What happened
On February 13, 2015, an Aviat A-1, operated by Air Sarina AG, was participating in a flight training program for mountain flight instructors. The flight, which originated from Saanen, was designed to familiarize a candidate instructor with a different aircraft type while performing maneuvers at various mountain landing sites.
Upon arriving at the Blümisalp landing site, the crew observed that snow conditions on the glacier were such that only the upper eastern section appeared suitable for use. After the candidate instructor performed initial reconnaissance, the instructor in the front seat demonstrated a landing and takeoff. The candidate instructor then successfully completed two subsequent landings and takeoffs. During the fourth approach, the candidate instructor utilized an incorrect landing reference. Following the landing, the instructor took control of the aircraft to reposition it further up the glacier to reach firmer snow for the departure.
While performing a left-hand turn to align the aircraft for takeoff, the right ski sank into the crusty snow, causing the aircraft to tip over onto its right side.
The investigation
The investigation focused on the ground maneuvers performed at the Blümable landing site and the environmental conditions of the glacier. Investigators examined the flight training objectives, the specific landing references used by the candidate instructor, and the physical state of the snow surface at the time of the incident.
Findings
- The aircraft sustained damage to the right wing and the right landing gear leg.
- The two occupants of the aircraft remained uninjured.
- The primary cause of the incident was the right ski sinking into crusty snow during a ground turn, which induced the aircraft to tip.
- The maneuver was being conducted as part of an instructor training program involving familiarization with a new aircraft type.