The F135 programme has won recent praise for overcoming a blade fatigue problem that set back testing for the short take-off and vertical landing (STOVL) variant. But as the debate over funding for the General Electric/Rolls-Royce F136 alternate engine heats up, P&W executives acknowledge that production costs for the F135 have not declined at the rate desired by JSF programme officials.
In mid-June, a "blue-ribbon" committee met at P&W's headquarters in Hartford, Connecticut, to review the engine manufacturer's cost-reduction strategy, which was accepted, says Hugh Risseeuw, P&W's director for navy and marine corps programmes.
The strategy includes higher upfront costs in some areas to make investments in the design of some engine components, he adds.
Despite the upfront investment, P&W's goal is to show improvement on the F135's costs in the next negotiated contract, says Risseeuw. The fourth lot of low-rate initial production is scheduled for contract award in the second quarter of 2010. This includes funding for at least 30 F135s, but Congress is debating whether to insert $600 million to also buy four F136s and continue development of the controversial rival.
Concerns about the F135's costs are driven by P&W's inability so far to achieve the expected "learning curve", or the rate of improving efficiency normally seen with steadily increasing production rates.
F-35 suppliers are required to achieve a rate of improving efficiency known as an 88% learning curve. This benchmark means costs are projected to decline by about 12% every time the production rate doubles. By contrast, a 100% learning curve means that costs never decline.
So far, P&W's learning curve for the F135 is "about halfway" between the goal of 88% and cost stagnation at 100%, Risseeuw says. This means the projected cost reduction when the production rate is doubled would also fall short of the 12% objective.
Risseeuw says the F135's cost reduction problem may have prompted a recent comment by JSF programme executive officer Brig Gen David Heinz, who said on 3 June: "I do not believe yet that Pratt feels compelled to act as though they are in competition."