Fort Worth, Texas - Boeing confirmed on Monday that it had reached a deal with the Department of Justice over two fatal 737 MAX crashes, with court documents showing the aviation giant set to plead guilty to fraud.

The agreement, blasted as a "sweetheart deal," comes after prosecutors concluded Boeing flouted an earlier settlement addressing the disasters, in which 346 people were killed in Ethiopia and Indonesia more than five years ago.

"We have reached an agreement in principle on terms of a resolution with the Justice Department," Boeing said in a statement.

Families of crash victims immediately filed an objection to the deal, arguing that it "unfairly makes concessions to Boeing that other criminal defendants would never receive."

Catherine Berthet, who lost her daughter Camille in the 2019 Ethiopian Airlines crash – involving a 737 MAX 8 – said the deal reflects "weakness and manifest contempt for the victims' families and public interest."

Court papers filed in Texas on Sunday said the company had agreed to plead guilty to "conspiracy to defraud the United States" during the certification of MAX airplanes.

The plea deal would see Boeing avoid a criminal trial and instead agree to a series of terms that includes a fresh $243.6 million fine. The company will also be required to make a minimum investment of $455 million in "compliance and safety programs."

The changes will be overseen by an independent monitor appointed by the government for a three-year term, while Boeing's board of directors will also be required to meet the families of crash victims.

The high-profile agreement follows the DOJ finding in May that Boeing failed to improve its compliance and ethics program, in breach of a 2021 deferred prosecution agreement (DPA) in the wake of the MAX crashes.

The families of victims will ask the court to reject the plea deal at an upcoming hearing.

"The generous plea agreement rests on deceptive and offensive premises," said the objection filed by their legal team Sunday.

In a statement shared by her lawyers, Berthet added that the agreement shows the DOJ's "deafness" despite an alarming rise in incidents.

The original DPA was announced in January 2021, over charges that Boeing knowingly defrauded US aviation regulators.

That agreement required Boeing to pay $2.5 billion in fines and restitution in exchange for immunity from criminal prosecution.

A three-year probationary period was set to expire this year.

But in January, Boeing was plunged back into crisis mode when a 737 MAX flown by Alaska Airlines was forced to make an emergency landing after a fuselage panel blew out mid-flight.

The incident launched a new wave of scrutiny into Boeing's manufacturing and safety practices, with formal probes initiated by regulators and Congress, and whistleblowers coming forward with shocking allegations.

More bad news hit Boeing Monday as the FAA announced that over 2,600 737 jets would need inspections, amid concerns that passenger oxygen masks could fail in emergencies.