1999 SA315B Lama accident at Alpe del Corgell (HB-XXS)

Accident overview and aircraft details On 28 August 1999 at 0920 local time, a Eurocopter France/Aerospatiale SA315B Lama helicopter, registration HB-XXS, was destroyed when its main rotor blades struck a rock wall at Alpe del Corgell in the Swiss canton of Ticino. The aircraft was operated by Heliswiss, based at Flugplatz Bern-Belpmoos, and owned by Helitrade AG. The 1977-built helicopter, serial number 2470, had approximately 4,230 flight hours. Its Turboméca Artouste III B1 engine, serial number 2337, had about 3,457 hours. The last 100-hour airframe inspection and 200-hour engine inspection were both completed on 25 August 1999. ## Flight operations and crew The pilot was a Swiss national born in 1967, holding a commercial helicopter pilot license with type ratings for the AS 350/B, B 206/206L, Hughes 300, R22, and SA315. He had 2,121 total flight hours, including 1,300 on the accident type, and 147 hours in the preceding 90 days, of which 63 were on the type. He was required to use corrective lenses and wore contact lenses. Alcohol testing was negative, and no physical impairment was indicated. ## Sequence of events The helicopter had completed three scheduled flights earlier that day. At Corippo, the pilot picked up a second flight assistant and three passengers. The planned task was to recover a large wooden cross that had fallen below the Alpe del Corgell plateau. After landing, one passenger disembarked, while the other two remained aboard. The flight assistant went to rig the cross with ropes and then climbed a nearby rock ledge to prepare to attach the load to the helicopter's center-of-gravity hook. With the pilot and two passengers aboard, the helicopter approached the work area with its nose facing uphill. The flight assistant attempted to attach the cable to the hook while the pilot moved closer to the rock wall to assist. The distance between the main rotor blades and the rock was extremely small, and the assistant missed the attachment by a few centimeters. As the pilot looked into the belly mirror, the helicopter moved slightly forward and the rotor blades contacted the rock. The helicopter entered autorotation, struck the wall with its fuselage, fell forward, overturned, and came to rest balanced on a rock ledge. The pilot remained suspended in his seatbelt, while the two unbelted passengers were thrown from their seats. The flight assistant, who had heard the collision, jumped from the ledge and landed unharmed below. ## Findings and probable cause The investigation found that the three passengers had not been asked to fasten their seatbelts and had not been issued flight tickets, contrary to the operator's Flight Operation Manual. The pilot explained that the passengers were to remain aboard for a planned flying landing at Püsceed. The FOM did not specify procedures for mixed operations involving suspended loads and passengers. The accident was caused by loss of control after the main rotor blades struck the rock wall. Contributing factors were insufficient preparation of the recovery operation and lack of coordination between the pilot and the flight assistant. The steep wall required the pilot to approach closer than the safety limit, and he lost sight of the rotor blades when looking into the belly mirror. The flight assistant, in an uncomfortable and dangerous position, did not perceive the danger until impact. ## Recommendations The investigation recommended that direct attachment of loads to the center-of-gravity hook be limited to areas free of obstacles, that flight assistants receive thorough training for their duties, and that the possibility of prohibiting passengers from remaining aboard during external-load operations be considered.