A LAM Linhas Aereas de Mocambique de Havilland Dash 8-400, registration C9-AUY performing flight TM-100 from Maputo to Beira (Mozambique), was climbing out of Maputo with LAM’s DH8D chief pilot in command of the aircraft, when due to traffic in opposite direction the aircraft needed to level off at 5000 feet. After being clear of the opposite traffic ATC cleared the flight to climb, the crew moved the power levers forward however inadvertently moved power lever #2 beyond the MAX detent, the right hand propeller accelerated to 1020 rpm. The crew identified the occurrence as a propeller overspeed, shut the right hand engine down and initiated a return to Maputo. While already positioning for the return the crew decided to attempt a restart of the engine, which went successful, all engine parameters were within normal. The crew therefore decided to cancel the return and continue to destination, where the aircraft landed safely.
The incident went unreported and came to light only through passengers reporting on social media, that the right hand propeller had stopped in flight and later on restarted with their flight landing in Beira. Those passenger reports eventually reached Mozambique’s Ministry of Transport several weeks later, who in turn initiated a safety review of LAM and Mocambique Expresso by Mozambique’s DGCA.
Sources told The Aviation Herald, that lack of system knowledge caused the incident. FADEC would automatically limit the revolutions per minute (RPM) to the permitted maximum 1020 revolutions per minute even if the power lever is moved beyond the MAX detent, a propeller overspeed did not occur. Control of the engine is regained by moving the lever back into the MAX detent and then to the desired setting.
The Aviation Herald
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