The newest wide-body plane from Boeing – once expected to hit the skies by 2020 – now likely won’t be cleared for takeoff until mid-2023.
That’s according to the U.S. Federal Aviation Administration, which, in a letter seen by Reuters, cited a number of issues in rejecting a key certification request from Boeing, and warned it "realistically" will not certify the 777X for another two years.
The letter, dated May 13th and which had not previously been made public, cites numerous concerns about the lack of data and the lack of a preliminary safety assessment for the FAA to review.
Boeing has been developing the twin-engine jet, a new version of its popular 777 aircraft, since 2013.
It will be the first major jet to be certified since software flaws in two Boeing 737 MAX planes caused fatal crashes and prompted accusations of cozy relations between the company and the FAA.
European regulators have said in particular that they will subject the 777X to extra scrutiny after the fatal crashes prompted the 20-month grounding of the 737 MAX.
A Boeing spokesperson said on Sunday that the company "remains fully focused on safety as our highest priority throughout 777X development."