Boeing has submitted its long-awaited safety improvement plan to the U.S. Federal Aviation Administration (FAA), as the planemaker looks to regain the trust of federal regulators.

On February 28, the FAA gave Boeing 90 days to put together a plan to address a long list of manufacturing issues, dating back to the blowout of a door plug aboard a 737 Max 9 in January. Weeks after the blowout incident, the FAA witnessed dozens of safety violations during an audit of Boeing's 737 Max production line. Regulators have also been investigating whether Boeing employees may have falsified inspection records for 787 Dreamliner planes. 

Boeing has not publicly released the details of its new safety plan, instead presenting it behind closed doors on May 30 during a three-hour meeting with FAA administrator Mike Whitaker, The New York Times reports. Moving forward, Boeing will meet with senior FAA leaders on a weekly basis to monitor performance metrics, progress, and potential roadblocks toward implementing the plan. 

Just days after the plan was submitted, an investigation from the Guardian unearthed new allegations from anonymous Boeing workers and union leaders, this time at the company's plant in Everett, Washington. One worker told the Guardian that managers have been "hounding" mechanics at the Everett facility to stay quiet over quality concerns, while claiming that the factory is "full of" faulty 787 Dreamliners. In April, a Boeing whistleblower told The New York Times that fuselages for 787 planes were in danger of coming apart over time, alleging that they had been improperly assembled for years.