Poor weather and technical difficulties can cause short runway landings, but “crew malfunctions” are most often to blame, one aviation expert said Monday as officials probe exactly why Air Canada Flight 624 crash-landed at Halifax airport on the weekend.
A report from the Transportation Safety Board said the plane came down 1,100 feet from the threshold of the airport’s main runway at about 12:40 a.m., plowing through power lines and a bank of antennae, and skidding just as far before stopping. The impact was “significant” and “caused substantial damage” to the Airbus A320, which carried 133 passengers and five crew. Twenty five of them were treated in hospital and released.
Investigators documented the wreckage Monday, tracking the impact marks and the debris in the field, and seizing the cockpit voice recorder and the flight data recorder.
While there’s much to be done before the lead investigative agency can say why the crash happened, Ron Coleman, an aviation consultant with CAVSCO who has 10 years experience leading plane crash investigations in Canada and abroad, said the pilots would have had ample warning they were dangerously low.
Airbuses of this size typically have a voice-activated “enhanced ground proximity warning system” and a radio altimeter that says exactly how many feet above ground they are flying.
The A320 was clearly below the “glide slope” — the proper path for a plane approaching a landing strip — because it severed the power lines and hit the “antennae array” on airport property, knocking out power.
“[I]t’s a good possibility the approach lights and the runway lights would have been extinguished, which would have made their perception of their landing considerably changed,” he said. “Those cues would be gone.”
The weather often plays a role in crash landings short of the runway, said Mr. Coleman. Environment Canada’s data at the airport for after midnight Sunday show only one kilometre of visibility and blowing snow.
However, he believes investigators are focusing on what happened inside the plane.
“What we’re talking about here in large measure is what was going on in that cockpit,” Mr. Coleman said.
Of the pilot and co-pilot, “I don’t know which one was flying, but one of them is flying and one of them is observing and looking for the runway. But he’s also responsible for making sure that they don’t violate their altitude.