Pilot Debrief

CESSNA 150J near Lodi, CA — 2021-03-03

Final reportWPR21LA121
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Date
2021-03-03
Location
Lodi, CA, USA
Aircraft
CESSNA 150J
Registration
N60290
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

A total loss of engine power during cruise flight due to a fatigue crack in the No. 3 cylinder connecting rod shaft resulting from either preignition or detonation, which resulted in a forced landing and impact with terrain.

NTSB narrative

The pilot receiving instruction and flight instructor had planned a local instructional flight on the day of the accident. Shortly into the flight after they reached their cruise flight altitude, they experienced a total loss of engine power. The airplane was substantially damaged during a forced landing in a field. Postaccident examination of the engine revealed that the connecting rod shaft for the No. 3 cylinder had fractured due to fatigue cracking. The buildup of combustion deposits suggested the event was caused by either preignition or detonation or both, which would have been the result of the use of a lower grade fuel or operating the engine at high power settings with an excessively lean mixture. Although a trace amount of automotive fuel was detected in the fuel line to the carburetor, fuel records indicate that the pilot had been using 100LL consistently. The operating fuel used by the previous owner is unknown; however, the previous owner implied that he used 100LL during conversations with the current owner. The pilot’s leaning practices showed that he regularly leaned the mixture to reach best rpm and enrichened three turns.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have checked fuel quality before flight to prevent engine failure.

NTSB coding

Evidence available

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

Docket documents8

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