Md Helicopter 369FF N67FF accident near Santa Clarita, California

Probable cause

The pilot's failure to maintain clearance from the water while maneuvering at low altitude as a result of the helicopter's grappling hook temporarily becoming ensnared with an underwater obstruction.

NTSB analysis

The pilot reported that he was maneuvering the helicopter about 10 feet above a reservoir in an attempt to use its rotor wash to propel an object to the shore. During this maneuver, the helicopter's long-line and attached grappling hook were submerged in the water. With the helicopter moving at low speed about 10 feet from the shoreline, the grappling hook became temporarily ensnared on an underwater obstruction and the helicopter made a rapid and violent turn. The pilot initiated emergency procedures and maneuvered the helicopter toward the shore. It touched down on uneven terrain with the left skid on dry land and the right skid in the water. Examination of the helicopter revealed that there was a torsional fracture and separation of the tail rotor drive shaft as a result of the tail rotor blades contacting the water. No anomalies with the main rotor controls were found.

Text from the NTSB. Open the NTSB docket for WPR09LA226 for the full record.