Piper PA-23-160 accident near Westbrook, Maine, March 23, 1991
On March 23, 1991 at about 9:08 pm local time, a Piper PA-23-160, registered N4155P, was substantially damaged in an accident near Westbrook, Maine (Portland airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 4 people were on board or involved. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
IMPROPER EMERGENCY PROCEDURES BY THE PILOT. FACTORS RELATED TO THE ACCIDENT WERE: THE PILOT'S LACK OF EXPERIENCE AND FLIGHT TIME IN TYPE OF AIRPLANE, THE PILOTS DECISION TO TAKE AN AIRPLANE WITH A KNOWN MECHANICAL DEFECT, A LEAKY ACCELERATOR PUMP SEAL ON THE CARBURETOR, AND INSTRUMENT METEOROLOGICAL CONDITIONS.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 23, 1991 · about 9:08 pm local time
- Place
- Westbrook, Maine · Portland
- Type
- Accident
- Injuries
- No one was hurt; 4 people were on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Piper PA-23-160 · all PA-23-160s on the register
- Registration
- N4155P · registry record · serial 23-1639
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
ON AN IFR FLIGHT IN IMC CONDITIONS THE RIGHT ENGINE STARTED TO SHUDDER AND PRODUCE BLACK SMOKE, AND THEN THE PROPELLER WENT INTO FEATHER WITHOUT ACTUATION OF THE PROPELLER CONTROL. THE PILOT WAS UNABLE TO MAINTAIN ALTITUDE AND THE PILOT MADE A FORCED LANDING IN AN OPEN FIELD. THE RIGHT ENGINE OIL WAS DILUTED BY GASOLINE, DUE TO A LEAK IN THE ACCELERATOR PUMP OF THE CARBURETOR WHICH CAUSED THE ENGINE TO RUN RICH. INTERVIEWS DISCLOSED THE PILOT HAD 'DENIAL' ON THE ENGINE PROBLEM, DID NOT SECURE THE ENGINE, AND DID NOT DECLARE AN EMERGENCY WITH ARC. BOTH ENGINES WERE HIGH TIME WITH HIGH TIME SINCE OVERHAUL. HARTZELL PROPELLERS PERSONNEL VERIFIED DILUTED OIL COULD CAUSE A PROPELLER TO GO INTO UNCOMMANDED FEATHER.
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: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 975 hours in all; 31 in this make and model; 139 in the last 90 days; 66 in the last 30 days; 904 as pilot in command; 518 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 5,297 hours
- Last inspection: 100-hour inspection, October 28, 1990; 131 hours since
- Maximum gross weight: 3,800 lb
- Seats: 5
- Landing gear: retractable
- Engine: Lycoming O-320B (piston); 0 hours total
- Operator: Phoenix East Aviation
The flight
- Departed from: MLT Millinocket ME at 7:40 pm
- Destination: LWM Lawrence MA
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 130° at 14 knots, gusting 23
- Sky: not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Observation at 9:11 pm from PWM, 6 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 | |||
| Passengers | 2 |
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.