Piper PA-18-150 accident near Douglas, Wyoming, June 4, 1990
On June 4, 1990 at about 5:30 pm local time, a Piper PA-18-150, registered N4720A, was substantially damaged in an accident near Douglas, Wyoming (Converse County airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE ACCIDENT TO BE IMPROPER INSTALLATION OF AILERON CONTROL SYSTEM BY MAINTENANCE PERSONNEL, AND FAILURE TO PERFORM AN AIRCRAFT PREFLIGHT BY THE PILOT IN COMMAND.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 4, 1990 · about 5:30 pm local time · cases in 1990
- Place
- Douglas, Wyoming · Converse County · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-18-150 · all PA-18-150s on the register
- Registration
- N4720A · registry record · serial 18-4941
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE AIRPLANE HAD BEEN COMPLETELY RECOVERED WITH NEW FABRIC AND THE PILOT WAS GOING TO FERRY IT BACK TO HIS RANCH. WITNESSES SAID THE PILOT DID NOT PERFORM A PREFLIGHT CHECK. THE AIRPLANE TOOK OFF, CLIMBED TO AN ALTITUDE OF 15 TO 30 FEET, THEN BANKED STEEPLY TO THE RIGHT AND CRASHED. EXAMINATION OF THE FLIGHT CONTROL SYSTEM DISCLOSED THE AILERON CONTROL CABLES HAD BEEN INADVERTENTLY CROSSED DURING REASSEMBLY.
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: 3,823 hours in all; 30 in the last 90 days; 9 in the last 30 days
- Medical certificate: Class 3 (expired)
- Seat: frt
The aircraft
- Airframe total time: 3,078 hours
- Last inspection: annual inspection, June 1, 1990
- Maximum gross weight: 1,750 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-A2A (piston); 0 hours total
- Operator: Norman Ranch Company
The flight
- Departed from: DGW at 5:30 pm
- Destination: NONE Rozet WY
- Flight plan: none
- Runway 28, 6,750 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 270° at 32 knots, gusting 37
- Visibility: 50 statute miles
- Sky: ovct at 25,000 ft
- Temperature: 82°F (28°C), dew point 30°F (-1°C)
- Altimeter: 29.00 inHg
- Observation at 5:50 pm from CPR, 48 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.
Connections how this case links to the rest of the register
- N4720A on the register today · the tail number may have moved to another aircraft since
- Piper PA-18 Super Cub 3,620 registered today · the model family and its accident history
- Piper 44,848 aircraft on the register
- Engine: Lycoming O-320-A2A 9 aircraft carry this series today · as the NTSB recorded it
- Converse County · nearest airport
- Accidents and incidents in Wyoming 778 since 1982 · 109 in the last ten years
- Wyoming 3,236 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/DEN90LA123.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.