Pilot Debrief

CESSNA 172L near Ventura, CA — 2022-09-16

Final reportWPR22LA351
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Date
2022-09-16
Location
Ventura, CA, USA
Aircraft
CESSNA 172L
Registration
N7917G
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Cruise

Probable cause

A partial loss of engine power due to the fatigue fracture of the No. 4 exhaust valve.

NTSB narrative

According to the pilot, while conducting a local flight, he heard a "pop" followed by a partial loss of engine power. The airframe started shaking badly, he pulled power to idle, established best glide, and contacted Air Traffic Control (ATC). ATC provided alternate airports and current weather information. Unable to maintain altitude, he initiated a forced landing to a clearing on the beach. During the landing roll, the airplane impacted a rock retaining wall, which resulted in substantial damage to the fuselage and left horizontal stabilizer. Examination of the engine revealed that the No. 4 exhaust valve was fractured. Metallurgical examination of the fracture surfaces on the exhaust valve revealed that it had fractured due to fatigue. The fatigue fracture of the No. 4 exhaust valve likely led to the partial loss of engine power.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have conducted a precautionary landing before engine power loss.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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