Amateur-built 133 accident near Mondamin, Iowa, September 5, 1982
On September 5, 1982 at about 9:30 pm local time, a amateur-built 133 (helicopter), registered N13420, was substantially damaged in an accident near Mondamin, Iowa. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. 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 5, 1982 · about 9:30 pm local time
- Place
- Mondamin, Iowa · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built 133
- Registration
- N13420 · no longer on the register · serial RW2958
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
AFTER A GROUND ADJUSTMENT TO THE COLLECTIVE PITCH ON HIS HOMEBUILT HELICOPTER, THE PILOT TOOKOFF TO PRACTICE HOVERING TAKEOFF AND LANDING. IN AN ATTEMPT TO HOVER CLOSE TO GROUND, HE RAISED THE COLLECTIVE AND THE AIRCRAFT SHOT UP ABOUT 30 FEET. IT THEN FELL OFF TO THE LEFT AND IMPACTED THE GROUND A LATER DISCUSSION WITH FACTORY REPRESENTATIVE DISCLOSED A DIFFERENCE BETWEEN VERBAL ADJUSTMENT INSTRUCTIONS AND THOSE ON THE PUBLISHED PLANS FOR BUILDING THE AIRCRAFT.
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: rotorcraft: helicopter
- Flight time: 73 hours in all; 11 in this make and model; 11 in the last 90 days; 41 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 10 hours
- Last inspection: inspection type not recorded; 10 hours since
- Maximum gross weight: 1,250 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway RW145 (piston); 0 hours total
The flight
- Departed from: Mondamin IA at 3:30 pm
- Destination: Mondamin IA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Sky: not recorded; clear
- Temperature: 167°F (75°C), dew point 0°F (-18°C)
- Observation at 4:30 pm
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.