Amateur-built TSUNAMI accident near Pierre, South Dakota, September 25, 1991
On September 25, 1991 at about 6:30 pm local time, a amateur-built TSUNAMI, registered NX39JR, was destroyed in an accident near Pierre, South Dakota (Pierre Municipal airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A BENDING OVERLOAD FAILURE OF THE WING FLAP CONTROL RODS AND REMEDIAL ACTION BY THE PILOT WAS NOT POSSIBLE. FACTORS IN THE ACCIDENT ARE THE INADEQUATE DESIGN OF THE WING FLAP SYSTEM BY THE PILOT/OPERATOR MANUFACTURER AND HIS LACK OF TOTAL EXPERIENCE IN TYPE OF AIRCRAFT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 25, 1991 · about 6:30 pm local time
- Place
- Pierre, South Dakota · Pierre Municipal · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built TSUNAMI
- Registration
- NX39JR · no longer on the register · serial 001
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE ACCIDENT AIRPLANE WAS OBSERVED TO SUDDENLY ROLL INVERTED DURING FINAL APPROACH AND DESCEND INTO THE GROUND. INVESTIGATION OF THE WRECKAGE SHOWED A BENDING OVERLOAD FAILURE OF THE EXTERNAL THREADED STEM TYPE ROD END BEARING ATTACHED TO THE PISTON OF EACH WING FLAP HYDRAULIC ACTUATOR. THE EXPERIMENTAL RACING AIRPLANE WAS ORIGINALLY BUILT AND FLOWN WITHOUT WING FLAPS. THE WING FLAPS WERE ADDED BY THE PILOT/OPERATOR AT A LATER DATE.
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: multi-engine land; single-engine land; instrument: airplane
- Flight time: 9,975 hours in all; 20 in this make and model
- Medical certificate: Class 2
- Seat: ctr
The aircraft
- Airframe total time: 200 hours
- Last inspection: annual inspection, January 2, 2000
- Maximum gross weight: 7,500 lb
- Seats: 1
- Landing gear: retractable
- Engine: Rolls-Royce V-1650-7 (piston); 0 hours total
The flight
- Departed from: CPR Casper WY at 5:15 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 310° at 20 knots, gusting 28
- Visibility: 45 statute miles
- Sky: scat at 25,000 ft
- Temperature: 68°F (20°C), dew point 28°F (-2°C)
- Altimeter: 30.00 inHg
- Observation at 6:32 pm from PIR, 1 miles away
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.