No fatalities

30 Dec 2019: Mitsubishi MU2B 60 (N43866) — Big Piney, WY

Big Piney, WY, United States

On 30 Dec 2019, a Mitsubishi MU2B 60 (registration N43866) was involved in an aviation accident near Big Piney, WY. No fatalities were reported. Investigators recorded the probable cause as: 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. This summary draws on records from NTSB; 4 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

On December 30, 2019, a Mitsubishi MU-2-60 (N43866) veered off the runway during landing at Miley Memorial Field Airport after asymmetric propeller beta operation, resulting in substantial damage but no injuries.

Accident Details

On December 30, 2019, at approximately 1445 mountain standard time, a Mitsubishi MU-2-60 airplane, registration N43866, sustained substantial damage in an accident at Miley Memorial Field Airport (BPI) in Big Piney, Wyoming. The private pilot and three passengers were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.

Sequence of Events

The pilot reported that the approach was normal, and no issues were encountered during initial runway contact. However, when he moved both throttles to the beta position, the left propeller appeared to engage beta while the right propeller did not. This asymmetry caused the airplane to deviate approximately 30 to 35 degrees from its intended heading. The pilot attempted to correct the drift using the nose gear steering control, but the effort was unsuccessful. The airplane departed the left side of the runway and began to turn, leading to the separation of the right main landing gear, contact of the right wing with terrain, and separation of the right wingtip. The airplane came to rest off the left side of the runway with the nose oriented toward the approach end.

Aftermath

The airplane was secured and retained at BPI for further examination. However, it was subsequently sold and removed from the airport before an examination could be coordinated.