History of the Flight
The accident occurred on 11 November 2010 at approximately 09:43 local time near Lanzenhäusern, municipality of Wahlern, Switzerland. The helicopter, a Schweizer 269C registered as HB-XYI, was operated by Heliswiss Schweizerische Helikopter AG and was conducting a visual flight rules (VFR) training flight. The crew consisted of a flight instructor and a trainee pilot who had recently obtained his private pilot license (PPL(H)) on 15 October 2010.
According to the Swiss Accident Investigation Board (SAIB) report, the trainee pilot had been advised to undergo additional training in off-field landings and autorotation procedures after his examination. A previous training flight on 3 November 2010 with the same instructor included six aerodrome circuits with autorotations.
On the day of the accident, the crew departed from Bern-Belp airport at 08:54. After completing several off-field landings and autorotation exercises without issues, they began their return flight. At 09:42, they contacted air traffic control, reporting an altitude of 3300 ft QNH and requesting clearance to return via reporting point HOTEL-WHISKEY. This was the last radio contact.
Shortly before 09:43, the crew initiated an autorotation exercise with a 180° turn into the wind near Wagerten. The maneuver began at approximately 4000 ft AMSL, about 1500 ft above the intended landing site. During the 180° left turn, the average rate of descent exceeded 3500 ft per minute. After the turn, the flight instructor noted an airspeed of 50 knots and instructed the trainee to adjust the attitude to increase speed. The helicopter was then at approximately 3000 ft AMSL, about 500 ft above the landing site. The rate of descent increased during the attitude change, and the subsequent flare could not reduce it sufficiently. The instructor reported an airspeed of at least 50 knots and a rotor speed of approximately 460 rpm in the final phase. He then increased throttle, leveled the helicopter, and fully pulled the collective lever.
The helicopter first contacted the slightly uphill terrain with its tail, then the landing skid after about 10 meters, and impacted hard approximately 24 meters from the first contact. The helicopter rotated about 30 degrees to the left. Both pilots, wearing helmets, exited the wreck unharmed. The flight instructor's helmet showed an impact mark on the front above the visor.
At 09:51, air traffic control attempted to contact the crew but received no response.
Meteorological Information
At the time of the accident, weather conditions were as follows: cloud cover 1/8 at approximately 5000 ft AMSL, visibility about 20 km, wind from the southwest at 5–7 knots gusting to 12 knots, temperature 5°C, dewpoint 1°C, QNH 1013 hPa. Locally weak turbulence was present. Daylight conditions prevailed with the sun at azimuth 141° and elevation 17°.
Aircraft Information
The Schweizer 269C is a single-engine, three-seat multipurpose helicopter with skid landing gear and a fully articulated three-blade main rotor. It was manufactured in 1991 with serial number S1538. The engine was a Lycoming HIO-360-D1A four-cylinder piston engine (serial number L-26415-51A). The airframe had 7960:32 hours since manufacture; the engine had 1021 hours since last overhaul. The maximum permitted take-off mass was 930 kg. At take-off, the mass was 825 kg; at the time of the accident, it was approximately 800 kg. Both mass and center of gravity were within limits. The last maintenance checks were certified on 3 November 2010. Fuel was AVGAS 100LL, with about 60 liters remaining at the time of the accident.
Injuries and Damage
No injuries were reported among the two crew members. The helicopter was severely damaged, and minor damage was incurred to a field.
Cause
The SAIB determined that the accident resulted from the helicopter colliding with terrain after a failed autorotation exercise.