What happened
On August 22, 1961, at approximately 16:53 CEST, a Bell 47G-2 helicopter, registration HB-XAX, was engaged in material transport operations at a high-altitude construction site near the Cavagnoli Glacier in Ticino, Switzerland. The aircraft, operated by Schweizerische Helikopter Aktiengesellschaft, was delivering supplies to a transmission tower site at an elevation of approximately 2,650 meters.
To conserve battery power, the pilot had been leaving the engine running during landings to avoid the need for frequent restarts. Upon completing its 23rd landing of the day, the pilot remained in his seat while the cargo was being secured. As the pilot prepared to exit the cockpit to inspect the load, a construction technician approached the aircraft from the uphill side of the landing platform. As the technician entered the rotor arc, a rotor blade struck him in the face, causing severe head injuries. The technician passed away later that evening.
The investigation
The investigation, conducted by the Swiss Federal Aircraft Accident Investigation Commission in coordination with the Ticino Cantonal Police, examined the site conditions, the aircraft's maintenance status, and the sequence of events leading to the contact. Investigators reviewed the pilot's previous flight experience and the weather conditions, which were noted as clear with moderate local winds. The investigation also looked into the safety instructions provided to the ground crew prior to the accident.
Findings
- The helicopter sustained only a minor dent in one rotor blade and no significant structural damage.
- The pilot had previously warned the contractor about the danger of approaching the aircraft from the downhill side due to the terrain, and instructions had been passed to the workers.
- The technician likely approached the aircraft with the intention of hitching a ride back to the valley station.
- The technician failed to recognize the danger of the rotating rotor blades, likely due to being distracted or because the motion of the blades was difficult to perceive at certain angles.
- Local wind conditions may have partially masked the sound of the engine, further reducing the technician's awareness of the active machinery.