Beech B90 accident near St. Paul, Minnesota, April 5, 1988
On April 5, 1988 at about 8:15 pm local time, a Beech B90, registered N181LL, was substantially damaged in an accident near St. Paul, Minnesota. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 5 people were on board or involved. The weather was instrument conditions (cloud, fog or low visibility).
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The NTSB's probable cause their words, unchanged
MECHANICAL FAILURE AND STICKING OF THE PILOTS THUMB OPERATED TRIM SWITCH CAUSING NOSE DOWN PITCH COMMAND. THE FAILURE OF THE CABIN HEATER AND THE LOW CABIN TEMPERATURE ARE CONTRIBUTING FACTORS.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 5, 1988 · about 8:15 pm local time
- Place
- St. Paul, Minnesota · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Beech B90 · all B90s on the register
- Registration
- N181LL · registry record · serial LJ-440
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
THE AIRPLANE WAS BEING OPERATED AS AN AIR AMBULANCE WHEN IT SUSTAINED SUBSTANTIAL DAMAGE DURING AN UNCOMMANDED HARD PITCHOVER. THE AIRPLANE WAS OPERATING IN VISUAL CONDITIONS ABOVE A SOLID CLOUD LAYER USING INSTRUMENT FLIGHT RULES. THE AIRPLANE RECOVERED FROM THE EXCURSION AND CONTINUED ON TO ITS DESTINATION. THE ATP RATED PILOT, THREE MEDICAL ATTENDANTS AND ONE PATIENT WERE NOT INJURED. TESTING OF THE PILOT'S WHEEL TRIM SWITCH SHOWED THE SWITCH WOULD STICK IN THE CLOSED OR ACTUATED POSITION AND NOT RETURN TO THE 'CENTER OFF' POSITION. THIS OCCURRED DURING TEMPERATURE CYCLING FROM ROOM TEMPERATURE TO BELOW FREEZING AND BACK AGAIN. THE CABIN HEATER HAD FAILED WITH AN OUTSIDE AIR TEMPERATURE OF -26 DEGS CELSIUS AND THE CABIN WAS COLD.
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: airline transport pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 5,005 hours in all; 900 in this make and model; 20 in the last 90 days; 2,800 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 5,950 hours
- Last inspection: inspection type not recorded; 140 hours since
- Maximum gross weight: 9,650 lb
- Seats: 7
- Landing gear: retractable
- Engine: P&W PT6A-135 (turboprop); 0 hours total
The flight
- Departed from: MOT Minot ND at 7:00 pm
- Destination: STP St. Paul MN
- Flight plan: IFR
- Runway 0
Weather at the time
- Light: daylight
- Sky: not recorded; not recorded
- Temperature: 18°F (-8°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 4 | |||
| Passengers | 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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number CHI88FA091.