N6555C

On February 27, 2025, about 0745 central standard time, a Robinson Helicopter Company, R44 II, N6555C, was involved in an accident near Edgemont, South Dakota. The pilot was not injured and the non-flight crewmember was seriously injured. The helicopter was not damaged. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight.

The purpose of the flight was to survey and capture elk and was operated with the pilot and a non-flight crewmember, the gunner. The gunner’s purpose was to tranquilize elk from the maneuvering helicopter as the pilot positioned the helicopter to match the speed of a target elk.

The pilot reported that the helicopter was maneuvering about 30 ft above ground level during an elk capture and surveying flight. The non-flight crewmember, who was seated in the right-rear passenger seat, fell out of the helicopter and was seriously injured. The pilot immediately landed the helicopter without further incident.

According to the helicopter manufacturer, the C421-2 tube (vertical) and the C423-4 upper seatback support tube (horizontal) were part of the optional 5-point seat belt installation available for the front seats (Figure 1). The purpose of the C423-4 upper seatback support tube was to properly position and support the four shoulder harnesses for the front seat occupants. The purpose of the C421-2 tube was to transfer any downward loads applied to the upper seatback support tube to the C423-1 lower seatback support tube in the event of a hard landing. The manufacturer stated that it was not designed to sustain any side loads and does not require periodic maintenance or inspection other than overall condition.

Post-flight examination of the helicopter revealed that the anchor point (vertical tube, C421-2) used to secure the supplemental restraint system to the helicopter separated from the surrounding structure (Figure 2). The hollow vertical tube remained intact but exhibited deformation on the outer circumference of one of its ends. The other end exhibited less deformation to the tube, its plastic cap, and hardware.

Figure 1. Airframe restraint system

Figure 2. Separated vertical tube

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 to secure it during the flight. He reported that the supplemental restraint system’s anchor point is secured to the helicopter by the pilot before each flight in a designated position and that he “clips in” his end of the harness to the anchor point end of the harness before the flight. The gunner stated that the pilot had selected the harness anchor point. It was the same anchor point used on previous flights.

The pilot reported that he briefed the gunner that the helicopter’s restraint system, which consisted of seat belts and shoulder harnesses, is the primary restraint and that any supplemental harness is secondary. He stated that he allows the gunner to place the anchor point for the supplemental restraint system at his or her discretion because it is not required by regulation.