Pilot Debrief

Piper PA-32-300 near Bethel, AK — 2019-04-12

Final reportANC19LA016
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Date
2019-04-12
Location
Bethel, AK, USA
Aircraft
Piper PA-32-300
Registration
N4466T
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

A total loss of engine power due to a fatigue failure of the crankshaft. A contributing factor was the inadequate inspection during the engine’s last overhaul.

NTSB narrative

The pilot reported that, while in cruise flight, the engine lost partial power, then total power, and the propeller stopped turning. During the subsequent off-airport forced landing on the tundra meadow, the main landing gear separated from the airplane, resulting in substantial damage to the right wing. Examination of the engine revealed a crankshaft failure that was likely a result of fatigue cracking that emanated from the surface of the main journal. The engine was overhauled at a certified repair station about 14 flight hours before the accident. The engine manufacturer overhaul manual stated that the crankshaft was to be inspected using a magnetic particle inspection procedure as part of the overhaul; however, the crankshaft was not inspected as part of the overhaul. It is likely that if the crankshaft had been inspected as indicated, the fatigue cracking would have been detected and corrected during overhaul.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Proper NDT inspection of the crankshaft could have prevented the failure.

NTSB coding

Evidence available

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

Docket documents12

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