Flight History
The pilot departed from the Gsteigwiler base at 0830 hours with the intention of transporting material and three workers to the Konkordiahütte. After collecting approximately 220 kg of material in a net at Grindelwald, the helicopter took off at around 0905 hours with three workers on board. The material was carried as a sling load on a nine-meter-long external load hook. At approximately 0915 hours, the pilot requested weather information for the Jungfraujoch and Konkordiahütte regions. The reported conditions indicated diffuse visibility at Jungfraujoch and good visibility at Konkordiahütte. The pilot acknowledged with a double click.
According to the surviving passenger, the flight proceeded as follows: after departing Grindelwald, the helicopter flew toward Jungfraujoch, where fog was present. The aircraft then turned back past the Eiger north face over the Mittellegigrat toward the Lower Mönchsjoch. This pass could not be crossed due to fog. The pilot attempted to fly along the Fiescherwand to the Klein Fiescherhorn to then cross the Grünhornlücke to reach the Konkordiahütte, but the pass at Klein Fiescherhorn was also fogged in. The helicopter returned to the Lower Mönchsjoch area, where the pilot gained altitude to improve visibility toward the Ewigschneefeld. While overflying the Lower Mönchsjoch, visibility rapidly deteriorated due to fog. The pilot changed course to return over the Fieschergrat toward Grindelwald, but by then visibility was so poor that no horizon could be discerned. Suddenly and unexpectedly, the sling load struck the rising snow slope of the Fieschergrat, pulling the helicopter to the ground. The impact killed the pilot and two passengers; the fourth occupant was seriously injured.
At 1030 hours, after the helicopter failed to arrive at Konkordiahütte and could not be raised by radio, a Rega helicopter departed Gsteigwiler for a search flight toward Lower Mönchsjoch. Because that area toward Konkordiaplatz was obscured by fog, the Rega helicopter flew along the Fiescherwand to Klein Fiescherhorn and over the Grünhornlücke toward Konkordiaplatz. When over Konkordiaplatz, the crew suddenly received emergency locator signals from the Ewigschneefeld area. The accident site was reached at approximately 1050 hours at coordinates 646 600 / 155 800, altitude about 3560 meters.
Aircraft Information
The helicopter was an SA 315B Lama (serial number 2567) manufactured in 1980 by SNIAS (Eurocopter France). It was powered by a Turboméca Artouste III B turbine engine producing 640 kW (870 hp). The main rotor blades were L.O.M. L3160-100-01. The aircraft held a certificate of airworthiness issued by the Federal Office of Civil Aviation (BAZL) on 7 June 1995, valid until revoked. The owner and operator was BOHAG of Gsteigwiler. The helicopter was approved for commercial VFR day operations and private VFR day and night operations, as well as takeoffs in ground fog or low stratus (HDF). At the time of the accident, the airframe had 2614 hours and the engine 2332 hours. The maximum takeoff mass with external load was 2300 kg; with internal load, 1950 kg. The actual mass was approximately 1905 kg (including 220 kg external load). Mass and center of gravity were within limits. Fuel remaining was about 200 liters, sufficient for approximately one hour of flight. The helicopter was equipped with an ELT.
Personnel
The pilot, a Swiss citizen born in 1962, held a professional pilot license (helicopter) issued by BAZL on 21 November 1986, valid until 19 May 1997, with endorsements for mountain landings, night flying, and takeoffs in ground fog. He had accumulated 4647 total flight hours, with about 3000 on the accident type; in the previous 90 days, he flew 80 hours (12 on type). His last medical examination on 28 March 1996 found him fit without remarks. The four passengers were Swiss citizens; three had no aviation experience. The passenger seated front left (born 1945) and the rear left (born 1967) sustained fatal injuries; the rear right (born 1970) survived with serious injuries.
Weather
According to the Swiss Meteorological Institute, a flat high-pressure system over central and southern Europe with moist air over the Alps prevailed. At the accident site at the time: light snowfall, fog, visibility below 1 km, wind 220° at 20 kts gusting to 30 kts, temperature -8°C, dew point -9°C, QNH 1035 hPa. The Alps were partly cloudy. Sun azimuth 125°, elevation 21°. Conditions improved later.
Wreckage and Impact
The helicopter impacted terrain after the external load struck the snow slope 15 meters prior. The aircraft overturned and came to rest on its roof, the cabin deeply embedded in snow. The three fatally injured occupants remained in their seats, while the survivor partially freed himself. The main rotor blades were bent, two stuck in snow. The tail rotor was intact but all three blades bent at the same point. The tail rotor drive shaft suffered a torsion fracture. The right skid broke at the forward attachment. The fuel filler was torn off, spilling kerosene into the snow. The retractable landing light was extended and switched on. The cargo hook was open; the impression of the net contents was visible in the snow. Dual controls had been removed; friction on the right cyclic was not tightened; the emergency release handle for the external load was broken. The altimeter was set to 1030 hPa and indicated 3815 m. Both front seats were torn from their mounts, as were the safety belt attachments. Rear seats and belts showed no damage.
Medical Findings
Autopsy of the pilot revealed death was due directly to injuries sustained in the crash, specifically heart failure from cardiac tamponade. No evidence of alcohol, drugs, or medication was found. Toxicology was negative. The front left passenger likely sustained similar fatal injuries. The rear center passenger, restrained with a lap belt, also died; the cabin filling with snow likely caused asphyxiation. The rear right passenger managed to release himself and await rescue in the lee of the wreck.
Fire
No fire occurred.