What happened
Approximately 10 minutes after takeoff, while climbing through 3,000 feet mean sea level, the pilot experienced a loud bang followed by extreme vibrations throughout the aircraft. This resulted in a complete loss of engine power. The pilot subsequently executed a forced landing on a four-lane highway located approximately 4 miles north of the departure airport.
During the landing flare, the pilot encountered a vehicle turning in front of the aircraft. While the pilot successfully avoided the car, the left wing made contact with trees during the maneuver. The Cessna aircraft came to rest in the highway median and sustained substantial damage.
The investigation
A post-accident inspection of the engine was conducted to determine the cause of the power loss. Investigators found that the crankshaft had failed aft of the number 2 main bearing journal. A metallurgical examination of the fracture surface revealed crack arrest markings, also known as beach marks, which are indicative of fatigue cracking.
Fatigue initiation was located at the surface of the main bearing journal, slightly forward of the aft radius. The adjacent journal surface exhibited roughness and discoloration, featuring multiple longitudinal parallel cracks, often referred to as ladder cracks. Under magnification, it was determined that the fatigue fracture originated from one of these ladder cracks and progressed aft through approximately 75 percent of the crank cheek before the ultimate failure occurred. While other journals showed light wear and circumferential scratches, they did not exhibit the significant surface damage found on the fractured main journal. Maintenance records indicated the engine had a total time of 3,109.8 hours and 876.8 hours since its last overhaul.