Amateur-built WD (BIGX) accident near Sheldahl, Iowa, July 19, 1986
On July 19, 1986 at about 3:55 pm local time, a amateur-built WD (BIGX), registered N31637, was destroyed in an accident near Sheldahl, Iowa. It was a personal flight under general aviation rules (Part 91). 3 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 19, 1986 · about 3:55 pm local time
- Place
- Sheldahl, Iowa · map
- Type
- Accident
- Injuries
- 3 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built WD (BIGX)
- Registration
- N31637 · no longer on the register · serial 6
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
WITNESSES STATE THAT THEY SAW TWO AIRPLANES, ONE SILVER AND ONE RED, CLIMBING NORTHBOUND TO CRUISE ALTITUDE IN LOOSE FORMATION WHEN THE RED AIRCRAFT'S ENGINE BACKFIRED AND THE ANTIQUE FABRIC-COVERED AIRCRAFT STARTED BURNING. FLAMES FIVE TO EIGHT FEET IN LENGTH BEGAN CONSUMING THE AIRCRAFT'S LEFT BOTTOM ENGINE COMPARTMENT AND FUSELAGE UNDERSIDE AS THE PILOT WAS ATTEMPTING AN EMERGENCY DESCENT INTO A SOY BEAN FIELD, ACCORDING TO WITNESSES. THE AIRCRAFT HAD THE FIELD MADE, AND WAS AT APPROXIMATELY FIVE HUNDRED FEET ABOVE GROUND LEVEL WHEN THE LEFT WING CAUGHT FIRE, THE AIRCRAFT FLIPPED INVERTED, AND NOSED DIVED INTO THE SOY BEAN FIELD WHERE IT EXPLODED ON IMPACT.
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: 570 hours in all; 50 in the last 90 days
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 1,400 hours
- Last inspection: annual inspection, March 31, 1986; 1 hours since
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin 6A4-150-B3 (piston); 0 hours total
The flight
- Departed from: Y76 Des Moines IA at 3:45 pm
- Destination: MCW Mason City IA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 350° at 6 knots
- Visibility: 12 statute miles
- Sky: scat at 8,000 ft
- Temperature: 84°F (29°C), dew point 72°F (22°C)
- Altimeter: 29.00 inHg
- Observation at 2:53 pm from DSM, 19 miles away
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.