Stinson 108-2 accident near Custer, South Dakota, March 7, 1989
On March 7, 1989, a Stinson 108-2, registered N150C, was substantially damaged in an accident near Custer, South Dakota (Custer County airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE IMPROPER MAINTENANCE BY THE PILOT IN COMMAND/OWNER IN THAT THE MAGNETO DRIVE GEAR RETAINING NUTS WERE NOT SAFETIED WHICH RESULTED IN THEM BACKING OFF, DISCONNECTING THE MAGNETOES AND ONE OF THE GEARS FALLING INTO THE ENGINE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 7, 1989
- Place
- Custer, South Dakota · Custer County · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Stinson 108-2 · all 108-2s on the register
- Registration
- N150C · registry record · serial 108-3150
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PRIVATE PLT WAS PERFORMING A FLIGHT FOLLOWING HIS INSTALLATION OF TWO MAGNETOS. A WITNESS AND THE PLT REPORTED THAT ON CLIMB OUT THE ENGINE QUIT. THE PLT SAID HE HEARD SOMETHING BREAK IN THE ENGINE. THE PLT ATTEMPTED TO LAND ON A GRAVEL DRIVEWAY SOUTH OF THE RUNWAY. AT IMPACT, THE MAIN LANDING GEAR COLLAPSED. THE PLANE CAME TO REST AFTER SLIDING 150 FT. A POST ACCIDENT INSPECTION REVEALED THAT BOTH MAGNETOS HAD BEEN INSTALLED WITHOUT COTTER PINS ON THE DRIVE GEAR RETAINING NUTS. THIS RESULTED IN THE NUTS BACKING OFF, DISCONNECTING THE MAGNETOS, AND ONE OF THE GEARS FALLING INTO THE ENGINE, RESULTING IN THE REPORTED STOPPAGE.
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: 600 hours in all; 40 in the last 90 days; 600 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 1,356 hours
- Last inspection: annual inspection, January 27, 1989; 3 hours since
- Maximum gross weight: 2,230 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin 6A4-165-B3 (piston); 0 hours total
The flight
- Departed from: SD01 Custer SD
- Destination: SD01
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 25 statute miles
- Sky: clear
- Temperature: 50°F (10°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.