Pilot Debrief

PIPER PA-28-180 near Show Low, AZ — 2020-10-21

Final reportWPR21LA020
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Date
2020-10-21
Location
Show Low, AZ, USA
Aircraft
PIPER PA-28-180
Registration
N7405W
Category
Airplane
Highest injury
None
Fatalities
0

Probable cause

A partial loss of engine power due to the failure of the No. 4 cylinder exhaust valve.

NTSB narrative

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 less than full power. 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, resulting in substantial damage. 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. The loss of engine power is consistent with the failure of the No. 4 cylinder exhaust valve; however, the reason for the valve failure could not be determined based on the available information.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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