On July 2, 1997, a Boeing Stearman B75N1 (registration N450GC) was involved in an aviation accident near Locust Grove, GA. Investigators recorded the probable cause as: The separation of the number 6 cylinder head from the engine, which resulted from high temperature separation or overstress. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A witness reported black smoke from the engine shortly after takeoff, followed by a rapid nose-down descent. Examination revealed the #6 cylinder head had separated due to high temperature or overstress.
What happened
Shortly after departing, an observer on the ground noticed a distinct puff of black smoke emitting from the aircraft's engine compartment. The pilot lost control shortly thereafter, causing the airplane to pitch downward and begin a rapid descent toward the ground.
The investigation
Investigators conducted an immediate examination of the engine upon recovery. They found that the number 6 cylinder head had completely separated from the main engine block. Metallurgical analysis of the fracture surface indicated that the failure was caused by either high-temperature separation or mechanical overstress.
Probable cause
The separation of the number 6 cylinder head from the engine, which resulted from high temperature separation or overstress.