Aviation accident LAX00GA297

failure of the compressor turbine disc due to cyclic fatigue brought about by repeated operation near or above the engines' temperature/power limits by company personnel over an extended period of time. Factors in the accident were: 1) the high density altitude, mountainous terrain, and the helicopter's resulting marginal single engine performance capability; 2) the design, fabrication, and installation of the emergency external load release system, which had the power supply wired to the nonessential bus that would automatically drop offline during an engine or generator failure; and 3) the pilot's resulting inability to electrically release the water load, bucket, or line while dealing with the engine failure.