Bell 407 N420PH accident near Cameron, Louisiana

Probable cause

The pilot's failure to remove a main rotor blade tiedown, which resulted in substantial damage to a main rotor blade when the engine was started.

NTSB analysis

The operator reported that the pilot landed and shutdown the helicopter on an offshore platform. He secured the main rotor system by attaching a tiedown to the forward left main rotor blade and he then attached this tiedown to the left front skid cross tube. Several hours later, the pilot entered the right front seat to begin the engine start sequence. The operator reported that the pilot proceeded to start the engine and noted a few seconds after initiating the engine start that the helicopter made an "unusual noise" and began to shake. The pilot then shut down the helicopter without further incident. A postflight inspection revealed substantial damage to the blue main rotor blade.

The operator 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 GAA16CA039 for the full record.