Boeing was aware of troubling instant messages between two employees regarding their communications with federal regulators over its now-grounded 737 Max jet, but the company waited months to disclose them.
Federal Aviation Administration chief Steve Dickson demanded an explanation from Boeing CEO Dennis Muilenburg in a letter Friday.
The content of the 2016 messages isn't clear, but FAA says they deal with communication between Boeing and the FAA when Boeing was seeking approval for the Max.
FILE - In this April 26, 2019, file photo a worker walks past a Boeing 737 MAX 8 airplane being built for Oman Air at Boeing's assembly facility in Renton, Wash. Passengers who refuse to fly on a Boeing Max won’t be entitled to compensation if they cancel. However, travel experts think airlines will be very flexible in rebooking passengers of giving them refunds if they’re afraid to fly on a plane that has crashed twice. (AP PhotoTed S. Warren, File)
FAA says it "finds the substance of the document concerning" and is disappointed that Boeing waited months before bringing them to the agency's attention.
International regulators have criticized Boeing's communication with FAA over a Max flight system implicated in crashes that killed 346 people.
Boeing shares are down almost 4%.