SUBPART E – POWERPLANT
Large Aeroplanes (CS-25) · CS-25 · CS 25.901 – CS 25.1207
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CS 25.901 Installation
For the purpose of this CS-25 the aeroplane powerplant installation includes each component that – (1) Is necessary for propulsion;
AMC 25.901(b)(2) Assembly of Components
CS 25.903 Engines
(See AMC 25.903) (a) Engine type certification. reserved (2) Any engine not certificated to CS-E must be shown to comply with CS-E 790 and CS-E 800 or be…
CS 25.904 Automatic Takeoff Thrust Control System (ATTCS)
Aeroplanes equipped with an engine power control system that automatically resets the power or thrust on the operating engine(s) when any engine fails…
CS 25.905 Propellers
(See AMC 25.905) (a) reserved (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated.
CS 25.907 Propeller vibration
(See CS-P 530 and CS-P 550.) (a) The magnitude of the propeller blade vibration stresses under any normal condition of operation must be determined by…
CS 25.925 Propeller clearance
Unless smaller clearances are substantiated, propeller clearances with the aeroplane at maximum weight, with the most adverse centre of gravity, and with…
CS 25.929 Propeller de-icing
(See AMC 25.929) (a) If certification for flight in icing conditions is sought, there must be a means to prevent or remove hazardous ice accumulations…
CS 25.933 Reversing systems
(See AMC 25.933) (a) For turbojet reversing systems: Each system intended for ground operation only must be designed so that either:
AMC 25.933(a)(1) Unwanted in-flight thrust reversal of turbojet thrust reversers
CS 25.934 Turbo-jet engine thrust reverser system tests
Thrust reversers installed on turbo-jet engines must meet the requirements of CS-E 890.
CS 25.937 Turbo-propeller-drag limiting systems
Turbo-propeller powered aeroplane propeller-drag limiting systems must be designed so that no single failure or malfunction of any of the systems during…
CS 25.939 Turbine engine operating characteristics
(See AMC 25.939) (a) Turbine engine operating characteristics must be investigated in flight to determine that no adverse characteristics (such as stall…
AMC 25.939(a) Turbine engine operating characteristics
CS 25.941 Inlet, engine, and exhaust compatibility
For aeroplanes using variable inlet or exhaust system geometry, or both – (a) The system comprised of the inlet, engine (including thrust augmentation…
CS 25.943 Negative acceleration
No hazardous malfunction of an engine or any component or system associated with the powerplant may occur when the aeroplane is operated at the negative…
CS 25.945 Thrust or power augmentation system
General. Each fluid injection system must provide a flow of fluid at the rate and pressure established for proper engine functioning under each intended…
CS 25.951 General
Each fuel system must be constructed and arranged to ensure a flow of fuel at a rate and pressure established for proper engine functioning under each…
CS 25.952 Fuel system analysis and test
Proper fuel system functioning under all probable operating conditions must be shown by analysis and those tests found necessary by the Agency.
CS 25.953 Fuel system independence
Each fuel system must meet the requirements of CS 25.903(b) by – (a) Allowing the supply of fuel to each engine through a system independent of each part…
CS 25.954 Fuel system lightning protection
(See AMC 25.954) (a) For the purposes of this paragraph— (1) A critical lightning strike is a lightning strike that attaches to the aeroplane in a…
CS 25.955 Fuel flow
(See AMC 25.955) (a) Each fuel system must provide at least 100% of the fuel flow required under each intended operating condition and manoeuvre.
CS 25.957 Flow between interconnected tanks
If fuel can be pumped from one tank to another in flight, the fuel tank vents and the fuel transfer system must be designed so that no structural damage…
CS 25.959 Unusable fuel supply
The unusable fuel quantity for each fuel tank and its fuel system components must be established at not less than the quantity at which the first…
CS 25.961 Fuel system hot weather operation
The fuel system must perform satisfactorily in hot weather operation.
CS 25.963 Fuel tanks: general
(See AMC 25.963) (a) Each fuel tank must be able to withstand, without failure, the vibration, inertia, fluid and structural loads that it may be…
AMC 25.963(a) Fuel tanks: General
AMC 25.963(d) Fuel tank strength in emergency landing conditions
CS 25.965 Fuel tank tests
It must be shown by tests that the fuel tanks, as mounted in the aeroplane can withstand, without failure or leakage, the more critical of the pressures…
CS 25.967 Fuel tank installations
(See AMC 25.967) (a) Each fuel tank must be supported so that tank loads (resulting from the weight of the fuel in the tanks) are not concentrated on…
CS 25.969 Fuel tank expansion space
Each fuel tank must have an expansion space of not less than 2% of the tank capacity.
