Southwest 737 MAX
An artist’s conception shows a Southwest Airlines 737 MAX taking to the air. (Boeing Illustration)

The Federal Aviation Administration today ordered the temporary grounding of Boeing’s next-generation 737 MAX jets, due to “new evidence” collected at the site of Sunday’s Ethiopian Airlines crash as well as data transmitted via satellite.

In its emergency order, the FAA said the evidence pointed to what appeared to be some similarities between the circumstances of the 737 MAX 8 crash in Ethiopia and the loss of a Lion Air 737 MAX 8 in Indonesia last October. Sunday’s crash killed all 157 people aboard Ethiopian Airlines Flight 302, while the October crash killed all 189 people aboard Lion Air Flight 610.

The similarities “warrant further investigation of the possibility of a shared cause for the two incidents that needs to be better understood and addressed,” the FAA said.

Airlines that fly 737 MAX jets in defiance of the order could have their certificates revoked, the FAA said.

in an earlier statement, the FAA said the grounding would remain in effect pending further investigation, “including examination of information from the aircraft’s flight data recorders and cockpit voice recorder.”

Southwest Airlines operates 34 737 MAX 8 planes, American Airlines has 24 MAX 8’s and United Airlines has 14 MAX 9’s, accounting for nearly 300 daily flights in all. All three airlines offered to rebook passengers whose flights were canceled. (Get the details for Southwest, American and United.)

Today’s announcement, which affects all 737 MAX aircraft operated by U.S. airlines or in U.S territory, came after scores of other nations took similar measures.

The move was signaled in advance by President Donald Trump, and came just hours after Canadian Transport Minister Marc Garneau said 737 MAX planes would be barred from arrivals, departures and overflights in Canada.

Like the FAA, Garneau said satellite data suggested there were similarities between the crashes in Ethiopia and Indonesia. In both cases, the pilots reported control difficulties just after takeoff, and the planes nose-dived shortly afterward.

Garneau said the readings transmitted via satellite were not conclusive, and he shied away from saying definitively that the crashes were related. “But it is something that points possibly in that direction, and at this point we feel that that threshold has been crossed and that is why we are taking these measures,” he said.

In its emergency order, the FAA said it saw indications of similarities based on “new information from the wreckage concerning the aircraft’s configuration just after takeoff,” combined with newly available data from satellite-based tracking of the Ethiopian aircraft’s flight path.

Virginia-based Aireon confirmed that it provided investigators with data that was transmitted from Ethiopian Airlines Flight 302 via an ADS-B satellite link. The Aireon system makes use of the Iridium NEXT constellation that was completed in January.

“We cannot comment on the cause of the tragedy or the outcome of the investigation, only that we have provided the data,” Aireon said in a tweeted statement. “This unfortunate tragedy further highlights the need for a global, real-time air traffic surveillance system.”

Preliminary findings from the Lion Air investigation focused on an automatic flight control system known as the Maneuvering Characteristics Augmentation System or MCAS. The system is designed to keep the 737 MAX from stalling under extreme aerodynamic conditions, but investigators said spurious data from a single sensor may have caused the MCAS to put the Lion Air plane into an unwarranted dive.

Boeing has laid out a procedure that pilots can use in such a scenario to switch off the MCAS system; however, that procedure wasn’t followed by the Lion Air pilots. The FAA said Boeing is due to update the MCAS software next month. The update will reportedly reprogram the system to take in information from multiple sensors, and take some of the burden off pilots when it comes to remembering the recommended safety procedures.

Today’s FAA announcement marked a rapid about-face: On Tuesday, the agency issued a statement saying that it saw “no basis to order grounding” 737 MAX airplanes, and that no other civil aviation authorities had furnished data that would warrant further action.

The 737 MAX is the latest incarnation of Boeing’s best-selling jet, and the company insists that the planes are safe. But in a statement released after today’s FAA order, Boeing said it supported the decision:

“Boeing continues to have full confidence in the safety of the 737 MAX.  However, after consultation with the U.S. Federal Aviation Administration (FAA), the U.S. National Transportation Safety Board (NTSB), and aviation authorities and its customers around the world, Boeing has determined — out of an abundance of caution and in order to reassure the flying public of the aircraft’s safety — to recommend to the FAA the temporary suspension of operations of the entire global fleet of 371 737 MAX aircraft.

” ‘On behalf of the entire Boeing team, we extend our deepest sympathies to the families and loved ones of those who have lost their lives in these two tragic accidents,’ said Dennis Muilenburg, president, CEO, chairman of the Boeing Company.

” ‘We are supporting this proactive step out of an abundance of caution. Safety is a core value at Boeing for as long as we have been building airplanes; and it always will be. There is no greater priority for our company and our industry. 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 makes this recommendation and supports the decision by the FAA.”

This is an updated version of a report that was first published at 10:49 a.m. PT March 13.

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