What happened
While cruising at 1000 feet AGL adjacent to a local golf course, the pilot of a banner tow aircraft experienced a gradual loss of engine power that eventually resulted in a complete loss of power. The pilot attempted to regain full power and tried to restart the engine, but these efforts were unsuccessful.
In response to the engine failure, the pilot maneuvered the airplane into position to approach a fairway and released the banner. The aircraft subsequently came to rest in a wooded area located 15 feet off the departure end of the fairway. The pilot was not injured.
The investigation
Subsequent examinations of the aircraft revealed that the #2 exhaust valve had failed. Records indicated that the engine had been last overhauled 2556 hours prior to the accident. The specific time in service for the failed exhaust valve was not determined.