Factual Information
The accident involved a Robinson R44 II helicopter, registration HB-ZGZ, operated by Valair AG of Sitterdorf, Switzerland. The pilot, a Swiss national born in 1969, held a Commercial Pilot License (Helicopter) with a type rating for the R44 valid until 20 September 2008. He had accumulated 958 total flight hours, of which 402 hours were on the accident type. On board were two passengers: a German camera operator (born 1979) and a German director (born 1969), neither of whom had flying experience.
The helicopter was equipped with a Cineflex V14 gyro-stabilized camera system mounted externally on the left side. The camera was controlled by the operator seated in the left front seat, while the director monitored the footage from the rear seat.
Sequence of Events
On 1 November 2007, the helicopter departed from Sitterdorf at approximately 12:00 LT for a film production flight over the Jungfrau region. After about one hour of filming, the crew landed at the former military airfield of Raron, where 90 liters of AVGAS 100LL were added to the tanks and two 20-liter plastic cans were also filled. Following a short break, the helicopter departed Raron at around 15:20 LT to continue filming in the Simplon area. After approximately 30 minutes of filming, the pilot planned a direct return flight to Sitterdorf across the Alps.
While approaching the Muotathal region, the pilot observed that the Swiss Plateau and the Muotathal valley were partly covered by fog. Concerned about the weather deterioration, he decided to make an intermediate landing at the Pragelpass to obtain weather information by telephone and to transfer the fuel from the cans into the helicopter's tanks.
The helicopter approached the Pragelpass from the south, heading toward a gravel area that the pilot considered suitable for landing. The on-board obstacle chart for the area was not consulted. Without performing a reconnaissance of the landing site, the pilot flew directly toward the intended spot at a speed of approximately 30–40 KIAS. Suddenly, the pilot noticed a cable ahead and immediately lowered the collective pitch lever.
A witness at the Hirschbödeli area, who was observing wildlife, saw the helicopter approach and feared a collision with a known hay cable in the region. He observed the tail rotor detach from the helicopter, after which the aircraft began to spin around its vertical axis and disappeared behind a hill. Shortly afterward, he heard impact sounds. He then drove toward the suspected accident site.
The camera operator, who was looking at a monitor with a sun shield, perceived the cable strike only as a jolt. The director, occupied with film work, also felt the impact but did not see the cable. According to the operator, the helicopter fell from an estimated height of 10 to 20 meters above ground. Shortly before impact, the pilot raised the collective to cushion the landing.
The helicopter came to rest lying on its right side. The pilot unfastened his seatbelt and assisted his passengers in evacuating. The accident occurred at approximately 16:30 LT. The helicopter was destroyed. The pilot and both passengers sustained light injuries.
Meteorological Conditions
At the accident site, the weather was influenced by a high-pressure system centered over Brittany. Winds were from the northeast at 10–15 knots with gusts up to 25 knots. Visibility exceeded 30 kilometers. There were isolated high cirrus clouds. The temperature was 6°C with a dew point of -5°C. Local turbulence due to the bise wind was possible.
Cause
The accident was caused by a collision of the helicopter with a cable followed by loss of control. The fact that no reconnaissance of the landing site was performed contributed to the accident.