Development funding and production ramp-up continue to be concerns for the Joint Strike Fighter programme despite US Congress fully funding procurement of 12 Lockheed Martin F-35s in fiscal year 2008.

Although Congress approved funding for six US Air Force F-35As and six US Marine Corps F-35Bs in FY2008, and added funding for development of the General Electric/Rolls-Royce F136 alternative engine, it imposed a $266 million cut in JSF development funding for previously announced overbilling by Lockheed.

In addition to fully funding the F136 at $480 million in FY08, Congress added $200 million to fund "production affordability initiatives and information assurance". But the cut for overbilling came as a surprise, says Lockheed, as the company has already repaid the amount overcharged, which was revealed in August.

"A $266 million reduction will be hard to deal with," says Lockheed vice-president and F-35 programme general manager Tom Burbage. The JSF joint programme office (JPO) could be allowed to use some of the extra $200 million to offset the cut, but "it will be a significant challenge to absorb the hit", he says.

Lockheed and the JPO are already wrestling with depletion of the management reserve within the JSF development budget, and have gained DoD approval to cut two development aircraft and trim flight testing to restore the reserve.

FY2008 procurement includes the first six production F-35B short take-off and vertical landing aircraft. The first development F-35B is on track to fly in May 2008, says Burbage. The flight is a requirement for release of funding for production.

The first F-35B has achieved power on, and is on track to roll out of the factory on 18 December, says Burbage. "We turned on the instrumentation first, then the 28V and lastly 270V systems. The aircraft came online system by system error-free."

Aircraft BF-1 is now on the moving-line dolly, although the final assembly line at Fort Worth, Texas will not begin moving until after the first couple of aircraft, he says. After ground tests, BF-1 is scheduled to begin hover-pit testing by February.

On the production ramp-up issue, Burbage says the concern with the current profile is the need to more than double output from 47 in lot 5 to 118 in lot 6, when five of the nine international JSF partners will also be buying aircraft. "That's difficult, although we did it on the F-16," he says.

Lockheed is working to pull aircraft forward into lot 5 to smooth out the ramp, but the high cost of early production F-35s is a deterrent. A proposed multi-year coalition purchase called Lightning Strike is still being discussed, but the international partners are not prepared to commit without the USA being involved.

The DoD does not plan to begin multi-year procurement until 2014, but Lockheed says there are proposals being considered that would bring multi-year pricing benefits to aircraft purchased as early as Lot 5.

[Editor's note: This story was corrected on 19 November to make clear the cut in JSF development funding is not a result of the Congressional decision to fund development of the F136 alternative engine.]