Summary
On 2 October 1988 at 1616 local time, a Piper PA-30 Turbo twin-engine aircraft, registration HB-LFA, departed Samedan Airport for a VFR/IFR flight to Zurich. The pilot and five passengers were on board. The aircraft was observed turning right over St. Moritz, then entering the Suvrettatal at low altitude (approximately 8000 ft ONH) while climbing. About 1.5 km before the Suvretta Pass, it initiated a sharp left turn, rolled around its longitudinal axis, and impacted the northeast slope at a steep angle. A fire broke out shortly after, followed by a strong explosion. The six occupants were fatally injured, and the aircraft was destroyed by fire. Ground damage was insignificant.
Flight History
The pilot had flown the same aircraft from Zurich to Samedan earlier that day, landing at 1515 after a 59-minute flight. The flight plan for the return leg specified a VFR segment to the ZUE VOR, then IFR to Zurich. The pilot filed for a 1605 departure with 60 minutes en route. Start was normal, and the aircraft rolled onto runway 21 as third in a group of five. The airport manager lost sight of the aircraft as it turned right over St. Moritz.
Accident Sequence
A witness hiking in the Suvrettatal observed the aircraft flying low and climbing, with altitude between 8000 and 8200 ft ONH. It stayed on the right side of the valley until the terrain steeply rose toward the Suvretta Pass (8580 ft). When the aircraft reached about 8400 ft ONH, it abruptly initiated a steep left bank of over 60°, rolled left once around its longitudinal axis, and struck the northeast slope at a steep angle. Post-impact fire and explosion ensued.
Aircraft Information
The aircraft was a 1969 Piper PA-30 Turbo, serial number 30-1789, equipped with two Lycoming IO-320-C1A engines (160 hp each) and Hartzell HC-E2YL-2B propellers. It had a valid Certificate of Airworthiness and was operated privately. At the time of the accident, the aircraft was 111 lbs over the maximum takeoff weight with empty tip tanks, but the center of gravity was within limits. The fuel reserve was approximately 3 hours 30 minutes. The landing gear and flaps were retracted, elevator trim neutral, and both engines were producing power at impact.
Cause
According to the investigation, the accident occurred because the pilot attempted a turn-around at too low an altitude and fell below the minimum flight speed. Contributing factors included mistaking the Suvrettatal for the Julier Pass, entering the valley at too low an altitude, and initiating the turn-around too late.