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SUBJECT 021 – AIRCRAFT GENERAL KNOWLEDGE – AIRFRAME, SYSTEMS AND POWER PLANT

ANNEX I (Part-FCL) · Regulation (EU) No 1178/2011 · EAR revision 25 Nov 2025

IRImplementing rule

SUBJECT 021 – AIRCRAFT GENERAL KNOWLEDGE – AIRFRAME, SYSTEMS AND POWER PLANT

Syllabus referenceBKSyllabus details and associated Learning ObjectivesAeroplaneHelicopterIRCB-IR(A)BIR ExamBIR BKRemarks
ATPLCPLATPL/IRATPLCPL
020 00 00 00AIRCRAFT GENERAL KNOWLEDGE
021 00 00 00AIRCRAFT GENERAL KNOWLEDGE — AIRFRAME, SYSTEMS AND POWER PLANT
021 01 00 00SYSTEM DESIGN, LOADS, STRESSES, MAINTENANCE
021 01 01 00System design
021 01 01 01Design concepts
(01)XDescribe the following structural design philosophy: safe life; fail-safe (multiple load paths); damage-tolerant.XXXXX
(02)Explain the purpose of redundancy in aircraft design.XXXXX
021 01 01 02Level of certification
(01)XExplain why some systems are duplicated or triplicated.XXXXX
(02)XExplain that all aircraft are certified according to specifications determined by the competent authority, and that these certification specifications cover aspects such as design, material quality and build quality.XXXXX
(03)XState that the certification specifications for aeroplanes issued by EASA are: CS-23 for Normal, Utility, Aerobatic and Commuter Aeroplanes; CS-25 for Large Aeroplanes.XX
(04)XState that the certification specifications for rotorcraft issued by EASA are: CS-27 for Small Rotorcraft; CS-29 for Large Rotorcraft.XXX
021 01 02 00Loads and stresses
021 01 02 01Stress, strain and loads
(01)Explain how stress and strain are always present in an aircraft structure both when parked and during manoeuvring. Remark: Stress is the internal force per unit area inside a structural part as a result of external loads. Strain is the deformation caused by the action of stress on a material.XXXXX
(02)Describe the following types of loads that an aircraft may be subjected to, when they occur, and how a pilot may affect their magnitude: static loads; dynamic loads; cyclic loads.XXXXX
(03)Describe the areas typically prone to stress that should be given particular attention during a pre-flight inspection, and highlight the limited visual cues of any deformation that may be evident.XXXXX
021 01 03 00Fatigue and corrosion
021 01 03 01Describe and explain fatigue and corrosion
(01)Describe the effects of corrosion and how it can be visually identified by a pilot during the pre-flight inspection.XXXXX
(02)Describe the operating environments where the risk of corrosion is increased and how to minimise the effects of the environmental factors.XXXXX
(03)Explain that aircraft have highly corrosive fluids on board as part of their systems and equipment.XXXXX
(04)Explain fatigue, how it affects the useful life of an aircraft, and the effect of the following factors on the development of fatigue: corrosion; number of cycles; type of flight manoeuvres; stress level; level and quality of maintenance.XXXXX
021 01 04 00Intentionally left blank
021 01 05 00Maintenance
021 01 05 01Maintenance methods: hard-time and on-condition monitoring
(01)Explain the following terms: hard-time or fixed-time maintenance; on-condition maintenance; condition monitoring.XXXXX
021 02 00 00AIRFRAME
021 02 01 00Attachment methods
021 02 01 01Attachment methods and detecting the development of faulty attachments
(01)Describe the following attachment methods used for aircraft parts and components: riveting; welding; bolting; pinning; adhesives (bonding); screwing.XXXXX
(02)Explain how the development of a faulty attachment between aircraft parts or components can be detected by a pilot during the pre-flight inspection.XXXXX
021 02 02 00Materials
021 02 02 01Composite and other materials
(01)XExplain the principle of a composite material, and give examples of typical non-metallic materials used on aircraft: carbon; glass; Kevlar aramid; resin or filler.XXXXX
(02)XState the advantages and disadvantages of composite materials compared with metal alloys by considering the following: strength-to-weight ratio; capability to tailor the strength to the direction of the load; stiffness; electrical conductivity (lightning); resistance to fatigue and corrosion; resistance to cost; discovering damage during a pre-flight inspection.XXXXX
(03)State that several types of materials are used on aircraft and that they are chosen based on type of structure or component and the required/desired material properties.XXXXX
021 02 03 00Aeroplane: wings, tail surfaces and control surfaces
021 02 03 01Design
(01)Describe the following types of design and explain their advantages and disadvantages: high-mounted wing; low-mounted wing; lowor mid-set tailplane; T-tail.XX
021 02 03 02Structural components
(01)Describe the function of the following structural components: spar and its components (web and girder or cap); rib; stringer; skin; torsion box.XX
021 02 03 03Loads, stresses and aeroelastic vibrations (flutter)
(01)Describe the vertical and horizontal loads on the ground and during normal flight.XX
(02)Describe the vertical and horizontal loads during asymmetric flight following an engine failure for a multi-engine aeroplane, and how a pilot may potentially overstress the structure during the failure scenario.XX
(03)Explain the principle of flutter and resonance for the wing and control surfaces.XX
(04)Explain the following countermeasures used to achieve stress relief and reduce resonance: chord-wise and span-wise position of masses (e.g. engines, fuel, balance masses for wing and control balance masses); torsional stiffness; bending flexibility; fuel-balancing procedures during flight (automatic or applied by the pilot).XX
021 02 04 00Fuselage, landing gear, doors, floor, windscreen and windows
021 02 04 01Construction, functions, loads
(01)XDescribe the following types of fuselage construction: monocoque, semi-monocoque.XXXXX
(01)Describe the construction and the function of the following structural components of a fuselage: frames; bulkhead; pressure bulkhead; stiffeners, stringers, longerons; skin, doublers; floor suspension (crossbeams); floor panels; firewall.XXXXX
(03)Describe the loads on the fuselage due to pressurisation.XX
(04)Describe the following loads on a main landing gear: touch-down loads (vertical and horizontal); taxi loads on bogie gear (turns).XX
(05)Describe the structural danger of a nose-wheel landing with respect to: fuselage loads; nose-wheel strut loads.XX
(06)Describe the structural danger of a tail strike with respect to: fuselage and aft bulkhead damage (pressurisation).XX
(07)Describe the door and hatch construction for pressurised and unpressurised aeroplanes including: door and frame (plug type); hinge location; locking mechanism.XX
(08)XExplain the advantages and disadvantages of the following fuselage cross sections: circular; double bubble; oval; rectangular.XX
(09)Explain why flight-deck windows are constructed with different layers.XX
(10)Explain the function of window heating for structural purposes.XX
(11)Explain the implication of a direct-vision window (see CS 25.773(b)(3)).XX
(12)Explain the need for an eye-reference position.XX
(13)Explain the function of floor venting (blow-out panels).XX
(14)Describe the construction and fitting of sliding doors.XXX
021 02 05 00Helicopter: structural aspects of flight controls
021 02 05 01Design and construction
(01)List the functions of flight controls.XXX
(02)Explain why vertical and horizontal stabilisers may have different shapes and alignments.XXX
021 02 05 02Structural components and materials
(01)Describe the fatigue life and methods of checking for serviceability of the components and materials of flight and control surfaces.XXX
021 02 05 03Loads, stresses and aeroelastic vibrations
(01)Describe the dangers and stresses regarding safety and serviceability in flight when the manufacturer’s design envelope is exceeded.XXX
(02)Explain that blade tracking is important both to minimise vibration and to help ensure uniformity of flow through the disc.XXX
(03)Describe the early indications and vibrations which are likely to be experienced when the main-rotor blades and tail rotor are out of balance or tracking, including the possible early indications due to possible fatigue and overload.XXX
(04)Explain how a vibration harmonic can be set up in other components which can lead to their early failure.XXX
(05)State the three planes of vibration measurement, i.e. vertical, lateral, fore and aft.XXX
021 02 06 00Structural limitations
021 02 06 01Maximum structural masses
(01)Define and explain the following maximum structural masses: maximum ramp mass; maximum take-off mass; maximum zero fuel mass; maximum landing mass. Remark: These limitations may also be found in the relevant part of Subjects 031 ‘Mass and balance’, 032 ‘Performance (aeroplane)’ and 034 ‘Performance (helicopter)’.XX
(02)Explain that airframe life is limited by fatigue, created by alternating stress and the number of load cycles.XX
(03)Explain the maximum structural masses: maximum take-off mass.XXX
(04)Explain that airframe life is limited by fatigue, created by load cycles.XXX
021 03 00 00HYDRAULICS
021 03 01 00Hydromechanics: basic principles
021 03 01 01Concepts and basic principles
(01)XExplain the concept and basic principles of hydromechanics including: hydrostatic pressure; Pascal’s law; the relationship between pressure, force and area; transmission of power: multiplication of force, decrease of displacement.XXXXX
021 03 02 00Hydraulic systems
021 03 02 01Hydraulic fluids: types, characteristics, limitations
(01)XList and explain the desirable properties of a hydraulic fluid with regard to: thermal stability; corrosiveness; flashpoint and flammability; volatility; viscosity.XXXXX
(02)XState that hydraulic fluids are irritating to skin and eyes.XXXXX
(03)List the two different types of hydraulic fluids: synthetic; mineral.XXXXX
(04)State that different types of hydraulic fluids cannot be mixed.XXXXX
(05)XState that at the pressures being considered, hydraulic fluid is considered incompressible.XXXXX
021 03 02 02System components: design, operation, degraded modes of operation, indications and warnings
(01)Explain the working principle of a hydraulic system.XXXXX
(02)Describe the difference in the principle of operation between a constant pressure system and a system pressurised only on specific demand.XXXXX
(03)State the differences in the principle of operation between a passive hydraulic system (without a pressure pump) and an active hydraulic system (with a pressure pump).XXXXX
(04)XList the main advantages and disadvantages of system actuation by hydraulic or purely mechanical means with respect to: weight; size; force.XXXXX
(05)List the main uses of hydraulic systems.XXXXX
(06)State that hydraulic systems can be classified as either high pressure (typically 3000 psi or higher) or low pressure (typically up to 2000 psi).XXXXX
(07)State that a high-pressure hydraulic system is typically operating at 3000 psi but on some aircraft a hydraulic pressure of 4000 to 5000 psi may also be used.XXXXX
