CS 25.672 Stability augmentation and automatic and power-operated systems

• ED Decision 2020/001/R found in: CS-25 Amdt 27 - Large Aeroplanes (Jan 2023)

CS 25.672 Stability augmentation and automatic and power-operated systems ED Decision 2020/001/R If the functioning of stability augmentation or other automatic or power-operated systems is necessary to show compliance with the flight characteristics requirements of this CS-25, such systems must comply with [CS 25.671](#_DxCrossRefBm1709820687) and the following: (a) A warning, which is clearly distinguishable to the pilot under expected flight conditions without requiring his attention, must be provided for any failure in the stability augmentation system or in any other automatic or power-operated system, which could result in an unsafe condition if the pilot were not aware of the failure. Warning systems must not activate the control systems. (b) The design of the stability augmentation system or of any other automatic or power-operated system must permit initial counteraction of failures of the type specified in CS 25.671(c) without requiring exceptional pilot skill or strength, by either the deactivation of the system, or a failed portion thereof, or by overriding the failure by movement of the flight controls in the normal sense. (c) It must be shown that after any single failure of the stability augmentation system or any other automatic or power-operated system: (1) The aeroplane is safely controllable when the failure or malfunction occurs at any speed or altitude within the approved operating limitations that is critical for the type of failure being considered. (2) The controllability and manoeuvrability requirements of this CS-25 are met within a practical operational flight envelope (for example, speed, altitude, normal acceleration, and aeroplane configurations) which is described in the Aeroplane Flight Manual; and (3) The trim, stability, and stall characteristics are not impaired below a level needed to permit continued safe flight and landing. [Amdt 25/18] [Amdt 25/24]