What happened
On July 2, 2009, an Eurocopter AS 350 B3, registration HB-ZBJ, was conducting a tactical training exercise near Walenstadt, Switzerland. The aircraft was being used by the Zurich Cantonal Police to train specialized police officers in various helicopter-based insertion techniques, including fast-roping and sliding.
During a specific maneuver involving sliding from the aircraft's skids onto a bunker roof, a police officer acting as a group leader attempted to exit the helicopter. As the officer moved from the skid to the rope, he was unable to establish a secure leg loop (beinschlüssel) in time. Due to the added weight of his tactical equipment—approximately 20 kg—the officer could not maintain his grip on the rope. He subsequently lost his balance and fell approximately two meters onto the roof of the bunker, resulting in a serious injury consisting of an open fracture to his right lower leg.
The investigation
The investigation examined the training protocols, the equipment used, and the specific mechanics of the exit technique. Investigators reviewed the Standard Operating Procedures (S/SOP) and the Flight Operations Manual (FOM) used by the police unit. The inquiry also looked into the physical requirements of the exit method, noting that when the rope is attached to a floor plate rather than a swing arm, the officer must lean significantly backward to ensure enough rope length is available to prevent their hands from striking the skid upon exit.
Findings
- The primary cause of the accident was that the police officer lost his balance and fell while sliding from the helicopter.
- The specific exit technique required by the existing deployment equipment contributed to the accident, as it necessitated a physically demanding maneuver to secure the rope.
- The weather conditions, including light rain and low wind, had no impact on the occurrence.
- The pilot and the training instructors were performing duties in accordance with established flight and operational manuals.