Pilot Debrief

UNIVERSAL STINSON 108 near Portland, ME — 2012-06-24

Final reportERA12LA411
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Date
2012-06-24
Location
Portland, ME, USA
Aircraft
UNIVERSAL STINSON 108
Registration
N39443
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Cruise

Probable cause

A fatigue failure of the No. 3 piston skirt, which resulted in a total loss of engine power and the subsequent ditching in the ocean.

NTSB narrative

The airplane was flying over the ocean, along the coast at altitudes between 500 to 1,000 feet mean sea level, when the pilot reported a total loss of engine power and indicated that he was not going to be able to glide to the shore. The airplane subsequently impacted water about 100 yards from the shore and sank to a depth of about 70 feet. Postaccident examination of the airplane’s engine revealed that the No. 3 piston skirt fractured, and the resultant debris entered the engine and camshaft gear, affecting the magneto timing. Metallurgical examination of the piston skirt revealed fatigue originating near a machined through-hole. Although the No. 3 piston was overhauled about 5 years before the accident, it was an original piston on the accident engine, which was more than 65 years old.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have opted to land at the nearest airport instead of continuing flight.

NTSB coding

Evidence available

  • ADS-B / radar
  • Photos
  • 10 docket documents
View NTSB final reportView NTSB docket

Docket documents10

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