What happened
On September 9, 2020, a Kaman K-1200 K-Max helicopter, registration HB-ZVM, was conducting a series of cargo transport flights near Meiggra in the Zermatt region. The aircraft was performing an external load operation, moving materials between various sites. After completing several rotations, the pilot attempted to land at a designated refueling point to replenish fuel while the rotors were still turning.
As the helicopter approached the landing spot, the pilot focused on aligning the left landing gear with specific ground markings to ensure precise positioning. During this maneuver, the aircraft's main rotor blades struck a small transport van that had been repositioned in the landing area. The impact caused the helicopter to tilt heavily onto its left side, resulting in significant damage to both the aircraft and the vehicle. There were no fatalities and no injuries to the crew, though one person on the ground was uninjured.
The investigation
SUST examined the operational procedures and the positioning of ground personnel at the time of the incident. The investigation established that the flight assistant acting as team leader had moved the van closer to the fuel tanks to facilitate the filling of fuel drums. However, due to the need to assist a less experienced colleague, the team leader failed to communicate the vehicle's new location to the pilot.
Investigators also analyzed the technical characteristics of the K-1200 K-Max. This specific model utilizes a coaxial rotor system, which requires a large, unobstructed area around the cockpit, particularly in the 7 to 10 o'clock and 2 to 5 o'clock positions. The investigation found no evidence of mechanical failure or technical defects in the helicopter prior to the collision.
Findings
- The primary cause of the accident was the collision between the rotating main rotor and a van that had been moved into the rotor arc without notice.
- The pilot's attention was focused on the precise placement of the landing gear, which prevented him from noticing the vehicle in his peripheral vision.
- The team leader's failure to notify the pilot of the vehicle's change in position contributed to the event.
- The high workload and the need to assist an inexperienced crew member likely led to the oversight regarding the vehicle's location.