It’s horrible news, but with a silver lining for Boeing and the FAA. Investigators have determined that the stall-detection system at the heart of an earlier Boeing 737 Max jet crash late last year also activated in the Ethiopian Airlines crash earlier this month. No final conclusions have emerged in either investigation, but the news confirms suspicions that Boeing’s new MCAS system on the 737 Max platform played significant roles in both deadly crashes:

Officials investigating the fatal crash of a Boeing Co. 737 MAX in Ethiopia have reached a preliminary conclusion that a suspect flight-control feature automatically activated before the plane nose-dived into the ground, according to people briefed on the matter, the first findings based on data retrieved from the 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.

In other words, Boeing will have some substantial liability in both crashes, and perhaps even in the costs associated with grounding the 737 Max fleet around the world. So what’s the silver lining? The finding doesn’t show any other equipment failure associated with the crash. Boeing and aviation safety officials felt as though they had identified one point of failure in the system, and these findings confirm that. That may be why Boeing’s shares ticked upward today in early trading.

Boeing believes they have a fix in place already which will get their fleet back in the air safely. They’re waiting for FAA approval, but perhaps as soon as two weeks from now, 737 Max planes should be back up in the air:

Boeing revealed updates to a scrutinized automated safety system in the new model on Wednesday while defending the original design, saying the software updates would make the design “more robust.”

In a briefing with reporters on Wednesday, Boeing said the highly anticipated changes would most importantly prompt the aircraft to utilize two sensors instead of just one to engage the MCAS, or Maneuvering Characteristics Augmentation System, designed to compensate for larger engines placed further forward on the wings of the MAX model, a new generation of the Boeing 737. Such a malfunction is believed to have been at play in the Lion Air crash after a sensor was poorly maintained. That accident killed 189 people on board. …

Federal aviation officials expect the software update — which was designed by Boeing based off findings from October’s Lion Air crash in Indonesia — will be approved by the Federal Aviation Administration in the coming days.

After the software update is approved, it would take about a day to deploy and an hour to upgrade each aircraft. Boeing will also provide training for pilots on the changes that a Boeing official told reporters on Wednesday would consist of only a half hour of computer training with no time in the simulator necessary, allowing for quick implementation for the airlines.

Had the Ethiopian Air black box data revealed some other failure as part of the crash sequence, Boeing might have had to go back to the drawing board. That would have frozen their 737 Max sales and kept their planes on the ground indefinitely. With investigators confirming the identical problem that appeared in the Lion Air crash last year, they can now move forward quickly with the fix.

That still leaves lots of questions to answer. How did the FAA allow this issue to slip past regulators and inspectors in the first place? Has the FAA been forced to cede too much oversight back to manufacturers? And until those questions get fully answered, there’s also this one: can the FAA certify that the fixes proposed by Boeing will really resolve the issue on the 737 Max?