What happened
On April 8, 1973, a Beech A-23A Musketeer (registration HB-ENN) departed from Altenrhein for a private VFR flight to Samedan with three passengers. Although the pilot had reviewed weather forecasts that indicated potential difficulties near the Julier Pass, the initial flight of the day had encountered favorable conditions.
During the afternoon leg, the pilot decided to deviate from the original route via Chur, instead choosing to fly through the Taminatal valley via Kunkelspass to reach the Hinterrheintal more directly. While visibility toward the pass initially appeared sufficient, the cloud ceiling rapidly descended near Vättis. Attempting to avoid the closing weather, the pilot initiated a right-hand turn but inadvertently entered the cloud layer. In an attempt to regain visual conditions, the pilot climbed at full power into the clouds. During this period of instrument meteorological conditions, the aircraft encountered sudden terrain, eventually striking a snowy slope at approximately 2,250 meters altitude. The impact caused the landing gear to collapse and the engine to shift significantly.
The investigation
The investigation, conducted alongside the St. Gallen Cantonal Police, examined the aircraft's flight path, the pilot's experience, and the prevailing meteorological conditions. Investigators analyzed the aircraft's maintenance records, finding the Beech A-23A to be airworthy and properly registered. The investigation also reviewed the pilot's flight logs, noting that while the pilot held a valid license, they had limited experience with this specific aircraft model and relatively low total flight hours.
Findings
- The pilot's decision to enter the Taminatal valley was based on a misjudgment of the weather situation, likely influenced by the deceptive visibility toward Kunkelspass.
- The aircraft was operating at a weight slightly exceeding its maximum allowable takeoff weight.
- The pilot entered the clouds due to unsuitable flight tactics, specifically failing to fly below the cloud base during the turn.
- The pilot's limited flight experience contributed to the inability to manage the rapidly deteriorating conditions.
- One passenger sustained fatal injuries due to internal bleeding, while the pilot and two other passengers survived the impact.
Safety action
No specific safety recommendations were recorded in the final report, though the investigation highlighted the dangers of navigating mountain valleys when weather conditions are uncertain.