• The Federal Aviation Administration grounded all Boeing 737 Max 8 and Max 9 models. President Trump announced the decision hours after Canada had grounded them, pointing to new satellite data suggesting similarities between the Ethiopian Airlines crash on Sunday and a crash in Indonesia in October. The F.A.A. had been the holdout regulator in allowing the jetliners to keep flying.
• New disclosures point to what appears to have been a struggle by pilots of Ethiopian Airlines Flight 302 to control their new Max 8 aircraft minutes after takeoff.
• Adding to pressure on Boeing, a major customer asked the company to compensate it financially for having to ground the aircraft.
• The company’s stock price fell on Mr. Trump’s announcement but rebounded to finish up slightly on Wall Street after two consecutive daily declines. Boeing shares are still down nearly 11 percent from last Friday.
• At least two pilots who flew United States routes on the Max 8 filed incident reports with the federal government that raised safety concerns and criticized a lack of training on the new plane.
U.S. grounds Boeing Max
President Trump said the United States would ground the 737 Max, reversing a decision by American regulators to keep the jets flying after a second deadly crash involving one of them, Ethiopian Airlines Flight 302, on Sunday.
For days, the Federal Aviation Administration had resisted calls to ground the plane, even as safety regulators in more than 40 countries banned flights by the aircraft.
Mr. Trump spoke hours after Transport Minister Marc Garneau of Canada grounded all Max 8 and Max 9 planes registered in the country. He also banned any entry into Canada’s airspace by the aircraft, a move that would have affected operations of carriers based in the United States that operated the planes.
The Max models of the 737 are among the best-selling commercial jetliners manufactured by Boeing.
Mr. Garneau said at a news conference that the step had been taken after a review of newly available satellite tracking data — presumably available to aviation regulators elsewhere — that suggested similarities in the Ethiopian Airlines crash and the crash last October of a Lion Air Max 8 in Indonesia.
The F.A.A. said in a statement that the decision to temporarily ground the planes was based on “new evidence collected at the site and analyzed today,” but did not go into detail. “This evidence,” it said, “together with newly refined satellite data available to F.A.A. this morning, led to this decision.”
The reversal by the agency came a day after Boeing’s chief executive, Dennis A. Muilenburg, spoke with Mr. Trump by phone to make the case that the plane was safe.
In a statement Wednesday after Mr. Trump’s announcement, Mr. Muilenburg said, “Boeing continues to have full confidence in the safety of the 737 Max.” But, he said, “We are supporting this proactive step out of an abundance of caution.”
Pilots struggled to control the plane within minutes
Shortly after takeoff from Addis Ababa’s Bole International Airport, the captain of the Ethiopian Airlines jetliner reported “flight-control problems” to air traffic control. That suggests the cockpit crew was having trouble with the mechanical instruments used to handle the aircraft, the computerized systems that fly it, or both.
The pilot’s alert was reported Wednesday by a spokesman for the airline, Asrat Begashaw; the airline’s chief executive, Tewolde GebreMariam, made similar remarks to CNN the day before.
Mr. Begashaw said the control tower had granted the crew’s request to return to the airport, and three minutes later it crashed, killing all aboard.
The disclosure added to suggestions that the plane had not responded to intended actions by the pilots. There has been no suggestion so far of terrorism or other outside interference in the functioning of the aircraft, which was only a few months old.
In earlier evidence pointing to the possibility of an intrinsic problem with the Max 8 model, control issues were reported by the crew of the Lion Air Max 8 that crashed minutes after takeoff in Indonesia last October.
Mr. Begashaw declined to specify what control problems may have led to the crash on Sunday, which killed all 157 people aboard.
After the American government announcement grounding the Max planes, F.A.A. officials said the flight data and voice recorders recovered from the Ethiopian Airlines crash site, known as the black boxes, would be sent to France for analysis. Investigators believe they may be critical to determining the cause of the crash.
U.S. Airlines scramble to rebook passengers
Southwest Airlines, with 34 Max 8s, and American Airlines, with 24, are the largest operators of the aircraft in the United States. Both said they were working to rebook passengers and minimize schedule disruptions after the F.A.A. grounded the planes.
Pilots on U.S. routes had reported concerns about the Max 8
At least two pilots who flew Boeing 737 Max 8 planes on routes in the United States had raised concerns in November about the noses of their planes suddenly dipping after engaging autopilot, according to a federal government database of incident reports.
The problems the pilots experienced appeared similar to those preceding the October crash of Lion Air Flight 610 in Indonesia, in which 189 people were killed. The cause of that crash remains under investigation, but it is believed that inaccurate readings fed into the Max 8’s computerized system may have made the plane enter a sudden, automatic descent.
In both of the American cases, the pilots safely resumed their climbs after turning off autopilot. One of the pilots said the descent began two to three seconds after turning on the automated system.
