Piper PA-18 accident near Montague Island, Alaska, October 16, 1991
On October 16, 1991, a Piper PA-18, registered N3850Z, was substantially damaged in an accident near Montague Island, Alaska. It was a business flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE POWER LOSS DUE TO THE CRANKSHAFT FAILURE. CONTRIBUTING TO THE ACCIDENT WAS IMPROPER MAINTENANCE DURING THE LAST ENGINE OVERHAUL.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 16, 1991
- Place
- Montague Island, Alaska · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-18 · all PA-18s on the register
- Registration
- N3850Z · no longer on the register · serial 18-7608
- Damage
- Substantial damage
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 1,000 hours in all; 75 in this make and model; 100 in the last 90 days; 40 in the last 30 days; 950 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 1,653 hours
- Last inspection: annual inspection, February 18, 1991; 63 hours since
- Maximum gross weight: 1,800 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-B2B (piston); 0 hours total
The flight
- Departed from: CDV Cordova AK at 4:15 pm
- Destination: CDV Cordova AK
- Flight plan: VFR
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 120° at 2 knots
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 39°F (4°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.