Officials believe a suspect automated flight-control system activated before a Boeing Co. 737 MAX nose-dived into the ground in Ethiopia, according to people briefed on investigators’ preliminary conclusion from data captured by the doomed flight’s black boxes.

The emerging consensus among investigators, one of these people said, was relayed during a high-level briefing at the Federal Aviation Administration on Thursday, and is the strongest indication yet that the same automated system, called MCAS, misfired in both the Ethiopian Airlines flight earlier this month and a Lion Air flight in Indonesia, which crashed less than five months earlier. The two crashes claimed 346 lives.

The preliminary finding from the “black box” recorders of Ethiopian Airlines Flight 302 is subject to revisions, according to the people briefed on the matter. U.S. government air-safety experts have been analyzing details gathered from Ethiopian investigators for the past few days, according to one of the people. A preliminary report from Ethiopian authorities is expected within days.

Investigators have been homing in on the MCAS as a potential cause in both of the recent crashes. Ethiopia’s Transport Minister Dagmawit Moges previously said earlier readings from black-box data showed “clear similarities were noted” between both fatal flights.

Earlier this week, federal transportation officials during hearings defended the government’s response to the two crashes, even as questions grew about how the jet was certified for commercial use. Acting FAA Administrator Daniel Elwell told a Senate panel that there had been no flight tests of the 737 MAX to gauge how pilots would react in the event that a malfunctioning sensor triggered the automated system.