Casualties unknown

2003-12-22: EUROCOPTER AS 350 B3 (HB-ZCS) — Talstation Sessellift Sex Rouge, VD, CH

Talstation Sessellift Sex Rouge, VD, CH

On December 22, 2003, an EUROCOPTER AS 350 B3 (registration HB-ZCS) was involved in an aviation accident near Talstation Sessellift Sex Rouge, VD, CH. Investigators recorded the probable cause as: The accident was caused by the pilot losing visual reference over the snowy glacier in diffuse light conditions, leading to collision with terrain. This summary draws on records from the Swiss Transportation Safety Investigation Board (STSB / SUST).

Sourcesthe Swiss Transportation Safety Investigation Board (STSB / SUST)Primary reportUpdated 1785639345Data APIEditorial standards

On 22 December 2003, Eurocopter AS350B3 HB-ZCS struck terrain near the Glacier du Sex Rouge chairlift base station. One passenger was fatally injured, the pilot seriously injured, and two passengers slightly injured. The helicopter was destroyed.

History of Flight

The deputy technical manager of the Glacier 3000 cable car company planned a flight to the top station with an intermediate landing to resolve technical issues. The initial operator declined due to poor weather at Saanen, so Heli Chablais in Leysin received the order at approximately 08:20. The pilot was tasked with transporting five employees for repairs.

At about 08:40, the helicopter HB-ZCS departed from its base. The flight from Leysin to the Col du Pillon base station was uneventful. The pilot shut down the engine to brief passengers, instructing the mechanics that a backpack could be dropped as a reference point at the landing site.

With six persons on board, the pilot departed at about 09:00 toward the intermediate station (Gemskopf). After landing, two mechanics disembarked. The flight continued to the Sex Rouge top station on the right side of the cableway cables. Below the top station, a descent toward the glacier lift base station was initiated.

During descent, the protruding rock ridge at the northern end of the glacier was flown around in a right turn. Visibility on the snow-covered glacier was diffuse. The pilot stopped the helicopter, and snow was blown up by rotor wash. The two rear-seat mechanics felt an impact and heard a dull sound, assuming they had landed. In reality, the helicopter had lost its tail boom due to collision with terrain. The helicopter then pitched forward, struck the ground, and came to rest on its right side.

The two slightly injured mechanics freed themselves and initiated an alarm. The seriously injured pilot and the fatally injured passenger were recovered about 1.5 hours later by rescue personnel.

Personnel Information

The pilot, a Swiss citizen born 1960, held a commercial helicopter pilot license. He had 792:38 total flight hours, with 268:21 on type. In the last 90 days, he flew 5:13 hours with 23 landings. He completed AS350B3 type rating on 24 June 2000. He was also managing director of Heli Chablais.

Aircraft Information

The Eurocopter AS350B3, registration HB-ZCS, serial number 3265, had 2349:01 hours total operating time. The Turbomeca ARRIEL 2B1 engine, serial number 22433, had 256:45 hours. The last 200-hour check was on 1 October 2003 at 2266:24 hours. The mass at the time of the accident was about 1840 kg, within limits.

Meteorological Information

Weather was influenced by a cold northerly flow with snow on the north side of the Alps. At the accident site, conditions included fog banks, occasional light snowfall, poor and diffuse visibility, north wind 10-15 kt gusting to 25 kt, temperature -15 °C, dew point -17 °C. Sun azimuth 140°, elevation 10°. Hazards: diffuse light conditions.

Wreckage and Impact

The accident site was a flat, open glacier at 2820 m. The helicopter lay on its right side. The fuselage was deformed with fractures, and the tail was separated. The tail rotor was 15 m behind the wreck, buried 1 m in fresh snow. The main rotor head and gearbox were torn from the platform. All main rotor blades were severely deformed. The front left part of the cabin floor was cut open by a rotor blade. The pilot and front passenger seats were torn from their anchors; the rear seat remained intact. The cabin heater was on; the landing light was off.

Survival Aspects

The two mechanics on the rear seat sustained minor injuries and reported the accident via service radio.

Probable cause

The accident was caused by the pilot losing visual reference over the snowy glacier in diffuse light conditions, leading to collision with terrain.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/1892_d.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.