
- A horizontal surface mounted ahead of the main wing to provide longitudinal stability and control. It may be a fixed, movable, or variable geometry surface, with or without control surfaces.
- FAA PHAK
- Canard configuration
- A configuration in which the span of the forward wings is substantially less than that of the main wing.
- FAA PHAK
- Cantilever
- A wing designed to carry loads without external struts.
- FAA PHAK
- CAO
- combined airworthiness organisation – Annex Vd to Commission Regulation (EU) 2019/1383
- EASA EPAS
- CAPP
- certification authorities for propulsion
- EASA EPAS
- CAS
- Calibrated airspeed.
- FAA PHAK
- CASA
- Civil Aviation Safety Authority of Australia
- EASA EPAS
- CAT
- commercial air transport
- EASA EPAS
- CAT I, II, III
- category I, II, III
- EASA EPAS
- CATA
- certification authorities for transport airplane
- EASA EPAS
- CAW
- continuing airworthiness
- EASA EPAS
- CB
- cumulonimbus
- EASA EPAS
- CBA
- cost-benefit analysis
- EASA EPAS
- CBTA
- competency-based training and assessment
- EASA EPAS
- CDI
- Course deviation indicator.
- FAA PHAK
- CE
- Critical Element
- EASA EPAS
- CEA
- cost-effectiveness analysis
- EASA EPAS
- Ceiling
- The height above the earth’s surface of the lowest layer of clouds, which is reported as broken or overcast, or the vertical visibility into an obscuration.EASA definition
- FAA PHAK
- Center of gravity (CG)
- The point at which an airplane would balance if it were possible to suspend it at that point. It is the mass center of the airplane, or the theoretical point at which the entire weight of the airplane is assumed to be concentrated. It may be expressed in inches from the reference datum, or in percentage of mean aerodynamic chord (MAC). The location depends on the distribution of weight in the airplane.
- FAA PHAK
- Center of gravity limits
- The specified forward and aft points within which the CG must be located during flight. These limits are indicated on pertinent airplane specifications.
- FAA PHAK
- Center of gravity range
- The distance between the forward and aft CG limits indicated on pertinent airplane specifications.
- FAA PHAK
- Center of pressure
- A point along the wing chord line where lift is considered to be concentrated. For this reason, the center of pressure is commonly referred to as the center of lift.
- FAA PHAK
- Center Radar ARTS Presentation/Processing (CENRAP)
- CENRAP was developed to provide an alternative to a non-radar environment at terminal facilities should an ASR fail or malfunction. CENRAP sends aircraft radar beacon target information to the ASR terminal facility equipped with ARTS.
- FAA IPH
- Centrifugal flow compressor
- An impeller-shaped device that receives air at its center and slings the air outward at high velocity into a diffuser for increased pressure. Also referred to as a radial outflow compressor.
- FAA PHAK
- Centrifugal force
- An outward force that opposes centripetal force, resulting from the effect of inertia during a turn.
- FAA PHAK
- Centripetal force
- A center-seeking force directed inward toward the center of rotation created by the horizontal component of lift in turning flight.
- FAA PHAK
- CERT-EU
- Computer Emergency Response Team
- EASA EPAS
- CFIT
- controlled flight into terrain
- EASA EPAS
- CG
- See center of gravity.
- FAA PHAK
- Changeover Point (COP)
- A COP indicates the point where a frequency change is necessary between navigation aids, when other than the midpoint on an airway, to receive course guidance from the facility ahead of the aircraft instead of the one behind. These COPs divide an airway or route segment and ensure continuous reception of navigational signals at the prescribed minimum en route IFR altitude.
- FAA IPH
- Chart Supplement (CS or d-CS for digital Chart Supplement)
- Regional booklets published by Aeronautical Information Services that provides general information (graphic and textual) about all airports, both VFR and IFR (in the A/FD section), Notices, Associated Data and Airport Diagrams. The A/FD section includes runway length and width, runway surface, load bearing capacity, runway slope, airport services, and hazards such as birds and reduced visibility.
- FAA IPH
- Chart Supplement U.S. (formerly Airport/Facility Directory)
- An FAA publication containing information on all airports, communications, and NAVAIDs.
- FAA PHAK
- Charted Visual Flight Procedure (CVFP)
- A CVFP may be established at some towered airports for environmental or noise considerations, as well as when necessary for the safety and efficiency of air traffic operations. Designed primarily for turbojet aircraft, CVFPs depict prominent landmarks, courses, and recommended altitudes to specific runways.
- FAA IPH
- Checklist
- A tool that is used as a human factors aid in aviation safety. It is a systematic and sequential list of all operations that must be performed to properly accomplish a task.
- FAA PHAK
- Chord line
- An imaginary straight line drawn through an airfoil from the leading edge to the trailing edge.
- FAA PHAK
- CIR
- candidate issue register
- EASA EPAS
- Circling approach
- A maneuver initiated by the pilot to align the aircraft with a runway for landing when a straight-in landing from an instrument approach is not possible or is not desirable.
- FAA PHAK
- Class A airspace
- Airspace from 18,000 feet MSL up to and including FL 600, including the airspace overlying the waters within 12 NM of the coast of the 48 contiguous states and Alaska; and designated international airspace beyond 12 NM of the coast of the 48 contiguous states and Alaska within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures are applied.
- FAA PHAK
- Class B airspace
- Airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of IFR operations or passenger numbers. The configuration of each Class B airspace is individually tailored and consists of a surface area and two or more layers, and is designed to contain all published instrument procedures once an aircraft enters the airspace. For all aircraft, an ATC clearance is required to operate in the area, and aircraft so cleared receive separation services within the airspace.
- FAA PHAK
- Class C airspace
- Airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports having an operational control tower, serviced by radar approach control, and having a certain number of IFR operations or passenger numbers. Although the configuration of each Class C airspace area is individually tailored, the airspace usually consists of a 5 NM radius core surface area that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that extends from 1,200 feet to 4,000 feet above the airport elevation.
- FAA PHAK
- Class D airspace
- Airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored, and when instrument procedures are published, the airspace is normally designed to contain the procedures.
- FAA PHAK
- Class E airspace
- Airspace that is not Class A, Class B, Class C, or Class D, and is controlled airspace.
- FAA PHAK
- Class G airspace
- Airspace that is uncontrolled, except when associated with a temporary control tower, and has not been designated as Class A, Class B, Class C, Class D, or Class E airspace.
- FAA PHAK
- Clean configuration
- A configuration in which all flight control surfaces have been placed to create minimum drag. In most aircraft this means flaps and gear retracted.
- FAA PHAK
- Clear ice
- Glossy, clear, or translucent ice formed by the relatively slow freezing of large, supercooled water droplets.
- FAA PHAK
- Clearance
- ATC permission for an aircraft to proceed under specified traffic conditions within controlled airspace, for the purpose of providing separation between known aircraft.
- FAA PHAK
- Clearance delivery
- Control tower position responsible for transmitting departure clearances to IFR flights.
- FAA PHAK
- Clearance limit
- The fix, point, or location to which an aircraft is cleared when issued an air traffic clearance.EASA definition
- FAA PHAK
- Clearance on request
- An IFR clearance not yet received after filing a flight plan.
- FAA PHAK
- Clearance void time
- Used by ATC, the time at which the departure clearance is automatically canceled if takeoff has not been made. The pilot must obtain a new clearance or cancel the IFR flight plan if not off by the specified time.
- FAA PHAK
- Closely Spaced Dependent Approaches
- Identifies dependent approaches to parallel runways spaced less than 2,500 feet apart where ATC is permitted to apply reduced diagonal separation and special wake turbulence procedures. turbulence procedures.
- FAA IPH
- CME
- continued medical education
- EASA EPAS
- CMH
- composite material handbook
- EASA EPAS
- CMPA
- complex motor-powered aircraft
- EASA EPAS
- CMT
- Certification Management Team
- EASA EPAS
- CNN
- Convolutional Neural Network (artificial intelligence)
- EASA EPAS
- CNS
- communication, navigation and surveillance
- EASA EPAS
- CO/CO2
- carbon monoxide/carbon dioxide
- EASA EPAS
- Cockpit Display of Traffic Information (CDTI)
- The display and user interface for information about air traffic within approximately 80 miles. It typically combines and shows traffic data from TCAS, TIS-B, and ADS-B. Depending on features, the display may also show terrain, weather, and navigation information.
- FAA IPH
- Coefficient of lift (CL)
- The ratio between lift pressure and dynamic pressure.
- FAA PHAK
- CofA
- certificate of airworthiness
- EASA EPAS
- Cold front
- The boundary between two air masses where cold air is replacing warm air.
- FAA PHAK
- Collision Hazard
- A condition, event, or circumstance that could induce an occurrence of a collision or surface accident or incident.
- FAA IPH
- Columns
- See database columns.
- FAA IPH
- Compass course
- A true course corrected for variation and deviation errors.
- FAA PHAK
- Compass locator
- A low-power, low- or medium-frequency (L/MF) radio beacon installed at the site of the outer or middle marker of an ILS.
- FAA PHAK
- Compass rose
- A small circle graduated in 360° increments, to show direction expressed in degrees.
- FAA PHAK
- Complex aircraft
- An aircraft with retractable landing gear, flaps, and a controllable-pitch propeller.
- FAA PHAK
- Compressor pressure ratio
- The ratio of compressor discharge pressure to compressor inlet pressure.
- FAA PHAK
- Compressor stall
- In gas turbine engines, a condition in an axial-flow compressor in which one or more stages of rotor blades fail to pass air smoothly to the succeeding stages. A stall condition is caused by a pressure ratio that is incompatible with the engine rpm. Compressor stall will be indicated by a rise in exhaust temperature or rpm fluctuation, and if allowed to continue, may result in flameout and physical damage to the engine.
- FAA PHAK
- Concentric rings
- Dashed-line circles depicted in the plan view of IAP charts, outside of the reference circle, that show en route and feeder facilities.
- FAA PHAK
- Condensation
- A change of state of water from a gas (water vapor) to a liquid.
- FAA PHAK
- Condensation nuclei
- Small particles of solid matter in the air on which water vapor condenses.
- FAA PHAK
- Cone of confusion
- A cone-shaped volume of airspace directly above a VOR station where no signal is received, causing the CDI to fluctuate.
- FAA PHAK
- Configuration
- This is a general term, which normally refers to the position of the landing gear and flaps.
- FAA PHAK
- Constant-speed propeller
- A controllable-pitch propeller whose pitch is automatically varied in flight by a governor to maintain a constant rpm in spite of varying air loads.
- FAA PHAK
- Contact Approach
- An approach where an aircraft on an IFR flight plan, having an air traffic control authorization, operating clear of clouds with at least one mile flight visibility, and a reasonable expectation of continuing to the destination airport in those conditions, may deviate from the instrument approach procedure and proceed to the destination airport by visual reference to the surface. This approach is only authorized when requested by the pilot and the reported ground visibility at the destination airport is at least one statute mile.
- FAA IPH
- Continuous flow oxygen system
- System that supplies a constant supply of pure oxygen to a rebreather bag that dilutes the pure oxygen with exhaled gases and thus supplies a healthy mix of oxygen and ambient air to the mask. Primarily used in passenger cabins of commercial airliners.
- FAA PHAK
- Control and performance
- A method of attitude instrument flying in which one instrument is used for making attitude changes, and the other instruments are used to monitor the progress of the change.
- FAA PHAK
- Control display unit
- A display interfaced with the master computer, providing the pilot with a single control point for all navigations systems, thereby reducing the number of required flight deck panels.
- FAA PHAK
- Control pressures
- The amount of physical exertion on the control column necessary to achieve the desired attitude.
- FAA PHAK
- Controllability
- A measure of the response of an aircraft relative to the pilot’s flight control inputs.
- FAA PHAK
- Controllable-pitch propeller (CPP)
- A type of propeller with blades that can be rotated around their long axis to change their pitch. If the pitch can be set to negative values, the reversible propeller can also create reverse thrust for braking or reversing without the need of changing the direction of shaft revolutions.
- FAA PHAK
- Controlled airspace
- An airspace of defined dimensions within which ATC service is provided to IFR and VFR flights in accordance with the airspace classification. It includes Class A, Class B, Class C, Class D, and Class E airspace.EASA definition
- FAA PHAK
- Controlled Flight Into Terrain (CFIT)
- A situation where a mechanically normally functioning aircraft is inadvertently flown into the ground, water, or an obstacle. There are two basic causes of CFIT accidents; both involve flight crew situational awareness. One definition of situational awareness is an accurate perception by pilots of the factors and conditions currently affecting the safe operation of the aircraft and the crew. The causes of CFIT are the flight crews’ lack of vertical position awareness or their lack of horizontal position awareness in relation to terrain and obstacles.
- FAA IPH
- Convective SIGMET
- Weather advisory concerning convective weather significant to the safety of all aircraft, including thunderstorms, hail, and tornadoes.
- FAA PHAK
- Convective weather
- Unstable, rising air found in cumiliform clouds.
- FAA PHAK
- Conventional landing gear
- Landing gear employing a third rear-mounted wheel. These airplanes are also sometimes referred to as tailwheel airplanes.
- FAA PHAK
- Coordinated flight
- Flight with a minimum disturbance of the forces maintaining equilibrium, established via effective control use.
- FAA PHAK
- COP
- See changeover point.
- FAA PHAK
- CORAL
- Certification and ORganisation ApprovaL information hub programme
- EASA EPAS
- Coriolis illusion
- The illusion of rotation or movement in an entirely different axis, caused by an abrupt head movement, while in a prolonged constant-rate turn that has ceased to stimulate the brain’s motion sensing system.
- FAA PHAK
- CORSIA
- Carbon Offsetting and Reduction Scheme for International Aviation
- EASA EPAS
- Coupled ailerons and rudder
- Rudder and ailerons are connected with interconnected springs in order to counteract adverse yaw. Can be overridden if it becomes necessary to slip the aircraft.
- FAA PHAK
- Course
- The intended direction of flight in the horizontal plane measured in degrees from north.
- FAA PHAK
- Cowl flaps
- Shutter-like devices arranged around certain air-cooled engine cowlings, which may be opened or closed to regulate the flow of air around the engine.
- FAA PHAK
- CPL
- commercial pilot licence
- EASA EPAS
- CRD
- comment-response document
- EASA EPAS
- Crew resource management (CRM)
- The application of team management concepts in the flight deck environment. It was initially known as cockpit resource management, but as CRM programs evolved to include cabin crews, maintenance personnel, and others, the phrase “crew resource management” was adopted. This includes single pilots, as in most general aviation aircraft. Pilots of small aircraft, as well as crews of larger aircraft, must make effective use of all available resources; human resources, hardware, and information. A current definition includes all groups routinely working with the flight crew who are involved in decisions required to operate a flight safely. These groups include, but are not limited to pilots, dispatchers, cabin crewmembers, maintenance personnel, and air traffic controllers. CRM is one way of addressing the challenge of optimizing the human/machine interface and accompanying interpersonal activities.
- FAA PHAK
- Critical altitude
- The maximum altitude under standard atmospheric conditions at which a turbocharged engine can produce its rated horsepower.
- FAA PHAK
- Critical angle of attack
- The angle of attack at which a wing stalls regardless of airspeed, flight attitude, or weight.
- FAA PHAK
- Critical areas
- Areas where disturbances to the ILS localizer and glideslope courses may occur when surface vehicles or aircraft operate near the localizer or glideslope antennas.
- FAA PHAK
- CRM
- crew resource management
- EASA EPAS
- Cross-check
- The first fundamental skill of instrument flight, also known as “scan,” the continuous and logical observation of instruments for attitude and performance information.
- FAA PHAK
- Cruise clearance
- An ATC clearance issued to allow a pilot to conduct flight at any altitude from the minimum IFR altitude up to and including the altitude specified in the clearance. Also authorizes a pilot to proceed to and make an approach at the destination airport.
- FAA PHAK
- CS(s)
- certification specification(s)
- EASA EPAS
- CS-22
- Certification Specifications for sailplanes and powered sailplanes
- EASA EPAS
- CS-23
- Certification Specifications for normal, utility, aerobatic and commuter aeroplanes
- EASA EPAS
- CS-25
- Certification Specifications for large aeroplanes
- EASA EPAS
- CS-26
- Certification Specifications for additional airworthiness specifications for operations
- EASA EPAS
- CS-27
- Certification Specifications for small rotorcraft
- EASA EPAS
- CS-29
- Certification Specifications for large rotorcraft
- EASA EPAS
- CS-34
- Certification Specifications for aircraft engine emissions and fuel venting
- EASA EPAS
- CS-ACNS
- Certification Specifications for Airborne Communication, Navigation and Surveillance
- EASA EPAS
- CS-APU
- Certification Specifications for Auxiliary Power Units
- EASA EPAS
- CS-CCD
- Certification Specifications for cabin crew data
- EASA EPAS
- CS-CO2
- Certification Specifications for Aeroplane CO Emissions 2
- EASA EPAS
- CS-E
- Certification Specifications for Engines
- EASA EPAS
- CS-ETSO
- Certification Specifications for European Technical Standard Orders
- EASA EPAS
- CS-FCD
- Certification Specifications for Flight Crew Data
- EASA EPAS
- CS-LSA
- Certification Specifications for Light Sport Aeroplanes
- EASA EPAS
- CS-MMEL
- Certification Specifications for Master Minimum Equipment List
- EASA EPAS
- CS-SIMD
- Certification Specifications for Simulator Data
- EASA EPAS
- CS-STAN
- Certification Specifications for Standard Changes/Standard Repairs
- EASA EPAS
- CS-VLA
- Certification Specifications for Very Light Aeroplanes
- EASA EPAS
- CS-VLR
- Certification Specifications for Very Light Rotorcraft
- EASA EPAS
- CTIG
- Common Training Initiative Group
- EASA EPAS
- Current induction
- An electrical current being induced into, or generated in, any conductor that is crossed by lines of flux from any magnet.
- FAA PHAK
- CVR
- cockpit voice recorder
- EASA EPAS
- CVS
- combined vision systems
- EASA EPAS
- CZ
- Czech Republic
- EASA EPAS
D
- D.C
- Direct current.
- FAA PHAK
- DA
- (European Commission) delegated act
- EASA EPAS
- DAH
- design approval holder: used only if all of the following items are included: holder of a type-certificate, a restricted type-certificate, a supplemental type-certificate, a European Technical Standard Order (ETSO) authorisation, a major repair design approval, a major change design approval or any other relevant approval or authorisation for the design of aeronautical products, parts and appliances deemed to have been issued under Commission Regulation (EU) No 748/2012.
- EASA EPAS
- Dark adaptation
- Physical and chemical adjustments of the eye that make vision possible in relative darkness.
- FAA PHAK
- DAT provider
- (aeronautical) data provider, indirectly, competent authority
- EASA EPAS
- Database Columns
- The spaces for data entry on each record. One column can accommodate one character.
- FAA IPH
- Database Field
- The collection of characters needed to define one item of information.
- FAA IPH
- Database Identifier
- A specific geographic point in space identified on an aeronautical chart and in a naviation database, officially designated by the controlling state authority or derived by Jeppesen. It has no ATC function and should not be used in filing flight plans nor used when communicating with ATC.
- FAA IPH
- Database Record
- A single line of computer data made up of the fields necessary to define fully a single useful piece of data.
- FAA IPH
- Datum (Reference Datum)
- An imaginary vertical plane or line from which all measurements of arm are taken. The datum is established by the manufacturer. Once the datum has been selected, all moment arms and the location of CG range are measured from this point.EASA definition
- FAA PHAK
- Dead reckoning
- Navigation of an airplane solely by means of computations based on airspeed, course, heading, wind direction and speed, groundspeed, and elapsed time.
- FAA PHAK
- Deceleration error
- A magnetic compass error that occurs when the aircraft decelerates while flying on an easterly or westerly heading, causing the compass card to rotate toward South.
- FAA PHAK
- Decision Altitude (DA)
- A specified altitude in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. The term “Decision Altitude (DA)” is referenced to mean sea level and the term “Decision Height (DH)” is referenced to the threshold elevation. Even though DH is charted as an altitude above MSL, the U.S. has adopted the term“DA” as a step toward harmonization of the United States and international terminology. At some point, DA will be published for all future instrument approach procedures with vertical guidance.
- FAA IPH
- Decision Height (DH)
- See Decision Altitude.
- FAA IPH
- DEFIS
- Defence Industry and Space
- EASA EPAS
- Deice
- The act of removing ice accumulation from an aircraft structure.
- FAA PHAK
- Delta
- A Greek letter expressed by the symbol Δ to indicate a change of values. As an example, ∆CG indicates a change (or movement) of the CG.
- FAA PHAK
- Density altitude
- Pressure altitude corrected for nonstandard temperature. Density altitude is used in computing the performance of an aircraft and its engines.
