Bell 206 N317RL incident near Gulf Of Mexico, Louisiana

Probable cause

The loss of main rotor rpm during takeoff for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies.

NTSB analysis

During takeoff from an offshore oil platform, the pilot reported a loss of main rotor rpm. The pilot activated the emergency float system and initiated an autorotation to the water. Upon touchdown, the engine was still operating. The pilot shut down the engine and prepared the passengers to evacuate. All three occupants safely evacuated the helicopter (which was upright on its skid-mounted float system) and boarded the emergency life raft that the pilot had inflated. The helicopter remained upright floating on the water and was later recovered and transported to the operator’s on-shore maintenance facility. The operator did immediate fuel quality tests at the facility where the helicopter had most recently been refueled and found no problems.

An examination of the helicopter drive systems and a test run of the engine did not reveal any preincident anomalies that would have precluded normal operation of the main rotor system. The cause of the loss of main rotor rpm could not be determined.

Text from the NTSB. Open the NTSB docket for CEN10IA438 for the full record.