US district judge Reed O'Connor last week ordered Boeing to appear to be arraigned on a 2021 felony charge after families of those killed in the two crashes objected to a 2021 plea deal. Boeing won immunity from criminal prosecution as part its US$2.5 billion January 2021 Justice Department deferred prosecution agreement over a 737 MAX fraud conspiracy charge related to the plane's flawed design.

Boeing declined to comment on Monday.

The families argued that the Justice Department "lied and violated their rights through a secret process," and asked O'Connor to rescind Boeing's immunity from criminal prosecution, Reuters reported.

O'Connor ruled in October that people killed in the two Boeing 737 MAX crashes are legally considered "crime victims," and family members had urged him to require Boeing to be arraigned on the felony charge.

The crashes in 2018 and 2019 in Indonesia and Ethiopia, which cost Boeing more than $20 billion, led to a 20-month grounding for the bestselling plane and prompted the US Congress to pass legislation reforming airplane certification.

Among those who plan to speak at the arraignment is Paul Njoroge, who lost his three children, his wife and mother-in-law in the crash, and Nadia Milleron and Michael Stumo, who lost their daughter, Samya Rose Stumo, according to the filing.

Paul G. Cassell, a lawyer representing relatives of those killed, said the "families look forward to addressing the company responsible for their loved ones’ deaths at the hearing."

Both Boeing and the Justice Department oppose reopening the deferred prosecution agreement, which included $500 million in victim compensation, a $243.6 million fine and $1.7 billion in compensation to airlines.

Boeing said in November that it opposed any effort to reopen the agreement, calling it "unprecedented, unworkable and inequitable" and noted it had been complying with the agreement for nearly two years.

Software failure

A 2019 Ethiopian Airlines plane crash that killed 157 people was caused by a flight software failure as suspected, the country's transport minister said Friday citing the investigators' final report.

The crash of the Nairobi-bound Boeing 737 MAX six minutes after take-off from Addis Ababa on March 10, 2019, which killed all passengers and crew aboard, triggered the global grounding of the MAX and the worst crisis in Boeing's history.

It came just months after the October 2018 crash of a 737 MAX operated by Lion Air in Indonesia, which killed 189 people when it crashed moments after leaving Soekarno-Hatta International Airport in Jakarta.

Both accidents saw uncontrolled drops in the aircraft's nose in the moments before the planes crashed, which investigators have blamed on the model's antistall flight system, the Maneuvering Characteristics Augmentation System (MCAS).

The Ethiopian investigators had already pointed out in a March 2020 progress report that the design of the MCAS system "made it vulnerable to undesirable activation". 

"The airplane's left angle of attack [AOA] sensor failed immediately after take-off, sending faulty data to the flight control system," Transport Minister Dagmawit Moges told reporters as quoted by AFP.

"The erroneous data entered triggered Maneuvering Characteristics Augmentation System, which repeatedly pitched the nose of the airplane down to the point and the pilot lost control."

The final report will be published in the coming days, the minister said, adding that it "is in line with the preliminary report".

After the twin crashes, the delivery and production of the 737 MAX was suspended and all existing aircraft were grounded for 20 months, before being gradually allowed to fly again from late 2020 after Boeing made the necessary corrections.