- FAA PHAK
- Departure End of Runway (DER)
- The end of runway available for the ground run of an aircraft departure. The end of the runway that is opposite the landing threshold, sometimes referred to as the stop end of the runway. Altitude, velocity vector, and direction to all other aircraft and air traffic control facilities within a specific area. Automatic dependent surveillance-broadcast (ADS-B) information is displayed in the flight deck via a cockpit display of traffic information (CDTI) unit, providing the pilot with greater situational awareness. ADS-B transmissions also provide controllers with a more complete picture of traffic and update that information more frequently than other surveillance equipment.
- FAA IPH
- Departure procedure (DP)
- Preplanned IFR ATC departure, published for pilot use, in textual and graphic format.
- FAA PHAK
- Deposition
- The direct transformation of a gas to a solid state, in which the liquid state is bypassed. Some sources use sublimation to describe this process instead of deposition.
- FAA PHAK
- Descend Via
- A descend via clearance instructs you to follow the altitudes published on a STAR. You are not authorized to leave your last assigned altitude unless specifically cleared to do so. If ATC amends the altitude or route to one that is different from the published procedure, the rest of the charted descent procedure is canceled. ATC will assign you any further route, altitude, or airspeed clearances, as necessary.
- FAA IPH
- Detonation
- The sudden release of heat energy from fuel in an aircraft engine caused by the fuel-air mixture reaching its critical pressure and temperature. Detonation occurs as a violent explosion rather than a smooth burning process.
- FAA PHAK
- Deviation
- A magnetic compass error caused by local magnetic fields within the aircraft. Deviation error is different on each heading.
- FAA PHAK
- Dew
- Moisture that has condensed from water vapor. Usually found on cooler objects near the ground, such as grass, as the near-surface layer of air cools faster than the layers of air above it.
- FAA PHAK
- Dewpoint
- The temperature at which air reaches a state where it can hold no more water.
- FAA PHAK
- DGPS
- Differential global positioning system.
- FAA PHAK
- DH
- See decision height.
- FAA PHAK
- Differential ailerons
- Control surface rigged such that the aileron moving up moves a greater distance than the aileron moving down. The up aileron produces extra parasite drag to compensate for the additional induced drag caused by the down aileron. This balancing of the drag forces helps minimize adverse yaw.
- FAA PHAK
- Differential Global Positioning System (DGPS)
- A system that improves the accuracy of Global Navigation Satellite Systems (GNSS) by measuring changes in variables to provide satellite positioning corrections.
- FAA PHAK
- Differential pressure
- A difference between two pressures. The measurement of airspeed is an example of the use of differential pressure.
- FAA PHAK
- Digital ATIS (D-ATIS)
- An alternative method of receiving ATIS reports by aircraft equipped with datalink services capable of receiving information in the flight deck over their Aircraft Communications Addressing and Reporting System (ACARS) unit.
- FAA IPH
- Digital Elevation Model (DEM)
- A digital representation of ground surface topography or terrain.
- FAA IPH
- Dihedral
- The positive acute angle between the lateral axis of an airplane and a line through the center of a wing or horizontal stabilizer. Dihedral contributes to the lateral stability of an airplane.
- FAA PHAK
- Diluter-demand oxygen system
- An oxygen system that delivers oxygen mixed or diluted with air in order to maintain a constant oxygen partial pressure as the altitude changes.
- FAA PHAK
- Direct indication
- The true and instantaneous reflection of aircraft pitch-and-bank attitude by the miniature aircraft, relative to the horizon bar of the attitude indicator.
- FAA PHAK
- Direct User Access Terminal System (DUATS)
- A system that provides current FAA weather and flight plan filing services to certified civil pilots, via personal computer, modem, or telephone access to the system. Pilots can request specific types of weather briefings and other pertinent data for planned flights.
- FAA PHAK
- Directional stability
- Stability about the vertical axis of an aircraft, whereby an aircraft tends to return, on its own, to flight aligned with the relative wind when disturbed from that equilibrium state. The vertical tail is the primary contributor to directional stability, causing an airplane in flight to align with the relative wind.
- FAA PHAK
- Distance circle
- See reference circle.
- FAA PHAK
- Distance measuring equipment (DME)
- A pulse-type electronic navigation system that shows the pilot, by an instrument-panel indication, the number of nautical miles between the aircraft and a ground station or waypoint.
- FAA PHAK
- Diverse Vector Area (DVA)
- An airport may establish a diverse vector area if it is necessary to vector aircraft below the minimum vectoring altitude to assist in the efficient flow of departing traffic. DVA design requirements are outlined in FAA Order 8260.3 and allow for the vectoring of aircraft immediately off the departure end of the runway below the MVA.
- FAA IPH
- DL
- deep learning (Artificial Intelligence)
- EASA EPAS
- DLS
- data link services
- EASA EPAS
- DM
- downlink message
- EASA EPAS
- DME
- See distance measuring equipment.
- FAA PHAK
- DME arc
- A flight track that is a constant distance from the station or waypoint.
- FAA PHAK
- DOA
- design organisation approval
- EASA EPAS
- DOD
- Department of Defense.
- FAA PHAK
- Doghouse
- A turn-and-slip indicator dial mark in the shape of a doghouse.
- FAA PHAK
- Domestic Reduced Vertical Separation Minimum (DRVSM)
- Additional flight levels between FL 290 and FL 410 to provide operational, traffic, and airspace efficiency.
- FAA PHAK
- Double gimbal
- A type of mount used for the gyro in an attitude instrument. The axes of the two gimbals are at right angles to the spin axis of the gyro, allowing free motion in two planes around the gyro.
- FAA PHAK
- DP
- direct publication (rulemaking procedure)
- EASA EPAS
- Drag
- The net aerodynamic force parallel to the relative wind, usually the sum of two components: induced drag and parasite drag.
- FAA PHAK
- Drag curve
- The curve created when plotting induced drag and parasite drag.
- FAA PHAK
- Drift angle
- Angle between heading and track.
- FAA PHAK
- DRVSM
- See Domestic Reduced Vertical Separation Minimum.
- FAA PHAK
- DTO
- declared training organisation
- EASA EPAS
- DUATS
- See direct user access terminal system.
- FAA PHAK
- Duplex
- Transmitting on one frequency and receiving on a separate frequency.
- FAA PHAK
- Dutch roll
- A combination of rolling and yawing oscillations that normally occurs when the dihedral effects of an aircraft are more powerful than the directional stability. Usually dynamically stable but objectionable in an airplane because of the oscillatory nature.
- FAA PHAK
- Dynamic hydroplaning
- A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires. When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski. When the tires are hydroplaning, directional control and braking action are virtually impossible. An effective anti-skid system can minimize the effects of hydroplaning.
- FAA PHAK
- Dynamic Magnetic Variation
- A field that is simply a computer model calculated value instead of a measured value contained in the record for a waypoint.
- FAA IPH
- Dynamic stability
- The property of an aircraft that causes it, when disturbed from straight-and-level flight, to develop forces or moments that restore the original condition of straight and level.
- FAA PHAK
E
- EACTB
- Engine/Aircraft Certification Tracking Board
- EASA EPAS
- EACWG
- Engine/Aircraft Certification Working Group
- EASA EPAS
- EAEG
- ECAC European Aviation Environmental Group
- EASA EPAS
- EAER
- European Aviation Environmental Report
- EASA EPAS
- EAFDM
- European Authorities Coordination Group on Flight Data Monitoring
- EASA EPAS
- EAPPRE
- European Action Plan for the Prevention of Runway Excursions
- EASA EPAS
- EAPPRI
- European Action Plan for the Prevention of Runway Incursions
- EASA EPAS
- EASA
- European Union Aviation Safety Agency
- EASA EPAS
- EASA MB
- European Union Aviation Safety Agency Management Board
- EASA EPAS
- EASP
- European Aviation Safety Programme
- EASA EPAS
- EATMN
- European air traffic management network
- EASA EPAS
- EBT
- evidence-based training
- EASA EPAS
- EC
- European Commission
- EASA EPAS
- ECAC
- EASA European Civil Aviation Conference
- EASA EPAS
- ECCSA
- European Centre for Cyber Security in Aviation
- EASA EPAS
- ECHA
- European Chemicals Agency
- EASA EPAS
- ECQB
- European Central Question Bank
- EASA EPAS
- ECR
- European Central Repository for accident and incident reports in aviation
- EASA EPAS
- Eddy current damping
- The decreased amplitude of oscillations by the interaction of magnetic fields. In the case of a vertical card magnetic compass, flux from the oscillating permanent magnet produces eddy currents in a damping disk or cup. The magnetic flux produced by the eddy currents opposes the flux from the permanent magnet and decreases the oscillations.
- FAA PHAK
- Eddy currents
- Current induced in a metal cup or disc when it is crossed by lines of flux from a moving magnet.
- FAA PHAK
- EDTO
- extended diversion time operation
- EASA EPAS
- EEA
- European Environment Agency
- EASA EPAS
- EFB
- electronic flight bag
- EASA EPAS
- EFC
- See expect-further-clearance.
- FAA PHAK
- EFD
- See electronic flight display.
- FAA PHAK
- EFVS
- enhanced flight vision systems
- EASA EPAS
- EFVS Operation
- An operation in which visibility conditions require an EFVS to be used in lieu of natural vision to perform an approach or landing, determine enhanced flight visibility, identify required visual references, or conduct a rollout.EASA definition
- FAA IPH
- EGT
- See exhaust gas temperature.
- FAA PHAK
- EHEST
- European Helicopter Safety Team
- EASA EPAS
- EHPU
- electric and hybrid propulsion unit
- EASA EPAS
- EHSIT
- European Helicopter Safety Implementation Team
- EASA EPAS
- EI
- Effective Implementation
- EASA EPAS
- ELA
- European light aircraft
- EASA EPAS
- ELA1 aircraft
- ELA1 aircraft’ means the following manned European light aircraft: — an aeroplane with a maximum take-off mass (MTOM) of 1 200 kg or less that is not classified as a complex motor-powered aircraft; — a sailplane or powered sailplane of 1 200 kg MTOM or less; — a balloon with a maximum design lifting gas or hot air volume of not more than 3 400 m3 for hot air balloons, 1 050 m3 for gas balloons, and 300 m3 for tethered gas balloons.EASA definition
- EASA EPAS
- Electronic Flight Bag (EFB)
- An electronic display system intended primarily for flight deck or cabin use. EFB devices can display a variety of aviation data or perform basic calculations (e.g., performance data, fuel calculations, etc.). In the past, some of these functions were traditionally accomplished using paper references or were based on data provided to the flight crew by an airline’s flight dispatch function.The scope of the EFB system functionality may also include various other hosted databases and applications. Physical EFB displays may use various technologies, formats, and forms of communication. These devices are sometimes referred to as auxiliary performance computers (APC) or laptop auxiliary performance computers (LAPC).EASA definition
- FAA IPH
- Electronic flight display (EFD)
- For the purpose of standardization, any flight instrument display that uses LCD or other image-producing system (cathode ray tube (CRT), etc.)
- FAA PHAK
- Elevator
- The horizontal, movable primary control surface in the tail section, or empennage, of an airplane. The elevator is hinged to the trailing edge of the fixed horizontal stabilizer.
- FAA PHAK
- Elevator illusion
- The sensation of being in a climb or descent, caused by the kind of abrupt vertical accelerations that result from up- or downdrafts.
- FAA PHAK
- Ellipsoid of Revolution
- The surface that results when an ellipse is rotated about one of its axes.
- FAA IPH
- EM wave
- Electromagnetic wave.
- FAA PHAK
- eMCO
- Extended Minimum-Crew Operations
- EASA EPAS
- Emergency
- A distress or urgent condition.
- FAA PHAK
- Empennage
- The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces.
- FAA PHAK
- Emphasis error
- The result of giving too much attention to a particular instrument during the cross-check, instead of relying on a combination of instruments necessary for attitude and performance information.
- FAA PHAK
- Empty-field myopia
- Induced nearsightedness that is associated with flying at night, in instrument meteorological conditions and/or reduced visibility. With nothing to focus on, the eyes automatically focus on a point just slightly ahead of the airplane.
- FAA PHAK
- EMS
- emergency medical services
- EASA EPAS
- En route facilities ring
- Depicted in the plan view of IAP charts, a circle which designates NAVAIDs, fixes, and intersections that are part of the en route low altitude airway structure.
- FAA PHAK
- En route high-altitude charts
- Aeronautical charts for en route instrument navigation at or above 18,000 feet MSL.
- FAA PHAK
- En route low-altitude charts
- Aeronautical charts for en route IFR navigation below 18,000 feet MSL.
- FAA PHAK
- En Route Obstacle Clearance Areas
- Obstacle clearance areas for en route planning are identified as primary, secondary, and turning areas, and they are designed to provide obstacle clearance route protection width for airways and routes.
- FAA IPH
- Encoding altimeter
- A special type of pressure altimeter used to send a signal to the air traffic controller on the ground, showing the pressure altitude the aircraft is flying.
- FAA PHAK
- Engine pressure ratio (EPR)
- The ratio of turbine discharge pressure divided by compressor inlet pressure, which is used as an indication of the amount of thrust being developed by a turbine engine.
- FAA PHAK
- Enhanced Flight Vision System (EFVS)
- An installed aircraft system which uses an electronic means to provide a display of the forward external scene topography (the natural or manmade features of a place or region especially in a way to show their relative positions and elevation) through the use of imaging sensors, including but not limited to forward-looking infrared, millimeter wave radiometry, millimeter wave radar, or low-light level image intensification. An EFVS includes the display element, sensors, computers and power supplies, indications, and controls.EASA definition
- FAA IPH
- EOC
- essential operational changes
- EASA EPAS
- EOFDM
- European Operators Flight Data Monitoring forum
- EASA EPAS
- EPAS
- European Plan for Aviation Safety
- EASA EPAS
- EPR
- See engine pressure ratio.
- FAA PHAK
- Equilibrium
- A condition that exists within a body when the sum of the moments of all of the forces acting on the body is equal to zero. In aerodynamics, equilibrium is when all opposing forces acting on an aircraft are balanced (steady, unaccelerated flight conditions).
- FAA PHAK
- Equivalent airspeed
- Airspeed equivalent to CAS in standard atmosphere at sea level. As the airspeed and pressure altitude increase, the CAS becomes higher than it should be, and a correction for compression must be subtracted from the CAS.
- FAA PHAK
- ERCS
- European Risk Classification Scheme
- EASA EPAS
- EREA
- European Research Establishments in Aeronautics
- EASA EPAS
- ESCP
- European Strategic Coordination Platform
- EASA EPAS
- ESPN-R
- European Safety Promotion Network Rotorcraft
- EASA EPAS
- ETOPS
- extended-range twin-engine operational performance standards
- EASA EPAS
- ETS
- European Union Emissions Trading System (EU ETS) is the cornerstone of the European Union's policy to tackle climate change and its key tool for cost-effective reduction of emissions of carbon dioxide (CO ) and other greenhouse gases (GHG) in the power, 2 aviation and industrial sectors. The EU ETS works on the 'cap and trade' principle and is a market-based measure where participants are required to monitor and report their emissions and surrender sufficient emission allowances to cover their reported emissions in each year.
- EASA EPAS
- ETSOA
- European technical standard order (authorisation)
- EASA EPAS
- EU
- European Union
- EASA EPAS
- EUROCAE
- European Organisation for Civil Aviation Equipment
- EASA EPAS
- Evaporation
- The transformation of a liquid to a gaseous state, such as the change of water to water vapor.
- FAA PHAK
- EVT
- evaluation task
- EASA EPAS
- EWIS
- Electrical Wiring Interconnection System
- EASA EPAS
- Exhaust gas temperature (EGT)
- The temperature of the exhaust gases as they leave the cylinders of a reciprocating engine or the turbine section of a turbine engine.
- FAA PHAK
- Expanded Service Volume
- When ATC or a procedures specialist requires the use of a NAVAID beyond the limitations specified for standard service volume, an expanded service volume (ESV) may be established. See standard service volume.
- FAA IPH
- Expect-further-clearance (EFC)
- The time a pilot can expect to receive clearance beyond a clearance limit.
- FAA PHAK
- Explosive decompression
- A change in cabin pressure faster than the lungs can decompress. Lung damage is possible.
- FAA PHAK
F
- FA
- See area forecast.
- FAA PHAK
- FAA
- Federal Aviation Administration
- EASA EPAS
- FAF
- See final approach fix.
- FAA PHAK
- False horizon
- Inaccurate visual information for aligning the aircraft, caused by various natural and geometric formations that disorient the pilot from the actual horizon.
- FAA PHAK
- FAR 33.90
- Federal Aviation Regulation Section 33.90 — Initial maintenance inspection test
- EASA EPAS
- FbW/FBW
- fly-by-wire
- EASA EPAS
- FC
- flight crew
- EASA EPAS
- FCD
- flight crew data
- EASA EPAS
- FCHWG
- ARAC Flight Controls Harmonization Working Group
- EASA EPAS
- FCL
- flight crew licensing
- EASA EPAS
- FCOM
- flight crew operating manual
- EASA EPAS
- FDI
- See flight director indicator.
- FAA PHAK
- FDM
- flight data monitoring
- EASA EPAS
- FDR
- flight data recorder
- EASA EPAS
- Federal airways
- Class E airspace areas that extend upward from 1,200 feet to, but not including, 18,000 feet MSL, unless otherwise specified. Feeder facilities. Used by ATC to direct aircraft to intervening fixes between the en route structure and the initial approach fix.
- FAA PHAK
- Feeder Route
- A feeder route is a route depicted on IAP charts to designate courses for aircraft to proceed from the en route structure to the IAF. Feeder routes, also referred to as approach transitions, technically are not considered approach segments but are an integral part of many IAPs.
- FAA IPH
- FEM
- flight examiner manual
- EASA EPAS
- Field
- See database field.
- FAA IPH
- Final approach
- Part of an instrument approach procedure in which alignment and descent for landing are accomplished.
- FAA PHAK
- Final Approach and Takeoff Area (FATO)
- The FATO is a defined heliport area over which the final approach to a hover or a departure is made. The touchdown and lift-off area (TLOF) where the helicopter is permitted to land is normally centered in the FATO. A safety area is provided around the FATO.
- FAA IPH
- Final approach fix (FAF)
- The fix from which the IFR final approach to an airport is executed, and which identifies the beginning of the final approach segment. An FAF is designated on government charts by a Maltese cross symbol for nonprecision approaches, and a lightning bolt symbol for precision approaches.
- FAA PHAK
- FIS
- flight information services
- EASA EPAS
- Fix
- A geographical position determined by visual reference to the surface, by reference to one or more radio NAVAIDs, by celestial plotting, or by another navigational device. Note: Fix is a generic name for a geographical position and is referred to as a fix, waypoint, intersection, reporting point, etc.
- FAA IPH
- Fixating
- Staring at a single instrument, thereby interrupting the cross-check process.
- FAA PHAK
- Fixed slot
- A fixed, nozzle shaped opening near the leading edge of a wing that ducts air onto the top surface of the wing. Its purpose is to increase lift at higher angles of attack.
- FAA PHAK
- Fixed-pitch propellers
- Propellers with fixed blade angles. Fixed-pitch propellers are designed as climb propellers, cruise propellers, or standard propellers.
- FAA PHAK
- FL
- flight level
- EASA EPAS
- Flameout
- A condition in the operation of a gas turbine engine in which the fire in the engine goes out due to either too much or too little fuel sprayed into the combustors.
- FAA PHAK
- Flaps
- Hinged portion of the trailing edge between the ailerons and fuselage. In some aircraft ailerons and flaps are interconnected to produce full-span “flaperons.” In either case, flaps change the lift and drag on the wing.
- FAA PHAK
- Flight configurations
- Adjusting the aircraft control surfaces (including flaps and landing gear) in a manner that will achieve a specified attitude.
- FAA PHAK
- Flight director indicator (FDI)
- One of the major components of a flight director system, it provides steering commands that the pilot (or the autopilot, if coupled) follows.
- FAA PHAK
- Flight Information Region (FIR)
- A FIR is an airspace of defined dimensions within which Flight Information Service and Alerting Service are provided. Flight Information Service (FIS) is a service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights. Alerting Service is a service provided to notify appropriate organizations regarding aircraft in need of search and rescue aid, and assist such organizations as required. Flight Level (FL). A flight level is a level of constant atmospheric pressure related to a reference datum of 29.92 "Hg. Each flight level is stated in three digits that represents hundreds of feet. For example, FL 250 represents an altimeter indication of 25,000 feet.EASA definition
- FAA IPH
- Flight level (FL)
- A measure of altitude (in hundreds of feet) used by aircraft flying above 18,000 feet with the altimeter set at 29.92 "Hg.EASA definition
- FAA PHAK
- Flight management system (FMS)
- Provides pilot and crew with highly accurate and automatic long-range navigation capability, blending available inputs from long- and short-range sensors.
- FAA PHAK
- Flight path
- The line, course, or track along which an aircraft is flying or is intended to be flown.
