Boeing's newest version of its best-selling airliner ever was supposed to boost its fortunes for years to come.
Instead it has turned into the company's biggest headache, with more than 40 countries — including the U.S., which had been one of the last holdouts — grounding the 737 Max 8 after a second fatal crash proved one too many.
On Wednesday, the U.S. Federal Aviation Administration issued an emergency order keeping the planes on the tarmac after refusing to do so in the days immediately following the crash of a Max 8 operated by Ethiopian Airlines that left 157 people dead. And on Thursday, Boeing told NBC News that it would be putting all future deliveries of the aircraft on pause.
The FAA said what made the difference was new, enhanced satellite tracking data and physical evidence on the ground that linked the Ethiopian jet's movements to those of an Indonesian Lion Air flight that plunged into the Java Sea in October and killed 189 people.
"It is in our minds now, a link that is close enough to ground the airplanes," acting FAA administrator Daniel Elwell said on the TODAY show Thursday.
Asked why the U.S. waited longer than all other countries to ground the plane, Elwell said his agency makes decisions based on data, not gut feeling, and that's "why U.S. aviation has been so incredibly safe."
Elwell is a former military and commercial pilot and airline lobbyist who took over the role in January 2018.
Officials at Lion Air have said sensors on their plane produced erroneous information on its last four flights, triggering an automatic nose-down command that the pilots were unable to overcome on its final voyage.
The French air accident investigation authority, known by its French acronym BEA, said Thursday it will handle the analysis of the black boxes retrieved from the crash site.
A BEA official told The Associated Press that they have already arrived in France but gave no time frame on how long the analysis could take. The BEA has experience with global air crashes, and its expertise is often sought whenever an Airbus plane crashes because the manufacturer is based in France.
Elwell said that, after the crash, the FAA had examined tens of thousands of flights and found no incident in which pilots had had to work with the system Lion Air flagged.
Since debuting in 2017, Boeing has delivered more than 350 of the Max in several versions that vary by size. Dozens of airlines around the world have embraced the plane for its fuel efficiency and utility for short and medium-haul flights.
The groundings will have a far-reaching financial impact on Boeing, at least in the short term, said John Cox, a veteran pilot and CEO of Safety Operating Systems.
In addition to the planes that have been grounded, there were more than 4,600 Boeing 737 Max 8 planes on backlog that are not yet delivered to airlines.
In a research note earlier this week, Morgan Stanley called the grounding of the fleet a "worst-case scenario" that would disrupt near-term profitability because the 737 covers 70 percent of Boeing's commercial production. The Max fleet was expected to make up most of the 737 deliveries this year and all deliveries over the next three years, according to data compiled by Morgan Stanley.
Shares in Chicago-based Boeing ended up $1.73 or about 0.5 percent, at $377.14 Wednesday after they lost more than 11 percent in the first two days this week. The stock is still up 17 percent for the year.
Boeing issued a statement saying it supported the FAA's decision even though it "continues to have full confidence" in the planes' safety.
The company also said it had recommended the suspension of the Max fleet after consultations with the government.
The FAA was under intense pressure to ground the planes and resisted even after Canada relented on Wednesday and agreed to bar the Max from the air, leaving the U.S. almost alone.
The agency, which prides itself on making data-driven decisions, had maintained there was nothing to show the Boeing jets were unsafe, and flights continued.
But President Donald Trump, who announced the grounding, was briefed that same day on new developments by Elwell and Transportation Secretary Elaine Chao, and they determined the planes should be grounded, the White House said. Trump spoke afterward with Boeing CEO Dennis Muilenberg and Boeing signed on.
"At the end of the day, it is a decision that has the full support of the secretary, the president and the FAA as an agency," Elwell said Wednesday.
Trump had criticized modern planes for becoming "far too complex to fly," requiring pilots to be experts in computer technology.
Elwell told TODAY that he has discussed that issue with Trump and said Trump was right that planes are more complex, but added, "I think most aviation experts will tell you that since we have automated aircraft … safety has improved dramatically."
AP video journalist Manuel Valdes and AP writers Elias Meseret, Yidnek Kirubel, Cathy Bussewitz and Alexandra Olson contributed to this story.