What happened
On May 24, 2012, an Agusta-Bell 206B helicopter, registration HB-XPQ, was conducting a flight near Eggschwand, in the municipality of Reichenbach/BE. During the flight, the aircraft struck the carrying cable of a transport cableway. The impact caused the helicopter to crash. The cableway in question was recorded in the aeronautical obstacle register, but it lacked any physical markings or markers to make it visible to pilots.
The investigation
An investigation by the Swiss Transportation Safety Investigation Board (SUST) established that the cableway's maximum height above ground was approximately 90 meters, placing it near the center of the valley. While the obstacle was documented in aeronautical charts, the investigation found that the cableway was extremely difficult to identify from the air. The investigators also examined the crew's preparation, noting that the flight instructor was managing a high workload due to various administrative and leadership roles within the flight school organization. Additionally, the investigation looked into the availability of collision warning technology, specifically the Floice system, which was not installed on the aircraft.
Findings
Determined causes of the accident included a lack of situational awareness regarding the aeronautical obstacle and the selection of a flight path that was inherently risky given the prevailing conditions. The absence of a Floice collision warning system was also a primary causal factor.
Contributing factors included the lack of any physical marking on the transport cableway and an incomplete flight preparation resulting from a lack of a pre-flight briefing. The investigation also identified a high chronic workload for the flight instructor as a risk factor, though not a direct cause of the collision.