Primary finding
Probable cause
a loss of engine power due to connecting rod bolt failure. The reason for the bolt failure was not determined. A contributing factor was the presence of trees in the emergency landing path.
Investigator assessment
Analysis narrative
While cruising at 3,500 feet mean sea level, the engine suddenly began knocking and vibrating. Moments later, all engine power was lost. The pilot initiated a forced landing on a nearby road, but during the approach collided with a tree. An inspection of the engine revealed several holes in the upper portion of the case in the vicinity of the number 6 cylinder. Further examination revealed that both of the number 6 connecting rod bolts were broken and the rod cap was crushed and fragmented. The owner reported that the rod bolts had been in service for about 1,185 hours. The engine's total time was about 2,350 hours.
Source record
Factual narrative
On March 27, 1997, at 1825 hours Pacific standard time, a Bellanca 14-13, N86851, owned and operated by the pilot, experienced a loss of engine power while cruising at 3,500 feet mean sea level near Oroville, California. According to the pilot, the sequence of events started when his "perfect running engine" suddenly began knocking and vibrating. Moments later, all engine power was lost. The commercial pilot attempted to land on a nearby road. During the approach the airplane collided with a tree, and the airplane was substantially damaged. The pilot was not injured. Visual meteorological conditions prevailed during the personal flight, and no flight plan was filed. The flight originated from Redding, California, at 1750. The pilot and the Federal Aviation Administration (FAA) coordinator inspected the airplane, manufactured in 1946, and the Franklin engine. The FAA reported observing several holes in the upper portion of the engine case in the vicinity of the number 6 cylinder. The largest hole was about 0.75 inches wide by 2.0 inches long. The FAA reported it appeared as though something was trying to get out from inside the engine. An additional examination of the engine revealed that both of the number 6 connecting rod bolts were broken and the rod cap was crushed and fragmented. According to the owner, the rod bolts had been in service for about 1,185 hours. The engine's total time was about 2,350 hours. -