FAI DETERMINATION SUMMARIES

Please note the Order in place on the Courts website.

When and where each of the deaths occurred

George Thomas Allison, born on 28 July 1956, who resided in Winchester, died at or about 17:17 hours UTC / 18:17 hours BST on 23 August 2013 at a location in the North Sea approximately 1.7 nautical miles west of Sumburgh Airport in Shetland.

Sarah Helen Darnley, born on 3 March 1968, who resided in Aberdeen, died at or about 17:17 hours UTC / 18:17 hours BST on 23 August 2013 at a location in the North Sea approximately 1.7 nautical miles west of Sumburgh Airport in Shetland.

Gary McCrossan, born on 21 November 1953, who resided in Inverness, died a short time after the crash as described below in a life raft at a location in the North Sea approximately 1.7 nautical miles west of Sumburgh Airport in Shetland.

Duncan Munro, born on 22 September 1966, who resided in Bishop Auckland, died at or about 17:17 hours UTC / 18:17 hours BST on 23 August 2013 at a location in the North Sea approximately 1.7 nautical miles west of Sumburgh Airport in Shetland. 

When and where the aircraft crash occurred

The accident resulting in the deaths of George Thomas Allison, Sarah Helen Darnley, Gary McCrossan and Duncan Munro occurred at or about 17:17 hours UTC / 18:17 hours BST on 23 August 2013 when the AS332 L2 Super Puma helicopter with registration G-WNSB operated by CHC Scotia Limited crashed into the North Sea approximately 1.7 nautical miles west of Sumburgh Airport in Shetland.

The cause or causes of each of the deaths

The cause of the death of George Thomas Allison was drowning due to being a passenger in the helicopter when it ditched in the North Sea.

The cause of the death of Sarah Helen Darnley was drowning due to being a passenger in the helicopter when it ditched in the North Sea.

The cause of death of Gary McCrossan was cardiac enlargement and coronary artery disease, triggered by the stress, both emotional and physical, caused by the crash of the helicopter when it ditched in the North Sea.

The cause of the death of Duncan Munro was drowning due to being a passenger in the helicopter when it ditched in the North Sea.

The flight crew of the helicopter failed to maintain the target approach airspeed and the stabilised approach criteria contained in the operator’s operations manual during the latter stages of the non-precision approach to Sumburgh Airport. This was due to the flight crew not effectively monitoring the helicopter’s flight instruments, thereby allowing the helicopter to enter a critically low energy state resulting in the loss of control of the aircraft.

The helicopter was on a routine flight plan transporting oil and gas workers to drilling platforms in the North Sea. The third flight of the day was from the Borgsten Dolphin drilling platform to Sumburgh Airport, Shetland, for a refuelling stop. The pilot flying was Captain Martin Miglans, a very experienced helicopter pilot with over 10,000 hours of flying experience. His co-pilot was Alan Bell with over 3,000 hours flying experience. The weather was poor with visibility at Sumburgh in mist of 2,800 m, few clouds at 200 ft and broken cloud at 300 ft. The surface wind was 12 kt.

During the approach to the airport Captain Miglans selected the 3-axes mode of auto pilot, which meant that he manually controlled the airspeed. That was an acceptable mode to select, although due to the accident the operator, CHC Scotia Limited, changed their operator’s manual to prescribe 4-axes mode, which means that the auto pilot controls the airspeed. The crew failed to monitor the flight instrument panel with the result that the airspeed fell below the minimum speed of 70kt and the helicopter deviated from the stabilised approach criteria required by the operator’s manual. By the time Captain Miglans tried to increase the airspeed the helicopter had entered a critically low energy state resulting in the loss of control of the aircraft. It crashed into the sea, immediately capsized and filled with water. Of the 16 passengers and crew, two passengers were unable to escape from the helicopter and drowned, one passenger escaped but drowned immediately before or on reaching the surface and one passenger suffered a heart attack and died. All the remaining passengers and crew were rescued from the sea by helicopter. Subsequent to the accident, one passenger, Samuel Bull, aged 24 at the time of the accident, suffered from post-traumatic stress disorder and in December 2017 took his own life. He took an active part in the sea to take care of the other survivors, including giving CPR to the passenger who suffered the heart attack.

While it is the case that the cause of the accident was pilot error, it is not known why. One possible reason is in the developing knowledge of the inability of the human brain continuously to monitor flight instruments in all forms of aircraft, particularly in automation modes. The aviation industry and regulatory authorities are looking closely at this developing science. The expert inspectors from the Air Accident and Investigation Branch of the Department of Transport concluded that the accident could have occurred with other pilots flying. One expert before the inquiry described the circumstances as “a perfect storm” and “millions to one against”.

During the inquiry, expert witnesses praised Mr Bell for his quick thinking in releasing the emergency flotation system which probably saved lives, as well as his actions to release the life rafts. One expert described his conduct as brave. Despite suffering from a serious back injury, Captain Miglans insisted that he be the last survivor winched from the sea.

The helicopter was in a serviceable condition. The CHC operating manuals were in satisfactory terms.

While some of the passengers experienced difficulties in escaping from the helicopter, and with their survival equipment, there was no obvious defect in survival training and instruction or the equipment. 

At the end of the inquiry the Crown took the opportunity given to them to explain the seven year delay before the inquiry took place. For the reasons given by them, the Crown and Police Scotland faced a number of obstacles in their investigations for which they cannot be held responsible. Indeed, in so far as they had control of events, they proceeded with the necessary diligence.

Evidence given by the Civil Aviation Authority showed that helicopter safety in North Sea operations has significantly improved over recent years.

Given the steps taken and the long term initiatives begun by the operators and manufacturers of helicopters and the regulators, no findings were made in relation to precautions which could reasonably have been taken; or any defects in the system of working which contributed to death; or any recommendations in relation to specific matters which might realistically prevent other deaths in similar circumstances.

Conclusion

“This was a dreadful accident with long term repercussions for the survivors and the families of the deceased which no determination by this court can properly describe. I do hope that it has at least assisted in an understanding of what occurred, the reasons for it and what has been done to ensure so far as practicable that such an accident does not occur again. My condolences go, in particular, to the families of the deceased, including – lest it be forgotten – the family of Mr Bull.”

Read the full determination published on the Scottish Courts and Tribunals website.

19 October 2020