(08)Explain the working principle of a low-pressure (0–2000 psi) system.XXXXX
(09)Explain the advantages and disadvantages of a high-pressure system over a low-pressure system.XXXXX
(10)Describe the working principle and functions of pressure pumps including: constant pressure pump (swash plate or cam plate); pressure pump whose output is dependent on pump revolutions per minute (rpm) (gear type).XXXXX
(11)Explain the following different sources of hydraulic pressure, their typical application and potential operational limitations: manual; engine gearbox; electrical; air (pneumatic and ram-air turbine); hydraulic (power transfer unit) or reversible motor pumps; accessory.XX
(12)Explain the following different sources of hydraulic pressure, their typical application and potential operational limitations: manual; engine; gearbox; electrical.XXX
(13)Describe the working principle and functions of the following hydraulic system components: reservoir (pressurised and unpressurised); accumulators; case drain lines and fluid cooler return lines; piston actuators (singleand double-acting); hydraulic motors; filters; non-return (check) valves; relief valves; restrictor valves; elector valves (linear and basic rotary selectors, two and four ports); bypass valves; shuttle valves; fire shutoff valves; priority valves; fuse valves; pressure and return pipes.XXXXX
(14)Explain the function of the demand pump installed on many transport aeroplanes.XX
(15)Explain how redundancy is obtained by giving examples.XXXXX
(16)Interpret a typical hydraulic system schematic to the level of detail as found in an aircraft flight crew operating manual (FCOM).XXXXX
(17)Explain the implication of a high system demand.XXXXX
(18)List and describe the instruments and alerts for monitoring a hydraulic system.XXXXX
(19)State the indications and explain the implications of the following malfunctions: system leak or low level; low pressure; high temperature.XXXXX
021 04 00 00LANDING GEAR, WHEELS, TYRES, BRAKES
021 04 01 00Landing gear
021 04 01 01Types
(01)XName, for an aeroplane, the following different landing-gear configurations: nose wheel; tail wheel.XX
(02)XName, for a helicopter, the following different landinggear configurations: nose wheel; tail wheel; skids.XXX
021 04 01 02System components, design, operation, indications and warnings, on-ground/in-flight protections, emergency extension systems
(01)Explain the function of the following components of a landing gear: oleo leg/shock strut; axles; bogies and bogie beam; drag struts; side stays/struts; torsion links; locks (over centre); gear doors.XX
(02)Explain the function of the following components of a landing gear: oleo leg/shock strut; axles; drag struts; side stays/struts; torsion links; locks (over centre); gear doors.XXX
(03)Name the different components of a landing gear, using a diagram.XXXXX
(04)Describe the sequence of events during normal operation of the landing gear.XXXXX
(05)State how landing-gear position indication and alerting is implemented.XXXXX
(06)Describe the various protection devices to avoid inadvertent gear retraction on the ground and explain the implications of taking off with one or more protection devices in place: ground lock (pins); protection devices in the gear retraction mechanism.XXXXX
(07)Explain the speed limitations for gear operation (VLO (maximum landing gear operating speed) and VLE (maximum landing gear extended speed)).XXXXX
(08)Describe the sequence for emergency gear extension: unlocking; operating; down-locking.XXXXX
(09)Describe some methods for emergency gear extension including: gravity/free fall; air or nitrogen pressure; manually/mechanically.XXXXX
021 04 02 00Nose-wheel steering
021 04 02 01Design, operation
(01)Explain the operating principle of nosewheel steering.XXXXX
(02)Explain, for a helicopter, the functioning of differential braking with free-castoring nose wheel.XXX
(03)Describe, for an aeroplane, the functioning of the following systems: differential braking with free-castoring nose wheel; tiller or hand wheel steering; rudder pedal nose-wheel steering.XX
(04)Explain the centring mechanism of the nose wheel.XXXXX
(05)Define the term ‘shimmy’ and the possible consequences of shimmy for the noseand the mainwheel system and explain the purpose of a shimmy damper to reduce the severity of shimmy.XX
(06)Explain the purpose of main-wheel (body) steering.XX
021 04 03 00Brakes
021 04 03 01Types and materials
(01)Describe the basic operating principle of a disc brake.XXXXX
(02)State the different materials used in a disc brake (steel, carbon).XXXXX
(03)Describe the characteristics, advantages and disadvantages of steel and carbon brake discs with regard to: weight; temperature limits; internal-friction coefficient; wear.XXXXX
021 04 03 02System components, design, operation, indications and warnings
(01)Explain the limitation of brake energy and describe the operational consequences.XX
(02)Explain how brakes are actuated: hydraulically, electrically.XXXXX
(03)Explain the purpose of an in-flight wheel brake system.XX
(04)Describe the function of a brake accumulator.XXXXX
(05)Describe the function of the parking brake.XXXXX
(06)Explain the function of brake-wear indicators.XX
(07)Explain the reason for the brake-temperature indicator.XX
021 04 03 03Anti-skid
(01)Describe the operating principle of antiskid where excessive brake pressure applied is automatically reduced for optimum breaking performance.XX
(02)Explain that the anti-skid computer compares wheel speed to aeroplane reference speed to provide the following: slip ratio for maximum braking performance; locked-wheel prevention (protection against deep skid on one wheel); touchdown protection (protection against brake-pressure application during touchdown); hydroplane protection.XX
(03)Give examples of the impact of an anti-skid system on performance, and explain the implications of anti-skid system failure.XX
021 04 03 04Autobrake
(01)Describe the operating principle of an autobrake system.XX
(02)Explain why the anti-skid system must be available when using autobrakes.XX
(03)Explain the difference between the three modes of operation of an autobrake system: OFF (system off or reset); Armed (the system is ready to operate under certain conditions); Activated/Deactivated (application of pressure on brakes).XX
(04)Describe how an autobrake system setting will either apply maximum braking (RTO or MAX) or result in a given rate of deceleration, where the amount of braking applied may be affected by: the use of reverse thrust; slippery runway.XX
021 04 04 00Wheels, rims and tyres
021 04 04 01Types, structural components and materials, operational limitations, thermal plugs
(01)XDescribe the different types of tyres such as: tubeless; diagonal (cross ply); radial (circumferential bias).XXXXX
(02)XDefine the following terms: ply rating; tyre tread; tyre creep; retread (cover).XXXXX
(03)Explain the function of thermal/fusible plugs.XX
(04)Explain the implications of and how to identify tread separation and wear or damage with associated increased risk of tyre burst.XX
(05)Explain why the ground speed of tyres is limited.XX
(06)Describe the following tyre checks a pilot will perform during the pre-flight inspection and identify probable causes: cuts and damages; flat spots.XX
021 04 05 00Helicopter equipment
021 04 05 01Flotation devices
(01)Explain flotation devices, how they are operated, and their limitations.XXX
(02)Explain why indicated airspeed (IAS) limitations before, during and after flotation-device deployment must be observed.XXX
021 05 00 00FLIGHT CONTROLS
021 05 01 00Aeroplane: primary flight controls
021 05 01 01Definition and control surfaces
(01)Define a ‘primary flight control’.XX
(02)List the following primary flight control surfaces: elevator; aileron, roll spoilers, flaperon; rudder.XX
(03)List the various means of control surface actuation including: manual; fully powered (irreversible); partially powered (reversible).XX
021 05 01 02Manual controls
(01)Explain the basic principle of a fully manual control system.XX
021 05 01 03Fully powered controls (irreversible)
(01)Explain the basic principle of a fully powered control system.XX
(02)Explain the concept of irreversibility in a flight control system.XX
(03)Explain the need for a ‘feel system’ in a fully powered control system.XX
(04)Explain the operating principle of a stabiliser trim system in a fully powered control system.XX
(05)Explain the operating principle of rudder and aileron trim in a fully powered control system.XX
021 05 01 04Partially powered controls (reversible)
(01)Explain the basic principle of a partially powered control system.XX
(02)Explain why a ‘feel system’ is not necessary in a partially powered control system.XX
021 05 01 05System components, design, operation, indications and warnings, degraded modes of operation, jamming
(01)List and describe the function of the following components of a flight control system: actuators; control valves; cables; electrical wiring; control surface position sensors.XX
(02)Explain how redundancy is obtained in primary flight control systems of large transport aeroplanes.XX
(03)Explain the danger of control jamming and the means of retaining sufficient control capability.XX
(04)Explain the methods of locking the controls on the ground and describe ‘gust or control lock’ warnings.XX
(05)Explain the concept of a rudder deflection limitation (rudder limiter) system and the various means of implementation (rudder ratio changer, variable stops, blow-back).XX
021 05 02 00Aeroplane: secondary flight controls
021 05 02 01System components, design, operation, degraded modes of operation, indications and warnings
(01)Define a ‘secondary flight control’.XX
(02)List the following secondary flight control surfaces: lift-augmentation devices (flaps and slats); speed brakes; flight and ground spoilers; trimming devices such as trim tabs, trimmable horizontal stabiliser.XX
(03)Describe secondary flight control actuation methods and sources of actuating power.XX
(04)Explain the function of a mechanical lock when using hydraulic motors driving a screw jack.XX
(05)Describe the requirement for limiting flight speeds for the various secondary flight control surfaces.XX
(06)For lift-augmentation devices, explain the load-limiting (relief) protection devices and the functioning of an auto-retraction system.XX
(07)Explain how a flap/slat asymmetry protection device functions, and describe the implications of a flap/slat asymmetry situation.XX
(08)Describe the function of an auto-slat system.XX
(09)Explain the concept of control surface blow-back (aerodynamic forces overruling hydraulic forces).XX
021 05 03 00Helicopter: flight controls
021 05 03 01Droop stops, control systems, trim systems, control stops
(01)Explain the methods of locking the controls on the ground.XXX
(02)Describe main-rotor droop stops and how rotor flapping is restricted.XXX
(03)Explain the principle of phase lag and advance angle.XXX
(04)Describe the following four axes of control operation, their operating principle and their associated cockpit controls: collective control; cyclic fore and aft (pitch axis); cyclic lateral (roll axis); yaw.XXX
