A helicopter crash during avalanche control work in the Kootenays this past March could have been much worse.
The Transportation Safety Board has wrapped up its investigation into the helicopter crash north of Nelson, which occurred on the afternoon of March 16, 2022.
B.C.'s Ministry of Transportation and Infrastructure had contracted Kootenay Valley Helicopters to conduct avalanche control work. The crew, consisting of a pilot, bombardier and blasting assistant, flew to the London Ridge area off Highway 31A, about 65 kilometres north of Nelson, at about 1:15 p.m.
The bombardier's role is to drop explosive charges – 12.5 kg bags of ammonium nitrate, fuel oil and igniters – from about 20 feet high onto particular areas of a slope above highways, to artificially trigger avalanches in a controlled manner.
When the crew approached the area, the bombardier requested an adjustment to the initial target.
“The pilot climbed the helicopter up the slope, nearer to the ridge and close to the base of the clouds,” the TSB says in its recent report.
“The trees in the new location were more sparse and covered with more snow. The pilot assessed the new location and estimated that, as previously anticipated, his exit strategy to turn left and then fly downhill would be appropriate.”
The pilot hovered above an area while the bombardier deployed the explosive. But as the explosive was deployed, the helicopter's rotor kicked up snow, causing “whiteout conditions.”
As the pilot went to leave the area, the tail rotor hit either a tree of the slope, causing a “high-frequency vibration” and forcing the pilot to make an emergency landing.
“The helicopter landed hard on its skids and tipped onto its right (the pilot’s) side,” the TSB says. “The main rotor and blades were fractured and the tail boom was partially severed.”
The helicopter landed about three to five metres downslope of the explosive, and it detonated about two and a half minutes after the crash. But luckily, the explosive did not trigger an avalanche.
The three people onboard were “disoriented and shaken,” but uninjured in the crash.
The pilot was able to manually turn on the emergency locator transmitter, and the signal was received by the Joint Rescue Coordination Centre in Victoria.
A portable radio onboard had been thrown from the helicopter during the crash, but after a 15-minute search through the snow, it was found and the pilot was able to contact Kootenay Valley Helicopters. Search and Rescue resources were not required, as a local helicopter company was able to rescue the crew about an hour after the crash.
As a result of the crash, Kootenay Valley Helicopters has implemented a new policy.
“If, during the approach phase, a new site is selected, the approach is discontinued,” the TSB said, describing the policy. “A thorough assessment of the new location is subsequently conducted and briefed, and a new approach is initiated.”
As a result of the crash, and in compliance with WorkSafeBC requirements, the Ministry of Transportation and Infrastructure also completed an internal investigation into avalanche-control operations.
“The deterioration of weather conditions or whiteout generated by the helicopter during flight can lead to disorientation and controlled flight into terrain,” the TSB says.
“Pilots must continuously exercise vigilance to reduce and mitigate the risks associated with changing weather, especially in the mountains.”