Accident Details
Probable Cause and Findings
A partial loss of engine power due to the failure of the No. 4 cylinder exhaust valve.
Aircraft Information
Registered Owner (Current)
Analysis
On October 21, 2020, about 1117 mountain standard time, a Piper PA-28-180 airplane, N7405W, was substantially damaged when it was involved in an accident near Show Low, Arizona. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.
The pilot reported that, while in cruise flight about 8,000 ft mean sea level, there was a loud bang followed by severe engine vibration and the engine lost partial power. The pilot attempted to troubleshoot; however, the engine continued to produce about 1,600 to 1,700 rpm. The pilot declared an emergency and performed a forced landing to a highway, during which the airplane’s right wing impacted a barbed wire fence.
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 found in the cylinder’s combustion chamber; the combustion chamber and piston dome exhibited damage consistent with repeated contact with the valve head.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# WPR21LA020