1996 AS350B2 Helicopter Accident in the Sägistalsee Area (HB-XXV)

Overview and Accident Description On 5 September 1996, at approximately 0840 local time, an AS350B2 helicopter, registration HB-XXV, collided with steep terrain in the Sägistalsee area of the municipality of Gündlischwand, Canton of Bern, Switzerland. The aircraft was on a flight from Gsteigwiler to Tschingelfeld in the Giessbachtal. Witnesses reported the helicopter in a steep descent before it struck a slope, was thrown from the ground, and crashed into the roof of a barn. The accident resulted in the deaths of all three persons on board. ## Investigation and Findings The investigation was conducted by the Swiss Bureau for Aircraft Accident Investigation (BFU) in cooperation with the Canton of Bern police. The aircraft was a single-engine, six-seat turbine helicopter manufactured by Société Nationale Industrielle Aérospatiale (SNIAS), with a 1990 build year and serial number 2'333. It was equipped with a Turbomeca Aeriel 1D1 engine. The helicopter was destroyed. ## Personnel The aircraft carried three occupants: the pilot, a rescue paramedic, and a doctor. All three were Swiss citizens. The pilot, born in 1954, held a commercial pilot license for helicopters issued by the Federal Office of Civil Aviation (BAZL). He had a total of 5,642 flight hours, including approximately 280 hours on the accident aircraft type. The paramedic was born in 1967 and the doctor in 1963; neither held a pilot's license. ## Aircraft and Operational Context The helicopter was owned and operated privately but was chartered for the flight. The flight was part of a task to transport dead livestock from difficult terrain to accessible roads, a service arranged by the Swiss Air Ambulance (Rega). The pilot was an employee of Berner Oberländer Helikopter AG (BOHAG), while the paramedic and doctor were Rega employees. The helicopter was registered in the flight operation manuals of both BOHAG and Rega. ## Weather and Conditions At the time of the accident, the weather was clear with visibility exceeding 20 km. The wind was variable at about 5 knots, and the temperature was 5°C with a dew point of 3°C. The sun was low in the sky at an azimuth of 99° and an elevation of 18°, causing significant glare. The accident area was in deep shadow. ## Wreck and Medical Findings The helicopter struck the terrain with its right front underside and tail rotor. The main structure crashed into the barn roof, while the cabin floor and fuel tank fell to the south side of the barn. All occupants struck the northeast side of the barn roof and sustained fatal injuries. An autopsy of the pilot found massive skull and heart injuries as the cause of death, with no pre-existing diseases or impairment from alcohol or medication. The engine was found to be operating at the time of impact, with no pre-existing defects identified. No fire occurred.