Amateur-built Backcountry Supercub accident near Casper, Wyoming, November 19, 2018
On November 19, 2018 at about 9:50 pm local time, a 2018 amateur-built Backcountry Supercub, registered N59BK, was substantially damaged in an accident during initial climb near Casper, Wyoming (Casper/Natrona County Intl airport). It was a flight test under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The seizure of two bearings in the reduction gearbox, resulting in the total loss of engine power. Contributing to the accident was a high descent rate which resulted in a hard landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 19, 2018 · about 9:50 pm local time
- Place
- Casper, Wyoming · Casper/Natrona County Intl · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Backcountry Supercub, built 2018
- Registration
- N59BK · no longer on the register · serial BC21115R006
- Damage
- Substantial damage
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot was flight testing the airplane to evaluate an experimental diesel engine reduction gearbox. During the takeoff, as the airplane climbed above 500 ft above ground level, the pilot increased engine power, but a total loss of engine power occurred shortly afterward. The pilot initiated a left descending turn to return to the runway. During the landing sequence, the airplane had a high descent rate. The airplane touched down hard, resulting in the separation of the left main landing gear axle and substantial damage to the left wing lift strut. Postaccident examination of the engine reduction gearbox found that two propeller shaft bearings inside the reduction gearbox seized, causing the total loss of engine power.
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
What happened, in order
- Loss of engine power (total) during initial climb defining event
- Loss of control in flight during landing (flare/touchdown)
- Hard landing during landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Accessory gear › boxes › (general) › Failure
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent rate › Not attained/maintained
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 20,322 hours in all; 1 in this make and model; 28 in the last 90 days; 2 in the last 30 days
- Last flight review: April 20, 2017
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
Passenger
- Seat: rear
- Injury: no injuries
The aircraft
- Airframe total time: 0.5 hours
- Maximum gross weight: 2,600 lb
- Seats: 2
- Landing gear: fixed
- Engine: Ckt TD240 (piston); 2 hours total
The flight
- Departed from: CPR Casper WY at 9:50 pm
- Destination: CPR Casper WY
- Flight plan: none
- Runway 21, 10,165 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 220° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 36°F (2°C), dew point 21°F (-6°C)
- Altimeter: 30.17 inHg
- Observation at 10:53 pm from KCPR
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The NTSB has not released the docket for this case yet. The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), is usually released when the investigation is nearly complete, and the list here is refreshed when it appears. Check 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.