Probable cause
The total loss of engine power during cruise flight due to a fractured crankshaft.
NTSB analysis
The float-equipped airplane was in cruise flight on a sightseeing flight when there was a total loss of engine power. After several unsuccessful attempts to restart the engine, the pilot made a forced landing on tundra-covered terrain, and the airplane nosed over. Postaccident disassembly of the engine found that the crankshaft had fractured at the No. 2 journal. Laboratory examination of the crankshaft found "ladder cracking" associated with the journal fracture, which is consistent with a reduced oil flow and overheating of the surface area. At the time of the accident, the engine had 441 hours of operation since major overhaul, which was performed on October 21, 2008.
Text from the NTSB. Open the NTSB docket for ANC10LA056 for the full record.
Event
- Date
- Jun 30, 2010
- Type
- Accident
- Place
- Iliamna, Alaska
- Highest injury
- Minor
- Minor injuries
- 1
- Weather
- Visual (VMC)
- Light
- Day
Cessna U206G
- N-number
- N4596U
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 135 (charter and commuter)
Other records under this N-number
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.