(05)Describe the swash plate or azimuth star control system including the following: swash plate inputs; the function of the non-rotating swash plate; the function of the rotating swash plate; how swash plate tilt is achieved; swash plate pitch axis; swash plate roll axis; balancing of pitch/roll/collective inputs to the swash plate to equalise torsional loads on the blades.XXX
(06)Describe the operation of the spider control system.XXX
(07)State the need for artificial feel in a hydraulically actuated flight control system.XXX
(08)Describe and explain the purpose of a trim system using the following terms: force-trim switch; force gradient; parallel trim actuator; cyclic 4-way trim switch; interaction of trim system with an SAS/SCAS/ASS stability system; trim-motor indicators.XXX
(09)Describe the different types of control runs.XXX
(10)Explain the use of control stops.XXX
021 05 04 00Aeroplane: fly-by-wire (FBW) control systems
021 05 04 01Composition, explanation of operation, modes of operation
(01)Explain that an FBW flight control system is composed of the following: pilot’s input command (control column/sidestick/rudder pedals); electrical signalling paths, including: pilot input to computer; computer to flight control surfaces; feedback from aircraft response to computer; flight control computers; actuators; flight control surfaces.XX
(02)State the advantages of an FBW system in comparison with a conventional flight control system including: weight; pilot workload; flight-envelope protection.XX
(03)Explain why an FBW system is always irreversible.XX
(04)Explain the different modes of operation: normal operation (e.g. normal law or normal mode); downgraded operation (e.g. alternate law or secondary mode); direct law.XX
(05)Describe the implications of mode degradation in relation to pilot workload and flight-envelope protection.XX
(06)Intentionally left blank
(07)For aircraft using sidestick for manual control, describe the implications of: dual control input made by the pilot; the control takeover facility available to the pilot.XX
(08)Intentionally left blank
(09)Explain why several types of computers are needed and why they should be dissimilar.XX
(10)Explain why several control surfaces on every axis are needed on FBW aircraft.XX
(11)Explain why several sensors are needed on critical parameters.XX
021 05 05 00Helicopter: fly-by-wire (FBW) control systems
To be introduced at a later date.XXX
021 06 00 00PNEUMATICS — PRESSURISATION AND AIRCONDITIONING SYSTEMS
021 06 01 00Pneumatic/bleed-air supply
021 06 01 01Piston-engine air supply
(01)Describe the following means of supplying air for the pneumatic systems for piston-engine aircraft: compressor; vacuum pump.XXXXX
(02)State that an air supply is required for the following systems: instrumentation; heating; de-icing.XXXXX
021 06 01 02Gas turbine engine: bleed-air supply
(01)State that the possible bleed-air sources for gas turbine engine aircraft are the following: engine; auxiliary power unit (APU); ground supply.XXXXX
(02)State that for an aeroplane a bleed-air supply can be used for the following systems or components: ice protection; engine air starter; pressurisation of a hydraulic reservoir; air-driven hydraulic pumps; pressurisation and air conditioning.XX
(03)State that for a helicopter a bleed-air supply can be used for the following systems or components: anti-icing; engine air starter; pressurisation of a hydraulic reservoir.XXX
(04)State that the bleed-air supply system can comprise the following: pneumatic ducts; isolation valve; pressure-regulating valve; engine bleed valve (HP/IP valves); fan-air pre-cooler; temperature and pressure sensors.XXXXX
(05)Interpret a basic pneumatic system schematic to the level of detail as found in an FCOM.XXXXX
(06)Describe the cockpit indications for bleed-air systems.XXXXX
(07)Explain how the bleed-air supply system is controlled and monitored.XXXXX
(08)State the following bleed-air malfunctions: over-temperature; over-pressure; low pressure; overheat/duct leak; and describe the potential consequences.XXXXX
021 06 02 00Helicopter: air-conditioning systems
021 06 02 01Types, system components, design, operation, degraded modes of operation, indications and warnings
(01)Describe the purpose of an air-conditioning system.XXX
(02)Explain how an air-conditioning system is controlled.XXX
(03)Describe the vapour cycle air-conditioning system including system components, design, operation, degraded modes of operation and system malfunction indications.XXX
(04)Identify the following components from a diagram of an air-conditioning system and describe the operating principle and function: air-cycle machine (pack, bootstrap system); pack-cooling fan; water separator; mixing valves; flow-control valves; isolation valves; recirculation fans; filters for recirculation; temperature sensors.XXX
(05)List and describe the controls, indications and warnings related to an air-conditioning system.XXX
021 06 03 00Aeroplane: pressurisation and air-conditioning system
021 06 03 01System components, design, operation, degraded modes of operation, indications and warnings
(01)Explain that a pressurisation and an air-conditioning system of an aeroplane controls: ventilation; temperature; pressure.XX
(02)Explain how humidity is controlled.XX
(03)Explain that the following components constitute a pressurisation system: pneumatic system as the power source; outflow valve; outflow valve actuator; pressure controller; excessive differential pressure-relief valve; negative differential pressure-relief valve.XX
(04)Explain that the following components constitute an airconditioning system and describe their operating principles and function: air-cycle machine (pack, bootstrap system); pack-cooling fan; water separator; mixing valves; flow-control valves (outflow valve); isolation valves; ram-air valve; recirculation fans; filters for recirculated air; temperature sensors. Remark: The bootstrap system is the only airconditioning system considered for Part-FCL aeroplane examinations.XX
(05)Describe the use of hot trim air.XX
(06)Define the following terms: cabin altitude; cabin vertical speed; differential pressure; ground pressurisation.XX
(07)Describe the operating principle of a pressurisation system.XX
(08)Describe the emergency operation by manual setting of the outflow valve position.XX
(09)Describe the working principle of an electronic cabinpressure controller.XX
(10)State how the maximum operating altitude is determined.XX
(11)Explain: why the maximum allowed value of cabin altitude is limited; a typical value of maximum differential pressure for large transport aeroplanes; the relation between cabin altitude, the maximum differential pressure and maximum aeroplane operating altitude.XX
(12)Explain the typical warning on a transport category aircraft when cabin altitude exceeds 10 000 ft.XX
(13)List and interpret typical indications of the pressurisation system.XX
(14)Describe the main operational differences between a bleed-air-driven air-conditioning system and an electrically driven air-conditioning system as found on aircraft without engine bleed-air system.XX
021 07 00 00ANTI-ICING AND DE-ICING SYSTEMS
021 07 01 00Types, operation, indications
021 07 01 01Types, design, operation, indications and warnings, operational limitations
(01)Explain the concepts of antiicing and deicing.XXXXX
(02)Name the components of an aircraft which can be protected from ice accretion.XXXXX
(03)State that on some aeroplanes the tail does not have an ice-protection system.XX
(04)State the different types of anti-icing/de-icing systems and describe their operating principle: hot air; electrical; fluid.XXXXX
(05)Describe the operating principle of the inflatable boot de-icing system.XX
021 07 02 00Ice warning systems
021 07 02 01Types, operation, and indications
(01)Describe the different operating principles of the following ice detectors: mechanical systems using air pressure; electromechanical systems using resonance frequencies.XX
(02)Describe the principle of operation of ice warning systems.XX
021 07 03 00Helicopter blade heating systems
021 07 03 01Limitations
(01)Explain the limitations on blade heating and the fact that on some helicopters the heating does not heat all the main-rotor blades at the same time.XXX
021 08 00 00FUEL SYSTEM
021 08 01 00Piston engine
021 08 01 01Fuel: types, characteristics, limitations
(01)State the types of fuel used by a piston engine and their associated limitations: diesel; JET-A1 (for high-compression engines); AVGAS; MOGAS.XXXXX
(02)State the main characteristics of these fuels and give typical values regarding their flash points, freezing points and density.XXXXX
021 08 01 02Design, operation, system components, indications
(01)State the tasks of the fuel system.XXXXX
(02)Name the following main components of a fuel system, and state their location and their function: lines; boost pump; pressure valves; filter, strainer; tanks (wing, tip, fuselage); vent system; sump; drain; fuel-quantity sensor; fuel-temperature sensor.XXXXX
(03)Describe a gravity fuel feed system and a pressure feed fuel system.XXXXX
(04)Describe the construction of the different types of fuel tanks and state their advantages and disadvantages: drum tank; bladder tank; integral tank.XXXXX
(05)Explain the function of cross-feed.XXXXX
(06)Define the term ‘unusable fuel’.XXXXX
(07)List the following parameters that are monitored for the fuel system: fuel quantity (low-level warning); fuel temperature.XXXXX
021 08 02 00Turbine engine
021 08 02 01Fuel: types, characteristics, limitations
(01)State the types of fuel used by a gas turbine engine: JET-A; JET-A1; JET-B.XXXXX
(02)State the main characteristics of these fuels and give typical values regarding their flash points, freezing points and density.XXXXX
(03)State the existence of additives for freezing.XXXXX
021 08 02 02Design, operation, system components, indications
(01)Explain the function of the fuel system: lines; centrifugal boost pump; pressure valves; fuel shut-off valve; filter, strainer; tanks (wing, tip, fuselage, tail); bafflers/baffles; sump; vent system; drain; fuel-quantity sensor; fuel-temperature sensor; refuelling/defueling system; fuel dump/jettison system.XXXXX
(02)Name the main components of the fuel system and state their location and their function: trim fuel tanks; bafflers; refuelling/defueling system; fuel dump/jettison system. Remark: For completion of list, please see 021 08 01 02 (02).XXXXX
(03)Interpret a typical fuel system schematic to the level of detail as found in an aircraft FCOM.XXXXX
(04)Explain the limitations in the event of loss of booster pump fuel pressure.XXXXX
(05)Describe the use and purpose of drip sticks (manual magnetic indicators) (may also be known as dip stick or drop stick).XX
(06)Explain the considerations for fitting a fuel dump/jettison system and, if fitted, its function.XXXXX
021 09 00 00ELECTRICS
Remark: For any reference to the direction of current flow, the conventional current flow shall be used, i.e. from positive to negative.