CS 25.971 Fuel tank sump
Each fuel tank must have a sump with an effective capacity, in the normal ground attitude, of not less than the greater of 0·10% of the tank capacity or…
CS 25.973 Fuel tank filler connection
Each fuel tank filler connection must prevent the entrance of fuel into any part of the aeroplane other than the tank itself.
CS 25.975 Fuel tank vents
Fuel tank vents. Each fuel tank must be vented from the top part of the expansion space so that venting is effective under any normal flight condition.
Appendix A Example of Calculation for Fuel-to-Air Ratio
Table A-1. Combustion Properties of Hexane Property Value Heat of combustion, BTU/lb.
CS 25.977 Fuel tank outlet
There must be a fuel strainer for the fuel tank outlet or for the booster pump.
CS 25.979 Pressure fuelling system
(See AMC 25.979) For pressure fuelling systems, the following apply:
CS 25.981 Fuel tank explosion prevention
No ignition source may be present at each point in the fuel tank or fuel tank system where catastrophic failure could occur due to ignition of fuel or…
AMC 25.981(a) Fuel Tank Ignition Source Prevention
CS 25.991 Fuel pumps
Main pumps. Each fuel pump required for proper engine operation, or required to meet the fuel system requirements of this Subpart (other than those in…
CS 25.993 Fuel system lines and fittings
Each fuel line must be installed and supported to prevent excessive vibration and to withstand loads due to fuel pressure and accelerated flight…
CS 25.994 Fuel system components
(See AMC 25.994) Fuel system components in an engine nacelle or in the fuselage must be protected from damage which could result in spillage of enough…
CS 25.995 Fuel valves
In addition to the requirements of CS 25.1189 for shut-off means, each fuel valve must – (a) Reserved.
CS 25.997 Fuel strainer or filter
There must be a fuel strainer or filter between the fuel tank outlet and the inlet of either the fuel metering device or an engine driven positive…
CS 25.999 Fuel systems drains
Drainage of the fuel system must be accomplished by the use of fuel strainer and fuel tank sump drains.
CS 25.1001 Fuel jettisoning system
A fuel jettisoning system must be installed on each aeroplane unless it is shown that the aeroplane meets the climb requirements of CS 25.119 and…
CS 25.1011 General
Each engine must have an independent oil system that can supply it with an appropriate quantity of oil at a temperature not above that safe for…
CS 25.1013 Oil tanks
Installation. Each oil tank installation must meet the requirements of CS 25.967.
CS 25.1015 Oil tank tests
Each oil tank must be designed and installed so that – (a) It can withstand, without failure, each vibration, inertia, and fluid load that it may be…
CS 25.1017 Oil lines and fittings
Each oil line must meet the requirements of CS 25.993 and each oil line and fitting in any designated fire zone must meet the requirements of CS 25.1183.
CS 25.1019 Oil strainer or filter
Each turbine engine installation must incorporate an oil strainer or filter through which all of the engine oil flows and which meets the following…
CS 25.1021 Oil system drains
A drain (or drains) must be provided to allow safe drainage of the oil system.
CS 25.1023 Oil radiators
Each oil radiator must be able to withstand, without failure, any vibration, inertia, and oil pressure load to which it would be subjected in operation.
CS 25.1025 Oil valves
Each oil shut-off must meet the requirements of CS 25.1189. The closing of oil shut-off means may not prevent propeller feathering.
CS 25.1027 Propeller feathering system
(See AMC 25.1027.) (a) If the propeller feathering system depends on engine oil, there must be means to trap an amount of oil in the tank if the supply…
CS 25.1041 General
The powerplant cooling provisions must be able to maintain the temperatures of powerplant components, and engine fluids, within the temperature limits…
CS 25.1043 Cooling tests
(See AMC 25.1043) (a) General. Compliance with CS 25.1041 must be shown by tests, under critical ground and flight operating conditions.
