In a move that echoes past budget maneuvering, the U.S. Navy says it can't afford to keep developing an alternative engine for the F-35 Joint Strike Fighter.

The U.S. Air Force, staring at shouldering the $3.4 billion F136 engine program alone, at a cost of about $400 million per year, is expected to go along with the move. Air Force planners say it's a better alternative than paying for it by delaying the F-35 program or cutting production totals of its conventional takeoff and landing variant of the aircraft. Veterans of many defense budget fights say it is a calculated move to draw lawmakers into adding money once the document gets to Capitol Hill.

The British, who want the new engine for aircraft carrier operations, are already mounting a counterattack, and they expect help from the U.S. Congress. British industry and government officials have been lobbying in Washington for the last two weeks to get the program back into the budget. The engine content is 50 percent General Electric, 40 percent Rolls-Royce and about 10 percent other international partners.

GE officials contend that British users are particularly keen to have the large-combuster, higher-thrust engine on the JSF for their aircraft carrier operations. Weapon "bring back" is a key user requirement for the British carrier-borne aircraft, in which weight and engine performance are critical. But Pratt & Whitney officials contest the claim that it will be a more powerful engine than their F-135 once it matures.

Because the F136 engine is largely the product of the U.S. Congress - which aimed to keep engine competition alive - it is expected by both Pentagon and aerospace industry officials that lawmakers will step in and add money to keep the program in existence.

"The alternative engine program has been killed before and Congress made sure it was funded," an industry official said. "And because of the international implications, putting it back into the budget this year is already getting a lot of support."

In fact, the proponents for the F136 faced a stiff battle to shake loose the money for the system development and demonstration phase. But after much back-and-forth, the $2.4 billion SDD contract that will run through 2013 was awarded in August. It covers seven ground set, six flight-test and one spare engine. It also kept on schedule the fielding time line for the F136, with a projected 2012 in-service date and a cut-in into the production line in the fourth lot of production.

One industry official suggests that with delays in the overall F-35 program, there may be a temptation to slow the F136 even if it is funded. Near-term development events would likely remain largely unaffected, with the first full-up F136 engine test slated in mid-2008, but risk reduction efforts expected to take place this year (CQ: 2006).

The F135 and F136 are designed to be completed interchangeable, so any F-35 can accept either engine, with the aircraft computer management system automatically detecting the engine change and making the required software adjustments.