021 09 01 00General, definitions, basic applications: circuit breakers, logic circuits
021 09 01 01Static electricity
(01)Explain static electricity and describe the flying conditions where aircraft are most susceptible to build-up of static electricity.XXXXX
(02)Describe a static discharger and explain the following: its purpose; typical locations; pilot’s role of observing it during pre-flight inspection.XXXXX
(03)Explain why an aircraft must first be grounded before refuelling/defueling.XXXXX
(04)Explain the reason for electrical bonding.XXXXX
021 09 01 02Direct current (DC)
(01)Explain the term ‘direct current’ (DC), and state that current can only flow in a closed circuit.XXXXX
(02)XExplain the basic principles of conductivity and give examples of conductors, semiconductors and insulators.XXXXX
(03)Describe the difference in use of the following mechanical switches and explain the difference in observing their state (e.g. ON/OFF), and why some switches are guarded: toggle switch; rocker switch; pushbutton switch; rotary switch. Explain the difference in observing their state (e.g. ON/OFF) and why some switches are guarded.XXXXX
(04)Define voltage and current, and state their unit of measurement.XXXXX
(05)XExplain Ohm’s law in qualitative terms.XXXXX
(06)XExplain the effect on total resistance when resistors are connected in series or in parallel.XXXXX
(07)XState that resistances can have a positive or a negative temperature coefficient (PTC/NTC) and state their use.XXXXX
(08)Define electrical power and state the unit of measurement.XXXXX
021 09 01 03Alternating current (AC)
(01)XExplain the term ‘alternating current’ (AC), and compare its use to DC with regard to complexity.XXXXX
(02)Define the term ‘phase’, and explain the basic principle of single-phase and three-phase AC.XXXXX
(03)State that aircraft can use single-phase or three-phase AC.XXXXX
(04)Define frequency and state the unit of measurement.XXXXX
(05)XDefine ‘phase shift’ in qualitative terms.XXXXX
021 09 01 04Intentionally left blank
021 09 01 05Intentionally left blank
021 09 01 06Electromagnetism
(01)State that an electrical current produces a magnetic field.XXXXX
(02)Describe how the strength of the magnetic field changes with the magnitude of the current.XXXXX
(03)Explain the purpose and the working principle of a solenoid.XXXXX
(04)Explain the purpose and the working principle of a relay.XXXXX
(05)Explain the principle of electromagnetic induction and how two electrical components or systems may affect each other through this principle.XXXXX
021 09 01 07Circuit protection
(01)Explain the working principle of a fuse and a circuit breaker.XXXXX
(02)Explain how a fuse is rated.XXXXX
(03)Describe the principal difference between the following types of circuit breakers: thermal circuit breaker sensing magnitude of current; magnetic circuit breaker sensing direction of current.XXXXX
(04)Describe how circuit breakers may be used to reset aircraft systems/computers in the event of system failure (when part of a described procedure).XXXXX
(05)Explain a short circuit in practical terms using Ohm’s Law, power and energy expressions highlighting the risk of fire due to power transfer and extreme energy dissipation.XXXXX
(06)Explain the risk of fire resulting from excessive heat in a circuit subjected to overcurrent.XXXXX
(07)Explain that overcurrent situations may be transient.XXXXX
(08)Explain the hazards of multiple resets of a circuit breaker or the use of incorrect fuse rating when replacing blown fuses.XXXXX
021 09 01 08Semiconductors and logic circuits
(01)Describe the effect of temperature on semiconductors with regard to function and longevity of the component.XXXXX
(02)Describe the following five basic logic functions, as used in aircraft FCOM documentation, and recognise their schematic symbols according to the ANSI/MIL standard: AND; OR; NOT; NOR; NAND.XXXXX
(03)Interpret a typical logic circuit schematic to the level of detail as found in an aircraft FCOM.XXXXX
021 09 02 00Batteries
021 09 02 01Types, characteristics and limitations
(01)State the function of an aircraft battery.XXXXX
(02)Name the types of rechargeable batteries used in aircraft: lead-acid; nickel-cadmium; lithium-ion; lithium-polymer.XXXXX
(03)Compare the different battery types with respect to: load behaviour; charging characteristics; risk of thermal runaway.XXXXX
(04)Explain the term ‘cell voltage’ and describe how a battery may consist of several cells that combined provide the desirable voltage and capacity.XXXXX
(05)Explain the difference between battery voltage and charging voltage.XXXXX
(06)Define the term ‘capacity of batteries’ and state the unit of measurement used.XXXXX
(07)State the effect of temperature on battery capacity and performance.XXXXX
(08)State that in the case of loss of all generated power (battery power only) the remaining electrical power is time-limited.XXXXX
(09)Explain how lithium-type batteries pose a threat to aircraft safety and what affects this risk: numbers of batteries on board an aircraft including those brought on board by passengers; temperature, of both battery and environment; physical condition of the battery; battery charging.XXXXX
(10)Describe how to contain a battery thermal runaway highlighting the following: how one cell can affect the neighbouring cells; challenges if it happens in an aircraft during flight.XXXXX
021 09 03 00Generation
Remark: For standardisation purposes, the following standard expressions are used: DC generator: produces DC output; DC alternator: produces AC, rectified by integrated rectifying unit, the output is DC; DC alternator: producing a DC output by using a rectifier; AC generator: produces AC output; starter generator: integrated combination of a generator and a starter motor; permanent magnet alternator/ generator: self-exciting AC generator.
021 09 03 01DC generation
(01)Describe the basic working principle of a simple DC generator or DC alternator.XXXXX
(02)Explain the principle of voltage control and why it is required.XXXXX
(03)Explain the purpose of reverse current protection from the battery/busbar to the alternator.XXXXX
(04)Describe the basic operating principle of a starter generator and state its purpose.XXXXX
021 09 03 02AC generation
(01)Describe the working principle of a brushless threephase AC generator.XXXXX
(02)State that the generator field current is used to control voltage.XXXXX
(03)State the relationship between output frequency and the rpm of a three-phase AC generator.XXXXX
(04)Explain the term ‘frequency wild generator’.XXXXX
(05)List the following different power sources that can be used for an aeroplane to drive an AC generator: engine; APU; RAT; hydraulic.XX
(06)List the following different power sources that can be used for a helicopter to drive an AC generator: engine; APU; gearbox.XXX
021 09 03 03Constant speed drive (CSD) and integrated drive generator (IDG) systems
(01)Describe the function of a CSD.XX
(02)Explain the parameters of a CSD that are monitored.XX
(03)Describe the function of an IDG.XX
(04)Explain the consequences of a mechanical disconnection during flight for a CSD and an IDG.XX
(05)Explain that a CSD/IDG has its own, independent oil system and how a leak from this may appear as an engine oil leak.XX
021 09 03 04Transformers, transformer rectifier units (TRUs), static inverters
(01)State the function of a transformer.XXXXX
(02)State the function of a TRU and its purpose, including type of output.XXXXX
(03)State the function of a static inverter and its purpose, including type of output.XXXXX
021 09 04 00Distribution
021 09 04 01General
(01)Explain the function of a busbar.XXXXX
(02)Describe the function of the following buses: AC bus; DC bus; emergency AC or DC bus; essential AC or DC bus; battery bus; hot bus, ground servicing or maintenance bus.XXXXX
(03)State that the aircraft structure can be used as a part of the electrical circuit (common earth) and explain the implications for electrical bonding.XXXXX
(04)Explain the function of external power.XXXXX
(05)State that a priority sequence exists between the different sources of electrical power on ground and in flight.XXXXX
(06)Explain the term ‘load sharing’.XXXXX
(07)Explain the term ‘load shedding’.XXXXX
(08)Describe typical systems that can be shed in the event of a supply failure, such as passenger entertainment system and galley power.XXXXX
(09)Interpret a typical electrical system schematic to the level of detail as found in an aircraft FCOM.XXXXX
(10)Explain the difference between a supply (e.g. generator) failure and a bus failure, and the operating consequences of either.XXXXX
021 09 04 02DC distribution
(01)Describe a simple DC electrical system of a single-engine aircraft.XXXXX
(02)Describe a DC electrical system of a multi-engine aircraft (CS-23/CS-27) including the distribution consequences of loss of generator(s) or bus failure.XXXXX
(03)Describe the DC part of an electrical system of a transport aircraft (CS-25/CS-29) including the distribution consequences of loss of DC supply or bus failure.XXXXX
(04)Give examples of DC consumers.XXXXX
021 09 04 03AC distribution
(01)Explain the difference in the principle of operation for a split AC electrical system and a parallel AC electrical system.XXXXX
(02)Describe the following distribution consequences: power transfer between different power supplies; power transfer in the event of a supply failure; loss of all normal AC supplies.XXXXX
(03)Give examples of AC consumers.XXXXX
(04)Explain the conditions to be met for paralleling AC generators.XXXXX
(05)State that volt-ampere (VA) is the unit for total power consumed in an AC system.XXXXX
021 09 04 04Electrical load management and monitoring systems: automatic generators and bus switching during normal and failure operation, indications and warnings
(01)Give examples of system control, monitoring and annunciators using the following terms: generator control unit (GCU) for monitoring generator output and providing network protection; exciter contactor/breaker/relay for control of generator exciter field; generator contactor/breaker/relay for connecting the generator to the network; bus-tie contactor/breaker/relay for connecting busbars together; generator switch on the flight deck for manual control of exciter contactor; IDG/CSD disconnect switch on the flight deck for mechanical disconnection of the generator; bus-tie switch on the flight deck with AUTO and OFF positions only.XXXXX
(02)Describe, for normal and degraded modes of operation, the following functions of an electrical load management system on ground and in flight using the terms in 021 09 04 04 (01): distribution; monitoring; protection in the event of incorrect voltage; protection in the event of incorrect frequency; protection in the event of a differential fault.XXXXX
(03)Describe the requirement for monitoring the aircraft batteries.XXXXX
(04)Explain the importance of monitoring the temperature of nickel-cadmium and lithium-type batteries.XXXXX
(05)Interpret various different ammeter indications of an ammeter which monitors the charge current of the battery.XXXXX
021 09 05 00Electrical motors
021 09 05 01General
(01)XState that the purpose of an electrical motor is to convert electrical energy into mechanical energy.XXXXX
(02)State that because of the similarity in design, a generator and an electrical motor may be combined into a starter generator.XXXXX
(03)Explain that the size of the engine determines how much energy is required for starting, and state the following: small turbine engines may be able to use the battery for a very limited number of start attempts; large turbine engines require one or more power sources, either external or on-board.XXXXX
021 09 05 02Operating principle
(01)Describe how the torque of an electrical motor is determined by the supplied voltage and current, and the resulting magnetic fields within the motor.XXXXX
(02)XState that electrical motors can be either AC or DC.XXXXX
(03)Explain the consequences of the following: rotor seizure; rotor runaway.XXXXX
021 09 05 03Components
(01)XName the following components of an electrical motor: rotor (rotating part of an electrical motor); stator (stationary part of an electrical motor).XXXXX
021 10 00 00PISTON ENGINES
Remark: This topic includes diesel and petrol engines.
