A helicopter carrying a boat crashed into a loch, killing the pilot, after the lifting chain hit the aircraft’s tail rotor, a report has found.
The boat became unstable and flew upwards as the AS350B2 Ecureuil helicopter was flying over Loch Scadavay on North Uist on June 13 last year.
After the lifting line struck the tail rotor, the helicopter became “uncontrollable and descended rapidly into the loch” an Air Accidents Investigation Branch (AAIB) report found.
Peter Clunas, 59, a pilot with more than 30 years’ experience, suffered a severe head injury and died.
The AAIB report found that he had successfully lifted one boat that morning and was asked to fly a second boat which was smaller and lighter than the first.
Asked by air traffic control (ATC) whether he would be doing the second lift, he replied: “They want me to do another lift but I’m not convinced it’s practical, so I’m just going to assess it and once I know whether I’m going to lift it or not I’ll get back in touch.”
At 9.11am he radioed to ATC that he was airborne with an underslung load but a short while later the helicopter crashed.
The pilot appeared to have jettisoned the boat from the helicopter but investigators said it seems everything happened so fast there was no time for this to have an effect.
The report said: “Eyewitnesses reported that within seconds of boat two spinning, it lifted into the air independently of the helicopter, like a kite. It paused momentarily, then lifted further up and over the tail boom of the helicopter. One witness remarked ‘(it) all happened really fast’.”
Investigators said: “The characteristics of boat two and the method in which it was carried created a load which became unstable so suddenly that any precautions taken by the crew were insufficient to prevent the accident.
“Although the pilot appeared to have jettisoned boat two from the helicopter, eyewitness accounts of it lifting quickly suggest there was insufficient time for this action to have had an effect.”
The report said: “The physical characteristics of the boat and the method by which it was carried increased the probability of it becoming unstable.”
The report found that the pilot, the only person on board, was wearing a helmet but the chin strap buckle was not fastened.
The AAIB said that since the incident the helicopter operator has taken a number of safety actions mainly relating to operational procedures and training.
It has also temporarily curtailed the carriage of boats, caravans and planes.
A spokesman for PDG Aviation Services, the helicopter’s owner and operator, said: “We have received the final report from the AAIB in relation to the accident which we consider to be a very thorough and comprehensive investigation.
“Although the accident occurred just over a year ago the passage of time has not made the loss of our pilot any easier to bear and our thoughts especially at this time are with his family and friends.”