What happened
On March 31, 1979, a Piper PA-31 departed Ascona, Switzerland, for a flight to Saarbrücken, Germany. The aircraft, registered D-IORA, was carrying a pilot and three passengers. Shortly after takeoff from runway 17, the aircraft performed a right turn over Ascalona and entered the Maggia Valley.
At approximately 16:40 local time, the aircraft struck a westward-sloping ridge of the Fleckistock at an altitude of roughly 3,400 meters. The impact, occurring about 16 meters below the summit, tore away the right wing and engine. The remaining fuselage was thrown across the main ridge to the northern side of the mountain, striking a glacier at approximately 3,020 meters. This second impact triggered an avalanche that carried the wreckage 200 to 300 meters downslope, where it eventually came to rest at an altitude of 2,910 meters.
All four occupants of the aircraft were killed. The wreckage was not located until April 2, 1979, as it was partially obscured by fresh snow, and the aircraft was not equipped with an emergency locator transmitter (ELT).
The investigation
Investigators examined the wreckage and the flight conditions at the time of the accident. The investigation established that the aircraft was in a controlled flight attitude—either level or in a climb—at the moment of the first impact. There were no evidence of mechanical failure; the engines were found to have been operating at high power during the collision.
Analysis of the cockpit revealed that the pilot in command was not in the left seat but was located in the passenger cabin and was unbuckled at the time of the crash. One passenger was found still buckled in their seat, while others were ejected from the cabin through a large opening on the right side of the fuselage caused by the impact. Medical examinations of the pilot in command also revealed a blood alcohol concentration of approximately 0.4 grams per per mille.
Findings
- The primary cause of the accident was insufficient vertical clearance from the cloud ceiling.
- The crew failed to climb to a safe altitude while flying in the favorable weather conditions present in southern Ticino, which would have allowed for a safe flight above the clouds.
- The aircraft was flying in an area with heavy cloud cover, and the pilot's altitude was inadequate relative to the upper limit of the clouds.
- The use of an outdated 1970 ICAO map, which lacked the specific minimum altitude sectors present in the 1978 edition, may have contributed to the lack of situational awareness regarding terrain clearance.