The U.S. Air Force will inform Congress this week of when it plans to begin operational flights of the F-35 fighter jet, the service's top civilian said.
The service must notify lawmakers by June 1 of the date it expects to have enough aircraft in the fleet to support missions, a milestone known in military parlance as initial operating capability, or IOC, according to Air Force Secretary Michael Donley.
"We will make an IOC notification to Congress next week," he said during a May 24 briefing at the Pentagon with reporters. "We owe them a report by June 1st. That's on track." Donley, who's retiring next month, appeared alongside Air Force Chief of Staff Gen. Mark Welsh.
The press conference came a day after the Defense Department released a report showing that the estimated cost to develop and build 2,457 F-35 Lighting IIs -- the Pentagon's most expensive weapons system -- declined 1 percent in the past year to $391 billion due in part to lower labor rates.
Donley didn't comment on news reports that the service plans to start flying its version of the aircraft, or F-35A, in mid-2016 rather than the following year by using a similar version of software as the Marine Corps' jump-jet variant, or F-35B, which takes off like a helicopter and flies like a plane.
The Pentagon in the fiscal year beginning Oct. 1 plans to spend $8.4 billion to buy 29 F-35 Lightning IIs, including 19 for the Air Force, six for the Marine Corps and four for the Navy, according to the budget request for fiscal 2014, which begins Oct. 1. The plane is designed to replace such aircraft as the F-16, A-10, F/A-18 and AV-8B.
While lawmakers are drafting legislation that would fully fund the Pentagon's request, they're also concerned that the slow pace of software development may delay the most lethal version of the aircraft.
Donley said the service continues to evaluate how much it will cost to operate and sustain the aircraft over its planned service life. The Pentagon previously projected the figure at more than $1 trillion over 50 years.
"There's no single number that locks in for the lifetime of the program," he said. "These numbers will adjust as we get smarter, as we continue to deploy the aircraft, as we find efficient ways to operate it."
The Pentagon figures the F-35 costs about $32,000 to fly per hour, compared with about $25,000 for the F-16, Welsh said.
"That number may continue to adjust itself," he said. "We're not flying it in a fully operational mode yet. It's still in tests. We're just started our training programs. That data has to mature, just like every airplane program that has a projected cost for support and sustainment. We don't really know until we support and sustain it for a while."