Summary
On 13 June 2018, an AS350B2 Ecureuil helicopter, registration G-PLMH, was destroyed when it crashed into Loch Scadavay, North Uist, during an underslung load operation. The pilot, the sole occupant, was fatally injured. The accident occurred when the boat being carried became unstable and flew upward, causing the lifting line to strike the helicopter's tail rotor. The helicopter became uncontrollable and descended rapidly into the loch.
Flight History
The pilot and a task specialist ground (TSG) departed from Inverness the previous day and completed an external sling load operation at Rangehead, South Uist. That afternoon, they were requested to transport a boat (Boat 1) from Loch Scadavay to Loch Hunder. The next morning, they departed from Rangehead at 0821 hrs, landed at Loch Scadavay at 0829 hrs, and met with the client and fish farm employees. After lifting and delivering Boat 1 without incident at 0855 hrs, Boat 2 arrived by trailer. The TSG noted that Boat 2 was smaller and lighter, and its single lifting eye did not appear strong enough for a vertical lift. The pilot landed and discussed rigging with the TSG. They agreed to transport Boat 2 on its side, with strops tied in place. The pilot started the engine, and the TSG attached Boat 2 using a 10 m lifting line. After a check, the TSG transmitted "good to go."
Accident Sequence
The helicopter lifted off and began climbing. At 0911:04 hrs, the pilot transmitted that he was airborne with an underslung load. Eyewitnesses reported that Boat 2 started to swing and spin soon after departure. The TSG radioed "slow down, slow down," and the helicopter appeared to slow. Within seconds, the boat lifted into the air like a "kite," paused, then lifted further up and over the tail boom. The helicopter moved erratically, entering a steep nose-first descent. Recorded data showed a descent rate of about 3,600 ft/min and a groundspeed of 40 kt when it struck the water. The helicopter came to rest on its left side, nearly fully submerged. The pilot was fatally injured. Subsequent inspection revealed that the load and lifting line appeared to have been jettisoned from the lifting hook.
Load Characteristics
The physical characteristics of Boat 2 and the method by which it was carried increased the probability of it becoming unstable. The lifting line struck the tail rotor, leading to loss of control.
Safety Actions
The helicopter operator has taken a number of safety actions mainly relating to its operational procedures and training. It has also temporarily curtailed the carriage of selected types of unstable or potentially unstable loads.