- FAA PHAK
- Flight patterns
- Basic maneuvers, flown by reference to the instruments rather than outside visual cues, for the purpose of practicing basic attitude flying. The patterns simulate maneuvers encountered on instrument flights such as holding patterns, procedure turns, and approaches.
- FAA PHAK
- Flight strips
- Paper strips containing instrument flight information, used by ATC when processing flight plans.
- FAA PHAK
- Floating Waypoints
- Floating waypoints represent airspace fixes at a point in space not directly associated with a conventional airway. In many cases, they may be established for such purposes as ATC metering fixes, holding points, RNAV-direct routing, gateway waypoints, STAR origination points leaving the en route structure, and SID terminating points joining the en route structure.
- FAA IPH
- Floor load limit
- The maximum weight the floor can sustain per square inch/foot as provided by the manufacturer.
- FAA PHAK
- Fly-by (FB) Waypoint
- A waypoint that requires the use of turn anticipation to avoid overshooting the next flight segment.
- FAA IPH
- Fly-over (FO) Waypoint
- A waypoint that precludes any turn until the waypoint is overflown, and is followed by either an intercept maneuver of the next flight segment or direct flight to the next waypoint.
- FAA IPH
- FMS
- flight management system
- EASA EPAS
- FoC
- Focused Consultation
- EASA EPAS
- FOD
- foreign object debris
- EASA EPAS
- Fog
- Cloud consisting of numerous minute water droplets and based at the surface; droplets are small enough to be suspended in the earth’s atmosphere indefinitely. (Unlike drizzle, it does not fall to the surface. Fog differs from a cloud only in that a cloud is not based at the surface, and is distinguished from haze by its wetness and gray color.)
- FAA PHAK
- Force (F)
- The energy applied to an object that attempts to cause the object to change its direction, speed, or motion. In aerodynamics, it is expressed as F, T (thrust), L (lift), W (weight), or D (drag), usually in pounds.
- FAA PHAK
- Foreign object damage (FOD)
- Damage to a gas turbine engine caused by some object being sucked into the engine while it is running. Debris from runways or taxiways can cause foreign object damage during ground operations, and the ingestion of ice and birds can cause FOD in flight.
- FAA PHAK
- Form drag
- The drag created because of the shape of a component or the aircraft.
- FAA PHAK
- Four Corner Post Configuration
- An arrangement of air traffic pathways in a terminal area that brings incoming flights over fixes at four corners of the traffic area, while outbound flights depart between the fixes, thus minimizing conflicts between arriving and departing traffic.
- FAA IPH
- FR
- France
- EASA EPAS
- Frise-type aileron
- Aileron having the nose portion projecting ahead of the hinge line. When the trailing edge of the aileron moves up, the nose projects below the wing’s lower surface and produces some parasite drag, decreasing the amount of adverse yaw.
- FAA PHAK
- FRM
- fatigue risk management
- EASA EPAS
- Front
- The boundary between two different air masses.
- FAA PHAK
- Frost
- Ice crystal deposits formed by sublimation when temperature and dewpoint are below freezing.EASA definition
- FAA PHAK
- FS
- flight standards
- EASA EPAS
- FSB
- Flight Standardisation Board (FAA)
- EASA EPAS
- FSTD
- flight simulation training device
- EASA EPAS
- FTL
- flight time limitation
- EASA EPAS
- FTS
- flight time specifications
- EASA EPAS
- Fuel load
- The expendable part of the load of the airplane. It includes only usable fuel, not fuel required to fill the lines or that which remains trapped in the tank sumps.
- FAA PHAK
- Fundamental skills
- Pilot skills of instrument cross-check, instrument interpretation, and aircraft control.
- FAA PHAK
- Fuselage
- The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane.
- FAA PHAK
- FW
- fixed wing
- EASA EPAS
G
- GA
- General Aviation: It means any civil aircraft operation other than aerial work or commercial air transport (Commission Implementing Regulation (EU) 2017/373)
- EASA EPAS
- GA.COM
- General Aviation Committee (EASA Advisory Body)
- EASA EPAS
- GAMA
- General Aviation Manufacturers Association.
- FAA PHAK
- GANP
- Global Air Navigation Plan
- EASA EPAS
- GASP
- Global Aviation Safety Plan (ICAO)
- EASA EPAS
- Gateway Fix
- A navigational aid or fix where an aircraft transitions between the domestic route structure and the oceanic route airspace.
- FAA IPH
- GBAS
- ground-based augmentation system
- EASA EPAS
- GDP
- gross domestic product
- EASA EPAS
- Geodetic Datum
- The reference plane from which geodetic calculations are made. Or, according to ICAO Annex 15, the numerical or geometrical quantity or set of such quantities (mathematical model) that serves as a reference for computing other quantities in a specific geographic region, such as the latitude and longitude of a point.
- FAA IPH
- GH
- Groundhandling
- EASA EPAS
- GHG
- greenhouse gas
- EASA EPAS
- Gimbal ring
- A type of support that allows an object, such as a gyroscope, to remain in an upright condition when its base is tilted.
- FAA PHAK
- Glidepath Angle (GPA)
- The angular displacement of the vertical guidance path from a horizontal plane that passes through the reference datum point (RDP). This angle is published on approach charts (e.g., 3.00°, 3.20°, etc.). GPA is sometimes referred to as vertical path angle (VPA).
- FAA IPH
- Glideslope (GS)
- Part of the ILS that projects a radio beam upward at an angle of approximately 3° from the approach end of an instrument runway. The glideslope provides vertical guidance to aircraft on the final approach course for the aircraft to follow when making an ILS approach along the localizer path.
- FAA PHAK
- Glideslope intercept altitude
- The minimum altitude of an intermediate approach segment prescribed for a precision approach that ensures obstacle clearance.
- FAA PHAK
- Global landing system (GLS)
- An instrument approach with lateral and vertical guidance with integrity limits (similar to barometric vertical navigation (BARO VNAV).
- FAA PHAK
- Global positioning system (GPS)
- Navigation system that uses satellite rather than ground-based transmitters for location information.
- FAA PHAK
- GLS
- GBAS (ground-based augmentation system) landing system
- EASA EPAS
- GM
- guidance material
- EASA EPAS
- GMP
- general medical practitioner
- EASA EPAS
- GNSS
- global navigation satellite system
- EASA EPAS
- Goniometer
- As used in radio frequency (RF) antenna systems, a direction-sensing device consisting of two fixed loops of wire oriented 90° from each other, which separately sense received signal strength and send those signals to two rotors (also oriented 90°) in the sealed direction-indicating instrument. The rotors are attached to the direction-indicating needle of the instrument and rotated by a small motor until minimum magnetic field is sensed near the rotors.
- FAA PHAK
- GPS
- global positioning system
- EASA EPAS
- GPS Approach Overlay Program
- An authorization for pilots to use GPS avionics under IFR for flying designated existing nonprecision instrument approach procedures, with the exception of LOC, LDA, and SDF procedures.
- FAA PHAK
- GPWS
- See ground proximity warning system.
- FAA PHAK
- Graveyard spiral
- The illusion of the cessation of a turn while still in a prolonged, coordinated, constant rate turn, which can lead a disoriented pilot to a loss of control of the aircraft.
- FAA PHAK
- Great circle route
- The shortest distance across the surface of a sphere (the Earth) between two points on the surface.
- FAA PHAK
- Ground adjustable trim tab
- Non-movable metal trim tab on a control surface. Bent in one direction or another while on the ground to apply trim forces to the control surface.
- FAA PHAK
- Ground Communication Outlet (GCO)
- An unstaffed, remotely controlled ground/ground communications facility. Pilots at uncontrolled airports may contact ATC and AFSS via very high frequency (VHF) radio to a telephone connection. This lets pilots obtain an instrument clearance or close a VFR/IFR flight plan.
- FAA IPH
- Ground effect
- The condition of slightly increased air pressure below an airplane wing or helicopter rotor system that increases the amount of lift produced. It exists within approximately one wing span or one rotor diameter from the ground. It results from a reduction in upwash, downwash, and wingtip vortices, and provides a corresponding decrease in induced drag.
- FAA PHAK
- Ground proximity warning system (GPWS)
- A system designed to determine an aircraft’s clearance above the Earth and provides limited predictability about aircraft position relative to rising terrain.
- FAA PHAK
- Groundspeed
- Speed over the ground, either closing speed to the station or waypoint, or speed over the ground in whatever direction the aircraft is going at the moment, depending upon the navigation system used.
- FAA PHAK
- GS
- See glideslope.
- FAA PHAK
- GSE
- ground support equipment
- EASA EPAS
- GWPS
- See ground proximity warning system.
- FAA PHAK
- Gyroscopic precession
- An inherent quality of rotating bodies, which causes an applied force to be manifested 90° in the direction of rotation from the point where the force is applied.
- FAA PHAK
H
- H2020
- Horizon 2020
- EASA EPAS
- HA
- higher airspace (above FL 600/650)
- EASA EPAS
- HAA
- See height above airport.
- FAA PHAK
- HAL
- See height above landing.
- FAA PHAK
- HAT
- See height above touchdown elevation.
- FAA PHAK
- Hazardous attitudes
- Five aeronautical decision-making attitudes that may contribute to poor pilot judgment: anti-authority, impulsivity, invulnerability, machismo, and resignation.
- FAA PHAK
- Hazardous Inflight Weather Advisory Service (HIWAS)
- An en route FSS service providing continuously updated automated of hazardous weather within 150 nautical miles of selected VORs, available only in the conterminous 48 states.
- FAA PHAK
- HE
- helicopter manufacturers, operators, training organisations, maintenance organisations
- EASA EPAS
- Head-Up Display (HUD)
- See head-up guidance system (HGS).
- FAA IPH
- Head-up Guidance System (HGS)
- A system that projects critical flight data on a display positioned between the pilot and the windscreen. In addition to showing primary flight information, the HUD computes an extremely accurate instrument approach and landing guidance solution, and displays the result as a guidance cue for head-up viewing by the pilot.
- FAA IPH
- Heading
- The direction in which the nose of the aircraft is pointing during flight.EASA definition
- FAA PHAK
- Heading indicator
- An instrument which senses airplane movement and displays heading based on a 360° azimuth, with the final zero omitted. The heading indicator, also called a directional gyro (DG), is fundamentally a mechanical instrument designed to facilitate the use of the magnetic compass. The heading indicator is not affected by the forces that make the magnetic compass difficult to interpret.
- FAA PHAK
- Headwork
- Required to accomplish a conscious, rational thought process when making decisions. Good decision-making involves risk identification and assessment, information processing, and problem solving.
- FAA PHAK
- Height above airport (HAA)
- The height of the MDA above the published airport elevation.
- FAA PHAK
- Height above landing (HAL)
- The height above a designated helicopter landing area used for helicopter instrument approach procedures.
- FAA PHAK
- Height Above Touchdown (HAT)
- The height of the DA above touchdown zone elevation (TDZE).
- FAA IPH
- Height above touchdown elevation (HAT)
- The DA/DH or MDA above the highest runway elevation in the touchdown zone (first 3,000 feet of the runway).
- FAA PHAK
- HEMS
- helicopter emergency medical services
- EASA EPAS
- HF
- human factors
- EASA EPAS
- HF CAG
- Human Factors Collaborative Analysis Group
- EASA EPAS
- Hg
- Abbreviation for mercury, from the Latin hydrargyrum.
- FAA PHAK
- High performance aircraft
- An aircraft with an engine of more than 200 horsepower.
- FAA PHAK
- Highway in the Sky (HITS)
- A graphically intuitive pilot interface system that provides an aircraft operator with all of the attitude and guidance inputs required to safely fly an aircraft in close conformance to air traffic procedures.
- FAA IPH
- Histotoxic hypoxia
- The inability of cells to effectively use oxygen. Plenty of oxygen is being transported to the cells that need it, but they are unable to use it.
- FAA PHAK
- HIWAS
- See Hazardous Inflight Weather Advisory Service.
- FAA PHAK
- Holding
- A predetermined maneuver that keeps aircraft within a specified airspace while awaiting further clearance from ATC.
- FAA PHAK
- Holding pattern
- A racetrack pattern, involving two turns and two legs, used to keep an aircraft within a prescribed airspace with respect to a geographic fix. A standard pattern uses right turns; nonstandard patterns use left turns.
- FAA PHAK
- Homing
- Flying the aircraft on any heading required to keep the needle pointing to the 0° relative bearing position.
- FAA PHAK
- Horizontal situation indicator (HSI)
- A flight navigation instrument that combines the heading indicator with a CDI, in order to provide the pilot with better situational awareness of location with respect to the courseline.
- FAA PHAK
- Horsepower
- The term, originated by inventor James Watt, means the amount of work a horse could do in one second. One horsepower equals 550 foot-pounds per second, or 33,000 foot-pounds per minute.
- FAA PHAK
- HOSSWG
- Helicopter Offshore Safety and Survival Working Group (JAA)
- EASA EPAS
- Hot start
- In gas turbine engines, a start which occurs with normal engine rotation, but exhaust temperature exceeds prescribed limits. This is usually caused by an excessively rich mixture in the combustor. The fuel to the engine must be terminated immediately to prevent engine damage.
- FAA PHAK
- HP
- human performance
- EASA EPAS
- HPA
- high-performance aircraft
- EASA EPAS
- HSI
- See horizontal situation indicator.
- FAA PHAK
- HTAWS
- helicopter terrain awareness warning systems
- EASA EPAS
- HUD
- head-up display
- EASA EPAS
- Human factors
- A multidisciplinary field encompassing the behavioral and social sciences, engineering, and physiology, to consider the variables that influence individual and crew performance for the purpose of optimizing human performance and reducing errors.
- FAA PHAK
- Hung start
- In gas turbine engines, a condition of normal light off but with rpm remaining at some low value rather than increasing to the normal idle rpm. This is often the result of insufficient power to the engine from the starter. In the event of a hung start, the engine should be shut down.
- FAA PHAK
- Hydroplaning
- A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires. When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski. When the tires are hydroplaning, directional control and braking action are virtually impossible. An effective anti-skid system can minimize the effects of hydroplaning.
- FAA PHAK
- Hypemic hypoxia
- A type of hypoxia that is a result of oxygen deficiency in the blood, rather than a lack of inhaled oxygen. It can be caused by a variety of factors. Hypemic means “not enough blood.”
- FAA PHAK
- Hyperventilation
- Occurs when an individual is experiencing emotional stress, fright, or pain, and the breathing rate and depth increase, although the carbon dioxide level in the blood is already at a reduced level. The result is an excessive loss of carbon dioxide from the body, which can lead to unconsciousness due to the respiratory system’s overriding mechanism to regain control of breathing.
- FAA PHAK
- Hypoxia
- A state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs.
- FAA PHAK
- Hypoxic hypoxia
- This type of hypoxia is a result of insufficient oxygen available to the lungs. A decrease of oxygen molecules at sufficient pressure can lead to hypoxic hypoxia.
- FAA PHAK
I
- IA
- (Commission) implementing act
- EASA EPAS
- IAF
- initial approach fix
- EASA EPAS
- IAP
- See instrument approach procedures.
- FAA PHAK
- IAS
- See indicated airspeed.
- FAA PHAK
- IAW
- initial airworthiness
- EASA EPAS
- ICA
- instructions for Continued Airworthiness
- EASA EPAS
- ICAO
- International Civil Aviation Organization
- EASA EPAS
- ICAO SL
- ICAO State letter
- EASA EPAS
- Ident
- Air Traffic Control request for a pilot to push the button on the transponder to identify return on the controller’s scope.
- FAA PHAK
- IFE
- in-flight entertainment
- EASA EPAS
- IFP
- instrument flight procedures
- EASA EPAS
- IFTSS
- individual flight time specification scheme
- EASA EPAS
- IHST
- International Helicopter Safety Team
- EASA EPAS
- ILS
- instrument landing system
- EASA EPAS
- ILS categories
- Categories of instrument approach procedures allowed at airports equipped with the following types of instrument landing systems:
- FAA PHAK
- ILS Category I:
- Provides for approach to a height above touchdown of not less than 200 feet, and with runway visual range of not less than 1,800 feet.
- FAA PHAK
- ILS Category II:
- Provides for approach to a height above touchdown of not less than 100 feet and with runway visual range of not less than 1,200 feet.
- FAA PHAK
- ILS Category IIIA:
- Provides for approach without a decision height minimum and with runway visual range of not less than 700 feet.
- FAA PHAK
- ILS Category IIIB:
- Provides for approach without a decision height minimum and with runway visual range of not less than 150 feet.
- FAA PHAK
- ILS Category IIIC:
- Provides for approach without a decision height minimum and without runway visual range minimum.
- FAA PHAK
- IMF
- International Monetary Fund
- EASA EPAS
- IMI
- initial maintenance inspection
- EASA EPAS
- Inclinometer
- An instrument consisting of a curved glass tube, housing a glass ball, and damped with a fluid similar to kerosene. It may be used to indicate inclination, as a level, or, as used in the turn indicators, to show the relationship between gravity and centrifugal force in a turn.
- FAA PHAK
- Indicated airspeed (IAS)
- Shown on the dial of the instrument airspeed indicator on an aircraft. Indicated airspeed (IAS) is the airspeed indicator reading uncorrected for instrument, position, and other errors. Indicated airspeed means the speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors. Calibrated airspeed (CAS) is IAS corrected for instrument errors, position error (due to incorrect pressure at the static port) and installation errors.
- FAA PHAK
- Indicated altitude
- The altitude read directly from the altimeter (uncorrected) when it is set to the current altimeter setting.
- FAA PHAK
- Indirect indication
- A reflection of aircraft pitch-and-bank attitude by instruments other than the attitude indicator.
- FAA PHAK
- Induced drag
- Drag caused by the same factors that produce lift; its amount varies inversely with airspeed. As airspeed decreases, the angle of attack must increase, in turn increasing induced drag.
- FAA PHAK
- Induction icing
- A type of ice in the induction system that reduces the amount of air available for combustion. The most commonly found induction icing is carburetor icing.
- FAA PHAK
- INF
- information management (in reflection to ATM Master Plan Level 3)
- EASA EPAS
- Initial approach fix (IAF)
- The fix depicted on IAP charts where the instrument approach procedure (IAP) begins unless otherwise authorized by ATC.
- FAA PHAK
- Initial Climb Area (ICA)
- An area beginning at the departure end of runway (DER) to provide unrestricted climb to at least 400 feet above DER elevation.
- FAA IPH
- Inoperative components
- Higher minimums are prescribed when the specified visual aids are not functioning; this information is listed in the Inoperative Components Table found in the United States Terminal Procedures Publications.
- FAA PHAK
- INS
- See inertial navigation system.
- FAA PHAK
- Instantaneous vertical speed indicator (IVSI)
- Assists in interpretation by instantaneously indicating the rate of climb or descent at a given moment with little or no lag as displayed in a vertical speed indicator (VSI).
- FAA PHAK
- Instrument approach procedures (IAP)
- A series of predetermined maneuvers for the orderly transfer of an aircraft under IFR from the beginning of the initial approach to a landing or to a point from which a landing may be made visually.
- FAA PHAK
- Instrument Approach Waypoint
- Fixes used in defining RNAV IAPs, including the feeder waypoint (FWP), the initial approach waypoint (IAWP), the intermediate waypoint (IWP), the final approach waypoint (FAWP), the RWY WP, and the APT WP, when required.
- FAA IPH
- Instrument flight rules (IFR)
- Rules and regulations established by the Federal Aviation Administration to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in the flight deck, and navigation is accomplished by reference to electronic signals.
- FAA PHAK
- Instrument Landing System (ILS)
- A precision instrument approach system that normally consists of the following electronic components and visual aids: localizer, glide slope, outer marker, middle marker, and approach lights.
- FAA IPH
- Instrument meteorological conditions (IMC)
- Meteorological conditions expressed in terms of visibility, distance from clouds, and ceiling less than the minimums specified for visual meteorological conditions, requiring operations to be conducted under IFR.EASA definition
- FAA PHAK
- Instrument Procedure with Vertical Guidance (IPV)
- Satellite or flight management system (FMS) lateral navigation (LNAV) with computed positive vertical guidance based on barometric or satellite elevation. This term has been renamed APV.
- FAA IPH
- Instrument takeoff
- Using the instruments rather than outside visual cues to maintain runway heading and execute a safe takeoff.
- FAA PHAK
- Intercooler
- A device used to reduce the temperatures of the compressed air before it enters the fuel metering device. The resulting cooler air has a higher density, which permits the engine to be operated with a higher power setting.
- FAA PHAK
- Interference drag
- Drag generated by the collision of airstreams creating eddy currents, turbulence, or restrictions to smooth flow.
- FAA PHAK
- International Civil Aviation Organization (ICAO)
- ICAO is a specialized agency of the United Nations whose objective is to develop standard principles and techniques of international air navigation and to promote development of civil aviation.
- FAA IPH
- International standard atmosphere (IAS)
- A model of standard variation of pressure and temperature.
