It took just 2 1/2 minutes for a combination of human and technical mistakes to turn a passenger and supply flight into a remote Arctic community from routine to calamitous.
A Transportation Safety Board report into the crash of First Air Flight 6560 blames an undetected autopilot change, a faulty compass reading and disagreement between the pilots about whether to abort the landing.
“This accident was the product of a complex series of events, all of them lining up together,” lead investigator Brian MacDonald said Tuesday as the report was released. “But what ultimately tied all these things together was that as the flight progressed each pilot developed a different understanding of the situation and they were unable to reconcile that difference.”
The crash at the Resolute airport Aug. 20, 2011, killed eight passengers and four crew members. Three passengers miraculously survived.
In cool, technical language the board’s report provides a second-by-second breakdown of what probably happened in the cockpit as the pilots crashed the Boeing 737 into a hillside more than a kilometre from the runway.
Problems began because on-board compasses were incorrectly adjusted by 17 degrees. That error was compounded when the captain turned into the final approach and unwittingly changed the operational mode of the plane’s autopilot. Busy with the landing checklist, in weather obscured by cloud, mist and light rain, neither he nor the co-pilot picked up the change.
“This incongruency would have negatively affected the pilots’ situational awareness and increased their workload as they attempted to understand and resolve this ambiguity,” the report says.
Within seconds after that final turn, the co-pilot realized the plane was off course and repeatedly told the pilot, reminding him about the large hill to the right of the runway. The pilot replied that the autopilot was working fine.
Puzzled as to why the plane’s navigational instruments weren’t lining up with ground-based systems, the co-pilot asked the pilot if they’d done something wrong. Five seconds later, he suggested they pull up and go around for another approach.
The pilot, fully focused on landing the plane and on figuring out why his instruments were giving confusing readings, refused.
“It is likely that the captain did not fully comprehend information that indicated that his original plan was no longer viable,” says the report.
Less than 10 seconds after first suggesting they pull up, the co-pilot asked again, pointing out that the plane wasn’t configured for a landing so close to the landing strip. The report suggests the pilot is likely to have understood the remark as a request to prepared the plane for landing.
Cockpit communication had broken down.
“The captain’s mental model was likely that the approach and landing could be salvaged, and the (co-pilot’s) mental model was almost certainly that there was significant risk to the safety of flight and that a go-around was required. These divergent mental models compromised the pilots’ ability to communicate and work together.”
Four seconds after his second request to pull up, the co-pilot asked the pilot to bank to the left. Their navigational confusion was evident when the co-pilot confused the shoreline of a small lake with the seashore.
Just under a minute after that, the co-pilot called the pilot by his first name and said: “I don’t like this.”
Almost immediately after, global-positioning systems on the plane began to ring alarms. About 160 seconds after making the final turn, the pilot tried to pull up and go around.
“There was insufficient altitude and time to execute the manoeuvre and avoid collision with terrain.”
The plane smashed into the hill and broke into three main pieces. Debris was strewn around the tundra.
Resolute residents and soldiers from a military exercise that happened to be underway nearby rushed to the scene to try to pull survivors from the flaming wreckage.
Several lawsuits have been filed over the disaster. The suits cast partial blame on the Canadian Forces, which had taken control over the small airport on the day of the crash.
The transportation board said the military’s presence was not a contributing factor in the crash.
The military had established a temporary air traffic control tower to guide in all planes. The airport was normally an uncontrolled airspace and pilots navigated themselves onto the runway.
The suits claim the military did not have enough people on duty to handle the air traffic and those working the tower were not briefed or properly trained to navigate civilian planes.
None of the allegations has been proven in court. Statements of defence were not immediately available.
The chartered plane was on a regular run from Yellowknife to Resolute. There were scientists on the plane along with staff heading back to work at a local inn and the inn owner’s two young granddaughters. There was also a load of food.
Two geologists, Nicole Williamson and Robin Wyllie, and one of the children on board, seven-year old Gabrielle Pelky, made it out of the wreckage with broken bones. Gabrielle’s six-year-old sister, Cheyenne Eckalook, was among the dead.
Pilot Blair Rutherford, 48, from Leduc, Alta.; co-pilot David Hare, 35, from Yellowknife; and flight attendants Anne Marie Chassie, 22, and Ute Merritt, both from Yellowknife, also died.
Martin Bergmann, 55, the Winnipeg-based director of Canada’s Polar Continental Shelf Project was also killed, along with hotel workers Randolph Reid, 56, of Sault Ste. Marie, Ont.; Michael Rideout, 65, of Mount Pearl, N.L.; Chesley Tibbo, 49, of Harbour Mille, N.L; Raymond Pitre, 39, of Bathurst, N.B.; Steven Girouard, 38, and his fiancee Lise Lamoureux, 23, also of Bathurst, N.B.