Amateur-built (MODIFIED) accident near Sioux Falls, South Dakota, September 24, 1983
On September 24, 1983 at about 3:23 pm local time, a amateur-built (MODIFIED) (ultralight), registered UNREG, was destroyed in an accident near Sioux Falls, South Dakota. It was a flight of an unrecorded kind under ultralight rules (Part 103). 1 person was 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
- September 24, 1983 · about 3:23 pm local time
- Place
- Sioux Falls, South Dakota
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built (MODIFIED)
- Registration
- UNREG · no longer on the register · serial 1531
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · ultralight rules (Part 103)
The NTSB's narrative final · quoted from the NTSB record
AFTER TAKEOFF, THE PLT OF THE WEIGHT-SHIFT CONTROLLED, ULTRALIGHT VEHICLE ENTERED A STEEP CLIMB, THEN BEGAN A SERIES OF MANEUVERS WHICH INCLUDED PAST VERTICAL WINGOVERS. REPORTEDLY, ON HIS LAST MANEUVER, HE PERFORMED A WHIP STALL. A GROUND WITNESS STATED THAT DURING THE RECOVERY, HE 'PULLED IN TIGHT TO GET AN IMPRESSIVE DIVE.' A PLT WITNESS & 2 FAA INSPECTORS REPORTED THAT WHEN THE NOSE DROPPED, IT WENT PAST A VERTICAL POSITION. THE PLT WITNESS STATED THAT DURING THE RECOVERY, THE PLT HELD THE NOSE IN APRX A 60 DEG DIVE FOR 3 TO 4 SEC. THE FAA INSPECTORS REPORTED THAT DURING THE PULL-OUT, THE WINGS FAILED. AN EXAM REVEALED THAT THE LEFT & RIGHT INBOARD COMPRESSION STRUTS HAD BUCKLED FROM POSITIVE LOADING. THE PLT HAD MODIFIED THE ULTRALIGHT BY INSTALLING A NON-STANDARD ENG-PROP REDUCTION DRIVE SYS, BY CHANGING THE PITCH TRIM, BY ADDING A LOWER TAIL BOOM BRACE & BY ADDING A 10 LB WT TO THE NOSE TO INCREASE THE FORWARD SPEED IN A DIVE.
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
- Ratings: single-engine land
- Medical certificate: Unknown
- Seat: ctr
The aircraft
- Airframe total time: 16 hours
- Last inspection: inspection type not recorded
- Seats: 1
- Landing gear: fixed
- Engine: Cuyuna 430 (piston); 0 hours total
The flight
- Departed from: Y14 Sioux Falls SD at 1:00 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 64°F (18°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.
Other NTSB records under UNREG the same tail number, which may have belonged to a different aircraft at the time
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.