Alternative Loading Conditions for CS 27.923 Compliance Demonstration During Flight Tests

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 rotorcraft, 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.