“I reviewed in my mind our automation setup and flight profile but can’t think of any reason the aircraft would pitch nose down so aggressively,” the pilot wrote.
A pilot on a separate flight reported in November a similar descent and hearing the same warnings in the cockpit, and said neither of the pilots on board was able to find an inappropriate setup.
“With the concerns with the MAX 8 nose down stuff, we both thought it appropriate to bring it to your attention,” the pilot said.
The complaints were listed in a public database maintained by NASA and filled with thousands of reports, which pilots file when they encounter errors or issues. The database does not include identifying information on the flights, including airline, the pilot’s name or the location.
Another pilot wrote of having been given insufficient training to fly the Max 8, a new, more fuel-efficient version of Boeing’s best-selling 737.
“I think it is unconscionable that a manufacturer, the F.A.A., and the airlines would have pilots flying an airplane without adequately training, or even providing available resources and sufficient documentation to understand the highly complex systems that differentiate this aircraft from prior models,” the pilot wrote.
The pilot continued: “I am left to wonder: what else don’t I know? The Flight Manual is inadequate and almost criminally insufficient.”
News of the incident reports was first reported by The Dallas Morning News and confirmed by The New York Times.
Other countries ban 737 Max 8 flights
Egypt, Vietnam and Kazakhstan banned flights by the Boeing 737 Max 8 aircraft on Wednesday. More than 41 countries have grounded the planes.
Hong Kong, a Chinese territory with its own aviation authorities, also announced a ban in its airspace on Tuesday.
Norwegian Air says it wants compensation from Boeing
Norwegian Air, a low-cost airline that has one of the largest Max 8 fleets outside the United States, said it would seek compensation from Boeing after European regulators had grounded the aircraft.
“It is obvious that the costs incurred by the temporary grounding of brand-new aircraft should be covered by those who have made the airplane,” the company said.
Belying its name, Norwegian flies routes all over Europe and beyond. According to the airline’s website, flights to European destinations were running with moderate delays and a handful of cancellations.
In a message to passengers, the airline said that it had 18 Max 8 aircraft in its fleet of more than 160 planes.
Norwegian had been operating the Max 8 from Providence, R.I. and Stewart Airport in New Windsor, N.Y. to Dublin. Norwegian announced Wednesday that it would now use a larger plane, the 787, for the flight from Stewart. Passengers from both airports will be rebooked on that flight, and Providence passengers will be bused to the other airport.
Some passengers take travel disruptions in stride
For some Canadian travelers whose itineraries were upended by the decision to ground the Boeing Max planes, the reaction was not irritation but relief.
Suzanne Waldman, returning home to Ottawa with her 11-year-old son after visiting her sister in Vancouver, had gone through airport security when WestJet informed them the flight had been canceled. Then she learned why: the plane was a 737 Max.
“I didn’t want to look and see if we were on this aircraft today,” said Ms. Waldman, who knew one of the passengers on the Ethiopian Airlines flight that crashed. “I knew it was a little bit of an issue, and I didn’t want to worry.”
WestJet rebooked them with an overnight layover in Calgary, Alberta, and Ms. Waldman said she was very happy.
Aaron Oram, returning home to Newfoundland from a family trip in Orlando, was stuck in Toronto because his connecting flight was canceled. When he learned the reason — the grounding order — Mr. Oram expressed approval.
“I’m 100 percent for the safety aspect,” Mr. Oram said, “I’m a nervous flyer.”
China is now an aviation safety leader
Once known for deadly skies, China has doubled down on aviation safety as it grows in wealth and power. This week, as it took the lead among world governments in grounding the Max 8, China showed willingness to assert itself in airline safety.
Chinese regulators acted swiftly, grounding 96 of the planes operated by Chinese carriers less than 20 hours after the Ethiopian Airlines crash on Sunday. Many other countries followed, but it was not until Wednesday that the Federal Aviation Administration in the United States grounded the planes.
That is a big shift from a generation ago, when Chinese regulators largely followed the F.A.A.’s lead. Today, Chinese airlines are among the safest in the world, according to industry statistics.
[We answered readers’ questions about the Boeing 737 Max 8.]
U.N. aviation agency takes no action on Max 8, for now
While regulators in much of the world have ordered temporary groundings of the Max models, the United Nations civil aviation agency said it would await definitive findings about what went wrong on Ethiopian Airlines Flight 302.
“Once the final report into this accident is available we will have verified and official causes and recommendations to consider,” the agency, the International Civil Aviation Organization, said in a statement on Tuesday.
The agency, based in Montreal, manages the Convention on International Civil Aviation, the agreement that ensures safe and orderly air travel around the world. According to its website, the agency, which has sanction powers to enforce compliance with the convention, works with United Nations member states and industry groups “in support of a safe, efficient, secure, economically sustainable and environmentally responsible civil aviation sector.”