Introduction
On Saturday, 6 June 1981, at approximately 1815 local time, a Piper PA-28-140/160 aircraft, registration HB-OHU, crashed at Col de Jaman in the canton of Vaud, Switzerland. The pilot and two passengers were killed, and one passenger was seriously injured. The aircraft was destroyed.
Flight History
The pilot, flying a private pleasure flight, had departed from Gruyères airfield earlier that afternoon for a flight to Sion with two passengers, returning to Gruyères. After refueling, he departed again at about 1755 local time with three passengers. The aircraft flew over Lake Geneva, then towards Montreux, entering the Gorge du Chauderon and following the Baye de Montreux valley north-eastward.
Witness Accounts
Two witnesses observed the aircraft. One, located at an alpine pasture at an altitude of 1138 m, reported seeing the aircraft climbing up the valley at an estimated height of about 100 m above his position. It entered the Vallon des Verraux and began a turn, after which the witness lost sight and heard a collision sound. The second witness, positioned above the accident site, saw the aircraft initiate a steep right turn over the Béviaux chalets, banking sharply enough to reveal its underside. The turn covered approximately 180 degrees before the aircraft struck a tree and crashed. The witness noted that before the turn, the aircraft had been climbing, but the turn itself was performed horizontally and at reduced speed.
Aircraft and Pilot Information
The aircraft, a Piper PA-28-140/160 (serial number 28-26808), was built in 1970 and powered by an Avco-Lycoming O-320-D2A engine of 160 hp. It was owned by Société d'aviation de la Gruyère S.A., Bulle. At the time of the accident, the aircraft had accumulated 1453.65 hours total flight time. Its weight and center of gravity were within limits.
The pilot, a Swiss national born in 1952, held a private pilot license valid until 9 June 1981. He had a total of 90 hours 8 minutes flight experience, with 19 hours 33 minutes on type. His mountain flying experience was weak. The surviving passenger, a schoolboy born in 1969, occupied the left rear seat.
Meteorological Conditions
The weather was fine, warm, and sunny in western Switzerland. At Montreux-Clarens, observations at 1800 local time indicated wind from 250° at 2 knots, visibility 10–20 km, and scattered clouds. At the accident site, the wind was westerly at 5–10 knots, visibility 10 km, with cumulus clouds at 1800–2000 m and cirrus above. Temperature was 16°C, relative humidity about 70%. There was low to moderate turbulence near the ground.
Wreckage and Examination
The aircraft struck a larch tree approximately 10 m above the ground, shearing the left wing near its tip. The wing showed two rearward bends. The collision pivoted the inverted aircraft left and downward. The propeller strikes indicated the engine was running at impact. The wreckage came to rest inverted in a stream bed, with the pilot's seat torn out and found downstream. The vertical stabilizer was intact. The ignition key was in the "BOTH" position, flaps were retracted, and fuel remained in the tanks. The cockpit was destroyed, and survival was largely improbable. The sole survivor was likely ejected during the initial impact and was protected from further crushing by a cavity.
Engine examination revealed no pre-impact irregularities.
Cause
According to the final report, the accident resulted from a collision with terrain, following inadequate tactics and lack of experience in mountain flying.