Accident Details
On September 16, 2022, at about 1630 Pacific daylight time, a Cessna 172L, registration N7917G, was substantially damaged in an accident near Ventura, California. The pilot was not injured, and both passengers sustained minor injuries. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight.
According to the pilot, while en route at approximately 2,000 ft mean sea level, a loud pop was heard, followed by a partial loss of engine power. The airframe began shaking severely. The pilot reduced power to idle, established best glide airspeed, and contacted Air Traffic Control (ATC). ATC provided information on alternate airports and current weather conditions.
Unable to maintain altitude, the pilot initiated a forced landing to a clearing on the beach. During the landing roll, the airplane struck a rock retaining wall.
Aircraft and Occupant Information
The airplane was a Cessna 172L, serial number N7917G. The three occupants comprised the pilot and two passengers. No injuries were reported for the pilot; both passengers received minor injuries.
Postaccident Examination
Postaccident inspection revealed substantial damage to the left wing and forward fuselage. A lighted borescope examination of the engine showed mechanical damage to the No. 4 cylinder's combustion dome and piston face. The No. 3 and No. 4 cylinders were subsequently removed. Metallic debris was found obstructing the No. 3 cylinder's intake valve. Inside the No. 4 cylinder, remnants of the exhaust valve were observed.
The No. 4 cylinder and the exhaust valve remnants were sent to the National Transportation Safety Board Materials Laboratory in Washington, DC, for examination. Analysis of the fracture surface of the No. 4 exhaust valve indicated characteristics consistent with a fatigue fracture.
Maintenance Records
Review of the airplane's maintenance records did not reveal any recent maintenance performed on the No. 4 cylinder.