Amateur-built RD-1 accident near St. Charles, Missouri, August 13, 1985
On August 13, 1985, a amateur-built RD-1 (gyroplane), registered N4741A, was destroyed in an accident near St. Charles, Missouri (St Charles City 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
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
- August 13, 1985
- Place
- St. Charles, Missouri · St Charles City · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built RD-1
- Registration
- N4741A · no longer on the register · serial 100
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE HOME BUILT GYROCOPTER WAS BEING FLOWN BY THE OWNER/BUILDER/DESIGNER WHO HAD AN AIRPLANE, SINGLE-ENG, LAND RATING. SHORTLY AFTER THE GYROCOPTER TOOK OFF, THE ENG WAS OPERATING AT A HIGH RPM WHEN A WITNESS HEARD A POP/NOISE. SUBSEQUENTLY, THE GYROCOPTER CRASHED IN A CORN FIELD ABOUT 1-1/2 MI FROM THE DEPARTURE POINT. THE MAIN WRECKAGE WAS FOUND INVERTED. ONE ROTOR BLADE, THE OIL COOLER & THE LEFT VERTICAL STABILIZER & RUDDER WERE FOUND 60 TO 150 FT FROM THE MAIN WRECKAGE. BOTH OF THE WOODEN PROP BLADES HAD SHATTERED. THE OIL COOLER HAD BEEN INSTALLED BELOW THE ENG & JUST FORWARD OF THE PROP. ITS UPPER SIDE HAD BEEN ATTACHED WITH A SINGLE SOLID MOUNT USING AN 'L' SHAPED ALUMINUM STRAP. ITS LOWER SIDE WAS FASTENED WITH A SEMIFLEXIBLE MOUNTING. THERE WAS EVIDENCE THAT THE UPPER MOUNT HAD FAILED & ALLOWED THE OIL COOLER TO MOVE AFT INTO THE PLANE OF ROTATION OF THE PROP BLADES. EXCEPT FOR THE OIL COOLER BRACKET, NO PRE- ACCIDENT MECHANICAL PROBLEMS WERE FOUND.
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: 52 hours in all; 2 in this make and model
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 2 hours
- Last inspection: inspection type not recorded
- Maximum gross weight: 630 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-290-G (piston); 0 hours total
The flight
- Flight plan: none
- Runway 36, 3,800 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 160° at 13 knots
- Visibility: 4 statute miles
- Sky: clear
- Temperature: 90°F (32°C), dew point 75°F (24°C)
- Altimeter: 29.00 inHg
- Observation at 11:45 pm from STL, 12 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.