WASHINGTON — A new report slams the F-35's costs as being "unaffordable" unless they're brought under control.
The Department of Defense, through 2046, plans to acquire 2,456 F-35 Lightning II Joint Strike Fighter aircraft to the tune of $400 billion, making it the most ambitious and costly weapon system in history.
Despite efforts to reduce costs, the Government Accountability Office says the price tag for operating the multi-service F-35 fleet has only increased.
If trends are not reversed, a new GAO report says "the services will collectively be confronted with tens of billions of dollars in sustainment costs that they project as unaffordable during the program."
Since 2012, the F-35's estimated sustainment costs over its 66-year life cycle have increased steadily, from $1.11 trillion to $1.27 trillion.
Besides costs, there are also questions about aircraft performance.
F-35 full mission capable rates -- the percentage of time during which the aircraft can fly and perform all of its tasked missions -- improved from 32 to 39 percent, but that metric is still well below the services' objectives.
GAO Director, Defense Capabilities and Management Diana Maurer says it's important that all these issues be addressed.
"There is definitely reason to be concerned," she said. "When we talk to pilots, pilots really love the aircraft. It has amazing capabilities. But, it's incredibly expensive to build. It's even more expensive to operate and sustain. And there are real questions about the military's ability to afford the number of planes they intend to buy."
The GAO recommends making future F-35 aircraft purchase decisions contingent upon the DOD's progress in achieving affordability constraints.