Robinson Helicopter Company R44 II N779DZ accident near Ketchikan, Alaska

Probable cause

The pilot's failure to maintain directional control during the engine start sequence, which resulted in the helicopter sliding on a steel deck and impacting a crane. Contributing to the accident was the absence of traction material on the helicopter operations portion of the steel deck.

NTSB analysis

The helicopter pilot reported that during the engine start sequence on an offshore barge with a bare steel deck, the main rotor system clutch was engaging, and the throttle was applied to maintain 60 percent engine revolutions per minute. He reported that the skid and tundra/snow board equipped helicopter began a rapid right yaw, left pedal was applied simultaneously with throttle closure, but the helicopter rapidly yawed left resulting in the vertical stabilizer and tail rotor blade system impacting a crane stationed on the deck. The pilot then shut down the helicopter without further incident. A postflight inspection revealed substantial damage to the vertical stabilizer and the tail rotor blade system.

The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for GAA16CA009 for the full record.