Md Helicopter 369D N155PH accident near Salem, Oregon

Probable cause

The pilot’s failure to maintain clearance between the longline and trees, which resulted in the longline snagging a tree and then recoiling into the main rotor blades and a subsequent loss of helicopter control.

NTSB analysis

The pilot reported that he was transporting tree bundles on a 25-foot longline. He placed a tree bundle on a truck and then went to pick up another load. He looked outside to set up for final approach to deliver the hook to ground personnel. He then lowered the collective, applied aft cyclic to slow the helicopter, and applied the right pedal to turn the helicopter, which allowed him the best possible view of the ground personnel. Just as he applied the right pedal, the pilot felt and heard a bang; the helicopter immediately started to shudder and then pitched forward violently with a left yaw. The pilot subsequently set up for an autorotation, and, after touchdown in a level attitude with a slight forward speed, the pilot-side landing gear collapsed.

During the postaccident examination of the helicopter at the accident site, a portion of the longline cable and/or wire was located beside a 7- to 9-foot-tall tree that had a section of its top broken off. The tail rotor was found 20 to 30 feet away. It is likely that the hook assembly snagged the tree, which swayed up to a point, pulled the longline taut, and turned the helicopter right. When the treetop broke away, the helicopter suddenly yawed left and pitched forward. The longline recoiled into the main rotor, which resulted in rotor damage, severe imbalance, and a loss of helicopter control. The pilot stated that he did not observe or feel the longline hook get hung up or dragged through the trees.

Text from the NTSB. Open the NTSB docket for WPR11LA048 for the full record.