The U.S. FAA, relying on refined satellite tracking data and new physical evidence that more closely links two crashes of Boeing 737 MAX 8s, grounded Boeing’s newest narrowbody Mar. 13, with immediate effect.

The move ends three days of cascading groundings after the Mar. 10 Ethiopian Airlines Flight 302 (ET302) accident, and leaves the world’s MAX fleet grounded.

“On Mar. 13, 2018, the investigation of the ET302 crash developed new information from the wreckage concerning the aircraft’s configuration just after takeoff that, taken together with newly refined data from satellite-based tracking of the aircraft’s flight path, indicates some similarities between the ET302 and [October 2018 Lion Air Flight] JT610 accidents that warrant further investigation of the possibility of a shared cause for the two incidents that needs to be better understood and addressed,” FAA said in its emergency order.

FAA Acting Administrator Dan Elwell, speaking to reporters after the order was released, made it clear that FAA made the decision to ground the aircraft. “The FAA is the safety authority for emergency airworthiness directives and orders,” he said. “FAA made the decision.”

After the EU grounded the aircraft in Europe, the FAA really had no choice.