“This is new information we received this morning,” began Canadian Transport Minister Marc Garneau at a news conference in Ottawa. One in which he would drop a bombshell in North American aviation.

Until that moment, Canada and the United States stood virtually alone among large aviation markets defending the Boeing 737 Max and allowing airlines to continue using their planes. Their colleagues in a growing number of countries had already made up their minds and decided the Max was not safe for their markets.

First, Canada acted, then a few hours later, the United States followed suit.

Hundreds of millions of dollars were at stake. Air Canada had 24 Max planes already in the fleet with 41 more to come, and Westjet had 13, with another 42 on the way. Sunwing, with only four planes, had already decided to suspend Max flights. The public’s confidence was eroding.

Garneau’s public appearance Wednesday morning was delayed almost 45 minutes, and it was clear events were evolving right up until the last second. “We had new information to examine this morning, that explains my lateness,” he said.

That new information showed striking similarities between the crash of an Ethiopian Airlines Boeing 737 Max 8 and an Indonesian Lion Air Max 8 less than five months earlier.

Garneau, a politician from Montreal, is also an engineer and former Canadian astronaut, and not prone to rash or emotional decisions. But evidence received from air traffic control data overnight convinced him he had no choice but to act.

The data, Garneau implied, were more precise and accurate than commercially-available information widely available on the internet. It all reflected a cautious approach to the unfolding crisis. Curiously, he did not reveal the precise source of the data.

“[The new data] comes from validated satellite tracking data (emphasis added) suggesting a possible, although unproven, similarity in the flight profile of the Lion Air aircraft.”

By early afternoon, however, a company called Aireon took to social media to say it provided the new information at the request of Transport Canada and the National Transportation Safety Board. Aireon is partnering with NavCanada – the country’s air traffic control provider – to develop satellite technology to track aircraft in real time.

It has been deployed in Edmonton and Gander, Newfoundland, where controllers cover vast unpopulated areas, without large radar facilities. Full use will begin once controllers have been trained on the new system. NavCanada is one of the first agencies to test and use the system.

“We cannot comment on the cause of the tragedy or the outcome of the investigation,” said Aireon in a statement, “only that we provided the data.”

That data showed the Ethiopian Airlines plane suffered angle of attack problems before finally crashing, just as happened to Lion Air.

“When an airplane takes off and climbs, there is a sensor called an angle of attack sensor that essentially measures the attitude of the aircraft – how steeply is it climbing, how shallow,” explained Garneau. “And if you lift up the airplane (nose) too high, it can stall. So the angle of attack sensor was faulty on the Indonesian flight and essentially gave the impression that the nose was too high. So the software, called MCAS software, said ‘oh, I better get the nose down,’ and it can actually force the nose down.

“And the pilot said ‘it’s not too high’ so he countered that. And then, a number of seconds later the MCAS software kicked in again and tried to force it down again, and he said ‘no, no, we gotta climb.’ And eventually, unfortunately, the pilot lost that fight.”

As a result, the plane oscillated, a stark similarity with what happened in Ethiopia.

“Air traffic controllers around the world use the data for places where they’re out in the ocean, that kind of thing. There is a capability to provide reasonable detailed data from a satellite provider. They work with air traffic controllers in different countries… to provide that additional level of detail [to supplement their radar data].”

As the dust settled, experts took issue with Garneau’s characterization of the data as “new,” wondering what took him so long to act compared to regulators in China, Australia and Europe.

“I would take issue with that,” John Pottinger, an aviation safety consultant, told the CBC. “The issue that he’s talking about – the satellite data – was the data that other states and other air carriers used beginning within hours of that accident to contribute to their decision-making, to be cautious.

“It’s not new data, the satellite data is picked up immediately. In fact, you or I could go get it on line.”

In the first hours after the crash, Garneau stood behind the Max 8, and said he would, without hesitation, fly on the plane. He stood by that line Tuesday but cancelled his meetings to focus on the evolving crisis. All the while, the evidence of the similarity between the crashes mounted.

“That should have raised alarm bells immediately,” said Pottinger. “And as soon as people realized that with the flight profile of Ethiopian, I think that’s when the pressure started being put on.”

At the same time, the minister’s approach won praise among pilots who fly the Max aircraft.

“[The Air Canada Pilots Association] looks forward to the continuation of the science and evidence-based International Civil Aviation Organization process into the Ethiopian Airlines Flight ET302 crash,” said spokesperson Chris Praught in a statement. “This investigation is being undertaken by the world’s foremost authorities in aviation safety, and ACPA has every confidence in the outcome of the investigation they are conducting.”

“This unfortunate tragedy further highlights,” said Aireon in a subtle nod to the minister’s scientific approach, “the need for a global, real-time air traffic surveillance system.”

Through it all, Garneau reflected a cautious, step-by-step approach to the problem.

“It would be a mistake to oversimplify and say ‘oh it looks exactly like the one that happened with Lion Air.’ It crossed a threshold in our minds in terms of the profile, and so that triggered our decision to put a safety notice out.”