According to the New York Times, the Boeing 737 Max jet’s automatic stabilizers could have played a role in both crashes.

The similarities between the doomed Boeing 737 Max 8 jet that crashed in Ethiopia last weekend, killing 157 people, and the fatal Lion Air crash in Indonesia in October keep growing.
According to a New York Times report, investigators at the crash site of the Ethiopian Airlines flight found evidence that suggests that the plane’s stabilizers were tilted upward. At that angle, the automatic stabilizers would have forced down the nose of the jet — a similarity with the Lion Air plane that crashed into the Java Sea 12 minutes after takeoff, killing all 189 passengers and crew.
Both investigations are both still in the early phases, but the new evidence potentially indicates that the two planes both had problems with a newly installed automated system, the Times’ Jack Nicas, Thomas Kaplan and James Glanz report. The new Boeing 737 Max 8 system, known as MCAS, is intended to prevent a stall:

Boeing designed the 737 Max as an updated, more fuel-efficient version of its best-selling 737 aircraft. The Max’s engines were bigger and mounted farther forward on its wings, a configuration that could push the nose upward toward a stall in certain circumstances. To compensate for that, Boeing installed MCAS to automatically push the nose down to counteract those forces, in the hopes of making the 737 Max safer and able to handle like its predecessors.
But the two crashes in the last few months are worrying signs that the system could have unforeseen risks.

In the case of the downed flight in Ethiopia, investigators at the crash site are specifically looking at a piece of equipment known as a jackscrew, which controls the angle of the horizontal stabilizers. The stabilizers could have been tilted for other reasons, but they can be triggered by the MCAS. And in the Lion Air crash, investigators are also examining whether the MCAS set up a struggle between the new flight control system and the pilots, as Nicas, Kaplan and Glanz note:
The automated system, which may have pushed down the nose of the aircraft in the Lion Air crash, activates if just one of two sensors mounted on the aircraft’s exterior says the nose is too high. That means a single malfunctioning sensor could force the plane in the wrong direction, as has been theorized in the Lion Air crash.

Boeing and the Federal Aviation Administration have continued to stand by and support the safety of 737 Max aircraft. Even so, the company is pushing to finish a software update and push it out by April that will modify features of the jet around the automated system.