A lawsuit against Boeing Co was filed in US federal court on Thursday in what appeared to be the first suit over a March 10 Ethiopian Airlines 737 Max crash that killed 157 people.

The lawsuit was filed in Chicago federal court by the family of Jackson Musoni, a citizen of Rwanda, and alleges that Boeing, which manufactures the 737 Max, had defectively designed the automated flight control system.

Boeing said it could not comment on the lawsuit.

“Boeing … is working with the authorities to evaluate new information as it becomes available,” it said, adding all inquiries about the ongoing accident investigation must be directed to the investigating authorities.

Countries worldwide banned the use of 737 Max 8 aircraft amid mounting safety concerns following two crashes in a short span of five months.

157 people were killed after an Ethiopian Airlines Boeing 737 Max 8 crashed 6 minutes after take-off from Ethiopian capital Addis Ababa on Sunday.

In October last year, an aircraft operated by Lion Air crashed killing over 180 people in Indonesia.

Boeing said on Wednesday it had reprogrammed software on its 737 Max to prevent erroneous data from triggering an anti-stall system that is facing mounting scrutiny in the wake of two deadly nose-down crashes in the past five months.

The planemaker said the anti-stall system, which is believed to have repeatedly forced the nose lower in at least one of the accidents, in Indonesia last October, would only do so once per event after sensing a problem, giving pilots more control.

Pilots and training officials from Southwest Airlines, American Airlines and United Airlines met Boeing officials on Saturday to review the software changes in the Seattle area, where the model is assembled, according to the sources.

US air carriers would like to see the plane return to the sky. America, which has 24 Max aircraft in its fleet, and Southwest, which has 34, agree with union statements that their pilots are trained well enough to deal with the incidents that the Lion Air pilots encountered.

On Sunday, the airline said in a statement that the cancellations would continue through April 24, resulting in 90 flights grounded every day.

The crash of Boeing’s passenger jet in Ethiopia raised the chances that families of the victims, even non-US residents, will be able to sue in US courts, where payouts are much larger than in other countries, some legal experts have said.

Wednesday’s complaint was filed by Musoni’s three minor children, who are Dutch citizens residing in Belgium.

The lawsuit says Boeing failed to warn the public, airlines and pilots of the airplane’s allegedly erroneous sensors, causing the aircraft to dive automatically and uncontrollably.

Ethiopian officials and some analysts have said the Ethiopian Airlines jet behaved in a similar pattern as the 737 MAX involved in October’s Lion Air disaster. The investigation into the March crash, which is being led by the Ethiopian Transport Ministry, is still at an early stage.

(With agency inputs)