On August 12, 1991, a Grumman G-164 (registration N4663) operated by Jack R. James was involved in an aviation accident near Wasco, CA. Investigators recorded the probable cause as: The pilot's inability to maintain control during a forced landing following a loss of engine power due to a fractured camshaft. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An agricultural airplane nosed over during a forced landing after losing engine power while conducting an aerial application, with investigation revealing a fractured camshaft.
What happened
The pilot of an agricultural aircraft experienced a sudden loss of engine power while conducting an aerial application. As the engine failed to maintain operation, the pilot attempted to execute a forced landing. During this maneuver, the aircraft nosed over upon impact with the ground.
The investigation
Following the accident, investigators examined the aircraft's propulsion system to determine the root cause of the power loss. The inspection revealed that the camshaft had fractured. This mechanical failure prevented the engine from functioning correctly, leading directly to the loss of power.
The maintenance history showed that the engine had been overhauled 1100 hours prior to the accident. At the time of the incident, the total time on the engine was approximately 4218 hours. The fracture in the camshaft component is identified as the primary mechanical failure associated with this event.
Probable cause
The pilot's inability to maintain control during a forced landing following a loss of engine power due to a fractured camshaft.