Robinson Helicopter Company R44 II N6555C accident near Edgemont, South Dakota

Probable cause

The pilot’s failure to properly identify the proper anchor point for the supplemental harness and the crew’s incorrect use of the restraint system structure as an anchor point, which resulted in the separation of the structure.

NTSB analysis

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 gunner, who was clipped into the helicopter with a safety harness, fell out of the helicopter while conducting the elk capture operation and sustained serious injuries. The pilot landed the helicopter without further incident.

A postaccident examination of the helicopter revealed that the anchor point for the front passenger seat restraint system separated and was still attached to the gunner’s harness. Examination of the separation surfaces revealed deformation along the circumference of each end of the tubing.

The gunner was not using the helicopter’s passenger seat restraint system when he fell out of the helicopter; rather, he was using a harness restraint system that was anchored to the vertical tube of the helicopter’s supplemental shoulder harness guide system.

The pilot stated that the gunner selected and secured the anchor point for the harness before the flight and the gunner stated that the pilot selected and secured the anchor point.

According to the helicopter manufacturer, the anchor point utilized for the harness was not designed to sustain side loads, which resulted in its separation and the gunner falling out of the helicopter.

Text from the NTSB. Open the NTSB docket for CEN25LA105 for the full record.