SEATTLE (AP) — The Federal Aviation Administration said Monday it has opened an investigation into Boeing after the beleaguered company reported that workers at a South Carolina plant falsified inspection records on certain 787 planes. Boeing said its engineers have determined that misconduct did not create “an immediate safety of flight issue.”

In an email to Boeing’s South Carolina employees on April 29, Scott Stocker, who leads the 787 program, said a worker observed an “irregularity” in a required test of the wing-to-body join and reported it to his manager.

“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 wrote.

Boeing notified the FAA and is taking “swift and serious corrective action with multiple teammates,” Stocker said.