Abnormal engine indications involving a Hughes Helicopters 369HS, VH-XAX, Gladstone, Queensland, on 7 September 1993

The pilot reported that, before starting the engine, he completed a routine daily inspection and found no defects. Approximately three minutes after startup, as the engine was being accelerated for take-off, the pilot heard a loud noise and felt the aircraft start to vibrate. The throttle was closed and the engine shut down.

Inspection found that one of the stainless-steel abrasion strips from a tail rotor blade had delaminated causing a serious imbalance of the tail rotor drive system. The out of balance situation caused the tail rotor gearbox to separate from its mounting. The particle separator (airbox) was also damaged by the abnormal flexing of the tail rotor drive.