On November 25, 1998, a Cessna 175 (registration N565ML) was involved in an aviation accident near Locust Grove, GA. Investigators recorded the probable cause as: A gear train failure in the accessory gearbox, which prevented the camshaft from actuating the valves. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot experienced a gradual engine power loss over 10-15 seconds during cruise, with no sputtering or shaking. An emergency landing in a pasture resulted in the airplane nosing over inverted. Examination found a gear train failure in the accessory gearbox preventing camshaft valve actuation.
Accident Overview
During cruise flight, the pilot reported a gradual loss of engine power over a period of 10 to 15 seconds. The pilot noted that there was no sputtering or shaking associated with the loss of power. In response, the pilot lined up with the contours of a pasture and attempted an emergency landing. Following touchdown, the airplane nosed over and came to rest inverted.
Pilot Report
According to the pilot, the engine power loss occurred without any preceding abnormal vibrations or sounds. The pilot's decision to align with the pasture's contours was based on the available terrain. The landing sequence resulted in the aircraft flipping onto its back.
Engine Examination
Post-accident examination of the engine revealed a failure in the gear train within the accessory gearbox. This failure prevented the camshaft from actuating the valves. Additionally, the examination showed that only one magneto drive rotated when the propeller was turned. The engine was not disassembled for further examination, limiting the scope of the investigation.
Probable cause
A gear train failure in the accessory gearbox, which prevented the camshaft from actuating the valves.