What caused Delta Flight 4819 to crash?

Article content

The alarming sight of a passenger jet on its roof on a runway isn’t as surprising to aviation specialists as it is to a gawking public. They can explain the flip.

Article content

Article content

“The right wing of the airplane departed the airplane and that departure meant that the left wing was still creating lift, and that’s what causes the airplane to roll on its back. That’s the physics of it,” said John Cox, a former airline pilot who is now an aviation safety specialist and chief executive officer with Safety Operating Systems, a Washington, D.C.,-based aviation safety company.

Article content

Paramedics said that out of 76 passengers and four crew on board Delta Air Lines Flight 4819, three people, including a child, were sent to hospital with critical but non-life-threatening injuries, in addition to others with less severe injuries. There are no reported deaths from the Monday afternoon crash at Toronto Pearson International Airport.

An airplane’s wings are a crucial component in keeping it in the air by creating lift, a force that pushes upwards on the wings. When a plane has only one wing, there is force pushing only on one side of the plane, spinning it.

The more important and perplexing problem is why the plane came to have only one wing.

“Now the investigators are going to look at the cause; why did the right wing leave the airplane? There are videos that show the airplane touchdown pretty firmly, and that has also been validated by a couple of passengers. They said the touchdown was quite firm,” said Cox.

“The investigators will look when they get the cockpit voice recorder and the digital flight data recorder. They’ll look and know exactly how firm that touchdown was. Was it enough to cause the wing to fail? That’s a question that they’ll have to answer.”

Article content

Article content

He said the state of the plane after the crash means crash investigators should know what went wrong by the end of the week, although it might be some time later that the information is released publicly.

The TSB has not released any update since Monday afternoon when it said a team was deploying to Pearson airport and “will gather information and assess the occurrence.” The agency did not respond to requests for information Tuesday.

David McNair, a former TSB investigator and long-time pilot who is now an aviation safety consultant with McNair Flight Safety Consulting, said the crash looked like it could be from “a hard landing,” based on video footage.

He also said he believed the catastrophe came from the “force of the landing.”

While the amount of snow was mentioned at the media briefing, the weather seemed to be downplayed by officials at public briefings.

Monday evening, Toronto Pearson Fire Chief Todd Aitken said: “It’s very early on, it’s really important that we do not speculate. What we can say is the runway was dry and there was no crosswind conditions.”

Article content

The crash occurred when blowing snow was visible in the area following a weekend winter storm. Cox said the chief’s statement is not correct.

A crosswind occurs when wind is blowing across the runway rather than straight along it. Cox said gusting wind was listed as coming from the west at 270-degrees while the runway is aligned at 240-degrees.

“So, there’s about a 30-degree difference in the way that the wind is blowing and the way that the runway is aligned. Consequently, you have to compensate for that as a pilot,” Cox said.

Asked on Tuesday about weather, Aitken declined further comment, saying it was all now part of the crash investigation.

McNair also raised crosswind as a possible factor.

“There was a bit of a challenge,” McNair said while flying because of crosswinds. He says winds might have contributed to the circumstances of the landing, even though other planes were present and landed successfully with the same conditions. He said pilots need to use a bit of force to land on one wheel when dealing with heavy winds.

Delta said it has resumed its flights from Pearson. Two larger Delta aircrafts will be operating “to allow for greater arrival and departure capacity Tuesday,” the airline said on social media.

Article content

“Our most pressing priority remains taking care of all customers and Endeavor crew members who were involved,” said Delta CEO Ed Bastian. “We’ll do everything we can to support them and their families in the days ahead, and I know the hearts, thoughts and prayers of the entire Delta community are with them. We are grateful for all the first responders and medical teams who have been caring for them.”

The aircraft that crashed is a Canadian-built CRJ-900, which were designed to carry up to 90 passengers, although variations in floor plans can decrease capacity.

The plane was operated by Endeavor Air, a wholly owned subsidiary of Delta. Endeavor is headquartered in Minneapolis, from where this plane had departed, and operates 130 regional jets to destinations in the United States, Canada, and the Caribbean, according to the company.

Article content