Cutbacks in F-35 procurement and the termination of the F-22 will lead to a 30% decrease next year in Pratt & Whitney’s production of fifth-generation combat engines, seriously challenging cost-reduction goals for the Joint Strike Fighter’s F135 powerplant.

“Our volume is coming down even as we continue to make great progress on the war on cost,” says Pratt & Whitney Military Engines President Bennett Croswell. The unit cost for the conventional-takeoff-and-landing (CTOL) F135 has come down 25% since 2009. “We took $1.5 million out of the engine last year, in just one year,” Croswell says.

Production of F119 engines for the F-22 helped Pratt reduce costs for the derivative F135 engine, as the two powerplants share several common features, such as integrated bladed rotors, hollow fan blades and low-observable coatings. The last F119, a final spare for the now out-of-production twin-engine F-22, is set for delivery in November.

The original cost-reduction plan presented by Pratt at the time of the 2009 Joint Assessment Team review outlined a declining cost curve through engine 250. But the movement of 179 aircraft to the right in the next five years means this milestone will not occur. When drawn up, this plan anticipated a faster production rate, with delivery of engine 250 in either the latter part of low-rate initial production (LRIP) Lot 6 or the initial part of Lot 7.

Lower volumes mean that Pratt delivered 27 engines last year instead of the expected 40, and it now plans to deliver 50 a year in 2012 and through the next three years before it prepares to start ramping up F135 production to 80 per year from 2016.

“We’re not signaling to anybody that we aren’t dedicated to continuing to come down that [cost] curve,” Croswell says. Targets for greater efficiency include manufacturing, the flow of parts in the shop, and savings from the supply chain.

“I was worried about our supply base — it might be difficult to get cost out of them without the expected volumes. But they’re hanging in there,” Croswell says.

He points out that total volumes over the life of the F-35 program have not been reduced, just stretched out. “I think this will be like the F100 program [the engine that powers F-15 and F-16 fighters], which is now in its 40th year of production.”

Recognizing the importance of cost reductions to the longer-term survival of the program as a whole, Croswell also says the death of the General Electric/Rolls-Royce F136 alternate engine in 2011 is not a factor. “We’re under a tremendous amount of scrutiny, whether there is another engine or not. The drive for cost reductions almost creates a competition in itself.”

Twelve production-standard F135s were delivered in 2010, 27 in 2011 and 24 through June of this year.