Boeing Co., the maker of the grounded 737 Max jet, knew for "some months" about messages between two employees in which one of them expressed serious concerns the troubled craft, officials said.
But the company delayed handing over the communications to federal regulators investigating the key flight-control system on its jet following two deadly crashes, according to the Federal Aviation Administration.
"Boeing alerted the Department of Transportation to the existence of instant messages between two Boeing employees, characterizing certain communications with the FAA during the original certification of the 737 MAX in 2016," according to a statement by the FAA.
"Boeing explained to the Department that it had discovered this document some months ago. The Department immediately brought this document to the attention of both FAA leadership and the Department’s Inspector General. The FAA finds the substance of the document concerning. The FAA is also disappointed that Boeing did not bring this document to our attention immediately upon its discovery. The FAA is reviewing this information to determine what action is appropriate."
The communication was an instant message chat between two employees in 2016, according to a copy of the communications obtained by NBC News.