Nighttime Helicopter Tail Rotor Impact During Repositioning (N431UM)

Incident Overview and Initial Conditions A helicopter sustained substantial damage during a nighttime repositioning maneuver when its tail rotor struck a roadway sign. The aircraft had previously landed on a roadway to pick up a patient for a medical evacuation flight. Before the repositioning began, the medical crew had already departed the helicopter, leaving the pilot as the only occupant on board. ## Pilot Account and Sequence of Events The pilot reported that he initiated taxiing and stated that he had cleared the tail to move left for a turnaround along M-59. He described starting to move the aircraft, which was then facing south into M-59, when the tail rotor hit a steel reflector post. The impact caused the aircraft to become airborne to approximately five or six feet. The pilot then lowered the collective and rolled the throttles to idle to stop the aircraft's rotation. ## Impact and Post-Accident Examination The helicopter impacted the ground on the left rear skid first and came to rest one hundred eighty degrees from its initial heading. A post-accident examination revealed that the tail rotor and gearbox had departed the helicopter. The pilot reported that there were no mechanical malfunctions with the helicopter prior to the accident.