History of the Flight
On 10 July 2003, a Schweizer Aircraft Corp. Helicopter 300C Model 269C, registration HB-XQF, operated by Heliswiss, was on a VFR training flight from Bern-Belpmoos to Geneva Airport, with a planned return including mountain landings in the Waadtländer Alps at up to 2000 m AMSL. The crew consisted of a flying instructor (total flying hours 3872:00, of which 1875:00 on type) and a trainee pilot (total flying hours 245:50, of which 50:00 on type). The trainee had completed mountain training and was practicing more difficult landings at performance limits.
The crew met at about 10:00 at Heliswiss AG in Belp. The trainee prepared the helicopter, fuelling it with 70 litres of AVGAS (total fuel on board approximately 35 USG). At 11:14 LT, the helicopter departed towards the “HW” reporting point, routing via Ecuvillens, Lausanne-Blecherette, and Geneva. After about 1.5 hours on the ground, including refuelling with 60 litres of AVGAS, the helicopter departed at approximately 13:20 LT towards Evian.
The flight continued to the Lac de l’Hongrin/Ayerne area, where several outlandings were performed up to 1600 m AMSL. The trainee was tasked with making a landing on Planachaux, a small area at the north-eastern end of a ridge. Wind was estimated as 5–10 kt from 030–070 degrees. Fuel remaining was approximately 25 USG.
The first approach was from the southwest at a flat angle with engine speed at 3200 rpm. The landing was completed but the instructor felt improvement was needed, so a second and third approach were performed. During the third approach, which was rather short, engine speed dropped to 3000 rpm and then to 2800 rpm. A landing was not possible. The instructor took over and attempted to turn away from the peak to the south. Despite slightly decreasing collective load, main rotor speed could not be recovered. The helicopter touched down at low forward speed, nose down, and the skids caught in a cattle fence. The helicopter rolled several times, the tailboom was torn off. After two rolls, the trainee unbuckled and leapt out; the instructor remained strapped in. After two more rolls, the helicopter came to rest on its right side on steep terrain.
Injuries and Damage
One person (trainee) was seriously injured; one (instructor) received minor injuries. The helicopter was destroyed. Minor crop damage occurred.
Aircraft Information
The accident aircraft was a Schweizer 300C Model 269C (serial number S1635, year of construction 1993), powered by a Textron Lycoming HIO-360-D1A engine. Airframe operating hours were 4472:32. Maximum permitted take-off mass was 2050 lb (930 kg). The empty mass was 1216.6 lb (551.8 kg), and the accident mass was approximately 1717 lb (779 kg), below the maximum. Centre of gravity was within limits. Fuel on board was about 25 USG (95 l). The last 200-hour and 300-hour checks were performed on 23.05.03, and the 50-hour check on 25.06.03. An open hold item noted "Squelch COM defective." The helicopter was equipped with an exhaust muffler installation; the main rotor blade tape kit was not fitted.
Power Calculation and Performance
The helicopter manufacturer provided hover performance data. For the 269C, HIGE performance at 3000 rpm gave a hover ceiling of 7411 ft PA with muffler; at 3200 rpm and 80% humidity, 8177 ft PA; at 3200 rpm and zero humidity, 8582 ft PA. HOGE (hover out of ground effect) performance was approximately 6800 ft PA with muffler. The pilot's flight manual (PFM) contained HOGE data in an unapproved section. The operator added an instruction cautioning that HOGE values must be reduced by about 2000 ft to achieve realistic performance.
Meteorological Information
MeteoSwiss provided general weather information; details were not specified in the source.
Probable Cause and Contributing Factors
The accident was attributed to the crew losing control during the approach because an approach without sufficient power reserves was attempted. Contributing factors were non-observance of known performance limits and late intervention by the flying instructor.