Summary
On 22 August 1961, a Bell 47G-2 helicopter, registration HB-XAX, was involved in a fatal accident on the Cavagnoli Glacier in Ticino, Switzerland. A technician employed by the Bernese Power Works was killed after being struck by the rotating rotor while the helicopter was stationary on a landing platform.
Facts
The accident occurred at 1653 Central European Time on a worksite at an elevation of approximately 2650 meters, near mast number 18 of the S. Carlo-Ulrichen transmission line. The helicopter was operated by Swiss Helicopter AG and was being used for material transport. The pilot, a professional with 3208 flight hours, had performed 23 landings that day without stopping the engine to conserve battery power. The rotor was turning at about 180-200 revolutions per minute.
Sequence of Events
The helicopter landed at 1652 with a load of material. The pilot remained seated until the load was secured, then exited to supervise unloading. At that moment, he saw the technician approaching from above the landing platform and heading into the rotor circle. The pilot shouted a warning, but the technician was struck in the face by a rotor blade and fell seriously injured. He was transported to a hospital in Cevio but died that evening at 2330.
Damage and Injuries
The helicopter sustained a minor dent on one rotor blade but no other damage. The technician suffered severe head injuries and died.
Weather
The weather was fine with cloudy skies and moderate local winds.
Discussion
The landing platform, about 8 by 10 meters, was situated on a moderately inclined rock ridge. The rotor circle, with a diameter of 10.7 meters, extended beyond the platform on the uphill side. The technician was positioned about 1 to 1.5 meters higher on the slope when struck. The pilot had previously warned the contractor about the danger of the rotating rotor, and instructions were given to workers. The technician was not present during that briefing but was informed later. He likely intended to return to the base station via helicopter. The noise of the engine may have been masked by wind, and the rotor blades, moving at about 100 m/s, may have been less noticeable from certain angles.
Conclusion
The accident occurred because the victim, who presumably intended to approach the helicopter, entered the rotor circle, which he apparently had not noticed.