021 10 01 00General
021 10 01 01Types of internal-combustion engines: basic principles, definitions
(01)Define the following terms and expressions: rpm; torque; manifold absolute pressure (MAP); power output; specific fuel consumption; compression ratio, clearance volume, swept (displaced) volume, total volume.XXXXX
021 10 01 02Engine: design, operation, components
(01)Describe the basic operating principle of a piston engine: crankcase; crankshaft; connecting rod; piston; piston pin; piston rings; cylinder; cylinder head; valves; valve springs; push rod; camshaft; rocker arm; camshaft gear; bearings.XXXXX
(02)Name and identify the various types of engine design with regard to cylinder arrangement and their advantages/disadvantages: horizontally opposed; in line; radial; and working cycle (four stroke: petrol and diesel).XXXXX
(03)Describe the differences between petrol and diesel engines with respect to: means of ignition; maximum compression ratio; regulating air or mixture supply to the cylinder; pollution from the exhaust.XXXXX
021 10 02 00Fuel
021 10 02 01Types, grades, characteristics, limitations
(01)Name the type of fuel used for petrol engines including its colour (AVGAS); 100 (green); 100LL (blue).XXXXX
(02)Name the type of fuel normally used for aviation diesel engines (JET-A1).XXXXX
(03)XDefine the term ‘octane rating’.XXXXX
(04)Define the term ‘detonation’ and describe the causes and effects of detonation for both petrol and diesel engines.XXXXX
(05)Define the term ‘pre-ignition’ and describe the causes and effects of pre-ignition for both petrol and diesel engines.XXXXX
(06)Identify the conditions and power settings that promote detonation for petrol engines.XXXXX
(07)Describe how detonation in petrol engines is recognised.XXXXX
(08)Describe the method and occasions for checking the fuel for water content.XXXXX
(09)State the typical value of fuel density for aviation gasoline and diesel fuel.XXXXX
(10)Explain volatility, viscosity and vapour locking for petrol and diesel fuels.XXXXX
021 10 03 00Engine fuel pumps
021 10 03 01Engine-driven fuel pump
(01)Explain the need for a separate engine-driven fuel pump.XXXXX
021 10 04 00Carburettor/injection system
021 10 04 01Carburettor: design, operation, degraded modes of operation, indications and warnings
(01)State the purpose of a carburettor.XXXXX
(02)Describe the operating principle of the simple float chamber carburettor.XXXXX
(03)Describe the methods of obtaining mixture control over the whole operating engine power setting range (compensation jet, diffuser).XXXXX
(04)Describe the methods of obtaining mixture control over the whole operating altitude range.XXXXX
(05)Explain the purpose and the operating principle of an accelerator pump.XXXXX
(06)Explain the purpose of power enrichment.XXXXX
(07)Describe the function of the carburettor heat system.XXXXX
(08)Explain the effect of carburettor heat on mixture ratio and power output.XXXXX
(09)Explain the purpose and the operating principle of a primer pump.XXXXX
(10)Discuss other methods for priming an engine (acceleration pumps).XXXXX
(11)Explain the danger of carburettor fire, including corrective measures.XXXXX
021 10 04 02Injection: design, operation, degraded modes of operation, indications and warnings
(01)Explain the advantages and difference in operation of an injection system compared with a carburettor system.XXXXX
021 10 04 03Icing
(01)Describe the causes and effects of carburettor icing and the action to be taken if carburettor icing is suspected.XXXXX
(02)Name the meteorological conditions under which carburettor icing may occur.XXXXX
(03)Describe the indications of the presence of carburettor icing for both a fixed pitch and a constant speed propeller.XX
(04)Describe the indications of the presence of carburettor icing for a helicopter.XXX
(05)Describe the indications that will occur upon selection of carburettor heat depending on whether ice is present or not.XXXXX
(06)Explain the reason for the use of alternate air on fuel injection systems and describe its operating principle.XXXXX
(07)State the meteorological conditions under which induction system icing may occur.XXXXX
021 10 05 00Cooling systems
021 10 05 01Design, operation, indications and warnings
(01)Specify the reasons for cooling a piston engine.XXXXX
(02)Describe the design features to enhance cylinder air cooling for aeroplanes.XX
(03)Describe the design features to enhance cylinder air cooling for helicopters (e.g. engine-driven impeller and scroll assembly, baffles).XXX
(04)Compare the differences between liquidand aircooling systems.XXXXX
(05)Identify the cylinder head temperature indication to monitor engine cooling.XXXXX
(06)Describe the function and the operation of cowl flaps.XX
021 10 06 00Lubrication systems
021 10 06 01Lubricants: characteristics, limitations
(01)Describe the term ‘viscosity’ including the effect of temperature.XXXXX
(02)Describe the viscosity grade numbering system used in aviation.XXXXX
021 10 06 02Design, operation, indications and warnings
(01)State the functions of a piston-engine lubrication system.XXXXX
(02)Describe the working principle of a dry-sump lubrication system and describe the functions of the following components: oil tank (reservoir) and its internal components: hot well, de-aerator, vent, expansion space; check valve (non-return valve); pressure pump and pressure-relief valve; scavenge pump; filters (suction, pressure and scavenge); oil cooler; oil cooler bypass valve (anti-surge and thermostatic); pressure and temperature sensors; lines.XXXXX
(03)Describe a wet-sump lubrication system.XXXXX
(04)State the differences between a wetand a dry-sump lubrication system and their advantages and disadvantages.XXXXX
(05)List the following factors that influence oil consumption: oil grade; cylinder and piston wear; condition of piston rings.XXXXX
(06)Describe the interaction between oil pressure, oil temperature and oil quantity.XXXXX
021 10 07 00Ignition circuits
021 10 07 01Design, operation
(01)Describe the working principle of a magneto-ignition system and the functions of the following components: magneto; contact-breaker points; capacitor (condenser); coils or windings; ignition switches; distributor; spark plug; high-tension (HT) cable.XXXXX
(02)State why piston engines are equipped with two electrically independent ignition systems.XXXXX
(03)State the function and operating principle of the following methods of spark augmentation: starter vibrator (booster coil); impulse-start coupling.XX
(04)State the function and operating principle of the following methods of spark augmentation: starter vibrator (booster coil); both magnetos live.XXX
(05)Explain the function of the magneto check.XXXXX
(06)Explain how combustion is initiated in diesel engines.XXXXX
021 10 08 00Mixture
021 10 08 01Definition, characteristic mixtures, control instruments, associated control levers, indications
(01)Define the following terms: mixture; chemically correct ratio (stoichiometric); best power ratio; lean (weak) mixture (lean or rich side of the exhaust gas temperature (EGT) top); rich mixture.XXXXX
(02)State the typical fuel-to-air ratio values or range of values for the above mixtures.XXXXX
(03)Describe the advantages and disadvantages of weak and rich mixtures.XXXXX
(04)Describe the relation between engine-specific fuel consumption and mixture ratio.XXXXX
(05)Describe the use of the exhaust gas temperature as an aid to mixture-setting.XXXXX
(06)Explain the relation between mixture ratio, cylinder head temperature, detonation and pre-ignition.XXXXX
(07)Explain the absence of mixture control in diesel engines.XXXXX
021 10 09 00Aeroplane: propellers
021 10 09 01Definitions, general
Remark: Definitions and aerodynamic concepts are detailed in Subject 081 ‘Principles of flight (aeroplane)’, Topic 07 (Propellers), but need to be appreciated for this Subject as well.XX
021 10 09 02Constant-speed propeller: design, operation, system components
(01)Describe the operating principle of a constant-speed propeller system under normal flight operations with the aid of a schematic.XX
(02)Explain the need for a MAP indicator to control the power setting with a constant-speed propeller.XX
(03)State the purpose of a torque-meter.XX
(04)State the purpose and describe the operation of a lowpitch stop (centrifugal latch).XX
(05)Describe the operating principle of a single-acting and a double-acting variable pitch propeller for singleand multi-engine aeroplanes.XX
(06)Describe the function and the basic operating principle of synchronising and synchro-phasing systems.XX
(07)Explain the purpose and the basic operating principle of an auto-feathering system and unfeathering.XX
021 10 09 03Reduction gearing: design
(01)State the purpose of reduction gearing.XX
021 10 09 04Propeller handling: associated control levers, degraded modes of operation, indications and warnings
(01)Describe the checks to be carried out on a constantspeed propeller system after engine start.XX
(02)Describe the operation of a constant-speed propeller system during flight at different true airspeeds (TAS) and rpm including an overspeeding propeller.XX
(03)Describe the operating principle of a variable pitch propeller when feathering and unfeathering, including the operation of cockpit controls.XX
(04)Describe the operating principle of a variable pitch propeller when reverse pitch is selected, including the operation of cockpit controls.XX
(05)Describe the operation of the propeller levers during different phases of flight.XX
021 10 10 00Performance and engine handling
021 10 10 01Performance
(01)Describe the effect on power output of a petrol and diesel engine taking into consideration the following parameters: ambient pressure, exhaust back pressure; temperature; density altitude; humidity.XXXXX
(02)Explain the term ‘normally aspirated engine’.XXXXX
(03)Power-augmentation devices: explain the requirement for power augmentation (turbocharging) of a piston engine.XXXXX
(04)Describe the function and the principle of operation of the following main components of a turbocharger: turbine; compressor; waste gate; waste-gate actuator.XXXXX
(05)Explain the difference between an altitude-boosted turbocharger and a ground-boosted turbocharger.XXXXX
(06)Explain turbo lag.XXXXX
(07)Define the term ‘critical altitude’.XXXXX
(08)Explain the function of an intercooler.XXXXX
(09)Define the terms ‘full-throttle height’ and ‘rated altitude’.XXXXX
(10)Explain the purpose of a supercharger and the basic differences from a turbocharger.XXXXX
021 10 10 02Engine handling
(01)State the correct procedures for setting the engine controls when increasing or decreasing power.XXXXX
(02)Define the following terms: take-off power; maximum continuous power.XXXXX
