The US Air Force general in charge of steering the F-35 Joint Strike Fighter programme says the fighter’s development has emerged from a “tragic past” and will meet future development milestones as advertised.

During a 3 September speech at the National Press Club in Washington, DC, Lt Gen Christopher Bogdan acknowledged the storms that the Lockheed Martin F-35 has weathered, including a recent engine fire that destroyed one of the jets, ballooning procurement costs that now top $400 billion and production delays of at least six years.

What is done cannot be undone, Bogdan says. Though the complex fifth-generation fighter is sure to encounter future problems, Bogdan says the Pentagon, Lockheed and engine manufacturer Pratt & Whitney will meet milestones, such as initial operating capability for the Marine Corps in July 2015.

“You guys got to get over the fact that we had to put $13 billion more dollars and six more years into this development program … to move it along,” Bogdan says. “You gotta get over that. OK? It’s done. It’s like a sunk cost. It’s terrible. The airplane, the program has had a tragic past. It’s not quite the same program it was back then.

Bogdan was referring to a 2010 technical baseline review (TBR) aimed at finding what was necessary to guide the programme through the system development and demonstration phase (SDD). The TBR showed the programme needed years more for software testing and another $13 billion, which was approved by Congress.

Since 2002, the total programme cost has risen from $177 billion in then-year dollars to $399 billion, according to the Defense Department’s 2012 selected acquisition report.

“You don’t have to believe me, my words. Just see what we’re doing. Just see the progress we’re making, see the milestones we commit to and if we’re making those, see if I come back and ask for more money, see if the price of the airplane is coming down like we expect it to and then you decide if it’s exactly that same tragedy that we had some years ago. I don’t think it is. I think it’s getting a whole lot better. It’s getting better slow, but it is getting better.”

Existing F-35s are flying under restrictions resulting from the June engine fire that have delayed delivery of the aircraft. Officials in the Pentagon are already planning for a future in which multiple allied nations will be flying the jets. By the end of the year, Bogdan says the US Defense Department will announce the locations of engine and airframe depot maintenance facilities in Europe and the Asia-Pacific region.