§29.672 Stability augmentation, automatic, and power-operated systems

If the functioning of stability augmentation or other automatic or power-operated sy stem is necessary to show com pliance with flight characteristics requirem ents of CS–29, the system must comply with CS 29.671 and the following: (a) A warning which is clearly distinguishable to the pilot under expected flight conditions without requiring the pilot’s attention m ust be provided for any failure in the stability augmentation system or in any other autom atic or power-operated system which could result in an unsafe condition if the pilot is unaware of the failure. W arning sy stems m ust not activate the control systems. (b) The design of the stability augm entation system or of any other autom atic or power-operated system must allow initial counteraction of failures without requiring exceptional pilot skill or strength, by overriding the failure by m oving the flight controls in the norm al sense, and by deactivating the failed system. (c) It m ust be shown that after any single failure of the stability augm entation sy stem or any other automatic or power-operated system: (1) The rotorcraft is safely controllable when the failure or m alfunction occurs at any speed or altitude within the approved operating limitations; (2) The controllability and manoeuvrability requirements of CS–29 are m et within a practical operational flight envelope (for example, speed, altitude, normal acceleration, and rotorcraft configurations) which is described in the rotorcraft flight manual; and (3) The trim and stability characteristics are not im paired below a level needed to allow continued safe flight and landing.