Stinson 108-1 accident near Longmont, Colorado, December 22, 1991
On December 22, 1991 at about 8:30 pm local time, a Stinson 108-1, registered N97962, was destroyed in an accident near Longmont, Colorado. It was a personal flight under general aviation rules (Part 91). 3 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A LOSS OF ENGINE POWER DUE TO FOULED SPARK PLUGS. THE INADEQUATE MAINTENANCE OF THE ENGINE WAS A FACTOR IN THE ACCIDENT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 22, 1991 · about 8:30 pm local time
- Place
- Longmont, Colorado
- Type
- Accident
- Injuries
- 3 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Stinson 108-1 · all 108-1s on the register
- Registration
- N97962 · no longer on the register · serial 108-962
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
ON INITIAL CLIMB FOLLOWING TAKEOFF, AT A GROSS WEIGHT APPROXIMATELY 50 POUNDS OVER MAXIMUM, THE AIRPLANE WOULD NEITHER CLIMB NOR ACCELERATE. AFTER TURNING CROSSWIND AT 250 FEET AGL AND 1/2 MILE BEYOND THE RUNWAY END, ENGINE RPM BEGAN TO 'CREEP DOWN.' THE PILOT WAS UNABLE TO RESTORE RPM, THEREFORE, A FORCED LANDING WAS PERFORMED IN A PASTURE. THE AIRPLANE COLLIDED WITH A DITCH AND FENCE, NOSED OVER, AND CAUGHT FIRE. AN ENGINE EXAMINATION REVEALED THAT THE SPARK PLUGS WERE FOULED, MAGNETO IMPULSE COUPLING WEAK, AND RUST AND EVIDENCE OF DETONATION WAS PRESENT IN THE CYLINDERS AND ON PISTON DOMES, WHICH DEGRADED POWER AVAILABLE.
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: private
- Ratings: single-engine land
- Flight time: 2,650 hours in all; 35 in this make and model; 25 in the last 90 days; 5 in the last 30 days; 2,630 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,391 hours
- Last inspection: annual inspection, June 11, 1991
- Maximum gross weight: 2,078 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin GA4-150-B3 (piston); 0 hours total
- Fire on the ground
The flight
- Destination: EMD Emporia KS
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 260° at 5 knots
- Visibility: 75 statute miles
- Sky: overcast at 22,000 ft; scat at 8,000 ft
- Temperature: 39°F (4°C), dew point 18°F (-8°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| 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.