Aircraft and Pilot Information
The accident aircraft was a Piper PA-18 '150' (registration HB-PMN), operated and owned by Association Snow Fish. The pilot, a Swiss citizen born in 1964, held a private pilot license (PPL(A)) and had accumulated 1017 total flight hours, including 703 hours on type and 7 hours 32 minutes in the preceding 90 days.
Accident Location and Date
The incident occurred on the Rosablanche glacier in the canton of Valais, Switzerland, at coordinates 594 022 / 102 117. The date was 6 April 2015, at 15:04 local time (UTC +2). The altitude at the site was approximately 3030 m.
Sequence of Events
According to the investigation, the pilot had completed three series of three landings and takeoffs at different spots on the glacier. On the final landing, he chose to touch down on a steep slope in the lower left area. The first landing and takeoff from that spot were uneventful. On the second landing, the pilot did not reach the top of the intended track and attempted to turn too late, resulting in the aircraft becoming stuck with the nose facing upslope. The pilot then shut down the engine and manually rotated the aircraft 90°, leaving the nose roughly perpendicular to the slope. During this maneuver, the tail ski became turned sideways and the pilot did not straighten it.
After a pause, both pilot and passenger re-entered the cockpit and started the engine. To quickly face downslope, the pilot applied full throttle and left rudder. The aircraft began moving from a standstill and, as soon as it was oriented downslope, the pilot attempted to correct the trajectory with right rudder. However, he was unable to stop a left rotation. The pilot then reduced power, but the aircraft continued turning left. The right ski dug into the snow, causing the right landing gear to collapse and the right wing to contact the surface. The aircraft decelerated sharply, and the nose pitched into the snow, coming to rest at approximately 60° from horizontal and 20° to the right.
Injuries and Damage
Both the pilot and passenger were uninjured and able to exit the aircraft unassisted. The aircraft sustained damage to the right landing gear, right ski, right wing, and right horizontal stabilizer. No other damage occurred.
Post-Accident Actions
The occupants had no GSM network coverage. The pilot used the aircraft radio to contact another airplane, requesting that a helicopter be dispatched for their repatriation. The pilot was able to alert Swiss air rescue (REGA) only at 18:05, after being flown to Sion by helicopter.