On April 27, 1990, an Enstrom F28F (registration N756H) operated by Hiser Helicopters, Inc. was involved in an aviation accident near Corona, CA. Investigators recorded the probable cause as: THE PARTIAL FAILURE OF THE ENGINE'S RIGHT MAGNETO, WHICH RESULTED IN A LOSS OF ENGINE POWER. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
While practicing quick stops in a helicopter, the engine sputtered and failed. The student pilot performed an autorotative descent but the helicopter rolled over after touchdown on soft terrain. Post-crash examination revealed abnormal magneto RPM drops.
Event Details
A student pilot was engaged in a training flight, assigned to practice steep approach landings, hovering, and quick stops. After flying for approximately 45 minutes, and while specifically practicing quick stops, the helicopter's engine began to sputter and cough before ultimately quitting. The pilot performed an autorotative descent to manage the emergency. Following touchdown, the helicopter rolled over due to the soft terrain conditions.
Engine Examination
A post-crash examination of the helicopter was conducted. During this inspection, the engine's RPM drop off associated with the operation of the left magneto was recorded at 150 RPM. The right magneto operation was associated with a drop of 400 RPM.
The source does not provide any further information regarding the cause of the engine failure or the events leading up to it.