Already the most expensive defense weapons program in history, the price tag on the F-35 Joint Strike Fighter jumped up another $4.3 billion in the last year – the latest hike in a program that’s gone $113 billion over its original projected cost, according to a new report from the Government Accountability Office.

The stealth F-35, long touted as the future backbone of America’s dominance in the air, has experienced a seemingly unending string of cost increases and delays since development began in 2001. Three variations on the plane are meant to replace legacy fighters for the U.S. Air Force, Navy and Marines and lead the way in next-generation electronic warfare. But the plane is so complex and was put into production so prematurely, according to the Pentagon’s top weapons buyer, that he once said that the error amounted to “acquisition malpractice.”



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The sophisticated jets were originally slated to join the battlefield in 2012, but the GAO report, published today, estimates the first variation – the Marines’ – won’t reach initial operational capability until this summer at best. The Navy’s won’t reach that point until 2018, if all goes well.

“[K]ey gaps in product knowledge persist. One of the critical technologies – the aircraft prognostic and health management system – is not mature and the program continues to experience design changes,” the GAO report says. “Developmental testing is progressing, but much of the testing remains, which will likely drive more changes… Software development and testing remains a significant risk. Further delays in development may put future milestones at risk.”

In September 2013 the Department of Defense Inspector General blasted the plane’s military overseers for not keeping a closer eye on how the plane was being made. In a report released then, the IG said it found 719 “issues” with the jet’s primary manufacturer, Lockheed Martin, and five other major contractors as they assembled the planes. In response, the military and Lockheed Martin said the report was based on old information and the program had taken corrective measures.

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The same month as the IG report, Sen. John McCain, R-Ariz., said the F-35 program was “one of the great national scandals that we have ever had, as far as the expenditure of taxpayers’ dollars are concerned.”

Joe DellaVedova, a spokesperson for the Pentagon’s F-35 program, told ABC News today his office couldn’t confirm the GAO’s figures, but acknowledged the cost overruns and said the military and Lockheed Martin have gotten a better hold on the program.

“Affordability is our number one priority, making the F-35 affordable… There’s been a lot of improvements and a lot of changes,” he said. “We have done a lot to reduce the cost of the program… It is going to be able to deliver on the capabilities that the warfighter is going to need.”

DellaVedova also noted that the F-35 price tag will in the future balance out against the priceless American and allied lives it could save in battle.

“The F-35 will be able to address more advanced threats” that legacy aircraft may not be able to handle, he said. The plane, he said, is a “game changer.”

At a Senate Armed Services Committee hearing this week, McCain got an update on the F-35 from Marines Commandant Gen. Joseph Dunford, who repeated the goal to have IOC by the summer, and Chief of Naval Operations Adm. John Greenert, who expressed concern about the plane’s software integration ahead of the F-35 joining his service in “’18 or ’19.”

“But so far, so good,” Greenert said. “We have to keep a really close watch on it.”

lee.h.ferran@abc.com



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