CALGARY –WestJet says early results of an investigation into an ice chunk that crashed through a Calgary home indicate one of its planes is to blame.
Airline spokeswoman Lauren Stewart said in an email that a preliminary investigation has concluded the ice on Friday evening fell from a WestJet plane on approach into Calgary from Regina.
Stewart said WestJet is inspecting the aircraft to determine the cause of the incident and is cooperating with local authorities and Nav Canada, the agency that is responsible for Canada’s civilian air navigation service.
Calgary’s fire department said the incident was originally reported as an explosion, but as the residents investigated further, they found a hole in their ceiling and fragments of ice on their basement stairs.
The ice made it all the way to the basement floor.
“This is a most unfortunate incident for the family whose home was damaged and we will be reaching out to pay for all necessary repairs to their home,” Stewart said in the email.
John Lee with the Transportation Safety Board said he has contacted the homeowner where Friday’s incident happened, and instructed the homeowner to keep the ice in the freezer until it can be tested.
Lee said incidents of ice crashing through roofs from passing planes are rare. However, he said the home where it happened Friday is very near to another home that had the same thing happen a number of years ago.
Lee said the ice from that incident fell from a Boeing 737 and originated in a lavatory sink. Planes don’t discharge their toilet water during flight, Lee explained, but they do eject the water that’s used for handwashing.
In order to keep that water from freezing as chunks, part of the drainage system is heated. However, Lee said the heating element on the 737 failed and ice formed as a ball at the end.
As the plane descended and the air became warmer, the ball melted and broke away.
“This ice has to come off at the right time and also be on a path that it’s going to hit a house. So I think the stars have to line up pretty good for this stuff to happen,” Lee said, although he admitted it could happen more than we know about.
“We only know about these things if it hits someone’s house or it hits the street.”
Lee said there are cases where water from aircraft toilets leaks from valves, forms ice and breaks away. Such cases were once known as “blue ice” but Lee said he isn’t sure if planes still use blue water in their toilets anymore.
Sometimes, he said, investigations into falling ice have a simpler explanation.
Lee said one case in Alberta turned out to be ice that broke away from the top of a steep roof.
“It slid down the roof and hit some lawn furniture,” Lee said.