Incident Overview
On September 22, 2016, at approximately 09:15 local time, a Robinson R22 BETA helicopter with registration HB-ZOG experienced a ground collision. The aircraft was operated by Schlosshotel-Brig AG and piloted by a Swiss national holding a private pilot license for helicopters (PPL(H)). The flight originated from Flugplatz Raron (LSTA) and was intended to return to the same location.
Operational Context
The pilot departed at 08:50 local time under visual flight rules (VFR). Weather conditions included clear skies, light easterly winds, and temperatures approximately ISA +8 °C. The helicopter flew south toward the Mattertal region before heading to the Äschhorn mountain landing site (LSVE), located at an elevation of roughly 11,600 ft AMSL.
Sequence of Events
During a low overflight of the Äschhorn site, the helicopter stirred up approximately 30 cm of fresh snow, creating a whiteout condition that threatened the pilot's visual reference to the ground. The pilot aborted the maneuver and attempted to accelerate forward to gain lift. However, the aircraft was operating at its performance limit; as forward speed increased, the main rotor RPM dropped, triggering a low RPM warning.
The helicopter touched down on a small snowdrift with its landing skids, which caused significant deceleration. Recognizing insufficient power reserves for a continued takeoff, the pilot reduced airspeed. The tail struck the snow and broke off, causing the aircraft to roll onto its left side. The impact was cushioned by the deep fresh snow. The pilot self-extricated without injury, and no fire occurred. Air Zermatt arrived at the scene 15 minutes after the alarm.
Technical Analysis
According to the Robinson R22 flight manual for the O-360-J2A engine configuration, the maximum height for hovering out of ground effect (HOGE) under the prevailing conditions was approximately 10,500 ft AMSL. The Äschhorn landing site is situated at about 11,600 ft AMSL, placing it roughly 1,000 ft above the maximum HOGE limit. This altitude constraint likely contributed to the lack of performance margin during the aborted maneuver.