After being notified by Boeing that some company employees failed to complete specific inspections on some 787 Dreamliners but reported the checks as having been completed, essentially falsifying inspection records, the Federal Aviation Administration has opened a formal investigation.

The inspections verify there is adequate bonding and grounding of the fasteners connecting the wings to the fuselage. The test aims to confirm that the plane is properly grounded against electrical currents like a lightning strike. 

A source familiar with the situation puts the potential number of aircraft involved as approximately 450, including around 60 aircraft still within Boeing’s production system. 

The planes still in Boeing’s possession are being re-inspected, according to the FAA. A source briefed on the situation says Boeing engineers made an assessment that there is not an immediate safety issue because the 787 was built with multiple redundancies to protect against events like a lightning strike. 

“As the investigation continues, the FAA will take any necessary action – as always – to ensure the safety of the flying public,” an FAA spokesman said in a statement to CBS News.                                                                                     

Boeing notified employees of the situation last Monday in an email from Scott Stocker, the vice president and general manager of the 787 program. The email, obtained by CBS News, says that Boeing’s engineering team has “assessed that this misconduct did not create an immediate safety of flight issue.”

Stocker credited a Boeing South Carolina worker for spotting the issue and reporting it. 

“The teammate saw what appeared to be an irregularity in a required conformance test in wing body join. He raised it with his manager, who brought it to the attention of executive leadership,” Stocker wrote. “After receiving the report, we quickly reviewed the matter and learned that several people had been violating Company policies by not performing a required test, but recording the work as having been completed.”

Stocker told employees that Boeing has “zero tolerance for not following processes designed to ensure quality and safety” and that the company is “taking swift and serious corrective action with multiple teammates.”

That email comes less than two weeks after a Boeing quality engineer testified before a Senate sub-committee about concerns he says he raised about the production of the 787 Dreamliner that were dismissed by management. 

Boeing declined to discuss specific numbers of aircraft involved, as it said it was still gathering information about the situation, but a potential population in the hundreds would indicate a situation that potentially had been going on for a significant period of time.

At this point the FAA has not determined there is, in a fact, a safety issue with the 787 or a shortcoming in the production process. Currently, the FAA has not determined there is not an immediate safety issue with Dreamliners currently in service.

The FAA investigation was first reported by the Wall Street Journal.