Canadian airlines fly 41 planes of the type that crashed in Ethiopia, killing 157 people including 18 Canadians on Sunday.
And one of those airlines added four more after a separate fatal crash in Indonesia took 189 lives in October.
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Air Canada has 24 Boeing 737 MAX 8s, WestJet Airlines Ltd. had 13 and Sunwing Airlines flies four, according to Transport Canada’s civil aircraft register.
Those planes represent just over 10 per cent of the Boeing 737s that it flies in total.
Asked why it added more of those planes following such a devastating crash, WestJet said it has an order for “50 MAX aircraft and have ongoing deliveries.”
“WestJet sends heartfelt condolences to those friends and family whose loved ones were on board Ethiopian Airlines flight 302,” it said.
“We are monitoring the situation closely and will not speculate on the cause of the incident at this time.”
A search of WestJet’s website showed that the airline uses the Boeing 737 MAX 8 on routes such as Toronto to Cancun and Calgary to Mazatlan,
Air Canada, meanwhile, said it has 24 Boeing 737 MAX 8 planes.
“These aircraft have performed excellently from a safety, reliability and customer satisfaction perspective,” it said in a statement.
Air Canada uses the 737 MAX on numerous routes, such as from Calgary and Vancouver to Honolulu, according to a search of the site.
Sunwing Airlines did not immediately respond to a request for comment from Global News.
The Lion Air crash in Indonesia preceded the Ethiopian Airlines crash by about four months.
That incident had Boeing issuing an Operations Manual Bulletin (OMB) to operators of the 737 MAX 8.
The Indonesia National Transportation Safety Committee determined that Lion Air flight 610 had experienced “erroneous input from one of its Angle of Attack (AOA) sensors.”
WATCH: Man who missed Ethiopian flight recalls moment he found out about plane crash
In response, Boeing directed operators to “existing flight crew procedures” where they found “erroneous input from an AOA sensor.”
However, Indonesia’s transportation safety committee also found that the Boeing 737 MAX 8 that crashed wasn’t in airworthy condition, according to a preliminary report.
A “stick shaker,” which is an instrument that warns of a stall, had vibrated the flight captain’s controls during the flight.
The pilot was trying to use controls in an effort to bring the plane’s nose up, but an anti-stall system pushed it down.
A more thorough report on the Indonesia crash is expected sometime later this year.
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In an interview with Global News, aviation expert Jock Williams said the story with the Ethiopia crash appears to be “virtually identical” to the one involving Lion Air.
He said both incidents suggest signs of pilots using old techniques on newly wired aeroplanes, but that he doesn’t have proof of that.
“In olden days we relieved the pressure on our arms so we didn’t have to continually pull, by trimming back on a great big trim wheel, which sat beside the pilot’s right knee,” he said.
“Nowadays, you don’t have to do that anymore. You pull back, it says, I sense you’re pulling back, I’ll just remove that pressure for you, and it automatically does so.”
But a problem, he said, emerges when pilots are in the habit of using particular switches.
“Then it says, boy, he must really want to put the nose up so it adds some more, and you didn’t really want to put it up anymore, you just wanted it about where it was but you were going to relieve the pressure,” Williams said.
“The plane is trying to help you, but if you don’t understand that it’s trying to help and you countermand its orders, or you even increase its orders, the plane becomes confused, and I think that’s basically what’s happening in these cases.”
In December, Lion Air wouldn’t rule out cancelling additional orders for Boeing 737 MAX 8 planes, as it had 190 jets ready to be delivered.
Asked numerous questions about the 737 MAX 8, Boeing would only offer an existing statement expressing sympathy for the passengers and crew of Ethiopian Airlines Flight 302.
“A Boeing technical team will be travelling to the crash site to provide technical assistance under the direction of the Ethiopia Accident Investigation Bureau and U.S. National Transportation Safety Board,” it said.