Boeing reported a second-quarter loss on Tuesday that exceeded analyst expectations, with the company absorbing a $280 million charge tied to the VC-25B program — the pair of 747-8 aircraft being built to serve as the next Air Force One.

The program's delivery schedule has slipped four years beyond prior projections, the company disclosed alongside its quarterly results. Boeing did not specify in its earnings materials which production or engineering problems drove the revised timeline.

The VC-25B contract was structured as a fixed-price agreement when Boeing won it in 2018, valued at approximately $3.9 billion for both aircraft. Fixed-price government contracts transfer cost-overrun risk to the contractor; Boeing has been absorbing that risk, quarter by quarter, ever since.

Tuesday's $280 million charge brings the program's cumulative losses well into the billions. The two planes remain undelivered. The original contract price has not changed.

Boeing's quarterly filing did not name a new target delivery date.