(03)Describe the start problems associated with extreme cold weather.XXXXX
(04)Describe the principal difference between a fullauthority digital engine control (FADEC) systemcontrolled engine and traditional manual engine controls.XXXXX
(05)Describe the engine controls available on the flight deck for a FADEC-controlled engine.XXXXX
(06)Explain that the FADEC has full authority of the control of all engine parameters ensuring efficient and correct running of the engine, including protection in the event of failure.XXXXX
(07)Explain the need for FADEC redundancy with regard to power supply and data input and output.XXXXX
021 11 00 00TURBINE ENGINES
021 11 01 00Basic principles
021 11 01 01Basic generation of thrust and the thrust formula
(01)Describe how thrust is produced by a basic gas turbine engine.XX
(02)Describe the simple form of the thrust formula for a basic, straight jet engine and perform simple calculations (including pressure thrust).XX
(03)State that thrust can be considered to remain approximately constant over the whole aeroplane subsonic speed range.XX
021 11 01 02Design, types and components of turbine engines
(01)List the main components of a basic gas turbine engine: inlet; compressor; combustion chamber; turbine; outlet.XXXXX
(02)Describe the variation of static pressure, temperature and axial velocity in a gas turbine engine under normal operating conditions and with the aid of a working cycle diagram.XXXXX
(03)Describe the differences between absolute, circumferential (tangential) and axial velocity.XXXXX
(04)List the different types of gas turbine engines: straight jet; turbofan; turboprop.XX
(05)State that a gas turbine engine can have one or more spools.XXXXX
(06)Describe how thrust is produced by turbojet and turbofan engines.XX
(07)Describe how power is produced by turboprop engines.XX
(08)Describe the term ‘equivalent horsepower’ (= thrust horsepower + shaft horsepower).XX
(09)Explain the principle of a free turbine or free-power turbine.XXXXX
(10)Define the term ‘bypass ratio’ and perform simple calculations to determine it.XX
(11)Define the terms ‘propulsive power’, ‘propulsive efficiency’, ‘thermal efficiency’ and ‘total efficiency’.XX
(12)Describe the influence of compressor-pressure ratio on thermal efficiency.XXXXX
(13)Explain the variations of propulsive efficiency with forward speed for turbojet, turbofan and turboprop engines.XX
(14)Define the term ‘specific fuel consumption’ for turbojets and turboprops.XX
021 11 01 03Coupled turbine engine: design, operation, components and materials
(01)Name the main assembly parts of a coupled turbine engine and explain its operation.XXX
(02)Explain the limitations of the materials used with regard to maximum turbine temperature, engine and drive train torque limits.XXX
(03)Describe the possible effects on engine components when limits are exceeded.XXX
(04)Explain that when engine limits are exceeded, this event must be reported.XXX
021 11 01 04Free-turbine engine: design, components and materials
(01)Describe the design methods to keep the engine’s size small for installation in helicopters.XXX
(02)List the main components of a free-turbine engine.XXX
(03)Describe how the power is developed by a turboshaft/free-turbine engine.XXX
(04)Explain how the exhaust gas temperature is used to monitor turbine stress.XXX
021 11 02 00Main-engine components
021 11 02 01Aeroplane: air intake
(01)State the functions of the engine air inlet/air intake.XX
(02)Describe the geometry of a subsonic (pitot-type) air inlet.XX
(03)Explain the gas-parameter changes in a subsonic air inlet at different flight speeds.XX
(04)Describe the reasons for, and the dangers of, the following operational problems concerning the engine air inlet: airflow separation; inlet icing; inlet damage; foreign object damage (FOD); heavy in-flight turbulence.XX
021 11 02 02Compressor and diffuser
(01)State the purpose of the compressor.XXXXX
(02)Describe the working principle of a centrifugal and an axial flow compressor.XXXXX
(03)Name the following main components of a single stage and describe their function for a centrifugal compressor: impeller; diffuser.XXXXX
(04)Name the following main components of a single stage and describe their function for an axial compressor: rotor vanes; stator vanes.XXXXX
(05)Describe the gas-parameter changes in a compressor stage.XXXXX
(06)Define the term ‘pressure ratio’ and state a typical value for one stage of a centrifugal and an axial flow compressor and for the complete compressor.XXXXX
(07)State the advantages and disadvantages of increasing the number of stages in a centrifugal compressor.XXXXX
(08)Explain the difference in sensitivity for FOD of a centrifugal compressor compared with an axial flow type.XXXXX
(09)Explain the convergent air annulus through an axial flow compressor.XXXXX
(10)Describe the reason for twisting the compressor blades.XXXXX
(11)State the tasks of inlet guide vanes (IGVs).XXXXX
(12)State the reason for the clicking noise whilst the compressor slowly rotates on the ground.XXXXX
(13)State the advantages of increasing the number of spools.XXXXX
(14)Explain the implications of tip losses and describe the design features to minimise the problem.XXXXX
(15)Explain the problems of blade bending and flapping and describe the design features to minimise the problem.XXXXX
(16)Explain the following terms: compressor stall; engine surge.XXXXX
(17)State the conditions that are possible causes of stall and surge.XXXXX
(18)Describe the indications of stall and surge.XXXXX
(19)Describe the design features used to minimise the occurrence of stall and surge.XXXXX
(20)Describe a compressor map (surge envelope) with rpm lines, stall limit, steady state line and acceleration line.XXXXX
(21)Describe the function of the diffuser.XXXXX
021 11 02 03Combustion chamber
(01)Define the purpose of the combustion chamber.XXXXX
(02)List the requirements for combustion.XXXXX
(03)Describe the working principle of a combustion chamber.XXXXX
(04)Explain the reason for reducing the airflow axial velocity at the combustion chamber inlet (snout).XXXXX
(05)State the function of the swirl vanes (swirler).XXXXX
(06)State the function of the drain valves.XXXXX
(07)Define the terms ‘primary airflow’ and ‘secondary airflow’, and explain their purpose.XXXXX
(08)Explain the following two mixture ratios: primary airflow to fuel; total airflow (within the combustion chamber) to fuel.XXXXX
(09)Describe the gas-parameter changes in the combustion chamber.XXXXX
(10)State a typical maximum value of the outlet temperature of the combustion chamber.XXXXX
(11)Describe the following types of combustion chambers and state the differences between them: can type; can-annular, cannular or turbo-annular; annular; reverse-flow annular.XXXXX
021 11 02 04Turbine
(01)Explain the purpose of a turbine in different types of gas turbine engines.XXXXX
(02)Describe the principles of operation of impulse, reaction and impulse-reaction axial flow turbines.XXXXX
(03)Name the main components of a turbine stage and their function.XXXXX
(04)Describe the working principle of a turbine.XXXXX
(05)Describe the gas-parameter changes in a turbine stage.XXXXX
(06)Describe the function and the working principle of active clearance control.XX
(07)Describe the implications of tip losses and the means to minimise them.XXXXX
(08)Explain why the available engine thrust is limited by the turbine inlet temperature.XX
(09)Explain the divergent gas-flow annulus through an axial-flow turbine.XXXXX
(10)Explain the high mechanical thermal stress in the turbine blades and wheels/discs.XXXXX
021 11 02 05Aeroplane: exhaust
(01)Name the following main components of the exhaust unit and their function: jet pipe; propelling nozzle; exhaust cone.XX
(02)Describe the working principle of the exhaust unit.XX
(03)Describe the gas-parameter changes in the exhaust unit.XX
(04)Define the term ‘choked exhaust nozzle’ (not applicable to turboprops).X
(05)Explain how jet exhaust noise can be reduced.XX
021 11 02 06Helicopter: air intake
(01)Name and explain the main task of the engine air intake.XXX
(02)Describe the use of a convergent air-intake ducting on helicopters.XXX
(03)Describe the reasons for and the dangers of the following operational problems concerning engine air intake: airflow separations; intake icing; intake damage; FOD; heavy in-flight turbulence.XXX
(04)Describe the conditions and circumstances during ground operations when FOD is most likely to occur.XXX
(05)Describe and explain the principles of air intake filter systems that can be fitted to some helicopters for operations in icing and sand conditions.XXX
(06)Describe the function of the heated pads on some helicopter air intakes.XXX
021 11 02 07Helicopter: exhaust
(01)Describe the working principle of the exhaust unit.XXX
(02)Describe the gas-parameter changes in the exhaust unit.XXX
021 11 03 00Additional components and systems
021 11 03 01Engine fuel system
(01)Name the main components of the engine fuel system and state their function: filters; low-pressure (LP) pump; high-pressure (HP) pump; fuel manifold; fuel nozzles; HP fuel cock; fuel control; or hydromechanical unit.XXXXX
(02)Name the two types of engine-driven high-pressure pumps, such as: gear-type; swash plate-type.XXXXX
(03)State the tasks of the fuel control unit.XXXXX
(04)List the possible input parameters to a fuel control unit to achieve a given thrust/power setting.XXXXX
021 11 03 02Engine control system
(01)State the tasks of the engine control system.XXXXX
(02)List the following different types of engine control systems: hydromechanical; hydromechanical with a limited authority electronic supervisor; single-channel FADEC with hydromechanical backup; dual-channel FADEC with no backup or any other combination.XXXXX
(03)Describe a FADEC as a full-authority dual-channel system including functions such as an electronic engine control unit, wiring, sensors, variable vanes, active clearance control, bleed configuration, electrical signalling of thrust lever angle (TLA) (see also AMC to CS-E-50), and an EGT protection function and engine overspeed.XXX
(04)Explain how redundancy is achieved by using more than one channel in a FADEC system.XXX
(05)State the consequences of a FADEC single input data failure.XXX
(06)State that all input and output data is checked by both channels in a FADEC system.XXX
(07)State that a FADEC system uses its own sensors and that, in some cases, also data from aircraft systems is used.XXX
(08)State that a FADEC must have its own source of electrical power.XXX
021 11 03 03Engine lubrication
(01)State the tasks of an engine lubrication system.XX
