On October 13, 2002, a Cessna 177RG (registration N7510V) was involved in an aviation accident near South Vienna, OH. Investigators recorded the probable cause as: The improper installation of the single drive, dual magneto, which resulted in its separation from the engine and a subsequent total loss of engine power. Factors included the crops in the forced landing field, and the night lighting conditions. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During a night cruise, a burning odor preceded a total engine power loss. A forced landing was made in a soybean field. Investigation found the single-drive dual magneto had detached from the engine due to untorqued attachment hardware.
Incident Overview
A pilot experienced a burning odor while cruising at night. The odor momentarily intensified, followed by a complete loss of engine power. Attempts to restart the engine were unsuccessful, and the pilot executed a forced landing in what was perceived as a dark area, which turned out to be a soybean field.
Examination Findings
Post-incident examination of the engine revealed that the single-drive, dual magneto had separated from its attachment point on the engine and was found lying in the engine cowling. The magneto attachment hardware was also located in the cowling. Examination of the lock washer showed no signs of having been torqued. The studs used to attach the magneto to the engine accessory housing were undamaged.
Maintenance History
The magneto had been removed and reinstalled approximately 60 hours prior to the incident during a replacement of the engine crankcase.