“Lack of visual clues” led to fatal Arctic chopper crash: TSB
Doomed pilot may have misjudged altitude on low-level flight
The wrecked Messerschmitt-Bölkow-Blohm BO 105 helicopter that plunged into the icy waters of M’Clure Strait on Sept. 9, 2013, killing all three people on board. (PHOTO COURTESY OF THE TSB)
A “lack of visual cues,” problems with flotation devices, and a delayed reaction from crew members aboard the research vessel CCGS Amundsen all contributed to the 2013 deaths of three people aboard a helicopter that crashed into the icy waters of M’Clure Strait, the Transportation Safety Board said Dec. 7 in an investigation report.
“The investigation found that there was a strong probability that a lack of visual cues to judge altitude while flying low over open water, combined with the possibility of pilot distraction, resulted in the loss of altitude and the collision with the water,” the TSB said Dec. 7 in a report.
The Messerschmitt-Bölkow-Blohm helicopter plunged into the sea on Sept. 9, 2013, about three nautical miles from its mother vessel, killing the master of the Amundsen, Marc Thibault, chopper pilot Daniel Dubé and University of Manitoba scientist Klaus Hochheim.
Hochheim, who sat on the left-hand seat at the front beside the pilot, was doing ice thickness measurements using special equipment carried on the helicopter. Thibault, who sat behind Hochheim, was doing ice reconnaissance work.
During the ice observations, the pilot flew at extremely low altitudes — six seven- to nine-minute survey runs at between 13 and 20 feet above the surface.
Dubé, a trained, experienced, fully certified pilot with Transport Canada since 1985, had come aboard the Amundsen at Resolute Bay on Sept. 5, 2013.
Dubé had logged 10,218 hours of total flight time in his career, and had racked up previous experience with over-water flights and ice patrols.
At the time of the crash, the Amundsen was sailing north of Banks Island in the Northwest Territories, en route to the Beaufort Sea, where researchers aboard the icebreaker, which is outfitted for science, planned to do the second leg of a big environmental assessment program.
At a spot about 670 kilometres west of Resolute, the helicopter took off from the deck of the Amundsen at 4:38 p.m. mountain time.
At 5:38 p.m., the helicopter pilot informed the crew of the Amundsen that they would return to the vessel in 10 minutes.
But that was the last communication the Amundsen received. The chopper crashed 3.2 nautical miles from the vessel and sank beneath 458 metres of water.
The ship should have received its next communication from the helicopter pilot at 5:47, when the chopper was expected to radio for clearance to land.
That meant the Amundsen should have launched search and rescue procedures at 6:03 p.m. — 15 minutes after the expected radio call did not materialize.
But due to problems with the ship’s flight following system, those on board the Amundsen didn’t start SAR measures until 6:24, when they made for the helicopter’s last known position.
When they got there, they found debris in the water and eventually recovered the bodies of all three crash victims.
All three men likely drowned after suffering physical incapacitation from the nearly ice-cold water, the TSB found.
The two passengers were wearing personal flotation devices that did not fully inflate. The pilot’s flotation device was found near his body.
The survival suits worn by all three men were full of water.
Just prior to the accident, the pilot had leveled off to an altitude of 36 feet and maintained an altitude of between 23 and 39 feet, the TSB said.
But after that point, the helicopter descended slowly until it collided with the water. Its last known altitude was only three feet, and the chopper was travelling at a ground speed of 68 knots.
The TSB said the pilot may have been distracted momentarily and was likely confused by the lack of “visual cues” on the flat surface of the water.
“Transitioning to flying over open water would have resulted in a sudden and significant reduction in visual cues available to judge height. This would have been particularly true in calm wind or if a skim coat of ice was present on the water,” the TSB found.
“There is a strong probability that while over the open water, the pilot experienced a lack of the visual cues required to judge altitude, which led to controlled flight into terrain.”
The aircraft was not equipped with a cockpit recorder or a flight data recorder, and was not required to by regulation.
Since the crash, Transport Canada has beefed up risk management rules for low-level helicopter flights and has introduced new survival suits and flotation devices.
New aircraft, equipped with automatic floats, externally-mounted life rafts, cockpit voice recorders and flight data recorders, have also replaced the BO 105.
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