1991-10-16: Piper PA-18 — Monnett, Charles W. — Montague Island, AK

Casualties unknown • Montague Island, AK, US

Probable cause

THE POWER LOSS DUE TO THE CRANKSHAFT FAILURE. CONTRIBUTING TO THE ACCIDENT WAS IMPROPER MAINTENANCE DURING THE LAST ENGINE OVERHAUL.

— NTSB Determination

Accident narrative

DURING CRUISE FLIGHT, THE ENGINE SEIZED WITHOUT WARNING. WITH NO SUITABLE LANDING AREA ON THE BEACH, THE PILOT DITCHED IN THE OCEAN AND SWAM ASHORE ABOUT 1/2 MILE AWAY. AN INVESTIGATION REVEALED THAT THE CRANKSHAFT HAD BROKEN AT THE FORWARD CHEEK OF THE #3 MAIN BEARING. A REDDISH SEALANT RESIDUE WAS FOUND AROUND THE MAIN BEARING THRU STUD HOLES OF THE CRANKCASE. ACCORDING TO LYCOMING SERVICE INSTRUCTION #1125A, SEALANT SHOULD NOT HAVE BEEN APPLIED IN THIS AREA.

Frequently asked questions

What happened in the 1991-10-16 Piper PA-18 accident near Montague Island, AK?

DURING CRUISE FLIGHT, THE ENGINE SEIZED WITHOUT WARNING. WITH NO SUITABLE LANDING AREA ON THE BEACH, THE PILOT DITCHED IN THE OCEAN AND SWAM ASHORE ABOUT 1/2 MILE AWAY. AN INVESTIGATION REVEALED THAT THE CRANKSHAFT HAD BROKEN AT THE FORWARD CHEEK OF THE #3 MAIN BEARING. A REDDISH SEALANT RESIDUE WAS FOUND AROUND THE…

What aircraft was involved and where did it happen?

The accident on 1991-10-16 involved a Piper PA-18, registration N3850Z, operated by Monnett, Charles W., at Montague Island, AK.

What was the probable cause of the accident?

THE POWER LOSS DUE TO THE CRANKSHAFT FAILURE. CONTRIBUTING TO THE ACCIDENT WAS IMPROPER MAINTENANCE DURING THE LAST ENGINE OVERHAUL.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X18220. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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