# NTSB WPR20LA054: Mitsubishi MU2B, N43866, Big Piney, WY, December 30, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: December 30, 2019, 14:45 local (21:45 UTC) - Place: Big Piney, WY - Coordinates: 42.582221, -110.108886 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.5822&lon=-110.1089&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Comm system malf/failure](https://openairdocs.org/ntsb-events/336) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FSDO - NTSB case key (mKey): 100754 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20LA054 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100754/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100754 - Page: https://openairdocs.org/ntsb/WPR20LA054 ## Probable cause 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. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Mitsubishi MU-2B-60, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=5780460), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Comm system malf/failure](https://openairdocs.org/ntsb-events/336) (defining event); cases with it: [Mitsubishi MU-2B-60, 1 case](https://openairdocs.org/ntsb-events/336/sequence.md?model=5780460), [All aircraft, 20 cases](https://openairdocs.org/ntsb-events/336/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Mitsubishi MU-2B-60, 2 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=5780460), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [After landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Mitsubishi MU-2B-60, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=5780460), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis 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. ## Factual narrative On December 30, 2019, about 1445 mountain standard time, a Mitsubishi MU-2-60 airplane, N43866, was substantially damaged when it was involved in an accident at the Miley Memorial Field Airport (BPI), Big Piney, Wyoming. The private pilot and three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the approach was normal, and he did not experience any issues when the airplane made contact with the runway. However, as he moved both throttles to the beta position, it appeared that the left propeller went to beta position while the right one did not. This resulted in a course deviation about 30°- 35°. An attempt to correct the drift with the nose gear control was unsuccessful. The airplane departed the runway and began to turn which, led to the separation of the right main landing gear, collision of the right wing with terrain, and the right-wing tip separation. The airplane came to rest off the left side of the runway with the nose of the airplane oriented towards the approach end. The airplane was secured and retained at BPI for further examination. The airplane was subsequently sold and removed from the airport before an examination could be coordinated. ## Aircraft - Registration: [N43866](https://openairdocs.org/deregistered/N43866-2021-05-15), registration cancelled 2021-05-15, S/N 757SA, built 1980 (OpenAirDocs) - Reported make and model: Mitsubishi MU2B (60) - Registry model: [Mitsubishi MU-2B-60](https://openairdocs.org/model/mitsubishi-mu-2b-60) (registry code 5780460) (OpenAirDocs) - Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 757SA - Year built: 1980 - Airframe hours: 7002 - Engines: Honeywell TPE 331-10 715 horsepower turbo prop; Honeywell TPE 331-10 715 horsepower turbo prop - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 24, 2019 - Departed: LBF, North Platte, NE - Destination: BPI, Big Piney, WY - Flight plan: IFR - Airport: BPI, Miley Memorial Field, runway 31, 6,803 × 75 ft, asphalt - Equipment: Stall warning system, Auto-pilot, Onboard weather, Electronic flight bag or handheld device, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: none; private; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 1, 2019; seat: left; restraint: 4-point; flight hours: 3,397 total, 915 in this make and model, 2,756 as pilot in command, 20 in the last 90 days, 9.6 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 3 knots - Visibility: 10 statute miles - Temperature: 1 °F, dew point -2 °F - Altimeter: 30.03 inHg - Observed at: KBPI ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20191230024089A](https://openairdocs.org/incident/20191230024089A), Dec 30, 2019: Mitsubishi MU-2B-60, Big Piney, WY, Substantial damage. Upon selection of beta during landing rollout, pilot lost directional control of aircraft which then departed the runway. Right main mount collapsed which… ## Docket (3 files) The files NTSB released with the investigation on April 26, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100754. 7.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 7.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10000213&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Record of conversation (item 2, PDF, 2 pages, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=9999729&FileExtension=pdf&FileName=records%20of%20conversation-Rel.pdf - Photo (unknown source) (item 3, PDF, 1 page, 125 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=9998671&FileExtension=pdf&FileName=Photo-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.