ED Decision 2007/015/R
(1) The applicant has the option to incorporate a rotor-locking device into the type design of the Engine in order not to have to comply with CS-E 525. Activation of the device will stop and prevent subsequent continued rotation of the Engine rotor(s) during flight when the Engine is not operating. The device is part of the Engine type design and is subject to the same test criteria as other components on the Engine. In addition, the rotor-locking device should satisfy the operational and endurance test specifications identified in CS-E 710 while the Engine is subjected to the environmental conditions that result in the maximum rotational torque. The assessment of the maximum rotational torque should consider both damaged and undamaged Engine rotors.
(2) An Engine that is shut down and that has a rotor locking device but continues to rotate due to Failure of the rotor locking device might not satisfy the safety objectives of CS-E 525. Therefore the design of the rotor-locking device should be assessed for all possible Failure modes under CS-E 510. The effects of an uncommanded or inadvertent activation of the rotor-locking device in flight should be considered.
(3) Due to the expected infrequency of using the rotor locking device, it should be designed such that under normal Engine operating conditions it will not deteriorate beyond serviceable limits to the extent that it fails to perform its intended function when activated during an Engine shut down (see also CS-E 510(e)).
(4) The rotor-locking device should be designed in such a manner that it is possible for the flight crew to unlock the Engine rotor(s) in order to initiate Engine restart attempts. In the event these attempts are unsuccessful, the flight crew should be able to re-lock the Engine rotor(s).
(5) The effects of the temperature of the induction air and external surfaces of the Engine should be considered where relevant to the design.
[Amdt. No.: E/1]
EASA engine certification requires rotor-locking devices, if used to avoid specific regulations, to undergo rigorous testing. These devices must prevent rotation after engine shutdown, withstand environmental conditions, and allow for in-flight unlocking/re-locking for restart attempts. Failure modes and unintended activation risks must be assessed, ensuring reliability despite infrequent use.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
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