One Of The Main Rotor Blades Then Struck The Tail Boom, And The Other Blade Flapped Down...

Location: Estacada, Oregon Accident Number: WPR24LA036
Date & Time: November 15, 2023, 07:45 Local Registration: N103WC
Aircraft: Bell OH-58A Aircraft Damage: Substantial
Defining Event: Loss of control in flight Injuries: 1 None
Flight Conducted Under: Part 133: Rotorcraft ext. load

Analysis: The pilot reported that he was relocating bundles of trees from the harvest field onto a truck bed. Approximately 30 minutes into the operation, the load hook did not immediately release when he was setting a bundle down. The pilot pressed the release button multiple times, as he had done in similar situations in the past. The helicopter’s momentum, as it moved back towards the field, caused the bundle to slide a few feet. One of the main rotor blades then struck the tail boom, and the other blade flapped down, cutting off the rear section of the tail boom, vertical stabilizer, and tail rotor. The helicopter spun several times before landing, resting flat on the skids. The landing impact was forceful enough to break the mast and dislodge the main transmission. The helicopter sustained substantial damage to the main rotor, tail boom, vertical stabilizer, tail rotor, and transmission. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operations.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- The pilot’s failure to maintain helicopter control during an external load operation, which resulted in the helicopter’s main rotor blades impacting the tail boom.

FMI: www.ntsb.gov