- FAA PHAK
- Interpolation
- The estimation of an intermediate value of a quantity that falls between marked values in a series. Example: In a measurement of length, with a rule that is marked in eighths of an inch, the value falls between 3/8 inch and 1/2 inch. The estimated (interpolated) value might then be said to be 7/16 inch.
- FAA PHAK
- Intersection
- Typically, the point at which two VOR radial position lines cross on a route, usually intersecting at a good angle for positive indication of position, resulting in a VOR/ VOR fix.
- FAA IPH
- Inversion
- An increase in temperature with altitude.
- FAA PHAK
- Inversion illusion
- The feeling that the aircraft is tumbling backwards, caused by an abrupt change from climb to straight-and-level flight while in situations lacking visual reference.
- FAA PHAK
- Inverter
- A solid-state electronic device that converts D.C. into A.C. current of the proper voltage and frequency to operate A.C. gyro instruments.
- FAA PHAK
- IPC
- Innovation Partnership Contract
- EASA EPAS
- IR
- (Commission) implementing rule
- EASA EPAS
- IR
- instrument rating
- EASA EPAS
- Isobars
- Lines which connect points of equal barometric pressure.
- FAA PHAK
- Isogonic lines
- Lines drawn across aeronautical charts to connect points having the same magnetic variation.
- FAA PHAK
- ITY
- interoperability (in reflection to ATM Master Plan Level 3)
- EASA EPAS
- IVSI
- See instantaneous vertical speed indicator.
- FAA PHAK
J
- JATR
- Joint Authorities Technical Review
- EASA EPAS
- Jet route
- A route designated to serve flight operations from 18,000 feet MSL up to and including FL 450.
- FAA PHAK
- Jet stream
- A high-velocity narrow stream of winds, usually found near the upper limit of the troposphere, which flows generally from west to east.
- FAA PHAK
- Judgment
- The mental process of recognizing and analyzing all pertinent information in a particular situation, a rational evaluation of alternative actions in response to it, and a timely decision on which action to take.
- FAA PHAK
K
- KIAS
- Knots indicated airspeed.
- FAA PHAK
- KNKT
- Komite Nasional Keselamatan Transportasi – National Transportation Safety Committee of Indonesia
- EASA EPAS
- Knot
- The knot is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph.
- FAA PHAK
- Kollsman window
- A barometric scale window of a sensitive altimeter used to adjust the altitude for the altimeter setting.
- FAA PHAK
- KPI
- key performance indicator
- EASA EPAS
- KRE
- key risk element
- EASA EPAS
L
- L/MF
- See low or medium frequency.
- FAA PHAK
- LAAS
- See local area augmentation system.
- FAA PHAK
- LAFI
- light aircraft flight instructor
- EASA EPAS
- Lag
- The delay that occurs before an instrument needle attains a stable indication.
- FAA PHAK
- Land as soon as possible
- Land without delay at the nearest suitable area, such as an open field, at which a safe approach and landing is assured.
- FAA PHAK
- Land as soon as practical
- The landing site and duration of flight are at the discretion of the pilot. Extended flight beyond the nearest approved landing area is not recommended.
- FAA PHAK
- Land breeze
- A coastal breeze flowing from land to sea caused by temperature differences when the sea surface is warmer than the adjacent land. The land breeze usually occurs at night and alternates with the sea breeze that blows in the opposite direction by day.
- FAA PHAK
- Land immediately
- The urgency of the landing is paramount. The primary consideration is to ensure the survival of the occupants. Landing in trees, water, or other unsafe areas should be considered only as a last resort.
- FAA PHAK
- Landing Distance Available (LDA)
- ICAO defines LDA as the length of runway, that is declared available and suitable for the ground run of an aeroplane landing.EASA definition
- FAA IPH
- LAPL
- light aircraft pilot licence
- EASA EPAS
- Lateral axis
- An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.
- FAA PHAK
- Lateral stability (rolling)
- The stability about the longitudinal axis of an aircraft. Rolling stability or the ability of an airplane to return to level flight due to a disturbance that causes one of the wings to drop.
- FAA PHAK
- Latitude
- Measurement north or south of the equator in degrees, minutes, and seconds. Lines of latitude are also referred to as parallels.
- FAA PHAK
- LDA
- See localizer-type directional aid.
- FAA PHAK
- Lead radial
- The radial at which the turn from the DME arc to the inbound course is started.
- FAA PHAK
- Leading edge
- The part of an airfoil that meets the airflow first.
- FAA PHAK
- Leading edge devices
- High lift devices which are found on the leading edge of the airfoil. The most common types are fixed slots, movable slats, and leading edge flaps.
- FAA PHAK
- Leading-edge flap
- A portion of the leading edge of an airplane wing that folds downward to increase the camber, lift, and drag of the wing. The leading-edge flaps are extended for takeoffs and landings to increase the amount of aerodynamic lift that is produced at any given airspeed.
- FAA PHAK
- Leans, the
- A physical sensation caused by an abrupt correction of a banked attitude entered too slowly to stimulate the motion sensing system in the inner ear. The abrupt correction can create the illusion of banking in the opposite direction.
- FAA PHAK
- Licensed empty weight
- The empty weight that consists of the airframe, engine(s), unusable fuel, and undrainable oil plus standard and optional equipment as specified in the equipment list. Some manufacturers used this term prior to GAMA standardization.
- FAA PHAK
- Lift
- A component of the total aerodynamic force on an airfoil and acts perpendicular to the relative wind.
- FAA PHAK
- Limit load factor
- Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs.
- FAA PHAK
- Lines of flux
- Invisible lines of magnetic force passing between the poles of a magnet.
- FAA PHAK
- LMM
- See locator middle marker.
- FAA PHAK
- LO
- learning objective
- EASA EPAS
- Load factor
- The ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertial forces, or ground or water reactions.
- FAA PHAK
- Loadmeter
- A type of ammeter installed between the generator output and the main bus in an aircraft electrical system.
- FAA PHAK
- LOC
- See localizer.
- FAA PHAK
- LOC-I
- loss of control – in-flight
- EASA EPAS
- Local Area Augmentation System (LAAS)
- LAAS further increases the accuracy of GPS and improves signal integrity warnings.
- FAA IPH
- Localizer (LOC)
- The portion of an ILS that gives left/right guidance information down the centerline of the instrument runway for final approach.
- FAA PHAK
- Localizer Performance with Vertical Guidance (LPV)
- LPV is one of the four lines of approach minimums found on an RNAV (GPS) approach chart. Lateral guidance accuracy is equivalent to a localizer. The HAT is published as a DA since it uses an electronic glide path that is not dependent on any ground equipment or barometric aiding and may be as low as 200 feet and 1⁄2 SM visibility depending on the airport terrain and infrastructure. WAAS avionics approved for LPV is required. Baro-VNAV is not authorized to fly the LPV line of minimums on a RNAV (GPS) procedure since it uses an internally generated descent path that is subject to cold temperature effects and incorrect altimeter settings.
- FAA IPH
- Localizer-type directional aid (LDA)
- A NAVAID used for nonprecision instrument approaches with utility and accuracy comparable to a localizer but which is not a part of a complete ILS and is not aligned with the runway. Some LDAs are equipped with a glideslope.
- FAA PHAK
- LOCART
- loss of control avoidance and recovery training
- EASA EPAS
- Locator middle marker (LMM)
- Nondirectional radio beacon (NDB) compass locator, collocated with a middle marker (MM).
- FAA PHAK
- Locator outer marker (LOM)
- NDB compass locator, collocated with an outer marker (OM).
- FAA PHAK
- LOI
- level of involvement
- EASA EPAS
- LOM
- See locator outer marker.
- FAA PHAK
- Longitude
- Measurement east or west of the Prime Meridian in degrees, minutes, and seconds. The Prime Meridian is 0° longitude and runs through Greenwich, England. Lines of longitude are also referred to as meridians.
- FAA PHAK
- Longitudinal axis
- An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its longitudinal axis.
- FAA PHAK
- Longitudinal stability (pitching)
- Stability about the lateral axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement.
- FAA PHAK
- Loss of Separation
- An occurrence or operation that results in less than prescribed separation between aircraft, or between an aircraft and a vehicle, pedestrian, or object.
- FAA IPH
- Low or medium frequency
- A frequency range between 190 and 535 kHz with the medium frequency above 300 kHz. Generally associated with nondirectional beacons transmitting a continuous carrier with either a 400 or 1,020 Hz modulation.
- FAA PHAK
- LPR
- language proficiency requirements
- EASA EPAS
- Lubber line
- The reference line used in a magnetic compass or heading indicator.
- FAA PHAK
- LVO
- low-visibility operation
- EASA EPAS
M
- M&S
- modeling and simulation
- EASA EPAS
- MA
- medical assessor
- EASA EPAS
- MAA
- See maximum authorized altitude.
- FAA PHAK
- MAB
- Member States Advisory Body
- EASA EPAS
- MAC
- mid-air collision
- EASA EPAS
- Mach meter
- The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying.
- FAA PHAK
- Mach number
- The ratio of the true airspeed of the aircraft to the speed of sound in the same atmospheric conditions, named in honor of Ernst Mach, late 19th century physicist.
- FAA PHAK
- Magnetic bearing (MB)
- The direction to or from a radio transmitting station measured relative to magnetic north.
- FAA PHAK
- Magnetic compass
- A device for determining direction measured from magnetic north.
- FAA PHAK
- Magnetic dip
- A vertical attraction between a compass needle and the magnetic poles. The closer the aircraft is to a pole, the more severe the effect.
- FAA PHAK
- Magnetic heading (MH)
- The direction an aircraft is pointed with respect to magnetic north.
- FAA PHAK
- Magnetic Variation
- The difference in degrees between the measured values of true north and magnetic north at that location.
- FAA IPH
- Magneto
- A self-contained, engine-driven unit that supplies electrical current to the spark plugs; completely independent of the airplane’s electrical system. Normally there are two magnetos per engine.
- FAA PHAK
- Magnus effect
- Lifting force produced when a rotating cylinder produces a pressure differential. This is the same effect that makes a baseball curve or a golf ball slice.
- FAA PHAK
- Mandatory altitude
- An altitude depicted on an instrument approach chart with the altitude value both underscored and overscored. Aircraft are required to maintain altitude at the depicted value.
- FAA PHAK
- Mandatory block altitude
- An altitude depicted on an instrument approach chart with two underscored and overscored altitude values between which aircraft are required to maintain altitude.
- FAA PHAK
- Maneuverability
- Ability of an aircraft to change directions along a flight path and withstand the stresses imposed upon it.
- FAA PHAK
- Maneuvering speed (VA)
- The design maneuvering speed. Operating at or below design maneuvering speed does not provide structural protection against multiple full control inputs in one axis or full control inputs in more than one axis at the same time.
- FAA PHAK
- Manifold absolute pressure
- The absolute pressure of the fuel/air mixture within the intake manifold, usually indicated in inches of mercury.
- FAA PHAK
- MAP
- See missed approach point.
- FAA PHAK
- Margin identification
- The top and bottom areas on an instrument approach chart that depict information about the procedure, including airport location and procedure identification.
- FAA PHAK
- Marker beacon
- A low-powered transmitter that directs its signal upward in a small, fan-shaped pattern. Used along the flight path when approaching an airport for landing, marker beacons indicate both aurally and visually when the aircraft is directly over the facility.
- FAA PHAK
- Mass
- The amount of matter in a body.
- FAA PHAK
- Maximum altitude
- An altitude depicted on an instrument approach chart with overscored altitude value at which or below aircraft are required to maintain altitude.
- FAA PHAK
- Maximum landing weight
- The greatest weight that an airplane normally is allowed to have at landing.
- FAA PHAK
- Maximum ramp weight
- The total weight of a loaded aircraft, including all fuel. It is greater than the takeoff weight due to the fuel that will be burned during the taxi and runup operations. Ramp weight may also be referred to as taxi weight.
- FAA PHAK
- Maximum takeoff weight
- The maximum allowable weight for takeoff.
- FAA PHAK
- Maximum weight
- The maximum authorized weight of the aircraft and all of its equipment as specified in the Type Certificate Data Sheets (TCDS) for the aircraft.
- FAA PHAK
- Maximum zero fuel weight (GAMA)
- The maximum weight, exclusive of usable fuel.
- FAA PHAK
- MB
- Management Board
- EASA EPAS
- MBT
- multimedia based training
- EASA EPAS
- MCA
- multi-criteria analysis
- EASA EPAS
- MCF
- maintenance check flight
- EASA EPAS
- MDA
- See minimum descent altitude.
- FAA PHAK
- MEA
- See minimum en route altitude.
- FAA PHAK
- Mean aerodynamic chord (MAC)
- The average distance from the leading edge to the trailing edge of the wing.
- FAA PHAK
- Mean sea level
- The average height of the surface of the sea at a particular location for all stages of the tide over a 19-year period.
- FAA PHAK
- MEL
- See minimum equipment list.
- FAA PHAK
- Meridians
- Lines of longitude.
- FAA PHAK
- Mesophere
- A layer of the atmosphere directly above the stratosphere.
- FAA PHAK
- MET
- meteorology/meteorologic
- EASA EPAS
- MET provider
- meteorological services provider, indirectly, competent authority
- EASA EPAS
- METAR
- See Aviation Routine Weather Report.
- FAA PHAK
- Metering Fix
- A fix along an established route over which aircraft are metered prior to entering terminal airspace. Normally, this fix should be established at a distance from the airport which facilitates a profile descent 10,000 feet above airport elevation (AAE) or above.
- FAA IPH
- MFD
- See multi-function display.
- FAA PHAK
- MGB
- main gearbox
- EASA EPAS
- MH
- See magnetic heading.
- FAA PHAK
- MH17
- Malaysia Airlines flight 17
- EASA EPAS
- MHz
- Megahertz.
- FAA PHAK
- Microburts
- A strong downdraft which normally occurs over horizontal distances of 1 NM or less and vertical distances of less than 1,000 feet. In spite of its small horizontal scale, an intense microburst could induce windspeeds greater than 100 knots and downdrafts as strong as 6,000 feet per minute.
- FAA PHAK
- Microwave landing system (MLS)
- A precision instrument approach system operating in the microwave spectrum which normally consists of an azimuth station, elevation station, and precision distance measuring equipment.
- FAA PHAK
- Mid-RVR
- The RVR readout values obtained from sensors located midfield of the runway.
- FAA IPH
- Mileage Break
- A point on a route where the leg segment mileage ends, and a new leg segment mileage begins, often at a route turning point.
- FAA IPH
- Mileage breakdown
- A fix indicating a course change that appears on the chart as an “x” at a break between two segments of a federal airway.
- FAA PHAK
- Military Airspace Management System (MAMS)
- A Department of Defense system to collect and disseminate information on the current status of special use airspace. This information is provided to the Special Use Airspace Management System (SAMS). The electronic interface also provides SUA schedules and historical activation and utilization data.
- FAA IPH
- Military operations area (MOA)
- Airspace established for the purpose of separating certain military training activities from IFR traffic.
- FAA PHAK
- Military training route (MTR)
- Airspace of defined vertical and lateral dimensions established for the conduct of military training at airspeeds in excess of 250 knots indicated airspeed (KIAS).
- FAA PHAK
- Minimum altitude
- An altitude depicted on an instrument approach chart with the altitude value underscored. Aircraft are required to maintain altitude at or above the depicted value.
- FAA PHAK
- Minimum Crossing Altitude (MCA)
- An MCA is the lowest altitude at certain fixes at which the aircraft must cross when proceeding in the direction of a higher minimum en route IFR altitude. MCAs are established in all cases where obstacles intervene to prevent pilots from maintaining obstacle clearance during a normal climb to a higher MEA after passing a point beyond which the higher MEA applies.
- FAA IPH
- Minimum Descent Altitude (MDA)
- The lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering in execution of a standard instrument approach procedure where no electronic glide slope is provided.
- FAA IPH
- Minimum drag
- The point on the total drag curve where the lift-to-drag ratio is the greatest. At this speed, total drag is minimized.
- FAA PHAK
- Minimum En Route Altitude (MEA)
- The MEA is the lowest published altitude between radio fixes that assures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes. The MEA prescribed for a Federal Airway or segment, RNAV low or high route, or other direct route applies to the entire width of the airway, segment, or route between the radio fixes defining the airway, segment, or route.
- FAA IPH
- Minimum equipment list (MEL)
- A list developed for larger aircraft that outlines equipment that can be inoperative for various types of flight including IFR and icing conditions. This list is based on the master minimum equipment list (MMEL) developed by the FAA and must be approved by the FAA for use. It is specific to an individual aircraft make and model.
- FAA PHAK
- Minimum IFR Altitude (MIA)
- Minimum altitudes for IFR operations are prescribed in 14 CFR Part 91. These MIAs are published on IFR charts and prescribed in 14 CFR Part 95 for airways and routes, and in 14 CFR Part 97 for standard instrument approach procedures.
- FAA IPH
- Minimum Obstruction Clearance Altitude (MOCA)
- The MOCA is the lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments that meets obstacle clearance requirements for the entire route segment. This altitude also assures acceptable navigational signal coverage only within 22 NM of a VOR. G-6
- FAA IPH
- Minimum Reception Altitude (MRA)
- An MRA is determined by FAA flight inspection traversing an entire route of flight to establish the minimum altitude the navigation signal can be received for the route and for off-course NAVAID facilities that determine a fix. When the MRA at the fix is higher than the MEA, an MRA is established for the fix, and is the lowest altitude at which an intersection can be determined.
- FAA IPH
- Minimum Safe Altitude (MSA)
- MSAs are published for emergency use on IAP charts. For conventional navigation systems, the MSA is normally based on the primary omnidirectional facility on which the IAP is predicated. For RNAV approaches, the MSA is based on the runway waypoint (RWY WP) for straight-in approaches, or the airport waypoint (APT WP) for circling approaches. For GPS approaches, the MSA center is the Missed Approach Waypoint (MAWP).
- FAA IPH
- Minimum Vectoring Altitude (MVA)
- Minimum vectoring altitude charts are developed for areas where there are numerous minimum vectoring altitudes due to variable terrain features or man-made obstacles. MVAs are established for use by ATC when radar ATC is exercised.
- FAA IPH
- Minimums section
- The area on an IAP chart that displays the lowest altitude and visibility requirements for the approach.
- FAA PHAK
- Missed approach
- A maneuver conducted by a pilot when an instrument approach cannot be completed to a landing.
- FAA PHAK
- Missed Approach Holding Waypoint
- An approach waypoint sequenced during the holding portion of the missed approach procedure that is a fly-over waypoint.
- FAA IPH
- Missed approach point (MAP)
- A point prescribed in each instrument approach at which a missed approach procedure shall be executed if the required visual reference has not been established.
- FAA PHAK
- Missed Approach Waypoint (MAWP)
- An approach waypoint sequenced during the missed approach procedure that is a fly-over waypoint.
- FAA IPH
- Mixed ice
- A mixture of clear ice and rime ice.
- FAA PHAK
- ML
- Machine Learning (artificial intelligence)
- EASA EPAS
- MLS
- See microwave landing system.
- FAA PHAK
- MM
- Middle marker.
- FAA PHAK
- MMEL
- master minimum equipment list
- EASA EPAS
- MO
- maintenance organisation
- EASA EPAS
- MOA
- See military operations area.
- FAA PHAK
- MoC
- Memorandum of Cooperation
- EASA EPAS
- MOCA
- See minimum obstruction clearance altitude.
- FAA PHAK
- Mode C
- Altitude reporting transponder mode.
- FAA PHAK
- Moment
- The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches (lb-in). Total moment is the weight of the airplane multiplied by the distance between the datum and the CG.
- FAA PHAK
- Moment arm
- The distance from a datum to the applied force.
- FAA PHAK
- Moment index (or index)
- A moment divided by a constant such as 100, 1,000, or 10,000. The purpose of using a moment index is to simplify weight and balance computations of airplanes where heavy items and long arms result in large, unmanageable numbers.
- FAA PHAK
- Monocoque
- A shell-like fuselage design in which the stressed outer skin is used to support the majority of imposed stresses. Monocoque fuselage design may include bulkheads but not stringers.
- FAA PHAK
- Monoplanes
- Airplanes with a single set of wings.
- FAA PHAK
- MOPSC
- maximum operational passenger seating configuration
- EASA EPAS
- Movable slat
- A movable auxiliary airfoil on the leading edge of a wing. It is closed in normal flight but extends at high angles of attack. This allows air to continue flowing over the top of the wing and delays airflow separation.
- FAA PHAK
- MPL
- multi-crew pilot licence
- EASA EPAS
- MRA
- See minimum reception altitude.
- FAA PHAK
- MRB
- Maintenance Review Board
- EASA EPAS
- MSA
- See minimum safe altitude.
- FAA PHAK
- MSL
- See mean sea level.
- FAA PHAK
- MST
- Member States’ task
- EASA EPAS
- MTO
- maintenance training organisation
- EASA EPAS
- MTOM
- maximum take-off mass
- EASA EPAS
- MTR
- See military training route.
