Probable cause
The seizure of the engine during flight for undetermined reasons, which led to a total loss of engine power.
NTSB analysis
The pilot reported that, while on the base leg approach, he heard a “loud bang,” and the engine lost total power. The pilot determined that the airplane would not be able to reach its intended destination, so he turned the airplane into the wind and made a forced landing on tundra-covered terrain, which resulted in substantial damage to the fuselage.
The airplane’s maintenance records were unremarkable. Postaccident examination of the engine revealed that it had seized and sheared the propeller spline into two pieces. The accessory wall could not be removed because of the extensive internal damage to the engine. As a result, the investigation was unable to determine the reason that the engine seized during the flight.
Text from the NTSB. Open the NTSB docket for ANC21LA094 for the full record.
Event
- Date
- Aug 21, 2021
- Type
- Accident
- Place
- Bettles, Alaska
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Dehavilland DHC-3
- N-number
- N560TR
- Category
- Airplane
- Year built
- 1956
- Damage
- Substantial
- Operating rule
- Part 135 (charter and commuter)
- Purpose of flight
- Business
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.