After two jet crashes killed 346 people, a $2.5 billion settlement agreement that would have spared Boeing criminal prosecution failed to resolve concerns about the aircraft safety of the aviation giant.

Federal prosecutors are now accusing the company of failing to comply with the terms of the 2021 settlement agreement. Boeing has agreed to plead guilty to charges of felony fraud under a new agreement reached with the Justice Department. The department is expected to submit a detailed plea agreement on Friday, but says it may take "a few days."

Corporate governance experts say whether the new agreement has a more lasting impact on safety than the earlier settlement may depend on how much power the independent monitor has, who will be appointed to oversee Boeing for three years. Prosecutors are appointing such a monitor as a condition of the plea agreement, which also requires Boeing to pay a new $243.6 million fine.

"What you really care about is preventing people from dying in future accidents, and the monitor's impact on that goes far beyond the amount of the fine," said John Coffee, a law professor at Columbia University who researches corporate governance and white-collar crime.

The final plea and sentencing will be filed in a US District Court in Fort Worth, Texas. The document will more accurately describe how the compliance monitor will be selected and the scope of the monitor's duties. The government seems to have abandoned a plan that would have allowed Boeing to have the greatest say in choosing a monitor.

Some relatives of passengers who died in the crashes say they plan to oppose the agreement. They want a trial rather than a plea agreement, and they say Boeing should pay a $24 billion fine. Family attorney Paul Cassell says relatives of crash victims should have a say in who the judge appoints as monitor.

The Justice Department initially planned to select a monitor from a list of three candidates submitted by Boeing, according to participants in a briefing for passengers' relatives and their lawyers on June 30, if necessary the department will ask the company for more names.

Under the agreement that Boeing 'principally accepted' a week later, the Justice Department will seek candidates through public notices on its website and then 'choose a candidate based on Boeing's feedback.' The extent of the company's role is unclear.

Once the Justice Department and Boeing agree on a selection, prosecutors will inform US District Judge Reed O'Connor. If he does not object within 10 days, the appointment will receive approval. According to the document, the person chosen will need to meet the 'specific qualifications' listed in the recruitment notice, as well as the department's guidance for selecting criminal case monitors.

The monitor will supervise Boeing's compliance with the plea agreement over a three-year probation period and during this time will write an 'annual government confidential report' and submit an executive summary to the court.

The use of a monitor in the guilty plea agreement with a convicted company reflects prosecutors' reluctance to issue indictments and take cases to trial.

Brandon Garrett, a law professor at Duke University who has been tracking white-collar criminal cases involving companies, said prosecutors have long been concerned that criminal prosecutions could destroy a large publicly traded corporation, so they tend to settle out of court in the most serious cases. He said the situation changed after the 2008 financial crisis, when people began to worry that companies were being seen as 'too big to jail,' a term he used in a 2014 headline.

The validity of plea and deferred prosecution agreements has been called into question, as they allow defendants such as Boeing in 2021 to evade criminal responsibility.

"Especially when companies are repeatedly prosecuted, we need to make some changes - maybe these companies really should have a criminal record," Garrett said. "That's when we started seeing more big cases where companies were convicted."

Nadia Milleron, whose 24-year-old daughter Samya Stumo died in the second of two fatal 737 Max crashes, said Boeing's plea agreement is much better than the settlement reached three and a half years ago. In January 2021, the Justice Department agreed not to prosecute the company for conspiring to defraud the US government, a charge based on Boeing's allegedly misleading regulators who approved the 737 Max nearly a decade ago.

Still, Milleron and other relatives of crash victims hope for a trial to expose more details of what Boeing discussed internally before the Indonesia crash in 2018 and the Ethiopian crash in 2019.

The Justice Department appears to be considering permanently dropping the 2021 charge until January, when an unused emergency exit cover panel fell off a Max jet operated by Alaska Airlines.

The Federal Aviation Administration has stepped up supervision, and its chief has said the manufacturing problems at Boeing "do not appear to have been resolved."

The Ministry of Justice has defended its decision to seek a plea agreement, stating that the agreement includes the harshest penalties Boeing may face in relation to the charges.

"We should be asking whether these prosecutions are effective and how to make them more effective," Garrett said. He suggested judges could actively monitor Boeing to ensure the company adheres to the new agreement after violating the old one.

Columbia Law School professor, C. Scott Hemphill, said the key to whether the agreement can prevent future violations by Boeing is a strong and independent monitor.

"Companies worry that a free agent will roam through their file," he said. "On the other hand, if the monitor doesn't have the power to go directly to the court and say 'they didn't comply with the terms of the agreement,' then you have an ineffective monitor."

In a notorious case, prosecutors halted a New York federal judge from releasing a monitor's report on HSBC, a bank based in London, which had signed a deferred prosecution agreement for failing to stop Mexican drug cartels from laundering money.

"I'm not saying we shouldn't have deferred prosecution agreements, but these agreements are often negotiated in favor of the defendant," he said.

The judge in the Boeing case said he would give victims' relatives seven days to object after the details of the plea agreement are submitted by the Justice Department. The government and Boeing will then have 14 days to respond.

The Justice Department decided not to prosecute Boeing in January 2021, during the last days of the Trump administration. According to data from the US Sentencing Commission, federal prosecutions of companies increased slightly during the Biden administration in 2022 and 2023.

"This year is an election year, so we'll be watching to see what priorities the Justice Department has after November, and whether the focus on corporate crime remains the same," said Kya Henley, a former Maryland public defender who now represents companies and individuals in white-collar cases. "Everyone can set their own agenda."