- FAA PHAK
- Multi-function display (MFD)
- Small screen (CRT or LCD) in an aircraft that can be used to display information to the pilot in numerous configurable ways. Often an MFD will be used in concert with a primary flight display. MVA. See minimum vectoring altitude.
- FAA PHAK
N
- N1
- Rotational speed of the low pressure compressor in a turbine engine.
- FAA PHAK
- N2
- Rotational speed of the high pressure compressor in a turbine engine.
- FAA PHAK
- NAA
- national aviation authority
- EASA EPAS
- Nacelle
- A streamlined enclosure on an aircraft in which an engine is mounted. On multiengine propeller-driven airplanes, the nacelle is normally mounted on the leading edge of the wing.
- FAA PHAK
- NACG
- See National Aeronautical Charting Group.
- FAA PHAK
- NAS
- See National Airspace System.
- FAA PHAK
- National Aeronautical Charting Group (NACG)
- A Federal agency operating under the FAA, responsible for publishing charts such as the terminal procedures and en route charts.
- FAA PHAK
- National Airspace System (NAS)
- Consists of a complex collection of facilities, systems, equipment, procedures, and airports operated by thousands of people to provide a safe and efficient flying environment.
- FAA IPH
- National Route Program (NRP)
- A set of rules and procedures designed to increase the flexibility of user flight planning within published guidelines.
- FAA PHAK
- National Security Area (NSA)
- Areas consisting of airspace of defined vertical and lateral dimensions established at locations where there is a requirement for increased security and safety of ground facilities. Pilots are requested to voluntarily avoid flying through the depicted NSA. When it is necessary to provide a greater level of security and safety, flight in NSAs may be temporarily prohibited. Regulatory prohibitions are disseminated via NOTAMs.
- FAA PHAK
- National Transportation Safety Board (NTSB)
- A United States Government independent organization responsible for investigations of accidents involving aviation, highways, waterways, pipelines, and railroads in the United States. NTSB is charged by congress to investigate every civil aviation accident in the United States.
- FAA PHAK
- NCC
- non-commercial air operations with complex motor-powered aircraft (The term ‘complex motor-powered aircraft’ is no longer defined in Regulation (EU) 2018/1139. Article 140(2) of that Regulation provides that no later than 12 September 2023, implementing rules adopted under Regulations (EC) Nos 216/2008 and 552/2004 shall be adapted to the new Basic Regulation. Until then, deleted or altered definitions will continue to apply.)
- EASA EPAS
- NCO
- non-commercial air operations with other-than complex motor-powered aircraft (The term ‘complex motor-powered aircraft’ is no longer defined in Regulation (EU) 2018/1139. Article 140(2) of that Regulation provides that no later than 12 September 2023, implementing rules adopted under Regulations (EC) Nos 216/2008 and 552/2004 shall be adapted to the new Basic Regulation. Until then, deleted or altered definitions will continue to apply.)
- EASA EPAS
- NDB
- non-directional beacon
- EASA EPAS
- Negative static stability
- The initial tendency of an aircraft to continue away from the original state of equilibrium after being disturbed.
- FAA PHAK
- Neutral static stability
- The initial tendency of an aircraft to remain in a new condition after its equilibrium has been disturbed.
- FAA PHAK
- Next Generation Air Transportation System (NextGen)
- Ongoing, wide-ranging transformation of the National Airspace System (NAS). NextGen represents an evolution from a ground-based system of air traffic control to a satellite-based system of air traffic management.
- FAA IPH
- NextGen
- next generation
- EASA EPAS
- NGAP
- Next Generation of Aviation Professionals programme (ICAO)
- EASA EPAS
- NGO
- non-governmental organisation
- EASA EPAS
- NM
- Nautical mile.
- FAA PHAK
- NN
- Neural Networks (artificial intelligence)
- EASA EPAS
- NO
- Norway
- EASA EPAS
- No procedure turn (NoPT)
- Term used with the appropriate course and altitude to denote that the procedure turn is not required.
- FAA PHAK
- No-gyro approach
- A radar approach that may be used in case of a malfunctioning gyro-compass or directional gyro. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues control instructions “turn right/left” or “stop turn,” as appropriate.
- FAA PHAK
- NOAA
- National Oceanic and Atmospheric Administration.
- FAA PHAK
- NoAs
- Network of Analysts
- EASA EPAS
- Non-Directional Radio Beacon (NDB)
- An L/MF or UHF radio beacon transmitting nondirectional signals whereby the pilot of an aircraft equipped with direction finding equipment can determine bearing to or from the radio beacon and “home”on or track to or from the station. When the radio beacon is installed in conjunction with the ILS marker, it is normally called a compass locator.
- FAA IPH
- Nondirectional radio beacon (NDB)
- A ground-based radio transmitter that transmits radio energy in all directions.
- FAA PHAK
- Nonprecision approach
- A standard instrument approach procedure in which only horizontal guidance is provided.
- FAA PHAK
- NoPT
- See no procedure turn.
- FAA PHAK
- NORAH
- Noise Related Annoyance, Cognition, and Health
- EASA EPAS
- NOTAM
- See Notice to Airmen.
- FAA PHAK
- Notice to Airmen (NOTAM)
- A notice filed with an aviation authority to alert aircraft pilots of any hazards en route or at a specific location. The authority in turn provides means of disseminating relevant NOTAMs to pilots.EASA definition
- FAA PHAK
- NPA
- notice of proposed amendment
- EASA EPAS
- NRP
- See National Route Program.
- FAA PHAK
- NSA
- national supervisory authority
- EASA EPAS
- NTSB
- National Transportation Safety Board
- EASA EPAS
- nvPM
- non-volatile particulate matter
- EASA EPAS
- NWS
- National Weather Service.
- FAA PHAK
O
- Obstacle Clearance Surface (OCS)
- An inclined or level surface associated with a defined area for obstruction evaluation.
- FAA IPH
- Obstacle Departure Procedure (ODP)
- A procedure that provides obstacle clearance. ODPs do not include ATC related climb requirements. In fact, the primary emphasis of ODP design is to use the least erroneous route of flight to the en route structure while attempting to accommodate typical departure routes.
- FAA IPH
- Obstacle departure procedures (ODP)
- A preplanned instrument flight rule (IFR) departure procedure printed for pilot use in textual or graphic form to provide obstruction clearance via the least onerous route from the terminal area to the appropriate en route structure. ODPs are recommended for obstruction clearance and may be flown without ATC clearance unless an alternate departure procedure (SID or radar vector) has been specifically assigned by ATC.
- FAA PHAK
- Obstacle Identification Surface (OIS)
- The design of a departure procedure is based on FAA Order 8260.3, a living document that is updated frequently. Departure design criteria assumes an initial climb of 200 Ft/NM after crossing the departure end of the runway (DER) at a height of at least 35 feet above the ground. Assuming a 200 Ft/NM climb, the departure is structured to provide at least 48 Ft/ NM of clearance above objects that do not penetrate the obstacle slope. The slope, known as the OIS, is based on a 40 to 1 ratio, which is the equivalent of a 152 Ft/NM slope.
- FAA IPH
- Obstruction lights
- Lights that can be found both on and off an airport to identify obstructions.
- FAA PHAK
- Occluded front
- A frontal occlusion occurs when a fast-moving cold front catches up with a slow moving warm front. The difference in temperature within each frontal system is a major factor in determining whether a cold or warm front occlusion occurs.
- FAA PHAK
- ODP
- See obstacle departure procedures.
- FAA PHAK
- OEM
- original equipment manufacturer
- EASA EPAS
- Off-Airway Routes
- The FAA prescribes altitudes governing the operation of aircraft under IFR for fairway routes in a similar manner to those on federal airways, jet routes, area navigation low or high altitude routes, and other direct routes for which an MEA is designated.
- FAA IPH
- Off-Route Obstruction Clearance Altitude (OROCA)
- An off-route altitude that provides obstruction clearance with a 1,000-foot buffer in nonmountainous terrain areas and a 2,000-foot buffer in designated mountainous areas within the U.S. This altitude may not provide signal coverage from groundbased navigational aids, air traffic control radar, or communications coverage.
- FAA IPH
- OHMPs
- occupational health medical practitioners
- EASA EPAS
- OJ
- Official Journal of the European Union
- EASA EPAS
- OM
- Outer marker.
- FAA PHAK
- Omission error
- The failure to anticipate significant instrument indications following attitude changes; for example, concentrating on pitch control while forgetting about heading or roll information, resulting in erratic control of heading and bank.
- FAA PHAK
- Operations Specifications (OpSpecs)
- A published document providing the conditions under which an air carrier and operator for compensation or hire must operate in order to retain approval from the FAA.
- FAA IPH
- OPS
- air operations
- EASA EPAS
- OpSpecs
- operations specifications
- EASA EPAS
- Optical illusion
- A misleading visual image. For the purpose of this handbook, the term refers to the brain’s misinterpretation of features on the ground associated with landing, which causes a pilot to misread the spatial relationships between the aircraft and the runway.
- FAA PHAK
- Orientation
- Awareness of the position of the aircraft and of oneself in relation to a specific reference point.
- FAA PHAK
- ORO.FC
- organisation requirements for air operations — flight crew
- EASA EPAS
- Otolith organ
- An inner ear organ that detects linear acceleration and gravity orientation.
- FAA PHAK
- Outer marker
- A marker beacon at or near the glideslope intercept altitude of an ILS approach. It is normally located four to seven miles from the runway threshold on the extended centerline of the runway.
- FAA PHAK
- Outside air temperature (OAT)
- The measured or indicated air temperature (IAT) corrected for compression and friction heating. Also referred to as true air temperature.
- FAA PHAK
- Overcontrolling
- Using more movement in the control column than is necessary to achieve the desired pitch-and-bank condition. Overboost. A condition in which a reciprocating engine has exceeded the maximum manifold pressure allowed by the manufacturer. Can cause damage to engine components.
- FAA PHAK
- Overpower
- To use more power than required for the purpose of achieving a faster rate of airspeed change.
- FAA PHAK
P
- P-factor
- A tendency for an aircraft to yaw to the left due to the descending propeller blade on the right producing more thrust than the ascending blade on the left. This occurs when the aircraft’s longitudinal axis is in a climbing attitude in relation to the relative wind. The P-factor would be to the right if the aircraft had a counterclockwise rotating propeller.
- FAA PHAK
- P-static
- See precipitation static.
- FAA PHAK
- PANS
- procedures for air navigation services (ICAO)
- EASA EPAS
- PAPI
- See precision approach path indicator.
- FAA PHAK
- PAR
- See precision approach radar.
- FAA PHAK
- Parallels
- Lines of latitude.
- FAA PHAK
- Parasite drag
- Drag caused by the friction of air moving over the aircraft structure; its amount varies directly with the airspeed.
- FAA PHAK
- Part 21
- Annex I to Regulation to Regulation (EU) 748/2012 - airworthiness and environmental certification of aircraft and related products, parts and appliances, as well as for the certification of design and production organisationsEASA definition
- EASA EPAS
- Part 21 Subpart H
- Annex I to Regulation to Regulation (EU) 748/2012 – Subpart H - airworthiness certificates and restricted certificates of airworthiness
- EASA EPAS
- Part-145
- Annex II to Commission Regulation (EU) No 1321/2014 - maintenance organisation approvals
- EASA EPAS
- Part-147
- Annex IV to Commission Regulation (EU) No 1321/2014 - training organisations requirements
- EASA EPAS
- Part-26
- Annex I to Regulation (EU) 2015/640 - additional airworthiness requirements for operations
- EASA EPAS
- Part-66
- Annex III to Commission Regulation (EU) No 1321/2014 - certifying staff
- EASA EPAS
- Part-ARO
- Annex II to Regulation (EU) 965/2012 - authority requirements for air operations
- EASA EPAS
- Part-FCL
- Annex I to Regulation (EU) 1178/2011 - flight crew licensing
- EASA EPAS
- Part-M
- Annex I to Commission Regulation (EU) No 1321/2014 - continuing airworthiness requirements
- EASA EPAS
- Part-MED
- Annex IV to Regulation (EU) 1178/2011 - medical certification of pilots, medical fitness of cabin crew, certification of AMEs and requirements of GMPs and OHMPs
- EASA EPAS
- Part-MET
- Annex V to Regulation (EU) 2017 373 - specific requirements for providers of meteorological services
- EASA EPAS
- Part-NCC
- Annex VI to Regulation (EU) 965/2012
- EASA EPAS
- Part-NCO
- Annex VII to Regulation (EU) 965/2012
- EASA EPAS
- Part-ORA
- Annex III to Regulation (EU) 1178/2011 - organisation requirements for aircrew
- EASA EPAS
- Part-ORO
- Annex III to Regulation (EU) 965/2012 - organisation requirements for air operations
- EASA EPAS
- Part-SPO
- Annex VIII to Regulation (EU) 965/2012
- EASA EPAS
- PBAOM
- performance based aerodrome operating minima
- EASA EPAS
- PBN
- performance-based navigation
- EASA EPAS
- PBR
- performance-based regulation
- EASA EPAS
- PCP
- pilot common project (SESAR)
- EASA EPAS
- PDRA
- predefined risk assessment
- EASA EPAS
- PED
- personal electronic device
- EASA EPAS
- Personality
- The embodiment of personal traits and characteristics of an individual that are set at a very early age and extremely resistant to change.
- FAA PHAK
- PFD
- See primary flight display.
- FAA PHAK
- Phugoid oscillations
- Long-period oscillations of an aircraft around its lateral axis. It is a slow change in pitch accompanied by equally slow changes in airspeed. Angle of attack remains constant, and the pilot often corrects for phugoid oscillations without even being aware of them.
- FAA PHAK
- PIC
- See pilot in command.
- FAA PHAK
- Pilot Briefing Information
- The current format for charted IAPs issued by Aeronautical Information Services. The information is presented in a logical order facilitating pilot briefing of the procedures. Charts include formatted information required for quick pilot or flight crew reference located at the top of the chart.
- FAA IPH
- Pilot in command (PIC)
- The pilot responsible for the operation and safety of an aircraft.
- FAA PHAK
- Pilot report (PIREP)
- Report of meteorological phenomena encountered by aircraft.
- FAA PHAK
- Pilotage
- Navigation by visual reference to landmarks.
- FAA PHAK
- Pilot’s Operating Handbook/Airplane Flight Manual (POH/AFM)
- FAA-approved documents published by the airframe manufacturer that list the operating conditions for a particular model of aircraft.
- FAA PHAK
- PIREP
- pilot report
- EASA EPAS
- PIS
- public interest sites
- EASA EPAS
- Pitot pressure
- Ram air pressure used to measure airspeed.
- FAA PHAK
- Pitot-static head
- A combination pickup used to sample pitot pressure and static air pressure.
- FAA PHAK
- Plan view
- The overhead view of an approach procedure on an instrument approach chart. The plan view depicts the routes that guide the pilot from the en route segments to the IAF.
- FAA PHAK
- Planform
- The shape or form of a wing as viewed from above. It may be long and tapered, short and rectangular, or various other shapes.
- FAA PHAK
- PM
- particulate matter
- EASA EPAS
- Pneumatic
- Operation by the use of compressed air.
- FAA PHAK
- POA
- production organisation approval
- EASA EPAS
- PoC
- proof of concept
- EASA EPAS
- POH/AFM
- See Pilot’s Operating Handbook/Airplane Flight Manual.
- FAA PHAK
- Point-in-Space (PinS) Approach
- An approach normally developed to heliports that do not meet the IFR heliport design standards but meet the standards for a VFR heliport. A helicopter PinS approach can be developed using conventional NAVAIDs or RNAV systems. These procedures have either a VFR or visual segment between the MAP and the landing area. The procedure specifies a course and distance from the MAP to the heliport(s) and includes a note to proceed VFR or visually from the MAP to the heliport, or conduct the missed approach.
- FAA IPH
- Point-in-space approach
- A type of helicopter instrument approach procedure to a missed approach point more than 2,600 feet from an associated helicopter landing area.
- FAA PHAK
- Poor judgment chain
- A series of mistakes that may lead to an accident or incident. Two basic principles generally associated with the creation of a poor judgment chain are: (1) one bad decision often leads to another; and (2) as a string of bad decisions grows, it reduces the number of subsequent alternatives for continued safe flight. ADM is intended to break the poor judgment chain before it can cause an accident or incident.
- FAA PHAK
- Position error
- Error in the indication of the altimeter, ASI, and VSI caused by the air at the static system entrance not being absolutely still.
- FAA PHAK
- Position report
- A report over a known location as transmitted by an aircraft to ATC.
- FAA PHAK
- Positive Course Guidance (PCG)
- The continuous display of accurate course and flight path data that enables a pilot to precisely fly along a specific track or course using RNAV, a ground-based NAVAID or a radar vector. For RNAV or a ground-based NAVAID, the guidance is displayed in the aircraft; for a radar vector, the guidance data is displayed in the radar facility
- FAA IPH
- Positive static stability
- The initial tendency to return to a state of equilibrium when disturbed from that state.
- FAA PHAK
- Power
- Implies work rate or units of work per unit of time, and as such, it is a function of the speed at which the force is developed. The term “power required” is generally associated with reciprocating engines.
- FAA PHAK
- Powerplant
- A complete engine and propeller combination with accessories.
- FAA PHAK
- PPL
- private pilot licence
- EASA EPAS
- Precession
- The characteristic of a gyroscope that causes an applied force to be felt, not at the point of application, but 90° from that point in the direction of rotation.
- FAA PHAK
- Precipitation
- Any or all forms of water particles (rain, sleet, hail, or snow) that fall from the atmosphere and reach the surface.
- FAA PHAK
- Precipitation static (P-static)
- A form of radio interference caused by rain, snow, or dust particles hitting the antenna and inducing a small radio-frequency voltage into it.
- FAA PHAK
- Precision approach
- A standard instrument approach procedure in which both vertical and horizontal guidance is provided.
- FAA PHAK
- Precision approach path indicator (PAPI)
- A system of lights similar to the VASI, but consisting of one row of lights in two- or four-light systems. A pilot on the correct glideslope will see two white lights and two red lights. See VASI.
- FAA PHAK
- Precision approach radar (PAR)
- A type of radar used at an airport to guide an aircraft through the final stages of landing, providing horizontal and vertical guidance. The radar operator directs the pilot to change heading or adjust the descent rate to keep the aircraft on a path that allows it to touch down at the correct spot on the runway.
- FAA PHAK
- Precision Runway Monitor (PRM)
- Provides air traffic controllers with high precision secondary surveillance data for aircraft on final approach to parallel runways that have extended centerlines separated by less than 4,300 feet. High resolution color monitoring displays (FMA) are required to present surveillance track data to controllers along with detailed maps depicting approaches and a no transgression zone.
- FAA IPH
- Preferential Departure Route (PDR)
- A specific departure route from an airport or terminal area to an en route point where there is no further need for flow control. It may be included in an instrument Departure Procedure (DP) or a Preferred IFR Route.
- FAA IPH
- Preferred IFR Routes
- A system of preferred IFR routes guides you in planning your route of flight to minimize route changes during the operational phase of flight, and to aid in the efficient orderly management of air traffic using federal airways.
- FAA IPH
- Preignition
- Ignition occurring in the cylinder before the time of normal ignition. Preignition is often caused by a local hot spot in the combustion chamber igniting the fuel-air mixture.
- FAA PHAK
- Pressure altitude
- Altitude above the standard 29.92 "Hg plane.
- FAA PHAK
- Pressure demand oxygen system
- A demand oxygen system that supplies 100 percent oxygen at sufficient pressure above the altitude where normal breathing is adequate. Also referred to as a pressure breathing system.
- FAA PHAK
- Prevailing visibility
- The greatest horizontal visibility equaled or exceeded throughout at least half the horizon circle (which is not necessarily continuous).
- FAA PHAK
- Preventive maintenance
- Simple or minor preservative operations and the replacement of small standard parts not involving complex assembly operation as listed in 14 CFR part 43, appendix A. Certificated pilots may perform preventive maintenance on any aircraft that is owned or operated by them provided that the aircraft is not used in air carrier service.
- FAA PHAK
- Primary and supporting
- A method of attitude instrument flying using the instrument that provides the most direct indication of attitude and performance.
- FAA PHAK
- Primary flight display (PFD)
- A display that provides increased situational awareness to the pilot by replacing the traditional six instruments used for instrument flight with an easy-to-scan display that provides the horizon, airspeed, altitude, vertical speed, trend, trim, and rate of turn among other key relevant indications.
- FAA PHAK
- Principal Operations Inspector (POI)
- Scheduled air carriers and operators for compensation or hire are assigned a POI who works directly with the company and coordinates FAA operating approval.
- FAA IPH
- PRM
- passengers with reduced mobility
- EASA EPAS
- Procedure turn
- A maneuver prescribed when it is necessary to reverse direction to establish an aircraft on the intermediate approach segment or final approach course.
- FAA PHAK
- Profile view
- Side view of an IAP chart illustrating the vertical approach path altitudes, headings, distances, and fixes.
