On March 11, 1997, a Grumman G-164B (registration N36265) was involved in an aviation accident near Winters, CA. Investigators recorded the probable cause as: The separation of the No. 1 engine cylinder head from the cylinder barrel due to fatigue failure. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An agricultural airplane experienced an in-flight engine failure when the No. 1 cylinder head separated from the barrel, leading to a forced landing and nosedown impact.
What happened
The agricultural airplane was operating in level flight when a mechanical failure occurred involving the powerplant. Specifically, the cylinder head of the No. 1 engine detached from the cylinder barrel while the aircraft was airborne. Following this separation, the pilot attempted to land the aircraft in a nearby field. During the landing sequence, the airplane nosed over upon impact with the ground.
The investigation
A postaccident examination was conducted on the separated components to determine the root cause of the failure. The inspection of the cylinder head revealed evidence consistent with a fatigue-type failure. This type of failure typically develops over time due to repeated stress cycles. However, records regarding the total operational time of the cylinder were not available for review, preventing a precise determination of the component's service life relative to its maintenance schedule.
Probable cause
The separation of the No. 1 engine cylinder head from the cylinder barrel due to fatigue failure.