Accident Overview
On October 21, 2020, at approximately 1117 mountain standard time, a Piper PA-28-180 airplane, registration N7405W, was substantially damaged in an accident near Show Low, Arizona. The pilot reported no injuries. The aircraft was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight and Emergency
According to the pilot, while cruising at about 8,000 feet mean sea level, a loud bang occurred, followed by severe engine vibration and a partial loss of engine power. The pilot attempted to troubleshoot the issue, but the engine continued producing approximately 1,600 to 1,700 rpm. The pilot declared an emergency and executed a forced landing onto a highway. During the landing, the airplane's right wing struck a barbed wire fence.
Post-Accident Examination
An examination of the engine revealed a stuck exhaust valve on the No. 4 cylinder. The exhaust valve head had separated from the valve stem. The loose valve head was discovered inside the cylinder's combustion chamber. Both the combustion chamber and the piston dome exhibited damage consistent with repeated contact with the detached valve head.
Aircraft Information
The airplane, a Piper PA-28-180, was registered as N7405W. The extent of the substantial damage included the right wing impact with the fence and the internal engine damage. No other injuries or damage were reported.