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CS 25.945 Thrust or power augmentation system

Large Aeroplanes (CS-25) · CS-25 · EAR revision 26 Jan 2023

IRImplementing rule

CS 25.945Thrust or power augmentation system

(a)General. Each fluid injection system must provide a flow of fluid at the rate and pressure established for proper engine functioning under each intended operating condition. If the fluid can freeze, fluid freezing may not damage the aeroplane or adversely affect aeroplane performance.

(b)Fluid tanks. Each augmentation system fluid tank must meet the following requirements:

(1)Each tank must be able to withstand without failure the vibration, inertia, fluid, and structural loads that it may be subjected to in operation.

(2)The tanks as mounted in the aeroplane must be able to withstand without failure or leakage an internal pressure 1·5 times the maximum operating pressure.

(3)If a vent is provided, the venting must be effective under all normal flight conditions.

(4)Reserved.

(5)Each tank must have an expansion space of not less than 2% of the tank capacity. It must be impossible to fill the expansion space inadvertently with the aeroplane in the normal ground attitude.

(c)Augmentation system drains must be designed and located in accordance with CS 25.1455 if –

(1)The augmentation system fluid is subject to freezing; and

(2)The fluid may be drained in flight or during ground operation.

(d)The augmentation liquid tank capacity available for the use of each engine must be large enough to allow operation of the aeroplane under the approved procedures for the use of liquidaugmented power. The computation of liquid consumption must be based on the maximum approved rate appropriate for the desired engine output and must include the effect of temperature on engine performance as well as any other factors that might vary the amount of liquid required.

IR · CS 25.945 — CS-25 · ED Decision 2003/2/RM · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

All rules in SUBPART E – POWERPLANT

Consolidated from the EASA Easy Access Rules (revision 26 Jan 2023, 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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