- FAA PHAK
- Prohibited area
- Designated airspace within which flight of aircraft is prohibited.EASA definition
- FAA PHAK
- Propeller
- A device for propelling an aircraft that, when rotated, produces by its action on the air, a thrust approximately perpendicular to its plane of rotation. It includes the control components normally supplied by its manufacturer.
- FAA PHAK
- Propeller/rotor modulation error
- Certain propeller rpm settings or helicopter rotor speeds can cause the VOR course deviation indicator (CDI) to fluctuate as much as ±6°. Slight changes to the rpm setting will normally smooth out this roughness.
- FAA PHAK
Q
- Q
- quarter
- EASA EPAS
- QMS
- quality management system
- EASA EPAS
R
- R&D
- research and development
- EASA EPAS
- R.COM
- Rotorcraft Committee (Advisory Body)
- EASA EPAS
- Rabbit, the
- High-intensity flasher system installed at many large airports. The flashers consist of a series of brilliant blue-white bursts of light flashing in sequence along the approach lights, giving the effect of a ball of light traveling toward the runway.
- FAA PHAK
- Radar
- A system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for Radio Detection and Ranging. The term has since entered the English language as a standard word, radar, losing the capitalization in the process.EASA definition
- FAA PHAK
- Radar approach
- The controller provides vectors while monitoring the progress of the flight with radar, guiding the pilot through the descent to the airport/heliport or to a specific runway.
- FAA PHAK
- Radar services
- Radar is a method whereby radio waves are transmitted into the air and are then received when they have been reflected by an object in the path of the beam. Range is determined by measuring the time it takes (at the speed of light) for the radio wave to go out to the object and then return to the receiving antenna. The direction of a detected object from a radar site is determined by the position of the rotating antenna when the reflected portion of the radio wave is received.
- FAA PHAK
- Radar summary chart
- A weather product derived from the national radar network that graphically displays a summary of radar weather reports.
- FAA PHAK
- Radar weather report (SD)
- A report issued by radar stations at 35 minutes after the hour, and special reports as needed. Provides information on the type, intensity, and location of the echo tops of the precipitation.
- FAA PHAK
- Radials
- The courses oriented from a station.
- FAA PHAK
- Radio frequency (RF)
- A term that refers to alternating current (AC) having characteristics such that, if the current is input to antenna, an electromagnetic (EM) field is generated suitable for wireless broadcasting and/or communications.
- FAA PHAK
- Radio magnetic indicator (RMI)
- An electronic navigation instrument that combines a magnetic compass with an ADF or VOR. The card of the RMI acts as a gyro-stabilized magnetic compass, and shows the magnetic heading the aircraft is flying.
- FAA PHAK
- Radio or radar altimeter
- An electronic altimeter that determines the height of an aircraft above the terrain by measuring the time needed for a pulse of radio-frequency energy to travel from the aircraft to the ground and return.
- FAA PHAK
- Radio wave
- An electromagnetic (EM) wave with frequency characteristics useful for radio transmission.
- FAA PHAK
- Radiosonde
- A weather instrument that observes and reports meteorological conditions from the upper atmosphere. This instrument is typically carried into the atmosphere by some form of weather balloon.
- FAA PHAK
- RAIM
- See receiver autonomous integrity monitoring.
- FAA PHAK
- RAM recovery
- The increase in thrust as a result of ram air pressures and density on the front of the engine caused by air velocity.
- FAA PHAK
- RAMP
- aerodrome ramp
- EASA EPAS
- Ranging signals
- Transmitted from the GPS satellite, signals allowing the aircraft’s receiver to determine range (distance) from each satellite.
- FAA PHAK
- Rapid decompression
- The almost instantaneous loss of cabin pressure in aircraft with a pressurized cockpit or cabin.
- FAA PHAK
- RASG
- Regional Aviation Safety Group
- EASA EPAS
- RASP
- Regional Aviation Safety Plan
- EASA EPAS
- RB
- See relative bearing.
- FAA PHAK
- RBI
- See relative bearing indicator.
- FAA PHAK
- RCO
- See remote communications outlet.
- FAA PHAK
- RE
- runway excursion
- EASA EPAS
- REACH
- Registration, Evaluation, Authorisation and Restriction of Chemicals — Regulation (EC) No 1907/2006
- EASA EPAS
- Receiver autonomous integrity monitoring (RAIM)
- A system used to verify the usability of the received GPS signals and warns the pilot of any malfunction in the navigation system. This system is required for IFR-certified GPS units.
- FAA PHAK
- Receiver-transmitter (RT)
- A system that receives and transmits a signal and an indicator.
- FAA PHAK
- ReCo
- reduced-crew operations
- EASA EPAS
- Recommended altitude
- An altitude depicted on an instrument approach chart with the altitude value neither underscored nor overscored. The depicted value is an advisory value.
- FAA PHAK
- Record
- See Database Record.
- FAA IPH
- Reduced vertical separation minimum (RVSM)
- Reduces the vertical separation between flight levels (FL) 290 and 410 from 2,000 feet to 1,000 feet, and makes six additional FLs available for operation. Also see DRVSM. Reference circle (also, distance circle). The circle depicted in the plan view of an IAP chart that typically has a 10 NM radius, within which chart the elements are drawn to scale.
- FAA PHAK
- Reduced Vertical Separation Minimums (RVSM)
- RVSM airspace is where air traffic control separates aircraft by a minimum of 1,000 feet vertically between flight level (FL) 290 and FL 410 inclusive. RVSM airspace is special qualification airspace; the operator and the aircraft used by the operator must be approved by the Administrator. Air traffic control notifies operators of RVSM by providing route planing information.
- FAA IPH
- Reference Landing Speed (VREF)
- The speed of the aircraft, in a specified landing configuration, at the point where it descends through the 50-foot height in the determination of the landing distance.
- FAA IPH
- Region of reverse command
- Flight regime in which flight at a higher airspeed requires a lower power setting and a lower airspeed requires a higher power setting in order to maintain altitude.
- FAA PHAK
- Regions of command
- The “regions of normal and reversed command” refers to the relationship between speed and the power required to maintain or change that speed in flight.
- FAA PHAK
- REIL
- See runway end identifier lights.
- FAA PHAK
- Relative bearing (RB)
- The angular difference between the aircraft heading and the direction to the station, measured clockwise from the nose of the aircraft.
- FAA PHAK
- Relative bearing indicator (RBI)
- Also known as the fixed-card ADF, zero is always indicated at the top of the instrument and the needle indicates the relative bearing to the station.
- FAA PHAK
- Relative humidity
- The ratio of the existing amount of water vapor in the air at a given temperature to the maximum amount that could exist at that temperature; usually expressed in percent.
- FAA PHAK
- Relative wind
- Direction of the airflow produced by an object moving through the air. The relative wind for an airplane in flight flows in a direction parallel with and opposite to the direction of flight; therefore, the actual flight path of the airplane determines the direction of the relative wind.
- FAA PHAK
- Remote Communications Outlet (RCO)
- An unmanned communications facility remotely controlled by air traffic personnel. RCOs serve FSSs and may be UHF or VHF. RCOs extend the communication range of the air traffic facility. RCOs were established to provide ground-to-ground communications between air traffic control specialists and pilots located at a satellite airport for delivering en route clearances, issuing departure authorizations, and acknowledging IFR cancellations or departure/landing times.
- FAA IPH
- Reporting Point
- A geographical location in relation to which the position of an aircraft is reported. (See Compulsory Reporting Points).EASA definition
- FAA IPH
- RES
- research actions
- EASA EPAS
- Restricted area
- Airspace designated under 14 CFR part 73 within which the flight of aircraft, while not wholly prohibited, is subject to restriction.EASA definition
- FAA PHAK
- Reverse sensing
- The VOR needle appearing to indicate the reverse of normal operation.
- FAA PHAK
- RF
- Radio frequency.
- FAA PHAK
- RFFS
- rescue and firefighting services
- EASA EPAS
- RFID
- radio frequency identification device
- EASA EPAS
- Rhodopsin
- The photosensitive pigments that initiate the visual response in the rods of the eye.
- FAA PHAK
- RI
- runway incursion
- EASA EPAS
- RIA
- regulatory impact assessment
- EASA EPAS
- Rigging
- The final adjustment and alignment of an aircraft and its flight control system that provides the proper aerodynamic characteristics.
- FAA PHAK
- Rigidity
- The characteristic of a gyroscope that prevents its axis of rotation tilting as the Earth rotates.
- FAA PHAK
- Rigidity in space
- The principle that a wheel with a heavily weighted rim spinning rapidly will remain in a fixed position in the plane in which it is spinning.
- FAA PHAK
- Rime ice
- Rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets.
- FAA PHAK
- Risk
- The future impact of a hazard that is not eliminated or controlled.
- FAA PHAK
- Risk elements
- There are four fundamental risk elements in aviation: the pilot, the aircraft, the environment, and the type of operation that comprise any given aviation situation.
- FAA PHAK
- Risk management
- The part of the decision-making process which relies on situational awareness, problem recognition, and good judgment to reduce risks associated with each flight.
- FAA PHAK
- RMI
- See radio magnetic indicator.
- FAA PHAK
- RMT
- rulemaking task
- EASA EPAS
- RNN
- Recurrent Neural Network (artificial intelligence)
- EASA EPAS
- RNP
- See required navigation performance.
- FAA PHAK
- Roll-Out RVR
- The RVR readout values obtained from sensors located nearest the rollout end of the runway.
- FAA IPH
- RSOO
- Regional Safety Oversight Organisation
- EASA EPAS
- RT
- radio telephony
- EASA EPAS
- Rudder
- The movable primary control surface mounted on the trailing edge of the vertical fin of an airplane. Movement of the rudder rotates the airplane about its vertical axis.
- FAA PHAK
- Ruddervator
- A pair of control surfaces on the tail of an aircraft arranged in the form of a V. These surfaces, when moved together by the control wheel, serve as elevators, and when moved differentially by the rudder pedals, serve as a rudder.
- FAA PHAK
- Runway centerline lights
- Runway lighting which consists of flush centerline lights spaced at 50-foot intervals beginning 75 feet from the landing threshold.
- FAA PHAK
- Runway edge lights
- A component of the runway lighting system that is used to outline the edges of runways at night or during low visibility conditions. These lights are classified according to the intensity they are capable of producing.
- FAA PHAK
- Runway end identifier lights (REIL)
- A pair of synchronized flashing lights, located laterally on each side of the runway threshold, providing rapid and positive identification of the approach end of a runway.
- FAA PHAK
- Runway Heading
- The magnetic direction that corresponds with the runway centerline extended, not the painted runway numbers on the runway. Pilots cleared to “fly or maintain runway heading” are expected to fly or maintain the published heading that corresponds with the extended centerline of the departure runway (until otherwise instructed by ATC), and are not to apply drift correction (e.g., RWY 4, actual magnetic heading of the runway centerline 044.22°, fly 044°).
- FAA IPH
- Runway Hotspots
- Locations on a particular airport that historically have hazardous intersections. Hot spots alert pilots to the fact that there may be a lack of visibility at certain points or the tower may be unable to see that particular intersection. Whatever the reason, pilots need to be aware that these hazardous intersections exist and they should be increasingly vigilant when approaching and taxiing through these intersections. Pilots are typically notified of these areas by a Letter to Airmen or by accessing the FAA Office of Runway Safety.
- FAA IPH
- Runway Incursion
- An occurrence at an airport involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in a loss of separation with an aircraft that is taking off, intending to take off, landing, or intending to land.
- FAA IPH
- Runway Safety Program (RSP)
- Designed to create and execute a plan of action that reduces the number of runway incursions at the nation’s airports.
- FAA IPH
- Runway Visibility Value (RVV)
- The visibility determined for a particular runway by a transmissometer. A meter provides a continuous indication of the visibility (reported in miles or fractions of miles) for the runway. RVV is used in lieu of prevailing visibility in determining minimums for a particular runway.
- FAA IPH
- Runway Visual Range (RVR)
- An estimate of the maximum distance at which the runway, or the specified lights or markers delineating it, can be seen from a position above a specific point on the runway centerline. RVR is normally determined by visibility sensors or transmissometers located alongside and higher than the centerline of the runway. RVR is reported in hundreds of feet.EASA definition
- FAA IPH
- RVR
- runway visual range
- EASA EPAS
- RVSM
- reduced vertical separation minima
- EASA EPAS
- RVV
- See runway visibility value.
- FAA PHAK
- RWY
- runway
- EASA EPAS
S
- SA
- See selective availability.
- FAA PHAK
- SA CAT I
- special authorisation CAT I
- EASA EPAS
- SAB
- Stakeholders Advisory Body
- EASA EPAS
- SAF
- Sustainable Aviation Fuels
- EASA EPAS
- SAF
- Safety Management (in reflection to ATM Master Plan Level 3)
- EASA EPAS
- SAR
- Standardisation Annual Report
- EASA EPAS
- SARPs
- Standards and Recommended Practices (ICAO)
- EASA EPAS
- SATCOM
- satellite communications
- EASA EPAS
- Satellite ephemeris data
- Data broadcast by the GPS satellite containing very accurate orbital data for that satellite, atmospheric propagation data, and satellite clock error data.
- FAA PHAK
- SBAS
- satellite-based augmentation system
- EASA EPAS
- SC
- special condition
- EASA EPAS
- Scan
- The first fundamental skill of instrument flight, also known as “cross-check;” the continuous and logical observation of instruments for attitude and performance information.
- FAA PHAK
- SDF
- See simplified directional facility.
- FAA PHAK
- Sea breeze
- A coastal breeze blowing from sea to land caused by the temperature difference when the land surface is warmer than the sea surface. The sea breeze usually occurs during the day and alternates with the land breeze that blows in the opposite direction at night.
- FAA PHAK
- Sea level engine
- A reciprocating aircraft engine having a rated takeoff power that is producible only at sea level.
- FAA PHAK
- Sectional aeronautical charts
- Designed for visual navigation of slow- or medium-speed aircraft. Topographic information on these charts features the portrayal of relief, and a judicious selection of visual check points for VFR flight. Aeronautical information includes visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions and related data.
- FAA PHAK
- SEI
- Safety Enhancement Initiative (ICAO) as defined in GASP
- EASA EPAS
- Selective availability (SA)
- A satellite technology permitting the Department of Defense (DOD) to create, in the interest of national security, a significant clock and ephemeris error in the satellites, resulting in a navigation error.
- FAA PHAK
- Semicircular canal
- An inner ear organ that detects angular acceleration of the body.
- FAA PHAK
- Semimonocoque
- A fuselage design that includes a substructure of bulkheads and/or formers, along with stringers, to support flight loads and stresses imposed on the fuselage.
- FAA PHAK
- SENS4ICE
- EU-funded project: SENSors and certifiable hybrid architectures for safer aviation in ICing Environment
- EASA EPAS
- Sensitive altimeter
- A form of multipointer pneumatic altimeter with an adjustable barometric scale that allows the reference pressure to be set to any desired level.
- FAA PHAK
- SERA IR
- standardised European rules of the air — implementing rule
- EASA EPAS
- Service ceiling
- The maximum density altitude where the best rate-of-climb airspeed will produce a 100-feet-per-minute climb at maximum weight while in a clean configuration with maximum continuous power.
- FAA PHAK
- Servo
- A motor or other form of actuator which receives a small signal from the control device and exerts a large force to accomplish the desired work.
- FAA PHAK
- Servo tab
- An auxiliary control mounted on a primary control surface, which automatically moves in the direction opposite the primary control to provide an aerodynamic assist in the movement of the control.
- FAA PHAK
- SES
- Single European Sky
- EASA EPAS
- SESAR
- Single European Sky ATM Research
- EASA EPAS
- SI/SIs
- safety issue/safety issues
- EASA EPAS
- SIA
- safety issue assessment
- EASA EPAS
- SIB
- Safety Information Bulletin
- EASA EPAS
- SID
- Standard Instrument Departure
- EASA EPAS
- SIDS
- See standard instrument departure procedures.
- FAA PHAK
- SIGMET
- The acronym for Significant Meteorological information. A weather advisory in abbreviated plain language concerning the occurrence or expected occurrence of potentially hazardous en route weather phenomena that may affect the safety of aircraft operations. SIGMET is warning information, hence it is of highest priority among other types of meteorological information provided to the aviation users.EASA definition
- FAA PHAK
- Signal-to-noise ratio
- An indication of signal strength received compared to background noise, which is a measure of the adequacy of the received signal.
- FAA PHAK
- Significant Point
- [ICAO Annex 11] A specified geographical location used in defining an ATS route or the flightpath of an aircraft and for other navigation and ATS purposes.EASA definition
- FAA IPH
- Significant weather prognostic
- Presents four panels showing forecast significant weather.
- FAA PHAK
- Simplex
- Transmission and reception on the same frequency.
- FAA PHAK
- Simplified directional facility (SDF)
- A NAVAID used for nonprecision instrument approaches. The final approach course is similar to that of an ILS localizer; however, the SDF course may be offset from the runway, generally not more than 3°, and the course may be wider than the localizer, resulting in a lower degree of accuracy.
- FAA PHAK
- Single-pilot resource management (SRM)
- The ability for a pilot to manage all resources effectively to ensure the outcome of the flight is successful.
- FAA PHAK
- SiPo
- Single-pilot operations
- EASA EPAS
- Situational awareness
- Pilot knowledge of where the aircraft is in regard to location, air traffic control, weather, regulations, aircraft status, and other factors that may affect flight.
- FAA PHAK
- SJU
- SESAR Joint Undertaking
- EASA EPAS
- Skidding turn
- An uncoordinated turn in which the rate of turn is too great for the angle of bank, pulling the aircraft to the outside of the turn.
- FAA PHAK
- Skills and procedures
- The procedural, psychomotor, and perceptual skills used to control a specific aircraft or its systems. They are the airmanship abilities that are gained through conventional training, are perfected, and become almost automatic through experience.
- FAA PHAK
- Skin friction drag
- Drag generated between air molecules and the solid surface of the aircraft.
- FAA PHAK
- SKPI
- safety key performance indicator
- EASA EPAS
- Slant range
- The horizontal distance from the aircraft antenna to the ground station, due to line-of-sight transmission of the DME signal.
- FAA PHAK
- Slaved compass
- A system whereby the heading gyro is “slaved to,” or continuously corrected to bring its direction readings into agreement with a remotely located magnetic direction sensing device (usually a flux valve or flux gate compass).
- FAA PHAK
- SLD
- super-cooled large droplets
- EASA EPAS
- Slipping turn
- An uncoordinated turn in which the aircraft is banked too much for the rate of turn, so the horizontal lift component is greater than the centrifugal force, pulling the aircraft toward the inside of the turn.
- FAA PHAK
- SM TeB
- Safety Management Technical Body
- EASA EPAS
- Small airplane
- An airplane of 12,500 pounds or less maximum certificated takeoff weight.
- FAA PHAK
- SMICG
- Safety Management International Collaboration Group
- EASA EPAS
- SMS
- safety management system
- EASA EPAS
- Somatogravic illusion
- The misperception of being in a nose-up or nose-down attitude, caused by a rapid acceleration or deceleration while in flight situations that lack visual reference.
- FAA PHAK
- SOP
- standard operating procedure
- EASA EPAS
- SORA
- specific operations risk assessment
- EASA EPAS
- SPAS
- State Plan for Aviation Safety
- EASA EPAS
- Spatial disorientation
- The state of confusion due to misleading information being sent to the brain from various sensory organs, resulting in a lack of awareness of the aircraft position in relation to a specific reference point.
- FAA PHAK
- SPD
- Single Programming Document
- EASA EPAS
- Special flight permit
- A flight permit issued to an aircraft that does not meet airworthiness requirements but is capable of safe flight. A special flight permit can be issued to move an aircraft for the purposes of maintenance or repair, buyer delivery, manufacturer flight tests, evacuation from danger, or customer demonstration. Also referred to as a ferry permit.
- FAA PHAK
- Special fuel consumption
- The amount of fuel in pounds per hour consumed or required by an engine per brake horsepower or per pound of thrust.
- FAA PHAK
- Special Instrument Approach Procedure
- A procedure approved by the FAA for individual operators, but not published in 14 CFR Part 97 for public use.
- FAA IPH
- Special use airspace
- Airspace in which flight activities are subject to restrictions that can create limitations on the mixed use of airspace. Consists of prohibited, restricted, warning, military operations, and alert areas.
- FAA PHAK
- Special Use Airspace Management System (SAMS)
- A joint FAA and military program designed to improve civilian access to special use airspace by providing information on whether the airspace is active or scheduled to be active. The information is available to authorized users via an Internet website.
- FAA IPH
- Speed
- The distance traveled in a given time.
- FAA PHAK
- SPI
- surveillance performance and interoperability
- EASA EPAS
- SPI
- safety performance indicator
- EASA EPAS
- Spin
- An aggravated stall that results in an airplane descending in a helical, or corkscrew path.
