What happened
The aircraft experienced a complete loss of engine power during flight. In response to this emergency, the pilot initiated an autorotation maneuver. However, the aircraft was unable to maintain sufficient lift or control authority during this phase and subsequently crashed.
The investigation
Following the accident, investigators conducted a detailed teardown of the failed engine to determine the root cause of the power loss. The examination focused on the internal components of the engine's rotating assembly.
The inspection revealed significant mechanical failure within the bearing system. Specifically, the number two bearing had failed catastrophically. Further analysis showed that several ball retainers within this bearing were broken and cracked between the ball pockets. This structural integrity failure allowed the impeller assembly to shift forward from its designed position.
Findings
The forward movement of the impeller assembly caused it to make direct physical contact with the diffuser assembly. This interference resulted in a complete loss of engine operating power, which directly led to the inability to complete the autorotation successfully and the subsequent crash.
- Engine teardown revealed bearing failure
- Ball retainers broken between pockets
- Impeller assembly moved forward
- Contact with diffuser assembly caused power loss
Safety message
This incident highlights the critical importance of regular inspection of engine bearings and retainers to prevent catastrophic mechanical failure during flight operations.