Incident Overview
On February 27, 2025, at approximately 0745 central standard time, a Robinson Helicopter Company R44 II, registration N6555C, was involved in an accident near Edgemont, South Dakota. The helicopter was conducting an aerial observation flight under Title 14 Code of Federal Regulations Part 91, with the purpose of surveying and capturing elk. The crew consisted of a pilot and a non-flight crewmember acting as a gunner, whose role was to tranquilize elk from the maneuvering helicopter.
Sequence of Events
The pilot reported that the helicopter was maneuvering at about 30 feet above ground level during the elk capture flight. The gunner, seated in the right-rear passenger seat, fell out of the helicopter and sustained serious injuries. The pilot immediately landed the helicopter without further incident. The pilot was not injured, and the helicopter was not damaged.
Restraint System Details
According to the helicopter manufacturer, the C421-2 vertical tube and the C423-4 upper seatback support tube (horizontal) were components of an optional 5-point seat belt installation available for the front seats. The C423-4 tube was designed to position and support the four shoulder harnesses for front seat occupants, while the C421-2 tube was intended to transfer downward loads to the C423-1 lower seatback support tube during a hard landing. The manufacturer stated that the C421-2 tube was not designed to sustain side loads and did not require periodic maintenance or inspection beyond general condition checks.
Post-Flight Examination
A post-flight examination revealed that the anchor point (vertical tube, C421-2) used to secure the supplemental restraint system to the helicopter had separated from the surrounding structure. The hollow vertical tube remained intact but exhibited deformation on the outer circumference of one end; the other end showed less deformation to the tube, its plastic cap, and hardware.
Crew Statements
The gunner reported that he secured the helicopter's shoulder restraints by tucking them behind the seat, and the lap belt was buckled and laid flat against the seat for the flight. He noted that the supplemental restraint system's anchor point was secured by the pilot before each flight in a designated position, and he would clip his end of the harness to the anchor point end before the flight. The gunner stated that the pilot had selected the harness anchor point, which was the same one used on previous flights.
The pilot reported that he briefed the gunner that the helicopter's primary restraint system (seat belts and shoulder harnesses) was the main restraint, and any supplemental harness was secondary. He stated that he allowed the gunner to place the anchor point for the supplemental restraint system at his or her discretion because it was not required by regulation.