On October 20, 1989, a Cessna 177RG (registration N34080) operated by Knoxville Flyers, Inc was involved in an aviation accident near Albertville, AL. Investigators recorded the probable cause as: The pilot's inability to maintain engine power due to a worn and burned magneto cam follower, which failed to allow the points to open, for which a required inspection service bulletin had not been accomplished. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot declared an emergency after experiencing an engine failure in cruise flight, executing a forced landing where the aircraft struck a ditch during the roll.
What happened
The pilot was operating the aircraft in cruise flight when an unexpected engine failure occurred. In response to the loss of power, the pilot immediately declared an emergency and initiated procedures for a forced landing. During the landing roll, the airplane collided with a ditch, resulting in damage to the airframe.
The investigation
A subsequent examination of the aircraft's engine revealed that the magneto cam follower was both worn and burned. This condition prevented the ignition points from opening properly, which disrupted the spark necessary for engine operation. Further review indicated that a service bulletin requiring inspection of the cam follower had not been accomplished prior to the incident.
Findings
The mechanical failure was directly linked to the lack of maintenance specified in the service bulletin. The worn and burned magneto cam follower is the primary factor that led to the engine stopping during flight.
Probable cause
The pilot's inability to maintain engine power due to a worn and burned magneto cam follower, which failed to allow the points to open, for which a required inspection service bulletin had not been accomplished.