Flight History
The aircraft, a Piper PA-28-181 registered as HB-PER, was operated by Motorfluggruppe Oberengadin. On the morning of 4 August 2017, it was used for sightseeing flights as part of a youth aviation camp in Engadine. The pilot, a Swiss citizen born in 1956, held a PPL(A) and had accumulated 359:38 hours total flying time, with 249:05 hours on type.
After a first flight with three passengers that departed at 08:42 and landed at 09:00, the aircraft was refueled with 50 litres, bringing the total fuel to about 100 litres (endurance ~150 minutes). For the second flight, three camp participants boarded: two born in 2002 and one born in 2000. The passenger on the front right seat was born in 2002.
Departure and Route
The pilot contacted Samedan flight information at 09:06, requested taxi clearance, and announced readiness for takeoff at 09:09, stating an intention to depart toward Maloja. Takeoff from runway 03 occurred at 09:09. After takeoff, the aircraft turned left for a left-hand downwind for runway 03, climbing at an average rate of 400 ft/min to 7000 ft AMSL by 09:14. The pilot then announced his intention to proceed toward Bernina Pass via the Sierra reporting point, instead of toward Maloja.
At 09:16, both HB-PER and another aircraft (Cirrus SR22, HB-KHG) were over Sierra, with HB-PER at 7600 ft and HB-KHG at 8600 ft. The pilot of HB-KHG informed the pilot of HB-PER that he planned to head toward Diavolezza, and the pilot of HB-PER agreed to follow.
Passenger Control
Near Pontresina, the front right passenger asked to take the controls, and the pilot approved. According to a later statement from the rear left passenger, camp group leaders had suggested that passengers in the front right seat might be allowed to handle the controls. The passenger took the control yoke, and flight path data from the Flarm system showed increased variations in climb rate after control was handed over.
Final Maneuvers
The aircraft continued climbing toward Bernina Pass at an average rate of 350 ft/min to about 9000 ft AMSL. While passing the lower station of the Bernina-Diavolezza cable car, the pilot gestured with his right hand for the passenger to start a left turn. During a three-quarter turn, the aircraft gained 275 ft, reaching 9200 ft AMSL. At the exit of the turn, the pilot pointed south-southwest.
HB-PER continued climbing toward Diavolezza, which has a peak elevation of 2958 m/M (9705 ft). The aircraft, still climbing, approached the west shore of Lake Lej da Diavolezza and passed east of Corn Diavolezza at about 9500 ft AMSL, flying over a col at approximately 25 m above ground with a ground speed of 80 kt. The pilot then instructed the front right passenger to...