The Transportation Safety Board of Canada (TSB) last week published its final report on the November 2013 crash of a Fairchild SA227 Metro III that led to the release of a Civil Aviation Safety Alert on the aircraft's Honeywell TPE331 engines. Five of the seven people aboard were killed in the crash. The crew had reported a five-mile final, but shortly thereafter declared an emergency. The aircraft later struck trees along with some power lines. It was destroyed by a post-impact fire.
The investigation found the crew experienced a loss of left-engine power at 500 feet above ground level due to the failure of an internal engine component. The crew could not identify the problem and also did not maintain control of the airplane. The landing gear was already down, generating extra drag that when combined with the engine malfunction resulted in the aircraft losing airspeed in an asymmetric power state. The crew lost control at an altitude from which a recovery was not possible.
Following the accident, Transport Canada issued a Civil Aviation Safety Alert regarding the negative torque sensing (NTS) system on Honeywell TPE331 engines to emphasize the need to feather and secure propellers during engine-power-loss events.