Md Helicopter 369 N500SC accident near Summersville, South Carolina

Probable cause

The copilot’s disabling of the flight controls of an operating helicopter without telling the pilot on the controls, which resulted in a subsequent loss of control and collision with terrain.

NTSB analysis

The pilot, seated in the left seat, reported that he taxied and landed the helicopter on a taxiway after completing a mission. After landing, the copilot, seated in the right seat, disembarked with the passenger to request fuel from the fixed-base operator. The copilot returned to the helicopter without boarding and instructed the pilot to reposition the helicopter to the airport's refueling station because the fuel truck was inoperative. Once the copilot was clear of the helicopter, the pilot brought the helicopter to a hover, but the helicopter began to spin clockwise. He then applied left pedal, but the helicopter continued to spin and climbed about 7 ft above ground level. The pilot stated that, after two revolutions, he realized that the right-seat, left antitorque pedal was "chocked" and added that he was not aware that the copilot had "chocked" the pedals. He immediately initiated an autorotation, but the helicopter's tail rotor and main rotor blades struck the ground. The copilot reported that, after exiting the cockpit, while the pilot had positive control of the flight controls, he chocked the pedals on the right side by removing the left antitorque pedal, rotating it 180°, and reinstalling it, which prevented full travel of the left antitorque pedal on both sides of the cockpit. He added that he did not tell the pilot he had chocked the pedals and that he did not know why he chocked the pedals. The helicopter sustained substantial damage to the main and tail rotor systems and tailboom. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for GAA19CA403 for the full record.