Boeing has grounded its entire global fleet of 737 Max aircraft after investigators uncovered new evidence at the scene of the fatal Ethiopian Airlines crash.
The Ethiopian Airlines crash on Sunday in Addis Ababa killed 157 people. Photo: 123RF
The US plane-maker said it would suspend all 371 of the aircraft.
The Federal Aviation Administration (FAA) said fresh evidence as well as newly refined satellite data prompted the decision to temporarily ban the jets.
The FAA had previously held out while many countries banned the aircraft.
The crash on Sunday in Addis Ababa killed 157 people.
It was the second fatal Max 8 disaster in five months after one crashed over Indonesia in October, claiming 189 lives.
Boeing said that it "continues to have full confidence in the safety of the 737 Max".
However, it said after consultation with the FAA and the National Transportation Safety Board it had decided to ground the flights "out of an abundance of caution and in order to reassure the flying public of the aircraft's safety".
"We are doing everything we can to understand the cause of the accidents in partnership with the investigators, deploy safety enhancements and help ensure this does not happen again," Boeing president and chief executive Dennis Muilenburg said.
The FAA has a team investigating the disaster at the Ethiopian Airlines crash site working with the National Transportation Safety Board.
"It became clear to all parties that the track of the Ethiopian Airlines [flight] was very close and behaved very similarly to the Lion Air flight," FAA acting administrator Dan Elwell said.
He said that "the evidence we found on the ground made it even more likely the flight path was very close to Lion Air's".
#FAA statement on the temporary grounding of @Boeing 737 MAX aircraft operated by U.S. airlines or in a U.S. territory. pic.twitter.com/tCxSakbnbH
— The FAA (@FAANews) March 13, 2019
President Donald Trump initially announced that the FAA would be making an emergency order following "new information and physical evidence that we've received from the site and from other locations and through a couple of other complaints".
The US is the latest country to suspend the Boeing 737 Max from flying after nations include the UK, the European Union, China, India, New Zealand and Australia all grounded the aircraft.
Up until today, the FAA position was that a review had showed "no systemic performance issues" and that there was no basis for grounding the aircraft.
Yesterday, Canada grounded the planes after its transport minister Marc Garneau said he had received new evidence about the crash.
He said that satellite data showed possible similarities between flight patterns of Boeing 737 Max planes operating in Canada and the Ethiopian Airlines plane that crashed.
Association of Flight Attendants-CWA president Sara Nelson said: "Lives must come first always. But a brand is at stake as well. And that brand is not just Boeing. It's America. What America means in international aviation and by extension in the larger world more generally-that we set the standard for safety, competence, and honesty in governance of aviation.
Shares in Boeing ticked higher to $377 each following the announcement.
However, the company's market value has dropped by nearly $26bn since the crash in Ethiopia at the weekend.
What have pilots said about the 737 Max 8?
Pilots in the US had complained late last year about problems controlling the Boeing 737 Max 8 during take-off.
They reported difficulties similar to those that contributed to the fatal Lion Air crash in Indonesia in October.
The Ethiopian Airlines plane crashed minutes into its flight.
Flightradar24, an air traffic monitor, said the plane's "vertical speed was unstable after take-off".
For a small measure of context surrounding the #737MAX grounding, here are all 13,900 flights we're tracking at the moment on https://t.co/A4mWRJu9Vi. pic.twitter.com/HGM9GtK1Tv
— Flightradar24 (@flightradar24) March 13, 2019
The last passenger carrying #737MAX is about to land in Newark. https://t.co/PnYDXJRasE pic.twitter.com/FCleiPABII
— Flightradar24 (@flightradar24) March 13, 2019
Documents reveal that pilots flying last November reported engaging autopilot only for the aircraft's nose to pitch lower, prompting the warning system to exclaim: "Don't sink! Don't sink!"
Two US pilots reported separate incidents involving the 737 Max's automatic anti-stalling system in November.
The feature, which was new to the 737 Max family, is designed to keep the plane from stalling.
The system prevents the aircraft from pointing upwards at too high an angle, where it could lose its lift.
However, according to filings with the US Aviation Safety Reporting System, which pilots use to disclose information anonymously, it appeared to force the nose down.
In both cases, pilots were forced to intervene to stop the plane from descending.
After the Lion Air crash, Boeing issued a bulletin on what to do regarding erroneous readings from the sensor, which sends out information about what angle a plane is flying at.
-BBC
