Hughes 369D N622PB accident near Bonners Ferry, Idaho

Probable cause

The pilot's inadequate preflight planning for the takeoff and the helicopter loading that exceeded the lift performance capability of the helicopter.

NTSB analysis

The pilot was assigned to pick up three firefighters and their gear from a mountain site and he completed load calculations prior to the flight. The pilot had planned for hover in ground effect performance, although the terrain in the area was sloped and contained vegetation and rocks. As he flew into the area, the pilot assessed the winds and noted that they were coming from the south from 5 to 7 knots. He landed into the wind, picked up the passengers, and stabilized the helicopter in a 3 to 4-foot hover to verify the power. He departed into the wind and began a slow steady climb to clear trees. The helicopter then began to descend toward the trees. The pilot applied additional power but could not stop the descent. He then force-landed the helicopter on downed trees and stumps. During the accident sequence, the tail rotor drive shaft sheared. After exiting the helicopter, the pilot noted that the winds had shifted. The passengers said the winds had been shifting prior to the pilot's arrival. There were no mechanical malfunctions reported with the helicopter. Review of the pilot’s duty time showed that he had worked in excess of the contract requirements, and may have been fatigued. Post accident review of the loaded weight of the helicopter revealed that it exceeded the load limits for the operation.

Text from the NTSB. Open the NTSB docket for SEA08TA188 for the full record.