Consultation expired with comments. The proposed Equivalent Safety Finding (ESF) has been editorially updated based on the comments received, and the corresponding Comment-Response Document (CRD) has been completed by EASA.
Details
Clarifications added to the final CPTS.
Identification of issue
CS 27.923 endurance test for the rotor drive system and control mechanism is typically performed on a rotorcraft attached to the ground (i.e. a tie-down rotorcraft).
Instead of using a conventional tie-down rotocraft, the applicant proposes to demonstrate the reliability of some parts of the rotor drive system and control mechanism by using prototype flight testing, using alternative loading conditions compared to those prescribed in CS 27.923, supported by associated flight test data and post-flight part inspections.
Considering all the above, the following Equivalent Safety Finding is proposed.
Note: This ESF was developed primarily for new Type Certificates. However, this ESF can also be applied to changes.