CS 25.1045 Cooling test procedures
Compliance with CS 25.1041 must be shown for the take-off, climb, en-route, and landing stages of flight that correspond to the applicable performance…
CS 25.1091 Air intake
(See AMC 25.1091) (a) The air intake system for each engine must supply – (1) The air required by that engine under each operating condition for which…
CS 25.1093 Air intake system de-icing and anti-icing provisions
(See AMC 25.1093) (a) Reserved. Turbine engines Each engine, with all icing protection systems operating, must:
CS 25.1103 Air intake system ducts and air duct systems
(See AMC 25.1103) (a) Reserved. Each air intake system must be – (1) Strong enough to prevent structural failure resulting from engine surging;
CS 25.1121 General
(See AMC 25.1121) For powerplant installations the following apply:
CS 25.1123 Exhaust piping
For powerplant installations, the following apply: Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due…
CS 25.1141 Powerplant controls: general
(See AMC 25.1141) Each powerplant control must be located, arranged, and designed under CS 25.777 to 25.781 and marked under CS 25.1555.
CS 25.1143 Engine controls
There must be a separate power or thrust control for each engine.
CS 25.1145 Ignition switches
Ignition switches must control each engine ignition circuit on each engine.
CS 25.1149 Propeller speed and pitch controls
There must be a separate propeller speed and pitch control for each propeller.
CS 25.1153 Propeller feathering controls
There must be a separate propeller feathering control for each propeller.
CS 25.1155 Reverse thrust and propeller pitch settings below the flight regime
(See AMC 25.1155) Each control for selecting propeller pitch settings below the flight regime (reverse thrust for turbo-jet powered aeroplanes) must have…
AMC 25.1155 Reverse thrust and propeller pitch settings below the flight regime
CS 25.1161 Fuel jettisoning system controls
Each fuel jettisoning system control must have guards to prevent inadvertent operation.
CS 25.1163 Powerplant accessories
Each engine-mounted accessory must – (1) Be approved for mounting on the engine involved;
CS 25.1165 Engine ignition systems
Each battery ignition system must be supplemented by a generator that is automatically available as an alternate source of electrical energy to allow…
CS 25.1167 Accessory gearboxes
For aeroplanes equipped with an accessory gearbox that is not certificated as part of an engine – (a) The engine with gearbox and connecting…
CS 25.1181 Designated fire zones: regions included
(See AMC 25.1181.) (a) Designated fire zones are – (1) The engine power section;
CS 25.1182 Nacelle areas behind firewalls, and engine pod attaching structures containing flammable fluid lines
Each nacelle area immediately behind the firewall, and each portion of any engine pod attaching structure containing flammable fluid lines, must meet…
CS 25.1183 Flammable fluid-carrying components
Except as provided in sub-paragraph (b) of this paragraph, each line, fitting, and other component carrying flammable fluid in any area subject to engine…
CS 25.1185 Flammable fluids
No tank or reservoir that is a part of a system containing flammable fluids or gases may be in a designated fire zone unless the fluid contained, the…
CS 25.1187 Drainage and ventilation of fire zones
There must be complete drainage of each part of each designated fire zone to minimise the hazards resulting from failure or malfunctioning of any…
CS 25.1189 Shut-off means
(See AMC 25.1189.) (a) Each engine installation and each fire zone specified in CS 25.1181(a)(5) must have a means to shut off or otherwise prevent…
CS 25.1191 Firewalls
Each engine, fuel-burning heater, other combustion equipment intended for operation in flight, and the combustion, turbine, and tailpipe sections of…
CS 25.1193 Cowling and nacelle skin
Each cowling must be constructed and supported so that it can resist any vibration, inertia, and air load to which it may be subjected in operation.
AMC 25.1193(e) Engine cowling and nacelle skin, APU compartment external skin
CS 25.1195 Fire-extinguisher systems
(See AMC 25.1195) (a) Except for combustor, turbine, and tail pipe sections of turbine engine installations that contain lines or components carrying…
CS 25.1197 Fire-extinguishing agents
(See AMC 25.1197.) (a) Fire-extinguishing agents must – (1) Be capable of extinguishing flames emanating from any burning of fluids or other combustible…
CS 25.1199 Extinguishing agent containers
Each extinguishing agent container must have a pressure relief to prevent bursting of the container by excessive internal pressures.
CS 25.1201 Fire extinguishing system materials
No material in any fire extinguishing system may react chemically with any extinguishing agent so as to create a hazard.
CS 25.1203 Fire-detector system
There must be approved, quick acting fire or overheat detectors in each designated fire zone, and in the combustion, turbine, and tailpipe sections of…
CS 25.1207 Compliance
Unless otherwise specified, compliance with the requirements of CS 25.1181 to 25.1203 must be shown by a full scale fire test or by one or more of the…
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