(02)Name the following main components of a lubrication system and state their function: oil tank and centrifugal breather; oil pumps (pressure and scavenge pumps); oil filters (including the bypass); oil sumps; chip detectors; coolers.XX
(03)Explain that each spool is fitted with at least one ball bearing and two or more roller bearings.XX
(04)Explain the use of compressor air in oil-sealing systems (e.g. labyrinth seals).XX
021 11 03 04Engine auxiliary gearbox
(01)State the tasks of the auxiliary gearbox.XX
(02)Describe how the gearbox is driven and lubricated.XX
021 11 03 05Engine ignition
(01)State the task of the ignition system.XX
(02)Name the following main components of the ignition system and state their function: power sources; igniters.XX
(03)State why jet turbine engines are equipped with two electrically independent ignition systems.XX
(04)Explain the different modes of operation of the ignition system.XX
021 11 03 06Engine starter
(01)Name the main components of the starting system and state their function.XX
(02)Explain the principle of a turbine engine start.XX
(03)Describe the following two types of starters: electric; pneumatic.XX
(04)Describe a typical start sequence (on ground/in flight) for a turbofan.XX
(05)Define ‘self-sustaining rpm’.XX
021 11 03 07Reverse thrust
(01)Name the following main components of a reverse-thrust system and state their function: reverse-thrust select lever; power source (pneumatic or hydraulic); actuators; doors; annunciations.XX
(02)Explain the principle of a reverse-thrust system.XX
(03)Identify the advantages and disadvantages of using reverse thrust.XX
(04)Describe and explain the following different types of thrust-reverser systems: hot-stream reverser; clamshell or bucket-door system; cold-stream reverser (only turbofan engines); blocker doors; cascade vanes.XX
(05)Explain the implications of reversing the cold stream (fan reverser) only on a high bypass ratio engine.XX
(06)Describe the protection features against inadvertent thrust-reverse deployment in flight as present on most transport aeroplanes.XX
(07)Describe the controls and indications provided for the thrust-reverser system.XX
021 11 03 08Helicopter specifics on design, operation and components for additional components and systems such as lubrication system, ignition circuit, starter, accessory gearbox
(01)State the task of the lubrication system.XXX
(02)List and describe the common helicopter lubrication systems.XXX
(03)Name the following main components of a helicopter lubrication system: reservoir; pump assembly; external oil filter; magnetic chip detectors, electronic chip detectors; thermostatic oil coolers; breather.XXX
(04)Identify and name the components of a helicopter lubrication system from a diagram.XXX
(05)Identify the indications used to monitor a lubrication system including warning systems.XXX
(06)Explain the differences and appropriate use of straight oil and compound oil, and describe the oil numbering system for aviation use.XXX
(07)Explain and describe the ignition circuit for engine start and engine relight facility when the selection is set for both automatic and manual functions.XXX
(08)Explain and describe the starter motor and the sequence of events when starting, and that for most helicopters the starter becomes the generator after the starting sequence is over.XXX
(09)Explain and describe why the engine drives the accessory gearbox.XXX
021 11 04 00Engine operation and monitoring
021 11 04 01General
(01)Explain the following aeroplane engine ratings: take-off; go-around; maximum continuous thrust/power; maximum climb thrust/power.XX
(02)Explain spool-up time.XXXXX
(03)Explain the reason for the difference between ground and approach flight idle values (rpm).XX
(04)State the parameters that can be used for setting and monitoring the thrust/power.XXXXX
(05)Describe the terms ‘alpha range’, ‘beta range’ and ‘reverse thrust’ as applied to a turboprop power lever.XX
(06)Explain the dangers of inadvertent beta-range selection in flight for a turboprop.XX
(07)Explain the purpose of engine trending.XX
(08)Explain how the exhaust gas temperature is used to monitor turbine stress.XXXXX
(09)Describe the effect of engine acceleration and deceleration on the EGT.XXXX
(10)Describe the possible effects on engine components when EGT limits are exceeded.XXXXX
(11)Explain why engine-limit exceedances must be reported.XXXXX
(12)Explain the limitations on the use of the thrust-reverser system at low forward speed.XXX
(13)Explain the term ‘engine seizure’.XXXXX
(14)State the possible causes of engine seizure and explain their preventative measures.XXXXX
(15)Describe the potential consequences of a leak in the following two designs of fuel and oil heat exchanger: oil pressure higher than fuel pressure with oil leaking into the fuel system, potentially affecting the combustion and running of the engine; fuel pressure higher than oil pressure with fuel leaking into the oil system, potentially increasing the risk of a fire due to fuel entering warm parts of the engine that should be free from fuel.XXXXX
(16)Explain oil-filter clogging (blockage) and the implications for the lubrication system.XXXXX
(17)Give examples of monitoring instruments of an engine.XXXXX
(18)Describe how to identify and assess engine damage based on instrument indications.XXXXX
021 11 04 02Starting malfunctions
(01)Describe the indications and the possible causes of the following aeroplane starting malfunctions: false (dry or wet) start; tailpipe fire (torching); hot start; abortive (hung) start; no N1 rotation; no FADEC indications.XX
(02)Describe the indications and the possible causes of the following helicopter starting malfunctions: false (dry or wet) start; tailpipe fire (torching); hot start; abortive (hung) start; no N1 rotation; freewheel failure; no FADEC indications.XXX
021 11 04 03Relight envelope
(01)Explain the relight envelope.XX
021 11 05 00Performance aspects
021 11 05 01Thrust, performance aspects, and limitations
(01)Describe the variation of thrust and specific fuel consumption with altitude at constant TAS.XX
(02)Describe the variation of thrust and specific fuel consumption with TAS at constant altitude.XX
(03)Explain the term ‘flat-rated engine’ by describing the change of take-off thrust, turbine inlet temperature and engine rpm with outside air temperature (OAT).XX
(04)Define the term ‘engine pressure ratio’ (EPR).XX
(05)Explain the use of reduced (flexible) and derated thrust for take-off, and explain the advantages and disadvantages when compared with a full-rated takeoff.XX
(06)Describe the effects of use of bleed air on rpm, EGT, thrust, and specific fuel consumption.XX
021 11 05 02Helicopter engine ratings, engine performance and limitations, engine handling: torque, performance aspects and limitations
(01)Describe engine rating torque limits for take-off, transient and maximum continuous.XXX
(02)Describe turbine outlet temperature (TOT) limits for take-off.XXX
(03)Explain why TOT is a limiting factor for helicopter performance.XXX
(04)Describe and explain the relationship between maximum torque available and density altitude, which leads to decreasing torque available with the increase of density altitude.XXX
(05)Explain that hovering downwind, on some helicopters, will noticeably increase the engine TOT.XXX
(06)Explain the reason why the engine performance is less when aircraft accessories (i.e. anti-ice, heating, hoist, filters) are switched on.XXX
(07)Describe the effects of use of bleed air on engine parameters.XXX
(08)Explain that, on some helicopters, exceeding the TOT limit may cause the main rotor to droop (slow down).XXX
(09)Describe overtorquing and explain the consequences.XXX
021 11 06 00Auxiliary power unit (APU)
021 11 06 01Design, operation, functions, operational limitations
(01)State that an APU is a gas turbine engine and list its tasks.XXX
(02)State the difference between the two types of APU inlets.XXX
(03)Define ‘maximum operating and maximum starting altitude’.XXX
(04)Name the typical APU control and monitoring instruments.XXX
(05)Describe the APU’s automatic shutdown protection.XXX
021 12 00 00PROTECTION AND DETECTION SYSTEMS
021 12 01 00Smoke detection
021 12 01 01Types, design, operation, indications and warnings
(01)Explain the operating principle of the following types of smoke detection sensors: optical; ionising.XXXXX
(02)Give an example of warnings, indications and function tests.XXXXX
021 12 02 00Fire-protection systems
021 12 02 01Fire extinguishing (engine and cargo compartments)
(01)Explain the operating principle of a built-in fireextinguishing system and describe its components.XXXXX
(02)State that two discharges must be provided for each engine (see CS 25.1195(c) Fire-extinguisher systems).XX
021 12 02 02Fire detection
(01)Explain the following principles of fire detection: resistance and capacitance; gas pressure.XXXXX
(02)Explain fire-detection applications such as: bimetallic; continuous loop; gaseous loop (gas-filled detectors).XXXXX
(03)Explain why generally double-loop systems are used.XXXXX
(04)Give an example of warnings, indications and function tests of a fire-protection system.XXXXX
021 12 03 00Rain-protection system
021 12 03 01Principle and method of operation
(01)Explain the principle and method of operation of the following windshield rain-protection systems for an aeroplane: wipers; liquids (rain-repellent); coating.XX
(02)Explain the principle and method of operation of wipers for a helicopter.XXX
021 13 00 00OXYGEN SYSTEMS
021 13 01 00Cockpit, portable and chemical oxygen systems
021 13 01 01Operating principles, actuation methods, comparison
(01)Describe the basic operating principle of a cockpit oxygen system and describe the following different modes of operation: normal (diluter demand); 100 %; emergency.XX
(02)Describe the operating principle and the purposes of the following two portable oxygen systems: smoke hood; portable bottle.XX
(03)Describe the following two oxygen systems that can be used to supply oxygen to passengers: fixed system (chemical oxygen generator or gaseous system); portable.XX
(04)Describe the actuation methods (automatic and manual) and the functioning of a passenger oxygen mask.XX
(05)Compare chemical oxygen generators to gaseous systems with respect to: capacity; flow regulation.XX
(06)State the dangers of grease or oil related to the use of oxygen systems.XX
021 14 00 00HELICOPTER: MISCELLANEOUS SYSTEMS
021 14 01 00Variable rotor speed, active vibration suppression, night-vision goggles (NVG)
021 14 01 01Variable rotor speed
(01)Explain the system for ‘beeping’ the NR to its upper limit.XXX
021 14 01 02Active vibration suppression
(01)Explain and describe how the active vibration suppression system works through high-speed actuators and accelerometer inputs.XXX
021 14 01 03NVG
