5 days ago
Faulty alarm distracted pilot in 2023 RCMP plane crash in Whitehorse, investigators find
An equipment failure led to a crash involving an RCMP plane at the Whitehorse airport two years ago that seriously injured one person, investigators have found.
In a report released on Tuesday, the Transportation Safety Board (TSB) says a failed sensor in the Pilatus PC-12 aircraft triggered a false stall signal and alarm, distracting the pilot and likely resulting in a failed landing attempt.
The plane was completely wrecked in the crash and the pilot — the only person on board, and identified earlier by RCMP as a special constable with the force — was seriously injured.
The incident happened on April 17, 2023, as the pilot attempted to take off from the Whitehorse airport en route to Yellowknife. The plane had just delivered two other RCMP members to Whitehorse and the pilot was departing to return to Yellowknife.
The report describes how soon after lift-off, the "continuous aural 'STALL' warning" was activated, prompting the pilot to turn around and attempt to land back at the airport. Investigators found that the warning was triggered in error, due to a faulty sensor — something the pilot was unaware of at the time.
The report says the pilot's first attempt to land was unsuccessful and so they turned the plane to try again from a different angle.
"At the same time, the pilot was also becoming increasingly concerned by the continuous aural stall warning and started to believe that there may be something seriously wrong with the aircraft," the report reads.
The crash happened as the pilot attempted to line up with the runway. The aircraft made a sudden "descending right turn," and its wing hit the ground. The other wing then also hit a millings pile alongside the runway and was torn off. The plane rolled over and slid about 40 metres before stopping on an airport service road.
The pilot suffered a head injury but managed to escape the wreckage with help from emergency responders. They were admitted to hospital and released the next day, the report says.
Investigators found that the stall system's aural warning stayed on until the crash, and "thus it created a distraction and increased pilot workload" as the pilot tried to focus on flying the plane.
"While attempting to align the aircraft for landing, the pilot experienced attentional narrowing due to an intense stress reaction in response to the continuous stall warning. As a result, the pilot's attention was focused outside the aircraft," it reads.
The stress and distraction meant the pilot then "unknowingly placed the aircraft in a flight regime that likely resulted in an aerodynamic stall at a very low height above ground," leading to the crash.
The TSB found that the pilot was unaware the aircraft had an inhibit switch to temporarily mute the audible warning signal. It could have been used, "to quickly eliminate the false aural stall warning that was a distraction for the duration of the flight." It says the PC-12 pilot operating handbook provided "limited guidance" about the use of that inhibit switch.
The board says RCMP have since enhanced emergency training and procedures for pilots of PC-12 aircraft and also reviewed its fleet and consulted the aircraft manufacturer about new sensors.