- FAA PHAK
- Spiral instability
- A condition that exists when the static directional stability of the airplane is very strong as compared to the effect of its dihedral in maintaining lateral equilibrium.
- FAA PHAK
- Spiraling slipstream
- The slipstream of a propeller-driven airplane rotates around the airplane. This slipstream strikes the left side of the vertical fin, causing the aircraft to yaw slightly. Rudder offset is sometimes used by aircraft designers to counteract this tendency.
- FAA PHAK
- SPN
- Safety Promotion Network
- EASA EPAS
- SPO
- specialised operations (aerial work)
- EASA EPAS
- Spoilers
- High-drag devices that can be raised into the air flowing over an airfoil, reducing lift and increasing drag. Spoilers are used for roll control on some aircraft. Deploying spoilers on both wings at the same time allows the aircraft to descend without gaining speed. Spoilers are also used to shorten the ground roll after landing.
- FAA PHAK
- SPT
- safety promotion task
- EASA EPAS
- SR/SRs
- safety recommendation/safety recomendations
- EASA EPAS
- SRIA
- Strategic Research and Innovation Agenda
- EASA EPAS
- SRM
- safety risk management
- EASA EPAS
- SSIP
- supplemental structural inspection programme
- EASA EPAS
- SSP
- state safety programme
- EASA EPAS
- SSR
- secondary surveillance radar
- EASA EPAS
- SST
- supersonic transport
- EASA EPAS
- SSV
- See standard service volume.
- FAA PHAK
- ST
- standard (rulemaking) procedure
- EASA EPAS
- St. Elmo’s Fire
- A corona discharge which lights up the aircraft surface areas where maximum static discharge occurs.
- FAA PHAK
- Stabilator
- A single-piece horizontal tail surface on an airplane that pivots around a central hinge point. A stabilator serves the purposes of both the horizontal stabilizer and the elevators.
- FAA PHAK
- Stability
- The inherent quality of an airplane to correct for conditions that may disturb its equilibrium, and to return or to continue on the original flight path. It is primarily an airplane design characteristic.
- FAA PHAK
- Stagnant hypoxia
- A type of hypoxia that results when the oxygen-rich blood in the lungs is not moving to the tissues that need it.
- FAA PHAK
- Stall
- A rapid decrease in lift caused by the separation of airflow from the wing’s surface, brought on by exceeding the critical angle of attack. A stall can occur at any pitch attitude or airspeed.
- FAA PHAK
- Standard atmosphere
- At sea level, the standard atmosphere consists of a barometric pressure of 29.92 inches of mercury ("Hg) or 1013.2 millibars, and a temperature of 15 °C (59 °F). Pressure and temperature normally decrease as altitude increases. The standard lapse rate in the lower atmosphere for each 1,000 feet of altitude is approximately 1 "Hg and 2 °C (3.5 °F). For example, the standard pressure and temperature at 3,000 feet mean sea level (MSL) are 26.92 "Hg (29.92 "Hg – 3 "Hg) and 9 °C (15 °C – 6 °C).
- FAA PHAK
- Standard empty weight (GAMA)
- This weight consists of the airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the airplane including fixed ballast, hydraulic fluid, unusable fuel, and full engine oil.
- FAA PHAK
- Standard holding pattern
- A holding pattern in which all turns are made to the right.
- FAA PHAK
- Standard Instrument Departure (SID)
- An ATC requested and developed departure route designed to increase capacity of terminal airspace, effectively control the flow of traffic with minimal communication, and reduce environmental impact through noise abatement procedures.
- FAA IPH
- Standard instrument departure procedures (SIDS)
- Published procedures to expedite clearance delivery and to facilitate transition between takeoff and en route operations.
- FAA PHAK
- Standard rate turn
- A turn in which an aircraft changes its direction at a rate of 3° per second (360° in 2 minutes) for low- or medium-speed aircraft. For high-speed aircraft, the standard rate turn is 1½° per second (360° in 4 minutes).
- FAA PHAK
- Standard Service Volume
- Most air navigation radio aids that provide positive course guidance have a designated standard service volume (SSV). The SSV defines the reception limits of unrestricted NAVAIDS that are usable for random/unpublished route navigation. Standard service volume limitations do not apply to published IFR routes or procedures. See the AIM (Chapter 1) for the SSV for specific NAVAID types.
- FAA IPH
- Standard service volume (SSV)
- Defines the limits of the volume of airspace which the VOR serves.
- FAA PHAK
- Standard Terminal Arrival (STAR)
- Provides a common method for departing the en route structure and navigating to your destination. A STAR is a preplanned instrument flight rule ATC arrival procedure published for pilot use in graphic and textual form to simplify clearance delivery procedures. STARs provide you with a transition from the en route structure to an outer fix or an instrument approach fix or arrival waypoint in the terminal area. STARs usually terminate with an instrument or visual approach procedure, but may also terminate with a heading or course to fly for radar vectors.
- FAA IPH
- Standard Terminal Arrival (STAR) Charts
- Designed to expedite air traffic control arrival procedures and to facilitate transition between en route and instrument approach operations. Each STAR procedure is presented as a separate chart and may serve a single airport or more than one airport in a given geographical location
- FAA IPH
- Standard terminal arrival route (STAR)
- A preplanned IFR ATC arrival procedure published for pilot use in graphic and/or textual form.
- FAA PHAK
- Standard weights
- Weights established for numerous items involved in weight and balance computations. These weights should not be used if actual weights are available.
- FAA PHAK
- Standardized Taxi Routes
- Coded taxi routes that follow typical taxiway traffic patterns to move aircraft between gates and runways. ATC issues clearances using these coded routes to reduce radio communication and eliminate taxi instruction misinterpretation.
- FAA IPH
- STAR
- Standard Terminal Arrival Route (USA), Standard Instrument Arrival (ICAO)
- EASA EPAS
- STAR Transition
- A published segment used to connect one or more en route airways, jet routes, or RNAV routes to the basic STAR procedure. It is one of several routes that bring traffic from different directions into one STAR. STARs are published for airports with procedures authorized by the FAA, and these STARs are included at the front of each Terminal Procedures Publication regional booklet.
- FAA IPH
- Start End of Runway (SER)
- The beginning of the takeoff runway available.
- FAA IPH
- Static longitudinal stability
- The aerodynamic pitching moments required to return the aircraft to the equilibrium angle of attack.
- FAA PHAK
- Static pressure
- Pressure of air that is still or not moving, measured perpendicular to the surface of the aircraft.
- FAA PHAK
- Static stability
- The initial tendency an aircraft displays when disturbed from a state of equilibrium.
- FAA PHAK
- Station
- A location in the airplane that is identified by a number designating its distance in inches from the datum. The datum is, therefore, identified as station zero. An item located at station +50 would have an arm of 50 inches.
- FAA PHAK
- Station Declination
- The angular difference between true north and the zero radial of a VOR at the time the VOR was last site-checked.
- FAA IPH
- Stationary front
- A front that is moving at a speed of less than 5 knots.
- FAA PHAK
- STC
- supplemental type certificate
- EASA EPAS
- STD
- synthetic training device
- EASA EPAS
- Steep turns
- In instrument flight, any turn greater than standard rate; in visual flight, anything greater than a 45° bank.
- FAA PHAK
- Stepdown fix
- The point after which additional descent is permitted within a segment of an IAP.
- FAA PHAK
- Strapdown system
- An INS in which the accelerometers and gyros are permanently “strapped down” or aligned with the three axes of the aircraft.
- FAA PHAK
- Stratoshere
- A layer of the atmosphere above the tropopause extending to a height of approximately 160,000 feet.
- FAA PHAK
- Stress
- The body’s response to demands placed upon it.
- FAA PHAK
- Stress management
- The personal analysis of the kinds of stress experienced while flying, the application of appropriate stress assessment tools, and other coping mechanisms.
- FAA PHAK
- Structural icing
- The accumulation of ice on the exterior of the aircraft.
- FAA PHAK
- Sublimation
- Process by which a solid is changed to a gas without going through the liquid state.
- FAA PHAK
- Suction relief valve
- A relief valve in an instrument vacuum system required to maintain the correct low pressure inside the instrument case for the proper operation of the gyros.
- FAA PHAK
- Supercharger
- An engine- or exhaust-driven air compressor used to provide additional pressure to the induction air so the engine can produce additional power.
- FAA PHAK
- Supercooled water droplets
- Water droplets that have been cooled below the freezing point, but are still in a liquid state.
- FAA PHAK
- Surface analysis chart
- A report that depicts an analysis of the current surface weather. Shows the areas of high and low pressure, fronts, temperatures, dewpoints, wind directions and speeds, local weather, and visual obstructions.
- FAA PHAK
- Surface Incident
- An event during which authorized or unauthorized/unapproved movement occurs in the movement area or an occurrence in the movement area associated with the operation of an aircraft that affects or could affect the safety of flight.
- FAA IPH
- Surface Movement Guidance Control System (SMGCS)
- Facilitates the safe movement of aircraft and vehicles at airports where scheduled air carriers are conducting authorized operations. The SMGCS low visibility taxi plan includes the improvement of taxiway and runway signs, markings, and lighting, as well as the creation of SMGCS low visibility taxi route charts.
- FAA IPH
- SVGS
- synthetic vision guidance system
- EASA EPAS
- SVS
- synthetic vision system
- EASA EPAS
- SWIM
- system wide information management
- EASA EPAS
- Synchro
- A device used to transmit indications of angular movement or position from one location to another.
- FAA PHAK
- Synthetic vision
- A realistic display depiction of the aircraft in relation to terrain and flight path.
- FAA PHAK
- Synthetic Vision Guidance System (SVGS)
- SVGS is a combination of flight guidance display technology and high precision position assurance monitors. The SVGS flight instrument display provides a continuous, geo-spatially correct depiction of the external scene topography, including obstacles, augmented by the display of the runway of intended landing. The SVGS display may be implemented on a head down Primary Flight Display, and/ or a Head-Up Display (HUD). SVGS includes additional symbology elements, integrity and performance monitors and annunciations that support and enable low visibility operations. Additional flight instrument symbology and monitors to assure accurate rendering of the external scene are included.
- FAA IPH
- Synthetic Vision System (SVS)
- An electronic means to display a synthetic vision image of the external scene topography to the flight crew.
- FAA IPH
- SYS inspections
- Standardisation Domain ‘Systemic Enablers for Safety Management’. Standardisation inspections in this domain focus on the implementation of Regulation (EU) No 376/2014 on occurrence reporting and the verification of the CA management system.
- EASA EPAS
- System Wide Information Management (SWIM)
- An advanced technology program designed to facilitate greater sharing of Air Traffic Management (ATM) system information, such as airport operational status, weather information, flight data, status of special use airspace, and National Airspace System (NAS) restrictions. SWIM supports current and future NAS programs by providing flexible and secure information management architecture for sharing NAS information.
- FAA IPH
T
- T-tail
- An aircraft with the horizontal stabilizer mounted on the top of the vertical stabilizer, forming a T.
- FAA PHAK
- TAA
- See terminal arrival area.
- FAA PHAK
- TACAN
- See tactical air navigation.
- FAA PHAK
- TACDWG
- Transport Aircraft Crashworthiness and Ditching Working Group
- EASA EPAS
- TAG
- Thematic Advisory Group
- EASA EPAS
- Takeoff decision speed (V1)
- Per 14 CFR section 23.51: “the calibrated airspeed on the ground at which, as a result of engine failure or other reasons, the pilot assumed to have made a decision to continue or discontinue the takeoff.”
- FAA PHAK
- Takeoff distance
- The distance required to complete an all-engines operative takeoff to the 35-foot height. It must be at least 15 percent less than the distance required for a one-engine inoperative engine takeoff. This distance is not normally a limiting factor as it is usually less than the one-engine inoperative takeoff distance.
- FAA PHAK
- Takeoff Distance Available (TODA)
- ICAO defines TODA as the length of the takeoff runway available plus the length of the clearway, if provided.
- FAA IPH
- Takeoff Runway Available (TORA)
- ICAO defines TORA as the length of runway declared available and suitable for the ground run of an aeroplane takeoff.
- FAA IPH
- Takeoff safety speed (V2)
- Per 14 CFR part 1: “A referenced airspeed obtained after lift-off at which the required one-engine-inoperative climb performance can be achieved.”
- FAA PHAK
- Tangent Point (TP)
- The point on the VOR/DME RNAV route centerline from which a line perpendicular to the route centerline would pass through the reference facility.
- FAA IPH
- TAWS
- See terrain awareness and warning system.
- FAA PHAK
- Taxiway lights
- Omnidirectional lights that outline the edges of the taxiway and are blue in color.
- FAA PHAK
- Taxiway turnoff lights
- Lights that are flush with the runway which emit a steady green color.
- FAA PHAK
- TBD
- to be determined
- EASA EPAS
- TBO
- time between overhaul
- EASA EPAS
- TC
- type certificate
- EASA EPAS
- TCAS
- traffic collision avoidance system
- EASA EPAS
- TCCA
- Transport Canada Civil Aviation
- EASA EPAS
- TCH
- See threshold crossing height.
- FAA PHAK
- TCO
- third-country operator
- EASA EPAS
- TDZE
- See touchdown zone elevation.
- FAA PHAK
- TeB
- Member State technical body
- EASA EPAS
- TeC
- Stakeholder technical body
- EASA EPAS
- Technique
- The manner in which procedures are executed.
- FAA PHAK
- Telephone information briefing service (TIBS)
- An FSS service providing continuously updated automated telephone recordings of area and/or route weather, airspace procedures, and special aviation-oriented announcements.
- FAA PHAK
- TEM
- threat and error management
- EASA EPAS
- Temporary flight restriction (TFR)
- Restriction to flight imposed in order to:
- FAA PHAK
- Tension
- Maintaining an excessively strong grip on the control column, usually resulting in an overcontrolled situation.
- FAA PHAK
- Terminal aerodrome forecast (TAF)
- A report established for the 5 statute mile radius around an airport. Utilizes the same descriptors and abbreviations as the METAR report.
- FAA PHAK
- Terminal Arrival Area (TAA)
- TAAs are the method by which aircraft are transitioned from the RNAV en route structure to the terminal area with minimal ATC interaction. The TAA consists of a designated volume of airspace designed to allow aircraft to enter a protected area, offering guaranteed obstacle clearance where the initial approach course is intercepted based on the location of the aircraft relative to the airport.
- FAA IPH
- Terminal instrument approach procedure (TERP)
- Prescribes standardized methods for use in designing instrument flight procedures.
- FAA PHAK
- Terminal radar service areas (TRSA)
- Areas where participating pilots can receive additional radar services. The purpose of the service is to provide separation between all IFR operations and participating VFR aircraft.
- FAA PHAK
- TERP
- See terminal instrument approach procedure.
- FAA PHAK
- Terrain awareness and warning system (TAWS)
- A timed-based system that provides information concerning potential hazards with fixed objects by using GPS positioning and a database of terrain and obstructions to provide true predictability of the upcoming terrain and obstacles.
- FAA PHAK
- TFR
- See temporary flight restriction.
- FAA PHAK
- Thermosphere
- The last layer of the atmosphere that begins above the mesosphere and gradually fades away into space.
- FAA PHAK
- Threshold crossing height (TCH)
- The theoretical height above the runway threshold at which the aircraft’s glideslope antenna would be if the aircraft maintained the trajectory established by the mean ILS glideslope or MLS glidepath. 1. Protect persons and property in the air or on the surface from an existing or imminent flight associated hazard; 2. Provide a safe environment for the operation of disaster relief aircraft;
- FAA PHAK
- Thrust
- The force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time or rate. The term “thrust required” is generally associated with jet engines. A forward force which propels the airplane through the air. 3. Prevent an unsafe congestion of sightseeing aircraft above an incident; 4. Protect the President, Vice President, or other public figures; and, 5. Provide a safe environment for space agency operations. Pilots are expected to check appropriate NOTAMs during flight planning when conducting flight in an area where a temporary flight restriction is in effect.
- FAA PHAK
- Thrust (aerodynamic force)
- The forward aerodynamic force produced by a propeller, fan, or turbojet engine as it forces a mass of air to the rear, behind the aircraft.
- FAA PHAK
- Thrust line
- An imaginary line passing through the center of the propeller hub, perpendicular to the plane of the propeller rotation.
- FAA PHAK
- Time and speed table
- A table depicted on an instrument approach procedure chart that identifies the distance from the FAF to the MAP, and provides the time required to transit that distance based on various groundspeeds.
- FAA PHAK
- Timed turn
- A turn in which the clock and the turn coordinator are used to change heading a definite number of degrees in a given time.
- FAA PHAK
- TIS
- See traffic information service.
- FAA PHAK
- Title 14 of the Code of Federal Regulations (14 CFR)
- Includes the federal aviation regulations governing the operation of aircraft, airways, and airmen.
- FAA PHAK
- TMA
- terminal maneuvering area
- EASA EPAS
- TMG
- touring motor glider
- EASA EPAS
- TO
- training organisation
- EASA EPAS
- Top Of Climb (TOC)
- An identifiable waypoint representing the point at which cruise altitude is first reached. TOC is calculated based on your current aircraft altitude, climb speed, and cruise altitude. There can only be one TOC waypoint at a time.
- FAA IPH
- Top Of Descent (TOD)
- Generally utilized in flight management systems, top of descent is an identifiable waypoint representing the point at which descent is first initiated from cruise altitude. TOD is generally calculated using the destination elevation (if available) and the descent speed schedule.
- FAA IPH
- ToR
- terms of reference
- EASA EPAS
- Torque
- (1) A resistance to turning or twisting. (2) Forces that produce a twisting or rotating motion. (3) In an airplane, the tendency of the aircraft to turn (roll) in the opposite direction of rotation of the engine and propeller. (4) In helicopters with a single, main rotor system, the tendency of the helicopter to turn in the opposite direction of the main rotor rotation.
- FAA PHAK
- Torquemeter
- An instrument used with some of the larger reciprocating engines and turboprop or turboshaft engines to measure the reaction between the propeller reduction gears and the engine case.
- FAA PHAK
- Total drag
- The sum of the parasite drag and induced drag.
- FAA PHAK
- Touchdown and Lift-Off Area (TLOF)
- The TLOF is a load bearing, usually paved, area at a heliport where the helicopter is permitted to land. The TLOF can be located at ground or rooftop level, or on an elevated structure. The TLOF is normally centered in the FATO.EASA definition
- FAA IPH
- Touchdown RVR
- The RVR visibility readout values obtained from sensors serving the runway touchdown zone.
- FAA IPH
- Touchdown Zone Elevation (TDZE)
- The highest elevation in the first 3,000 feet of the landing surface.
- FAA IPH
- Touchdown zone lights
- Two rows of transverse light bars disposed symmetrically about the runway centerline in the runway touchdown zone.
- FAA PHAK
- Tower En Route Control (TEC)
- The control of IFR en route traffic within delegated airspace between two or more adjacent approach control facilities. This service is designed to expedite air traffic and reduces air traffic control and pilot communication requirements.
- FAA IPH
- TPP
- See United States Terminal Procedures Publication.
- FAA PHAK
- TRACAB
- A new type of air traffic facility that consists of a radar approach control facility located in the tower cab of the primary airport, as opposed to a separate room.
- FAA IPH
- Tracking
- Flying a heading that will maintain the desired track to or from the station regardless of crosswind conditions.
- FAA PHAK
- Traffic Alert Collision Avoidance System (TCAS)
- An airborne system developed by the FAA that operates independently from the ground-based Air Traffic Control system. Designed to increase flight deck awareness of proximate aircraft and to serve as a “last line of defense” for the prevention of midair collisions.
- FAA PHAK
- Traffic information service (TIS)
- A ground-based service providing information to the flight deck via data link using the S-mode transponder and altitude encoder to improve the safety and efficiency of “see and avoid” flight through an automatic display that informs the pilot of nearby traffic.
- FAA PHAK
- Traffic Information Service-Broadcast (TIS-B)
- An air traffic surveillance system that combines all available traffic information on a single display.
- FAA IPH
- Traffic Management Advisor (TMA)
- A software suite that helps air traffic controllers to sequence arriving air traffic.
- FAA IPH
- Trailing edge
- The portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow.
- FAA PHAK
- Transcribed Weather Broadcast (TWEB)
- An FSS service, available in Alaska only, providing continuously updated automated broadcast of meteorological and aeronautical data over selected L/MF and VOR NAVAIDs.
- FAA PHAK
- Transition Altitude (QNH)
- The altitude in the vicinity of an airport at or below which the vertical position of an aircraft is controlled by reference to altitudes (MSL).EASA definition
- FAA IPH
- Transition Height (QFE)
- Transition height is the height in the vicinity of an airport at or below which the vertical position of an aircraft is expressed in height above the airport reference datum.
- FAA IPH
- Transition Layer
- Transition layer is the airspace between the transition altitude and the transition level. Aircraft descending through the transition layer will set altimeters to local station pressure, while departing aircraft climbing through the transition layer will be using standard altimeter setting (QNE) of 29.92 inches of Mercury, 1013.2 millibars, or 1013.2 hectopascals.
