Mitsubishi MU2B accident near Big Piney, Wyoming, December 30, 2019
On December 30, 2019 at about 9:45 pm local time, a 1980 Mitsubishi MU2B, registered N43866, was substantially damaged in an accident during landing (landing roll) near Big Piney, Wyoming (Miley Memorial Field). It was a personal flight under general aviation rules (Part 91). No one was hurt; 4 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the right propeller position to correspond to the throttle change when moved to the beta position for reasons that could not be determined based on available evidence.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 30, 2019 · about 9:45 pm local time
- Place
- Big Piney, Wyoming · Miley Memorial Field · map
- Type
- Accident
- Injuries
- No one was hurt; 4 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mitsubishi MU2B 60, built 1980 · all MU2Bs on the register
- Registration
- N43866 · no longer on the register · serial 757SA
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that the approach and landing flare were normal; however, as he moved both throttles to the beta position, it appeared that the left propeller went into the beta position while the right one did not. This resulted in a course deviation and runway excursion to the left, which led to the separation of the right main landing gear and substantial damage to the right wing. The National Transportation Safety Board was unable to conduct a follow-up examination, as the airplane has been sold and a chain of custody had been compromised. As a direct result of the airplane not being able to be examined, the cause of the right propeller failure to correspond to the throttle movement to the beta position is undetermined.
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 control on ground during landing (landing roll)
- Collision with terrain or object (not controlled flight into terrain) during after landing
- Comm system malf/failure during landing (landing roll) defining event
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 3,397 hours in all; 915 in this make and model; 20 in the last 90 days; 9.6 in the last 30 days; 2,756 as pilot in command
- Last flight review: June 1, 2019
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
Passenger
- Seat: rgt
- Injury: no injuries
Passenger
- Seat: rgt
- Injury: no injuries
Passenger
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 7,002 hours
- Last inspection: annual inspection, October 24, 2019
- Maximum gross weight: 11,575 lb
- Seats: 10
- Landing gear: retractable
- Engine 1: Honeywell TPE 331-10 (turboprop); 0 hours total
- Engine 2: Honeywell TPE 331-10 (turboprop); 0 hours total
The flight
- Departed from: LBF North Platte NE at 7:45 pm
- Destination: BPI Big Piney WY
- Flight plan: IFR
- Runway 31, 6,803 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 200° at 3 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 4,300 ft
- Temperature: 1°F (-17°C), dew point -2°F (-19°C)
- Altimeter: 30.03 inHg
- Observation at 8:53 pm from KBPI
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on April 26, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 11 pages | View Download |
| 2 | Record of Conversation | PDF, 2 pages | View Download |
| 3 | Photo (Unknown Source) | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.