To be introduced at a later date.XXX
021 15 00 00HELICOPTER: ROTOR HEADS
021 15 01 00Main rotor
021 15 01 01Types
(01)Describe the following rotor-head systems: teetering (semi-articulated); articulated; hingeless (rigid); bearingless (semi-articulated).XXX
(02)Describe in basic terms the following configuration of rotor systems and their advantages and disadvantages: tandem; coaxial; side by side.XXX
(03)Explain how flapping, dragging and feathering is achieved in each rotor-head system.XXX
021 15 01 02Structural components and materials, stresses, structural limitations
(01)Identify from a diagram the main structural components of the main types of rotor-head systems.XXX
(02)List and describe the methods used to detect damage and cracks.XXX
(03)Explain and describe the structural limitations to respective rotor systems, including the dangers of negative G inputs to certain rotor-head systems.XXX
(04)Describe the various rotor-head lubrication methods.XXX
021 15 01 03Design and construction
(01)Describe the material technology used in rotor-head design, including construction, using the following materials or mixture of materials: composites; fibreglass; alloys; elastomers.XXX
021 15 01 04Adjustment
(01)Describe and explain the methods of adjustment which are possible on various helicopter rotor-head assemblies.XXX
021 15 02 00Tail rotor
021 15 02 01Types
(01)Describe the following tail-rotor systems: delta-3 hinge effect; multi-bladed delta-3 effect; Fenestron or ducted fan tail rotor; no tail rotor (NOTAR) low-velocity air jet flows from tangential slots (the Coandă effect); NOTAR high-velocity air jet flows from adjustable nozzles (the Coandă effect).XXX
(02)Identify from a diagram the main structural components of the four main types of tail-rotor systems.XXX
(03)Explain and describe the methods to detect damage and cracks on the tail rotor and assembly.XXX
(04)Explain and describe the structural limitations to the respective tail-rotor systems and possible limitations regarding the turning rate of the helicopter.XXX
(05)Explain and describe the following methods that helicopter designers use to minimise tail-rotor drift and roll: reducing the couple arm (tail rotor on a pylon); offsetting the rotor mast; use of ‘bias’ in cyclic control mechanism.XXX
(06)Explain pitch-input mechanisms.XXX
(07)Explain the relationship between tail-rotor thrust and engine power.XXX
(08)Describe how the vertical fin on some types reduces the power demand of the tail rotor.XXX
021 15 02 02Design and construction
(01)List and describe the various tail-rotor designs and construction methods used on helicopters currently in service.XXX
021 16 00 00HELICOPTER: TRANSMISSION
021 16 01 00Main gearbox
021 16 01 01Different types, design, operation, limitations
(01)Describe the following main principles of helicopter transmission systems for singleand twin-engine helicopters: drive for the main and tail rotor; accessory drive for the generator(s), alternator(s), hydraulic and oil pumps, oil cooler(s) and tachometers.XXX
(02)Describe the reason for limitations on multi-engine helicopter transmissions in various engine-out situations.XXX
(03)Describe how the passive vibration control works with gearbox mountings.XXX
021 16 02 00Rotor brake
021 16 02 01Types, operational considerations
(01)Describe the main function of the disc type of rotor brake.XXX
(02)Describe both hydraulicand cable-operated rotorbrake systems.XXX
(03)Describe the different options for the location of the rotor brake.XXX
(04)List the following operational considerations for the use of rotor brakes: rotor speed at engagement of rotor brake; risk of blade sailing in windy conditions; risk of rotor-brake overheating and possible fire when brake is applied above the maximum limit, particularly when spilled hydraulic fluid is present; avoid stopping blades over jet-pipe exhaust with engine running; cockpit annunciation of rotor-brake operation.XXX
021 16 03 00Auxiliary systems
021 16 03 01Powering the air-conditioning system
(01)Explain how power for the air-conditioning system is taken from the auxiliary gearbox.XXX
021 16 04 00Driveshaft and associated installation
021 16 04 01Power, construction, materials, speed and torque
(01)Describe how power is transmitted from the engine to the main-rotor gearbox.XXX
(02)Describe the material and construction of the driveshaft.XXX
(03)Explain the need for alignment between the engine and the mainrotor gearbox.XXX
(04)Identify how temporary misalignment occurs between driving and driven components.XXX
(05)Explain the relationship between driveshaft speed and torque.XXX
(06)Describe the methods with which power is delivered to the tail rotor.XXX
(07)Describe and identify the construction and materials of tail-rotor/Fenestron driveshafts.XXX
021 16 05 00Intermediate and tail gearbox
021 16 05 01Lubrication, gearing
(01)Explain and describe the various arrangements when the drive changes direction and the need for an intermediate or tail gearbox.XXX
(02)Explain the lubrication requirements for intermediate and tail-rotor gearboxes and methods of checking levels.XXX
(03)Explain how on most helicopters the tail-rotor gearbox contains gearing, etc., for the tail-rotor pitch-change mechanism.XXX
021 16 06 00Clutches
021 16 06 01Purpose, operation, components, serviceability
(01)Explain the purpose of a clutch.XXX
(02)Describe and explain the operation of a: centrifugal clutch; actuated clutch.XXX
(03)List the typical components of the various clutches.XXX
(04)Identify the following methods by which clutch serviceability can be ascertained: brake-shoe dust; vibration; main-rotor run-down time; engine speed at time of main-rotor engagement; belt tensioning; start protection in a belt-drive clutch system.XXX
021 16 07 00Freewheels
021 16 07 01Purpose, operation, components, location
(01)Explain the purpose of a freewheel.XXX
(02)Describe and explain the operation of a: camand roller-type freewheel; sprag-clutch-type freewheel.XXX
(03)List the typical components of the various freewheels.XXX
(04)Identify the various locations of freewheels in power plant and transmission systems.XXX
(05)Explain the implications regarding the engagement and disengagement of the freewheel.XXX
021 17 00 00HELICOPTER: BLADES
021 17 01 00Main-rotor design and blade design
021 17 01 01Design, construction
(01)Describe the different types of blade construction and the need for torsional stiffness.XXX
(02)Describe the principles of heating systems/pads on some blades for anti-icing/de-icing.XXX
(03)Describe the fully articulated rotor with hinges and feathering hinges.XXX
021 17 01 02Structural components and materials
(01)List the materials used in the construction of mainrotor blades.XXX
(02)List the main structural components of a main-rotor blade and their function.XXX
(03)Describe the drag hinge of the fully articulated rotor and the lag flexure in the hingeless rotor.XXX
(04)Explain the necessity for drag dampers.XXX
021 17 01 03Forces and stresses
(01)Describe main-rotor blade-loading on the ground and in flight.XXX
(02)Describe where the most common stress areas are on rotor blades.XXX
(03)Show how the centrifugal forces depend on rotor rpm and blade mass and how they pull on the blade’s attachment to the hub. Justify the upper limit of the rotor rpm.XXX
(04)Assume a rigid attachment and show how thrust may cause huge oscillating bending moments which stress the attachment.XXX
(05)Explain why flapping hinges do not transfer such moments. Show the small flapping hinge offset on fully articulated rotors and zero offset in the case of teetering rotors.XXX
(06)Describe the working principle of the flexible element in the hingeless rotor and describe the equivalent flapping hinge offset compared to that of the articulated rotor.XXX
021 17 01 04Structural limitations
(01)Explain the structural limitations in terms of bending and rotor rpm.XXX
021 17 01 05Adjustment
(01)XExplain the use of trim tabs.XXX
021 17 01 06Tip shape
(01)Describe the various blade-tip shapes used by different manufacturers and compare their advantages and disadvantages.XXX
021 17 01 07Origins of the vertical vibrations
(01)Explain the lift (thrust) variations per revolution of a blade and the resulting vertical total rotor thrust (TRT) variation in the case of perfectly identical blades.XXX
(02)Show the resulting frequencies and amplitudes as a function of the number of blades.XXX
(03)Explain the thrust variation in the case of an out-of-track blade, causes, and frequencies (one-per-revolution).XXX
021 17 01 08Lateral vibrations
(01)Explain blade imbalances, causes, and effects.XXX
021 17 02 00Tail-rotor design and blade design
021 17 02 01Design, construction
(01)Describe the most common design of tail-rotor blade construction, consisting of stainless steel shell reinforced by a honeycomb filler and stainless steel leading abrasive strip.XXX
(02)Explain that ballast weights are located at the inboard trailing edge and tip of blades, and that the weights used are determined when the blades are manufactured.XXX
(03)Describe how, for some helicopters, anti-icing/de-icing systems are designed into the blade construction.XXX
(04)Describe the two-bladed rotor with a teetering hinge, and rotors with more than two blades.XXX
(05)Describe the dangers to ground personnel and to the rotor blades, and how to minimise these dangers.XXX
021 17 02 02Intentionally left blank
021 17 02 03Stresses, vibrations and balancing
(01)Describe the tail-rotor blade-loading on the ground and in flight.XXX
(02)Explain the sources of vibration of the tail rotor and the resulting high frequencies.XXX
(03)Explain balancing and tracking of the tail rotor.XXX
021 17 02 04Structural limitations
(01)Describe the structural limitations of the tail-rotor blades.XXX
(02)Describe the method of checking the strike indicators placed on the tip of some tail-rotor blades.XXX
021 17 02 05Adjustment
(01)Describe the adjustment of yaw pedals in the cockpit to obtain full-control authority of the tail rotor.XXX
021 17 02 06The Fenestron
(01)Describe the technical layout of a Fenestron tail rotor.XXX
(02)Explain the advantages and disadvantages of a Fenestron tail rotor.XXX
021 17 02 07No tail rotor (NOTAR)
(01)Describe the technical layout of a NOTAR design.XXX
(02)Explain the control concepts of a NOTAR.XXX
(03)Explain the advantages and disadvantages of a NOTAR design.XXX

IR — Regulation (EU) No 1178/2011 · ED Decision 2020/018/R · Aircrew Easy Access Rules · EAR revision 25 Nov 2025

All rules in SUBPART D – COMMERCIAL PILOT LICENCE – CPL

Consolidated from the EASA Easy Access Rules (revision 25 Nov 2025, extracted 17 Aug 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.

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