- FAA IPH
- Transition Level (QNE)
- The lowest flight level available for use above the transition altitude.EASA definition
- FAA IPH
- Transponder
- The airborne portion of the ATC radar beacon system.
- FAA PHAK
- Transponder code
- One of 4,096 four-digit discrete codes ATC assigns to distinguish between aircraft.
- FAA PHAK
- Trend
- Immediate indication of the direction of aircraft movement, as shown on instruments.
- FAA PHAK
- Tricycle gear
- Landing gear employing a third wheel located on the nose of the aircraft.
- FAA PHAK
- Trim
- To adjust the aerodynamic forces on the control surfaces so that the aircraft maintains the set attitude without any control input.
- FAA PHAK
- Trim tab
- A small auxiliary hinged portion of a movable control surface that can be adjusted during flight to a position resulting in a balance of control forces.
- FAA PHAK
- Tropopause
- The boundary layer between the troposphere and the stratosphere which acts as a lid to confine most of the water vapor, and the associated weather, to the troposphere.
- FAA PHAK
- Troposphere
- The layer of the atmosphere extending from the surface to a height of 20,000 to 60,000 feet, depending on latitude.
- FAA PHAK
- True airspeed
- Actual airspeed, determined by applying a correction for pressure altitude and temperature to the CAS.
- FAA PHAK
- True altitude
- The vertical distance of the airplane above sea level—the actual altitude. It is often expressed as feet above mean sea level (MSL). Airport, terrain, and obstacle elevations on aeronautical charts are true altitudes.
- FAA PHAK
- Truss
- A fuselage design made up of supporting structural members that resist deformation by applied loads. The truss-type fuselage is constructed of steel or aluminum tubing. Strength and rigidity is achieved by welding the tubing together into a series of triangular shapes, called trusses.
- FAA PHAK
- TSO
- technical standard order
- EASA EPAS
- Turbine discharge pressure
- The total pressure at the discharge of the low-pressure turbine in a dual-turbine axial-flow engine.
- FAA PHAK
- Turbine engine
- An aircraft engine which consists of an air compressor, a combustion section, and a turbine. Thrust is produced by increasing the velocity of the air flowing through the engine.
- FAA PHAK
- Turbocharger
- An air compressor driven by exhaust gases, which increases the pressure of the air going into the engine through the carburetor or fuel injection system.
- FAA PHAK
- Turbofan engine
- A fanlike turbojet engine designed to create additional thrust by diverting a secondary airflow around the combustion chamber.
- FAA PHAK
- Turbojet engine
- A turbine engine which produces its thrust entirely by accelerating the air through the engine.
- FAA PHAK
- Turboprop engine
- A turbine engine which drives a propeller through a reduction gearing arrangement. Most of the energy in the exhaust gases is converted into torque, rather than using its acceleration to drive the aircraft.
- FAA PHAK
- Turboshaft engine
- A gas turbine engine that delivers power through a shaft to operate something other than a propeller.
- FAA PHAK
- Turn Anticipation
- The capability of RNAV systems to determine the point along a course, prior to a turn WP, where a turn should be initiated to provide a smooth path to intercept the succeeding course and to enunciate the information to the pilot.
- FAA IPH
- Turn coordinator
- A rate gyro that senses both roll and yaw due to the gimbal being canted. Has largely replaced the turn-and-slip indicator in modern aircraft.
- FAA PHAK
- Turn WP (Turning Point)
- A WP that identifies a change from one course to another.
- FAA IPH
- Turn-and-slip indicator
- A flight instrument consisting of a rate gyro to indicate the rate of yaw and a curved glass inclinometer to indicate the relationship between gravity and centrifugal force. The turn-and-slip indicator indicates the relationship between angle of bank and rate of yaw. Also called a turn-and-bank indicator.
- FAA PHAK
- TWEB
- See Transcribed Weather Broadcast.
- FAA PHAK
U
- UA
- unmanned aircraft
- EASA EPAS
- UAS
- unmanned aircraft system
- EASA EPAS
- UHF
- See ultra-high frequency.
- FAA PHAK
- UK
- United Kingdom
- EASA EPAS
- ULD
- unit load device
- EASA EPAS
- Ulitimate load factor
- In stress analysis, the load that causes physical breakdown in an aircraft or aircraft component during a strength test, or the load that according to computations, should cause such a breakdown.
- FAA PHAK
- Ultra-high frequency (UHF)
- The range of electromagnetic frequencies between 300 MHz and 3,000 MHz.
- FAA PHAK
- Uncaging
- Unlocking the gimbals of a gyroscopic instrument, making it susceptible to damage by abrupt flight maneuvers or rough handling.
- FAA PHAK
- Uncontrolled airspace
- Class G airspace that has not been designated as Class A, B, C, D, or E. It is airspace in which air traffic control has no authority or responsibility to control air traffic; however, pilots should remember there are VFR minimums which apply to this airspace.
- FAA PHAK
- Underpower
- Using less power than required for the purpose of achieving a faster rate of airspeed change.
- FAA PHAK
- United States Terminal Procedures Publication (TPP)
- Booklets published in regional format by FAA Aeronautical Navigation Products (AeroNav Products) that include DPs, STARs, IAPs, and other information pertinent to IFR flight.
- FAA PHAK
- Universal Communications (UNICOM)
- An air-ground communication facility operated by a private agency to provide advisory service at uncontrolled aerodromes and airports.
- FAA IPH
- Unusual attitude
- An unintentional, unanticipated, or extreme aircraft attitude.
- FAA PHAK
- UPRT
- upset prevention and recovery training
- EASA EPAS
- Useful load
- The weight of the pilot, copilot, passengers, baggage, usable fuel, and drainable oil. It is the basic empty weight subtracted from the maximum allowable gross weight. This term applies to general aviation aircraft only.
- FAA PHAK
- User Request Evaluation Tool (URET)
- The URET helps provide enhanced, automated flight data management. URET is an automated tool provided at each radar position in selected en route facilities. It uses flight and radar data to determine present and future trajectories for all active and proposed aircraft flights. A graphic plan display depicts aircraft, traffic, and notification of predicted conflicts. Graphic routes for current plans and trial plans are displayed upon controller request. URET can generate a predicted conflict of two aircraft, or between aircraft and airspace.
- FAA IPH
- User-Defined Waypoint
- User-defined waypoints typically are created by pilots for use in their own random RNAV direct navigation. They are newly established, unpublished airspace fixes that are designated geographic locations/ positions that help provide positive course guidance for navigation and a means of checking progress on a flight. They may or may not be actually plotted by the pilot on en route charts, but would normally be communicated to ATC in terms of bearing and distance or latitude/longitude. An example of user-defined waypoints typically includes those derived from database-driven area navigation (RNAV) systems whereby latitude/longitude coordinate-based waypoints are generated by various means including keyboard input, and even electronic map mode functions used to establish waypoints with a cursor on the display. Another example is an offset phantom waypoint, which is a point in space formed by a bearing and distance from NAVAIDs, such as VORs, VORTACs, and TACANs, using a variety of navigation systems.
- FAA IPH
- User-defined waypoints
- Waypoint location and other data which may be input by the user, this is the only GPS database information that may be altered (edited) by the user.
- FAA PHAK
- USOAP
- Universal Safety Oversight Audit Programme (ICAO)
- EASA EPAS
- UTM
- unmanned traffic management
- EASA EPAS
V
- V-G diagram
- A chart that relates velocity to load factor. It is valid only for a specific weight, configuration and altitude and shows the maximum amount of positive or negative lift the airplane is capable of generating at a given speed. Also shows the safe load factor limits and the load factor that the aircraft can sustain at various speeds.
- FAA PHAK
- V-tail
- A design which utilizes two slanted tail surfaces to perform the same functions as the surfaces of a conventional elevator and rudder configuration. The fixed surfaces act as both horizontal and vertical stabilizers.
- FAA PHAK
- V2
- See takeoff safety speed.
- FAA PHAK
- VA
- See maneuvering speed.
- FAA PHAK
- Vapor lock
- A problem that mostly affects gasoline-fuelled internal combustion engines. It occurs when the liquid fuel changes state from liquid to gas while still in the fuel delivery system. This disrupts the operation of the fuel pump, causing loss of feed pressure to the carburetor or fuel injection system, resulting in transient loss of power or complete stalling. Restarting the engine from this state may be difficult. The fuel can vaporize due to being heated by the engine, by the local climate or due to a lower boiling point at high altitude.
- FAA PHAK
- Variation
- Compass error caused by the difference in the physical locations of the magnetic north pole and the geographic north pole.
- FAA PHAK
- VASI
- See visual approach slope indicator.
- FAA PHAK
- VDP
- See visual descent point.
- FAA PHAK
- Vector
- A force vector is a graphic representation of a force and shows both the magnitude and direction of the force.
- FAA PHAK
- Vectoring
- Navigational guidance by assigning headings.
- FAA PHAK
- VEF
- Calibrated airspeed at which the critical engine of a multi-engine aircraft is assumed to fail.EASA definition
- FAA PHAK
- Velocity
- The speed or rate of movement in a certain direction.
- FAA PHAK
- Venturi tube
- A specially shaped tube attached to the outside of an aircraft to produce suction to allow proper operation of gyro instruments.
- FAA PHAK
- Vertical axis
- An imaginary line passing vertically through the center of gravity of an aircraft. The vertical axis is called the z-axis or the yaw axis.
- FAA PHAK
- Vertical card compass
- A magnetic compass that consists of an azimuth on a vertical card, resembling a heading indicator with a fixed miniature airplane to accurately present the heading of the aircraft. The design uses eddy current damping to minimize lead and lag during turns.
- FAA PHAK
- Vertical speed indicator (VSI)
- A rate-of-pressure change instrument that gives an indication of any deviation from a constant pressure level.
- FAA PHAK
- Vertical stability
- Stability about an aircraft’s vertical axis. Also called yawing or directional stability.
- FAA PHAK
- Very-high frequency (VHF)
- A band of radio frequencies falling between 30 and 300 MHz.
- FAA PHAK
- Very-high frequency omnidirectional range (VOR)
- Electronic navigation equipment in which the flight deck instrument identifies the radial or line from the VOR station, measured in degrees clockwise from magnetic north, along which the aircraft is located.
- FAA PHAK
- Vestibule
- The central cavity of the bony labyrinth of the ear, or the parts of the membranous labyrinth that it contains.
- FAA PHAK
- VFE
- The maximum speed with the flaps extended. The upper limit of the white arc.
- FAA PHAK
- VFR on top
- ATC authorization for an IFR aircraft to operate in VFR conditions at any appropriate VFR altitude.
- FAA PHAK
- VFR over the top
- A VFR operation in which an aircraft operates in VFR conditions on top of an undercast.
- FAA PHAK
- VFR terminal area chart
- At a scale of 1:250,000, a chart that depicts Class B airspace, which provides for the control or segregation of all the aircraft within the Class B airspace. The chart depicts topographic information and aeronautical information including visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions, and related data.
- FAA PHAK
- VHF
- very high frequency
- EASA EPAS
- VHM
- vibration health monitoring
- EASA EPAS
- Victor airways
- Airways based on a centerline that extends from one VOR or VORTAC navigation aid or intersection, to another navigation aid (or through several navigation aids or intersections); used to establish a known route for en route procedures between terminal areas.
- FAA PHAK
- Visual Approach
- A visual approach is an ATC authorization for an aircraft on an IFR flight plan to proceed visually to the airport of intended landing; it is not an IAP. Also, there is no missed approach segment. When it is operationally beneficial, ATC may authorize pilots to conduct a visual approach to the airport in lieu of the published IAP. A visual approach can be initiated by a pilot or the controller.
- FAA IPH
- Visual approach slope indicator (VASI)
- A visual aid of lights arranged to provide descent guidance information during the approach to the runway. A pilot on the correct glideslope will see red lights over white lights.
- FAA PHAK
- Visual Climb Over the Airport (VCOA)
- An option to allow an aircraft to climb over the airport with visual reference to obstacles to attain a suitable altitude from which to proceed with an IFR departure.
- FAA IPH
- Visual descent point (VDP)
- A defined point on the final approach course of a nonprecision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the runway environment is clearly visible to the pilot.
- FAA PHAK
- Visual flight rules (VFR)
- Flight rules adopted by the FAA governing aircraft flight using visual references. VFR operations specify the amount of ceiling and the visibility the pilot must have in order to operate according to these rules. When the weather conditions are such that the pilot cannot operate according to VFR, he or she must use instrument flight rules (IFR).
- FAA PHAK
- Visual meteorological conditions (VMC)
- Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling meeting or exceeding the minimums specified for VFR.EASA definition
- FAA PHAK
- VLD
- very large-scale demonstration
- EASA EPAS
- VLE
- Landing gear extended speed. The maximum speed at which an airplane can be safely flown with the landing gear extended.
- FAA PHAK
- VLO
- Landing gear operating speed. The maximum speed for extending or retracting the landing gear if using an airplane equipped with retractable landing gear.
- FAA PHAK
- VLOS
- visual line of sight
- EASA EPAS
- VMC
- Minimum control airspeed. This is the minimum flight speed at which a light, twin-engine airplane can be satisfactorily controlled when an engine suddenly becomes inoperative and the remaining engine is at takeoff power.EASA definition
- FAA PHAK
- VNE
- The never-exceed speed. Operating above this speed is prohibited since it may result in damage or structural failure. The red line on the airspeed indicator.
- FAA PHAK
- VNO
- The maximum structural cruising speed. Do not exceed this speed except in smooth air. The upper limit of the green arc.
- FAA PHAK
- VOR
- VHF omnidirectional range
- EASA EPAS
- VOR test facility (VOT)
- A ground facility which emits a test signal to check VOR receiver accuracy. Some VOTs are available to the user while airborne, while others are limited to ground use only.
- FAA PHAK
- VORTAC
- A facility consisting of two components, VOR and TACAN, which provides three individual services: VOR azimuth, TACAN azimuth, and TACAN distance (DME) at one site.
- FAA PHAK
- VOT
- See VOR test facility.
- FAA PHAK
- VR
- virtual reality
- EASA EPAS
- VS0
- The stalling speed or the minimum steady flight speed in the landing configuration. In small airplanes, this is the power-off stall speed at the maximum landing weight in the landing configuration (gear and flaps down). The lower limit of the white arc.
- FAA PHAK
- VS1
- The stalling speed or the minimum steady flight speed obtained in a specified configuration. For most airplanes, this is the power-off stall speed at the maximum takeoff weight in the clean configuration (gear up, if retractable, and flaps up). The lower limit of the green arc.
- FAA PHAK
- VSI
- See vertical speed indicator.
- FAA PHAK
- VTOL
- vertical take-off and landing aircraft
- EASA EPAS
- VX
- Best angle-of-climb speed. The airspeed at which an airplane gains the greatest amount of altitude in a given distance. It is used during a short-field takeoff to clear an obstacle.
- FAA PHAK
- VY
- Best rate-of-climb speed. This airspeed provides the most altitude gain in a given period of time.
- FAA PHAK
- VYSE
- Best rate-of-climb speed with one engine inoperative. This airspeed provides the most altitude gain in a given period of time in a light, twin-engine airplane following an engine failure.
- FAA PHAK
W
- WAAS
- See wide area augmentation system.
- FAA PHAK
- Wake turbulence
- Wingtip vortices that are created when an airplane generates lift. When an airplane generates lift, air spills over the wingtips from the high pressure areas below the wings to the low pressure areas above them. This flow causes rapidly rotating whirlpools of air called wingtip vortices or wake turbulence.
- FAA PHAK
- Warm front
- The boundary area formed when a warm air mass contacts and flows over a colder air mass. Warm fronts cause low ceilings and rain.
- FAA PHAK
- Warning area
- An area containing hazards to any aircraft not participating in the activities being conducted in the area. Warning areas may contain intensive military training, gunnery exercises, or special weapons testing.
- FAA PHAK
- WARP
- See weather and radar processing.
- FAA PHAK
- Waste gate
- A controllable valve in the tailpipe of an aircraft reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of exhaust gases forced through the turbocharger turbine.
- FAA PHAK
- Waypoint
- A designated geographical location used for route definition or progress-reporting purposes and is defined in terms of latitude/longitude coordinates.
- FAA PHAK
- Waypoint (WP)
- A predetermined geographical position used for route/instrument approach definition, progress reports, published VFR routes, visual reporting points or points for transitioning and/or circumnavigating controlled and/or special use airspace, that is defined relative to a VORTAC station or in terms of latitude/longitude coordinates.
- FAA IPH
- Waypoints
- Area navigation waypoints are specified geographical locations, or fixes, used to define an area navigation route or the flightpath of an aircraft employing area navigation. Waypoints may be any of the following types: predefined, published, floating, user-defined, fly-by, or fly-over.
- FAA IPH
- WCA
- See wind correction angle.
- FAA PHAK
- Weather and radar processor (WARP)
- A device that provides real-time, accurate, predictive, and strategic weather information presented in an integrated manner in the National Airspace System (NAS).
- FAA PHAK
- Weather depiction chart
- Details surface conditions as derived from METAR and other surface observations.
- FAA PHAK
- Weight
- The force exerted by an aircraft from the pull of gravity.
- FAA PHAK
- WFD
- widespread fatigue damage
- EASA EPAS
- WG
- working group
- EASA EPAS
- WIDDCWG
- Water Impact, Ditching Design and Crashworthiness Working Group (JAA)
- EASA EPAS
- Wide Area Augmentation System (WAAS)
- A method of navigation based on GPS. Ground correction stations transmit position corrections that enhance system accuracy and add vertical navigation (VNAV) features.
- FAA IPH
- Wind correction angle (WCA)
- The angle between the desired track and the heading of the aircraft necessary to keep the aircraft tracking over the desired track.
- FAA PHAK
- Wind direction indicators
- Indicators that include a wind sock, wind tee, or tetrahedron. Visual reference will determine wind direction and runway in use.
- FAA PHAK
- Wind shear
- A sudden, drastic shift in windspeed, direction, or both that may occur in the horizontal or vertical plane.
- FAA PHAK
- Winds and temperature aloft forecast (FB)
- A twice daily forecast that provides wind and temperature forecasts for specific locations in the contiguous United States.
- FAA PHAK
- Wing area
- The total surface of the wing (in square feet), which includes control surfaces and may include wing area covered by the fuselage (main body of the airplane), and engine nacelles.
- FAA PHAK
- Wing root
- The wing root is the part of the wing on a fixed-wing aircraft that is closest to the fuselage. Wing roots usually bear the highest bending forces in flight and during landing, and they often have fairings to reduce interference drag between the wing and the fuselage. The opposite end of a wing from the wing root is the wing tip.
- FAA PHAK
- Wing span
- The maximum distance from wingtip to wingtip.
- FAA PHAK
- Wing twist
- A design feature incorporated into some wings to improve aileron control effectiveness at high angles of attack during an approach to a stall.
- FAA PHAK
- Wings
- Airfoils attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight.
- FAA PHAK
- Wingtip vortices
- The rapidly rotating air that spills over an airplane’s wings during flight. The intensity of the turbulence depends on the airplane’s weight, speed, and configuration. Also referred to as wake turbulence. Vortices from heavy aircraft may be extremely hazardous to small aircraft.
- FAA PHAK
- Work
- A measurement of force used to produce movement.
- FAA PHAK
- World Aeronautical Charts (WAC)
- A standard series of aeronautical charts covering land areas of the world at a size and scale convenient for navigation (1:1,000,000) by moderate speed aircraft. Topographic information includes cities and towns, principal roads, railroads, distinctive landmarks, drainage, and relief. Aeronautical information includes visual and radio aids to navigation, airports, airways, restricted areas, obstructions and other pertinent data.
- FAA PHAK
- WP
- working paper/working package
- EASA EPAS
- WPGR
- Report of the Wise Person Group on the future of the Single European Sky, April 2019
- EASA EPAS
Z
- Zone of confusion
- Volume of space above the station where a lack of adequate navigation signal directly above the VOR station causes the needle to deviate.
- FAA PHAK
- Zulu time
- A term used in aviation for coordinated universal time (UTC) which places the entire world on one time standard.
- FAA PHAK
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Where these definitions come from
Every definition on this page is reproduced from one of the following official publications, named by the short label shown beside each term.
- FAA IPH
Federal Aviation Administration, Instrument Procedures Handbook — Glossary (FAA-H-8083-16B), 2017.
Official PDF (opens in a new tab) - FAA PHAK
Federal Aviation Administration, Pilot's Handbook of Aeronautical Knowledge — Glossary (FAA-H-8083-25C), 2023.
Official PDF (opens in a new tab) - EASA EPAS
European Union Aviation Safety Agency, European Plan for Aviation Safety (EPAS) — Supporting information: Acronyms and definitions, 2020.
Official PDF (opens in a new tab)
Informational only. Definitions reflect the editions cited above; always verify against the current official publication before acting on it.