The US Department of Defense is considering further "tweaks" to the Lockheed Martin F-35 procurement account in the fiscal year 2013 budget request, US Air Force leaders have confirmed.
Secretary of the Air Force Michael Donley said on 20 September he expects the F-35 programme will be adjusted again through the process.
In the past two years, the DoD has removed 246 F-35s out of the original 2010 spending plan for the seven-year period between FY2011 and FY2017. This represents a 34% cut.
The cuts were carried out despite statements from both the USAF and US Congress that re-affirm their support for the F-35.
© Lockheed Martin
"Simply put, there is no alternative to the F-35 programme. It must succeed," Donley said.
But the DoD and key lawmakers continued to review the programme's budget, over concerns about the overlap of development and production. Such an overlap can increase costs, if early F-35 production models have to be modified to fix problems discovered during testing.
"We're struggling with the concurrency of this programme that has been with it for over a decade now," Donley said. "But it is actually right now that we're living this [concurrency] for these few years."
The Senate's appropriations committee also warned about the increased costs associated with the F-35 programme's "severe concurrency", although it expressed "full support" for the project.
The committee's report on the FY2012 defence budget added that 167 to 229 F-35s could be delivered to the DoD before the hardware is fully qualified. If the F-35's modification costs are similar to the F-22, the DoD could face a bill of up to $2.29 billion to retrofit these aircraft to the production standard, according to the report.
However, Tom Burbage, Lockheed's executive vice president for the F-35, said the modification costs could be significantly lower than the committee's estimates.
Lockheed plans to start building F-35s using the final production hardware configuration next year. The aircraft would be modified with a new computer processor, unspecified sensor changes and certain design changes - such as a new 496 bulkhead design for the short take-off and vertical landing model.
"We're hoping we're going to turn the corner and go up on the production ramp pretty soon," Burbage added.
The Senate's appropriators, however, sounded less optimistic in their report.
"If the [F-35] continues on the same path and its costs are not brought under control, the committee believes the programme's future could be in jeopardy," the report concluded.
On 20 September, Lockheed said test activities with the F-35 fleet had totalled 642 flights this year so far, with its sortie rate running 8% above the established target for 2011.