By Marina Malenic

The Pentagon is putting a jump-jet version of the F-35 Joint Strike Fighter being developed for the Marine Corps on a two-year “probation” to give prime contractor Lockheed Martin [LMT] time to redesign aspects of the technologically complex aircraft, senior defense officials said yesterday.

Defense Secretary Robert Gates told reporters at the Pentagon that the Marines’ short take-off/vertical landing (STOVL) variant of the F-35 will be moved to the end of planned development and production. It had been the first of the three models in line for delivery and deployment.

“The Marine Corps made a compelling case that they need some time to get things right with the STOVL and we will give them that opportunity,” Gates said.

He added that if the B-model development effort is not “back on track” after two years, it “should be canceled.”

Lockheed Martin CEO Robert Stevens said changes to the program outlined by Gates “define a path to manage risk, provide funding and focus, and ensure the program’s success and central place in the future of U.S. military aviation.

“We recognize our role and responsibility to deliver extraordinary fighters in three variants,” Stevens said. “We’re committed to doing that, and we’re confident that we’ll succeed, including delivering the STOVL variant.”

The company is building three versions of the F-35 for the Air Force, Navy and Marine Corps, as well as for several foreign militaries. The A model, to be flown by the Air Force, takes off and lands conventionally; the Marine Corps is to fly the STOVL-variant B model; and the C model is to be flown from carriers by Navy fighter pilots.

In November, Lockheed Martin officials revealed that an F-35B ground test aircraft had suffered fatigue cracks in its bulkhead. A spokesman for the company said that, following a thorough root-cause analysis, engineers determined that those cracks resulted from a “large concentration of stress created by wing-bending forces that normally would be distributed through the aircraft structure.” A redesign of the bulkhead has been completed and an implementation plan has been developed, according to John Kent, a company spokesman.

Gates also said that the Department of the Navy, which includes the Marines, will buy more Boeing [BA] F/A-18E/F Super Hornets at least until problems with the F-35B can be resolved. In addition to buying new F/A-18s in place of F-35Bs in the near-term, the Navy will extend the life of 150 F/A-18s currently in service, Gates said.

He said he expects a new program overhaul–which includes a more realistic production schedule–to generate $4 billion in savings. He also said F-35 orders would be capped at 32 this year.

The plans were announced as part of a package of budget proposals aimed at reinvesting $100 billion taken from “unneeded programs and overhead” over the next five years. Gates wants that money to be spent on higher defense priorities.

Gates first outlined his plans for the F-35B to Gen. James Amos, the Marine Corps commandant, in early December, according to Marine Corps sources. The Marines have said the aircraft is needed to replace the 25-year-old AV-B Harrier, which is used when landing on amphibious warfare vessels and improvised airstrips.

The United Kingdom, which had been the Pentagon’s most significant international partner in the venture until earlier this fall, had plans to purchase the STOVL version of the aircraft. However, in October London released its Strategic Defense and Security Review, which recommends cutting defense spending by eight percent over four years. In that review, the number of F-35s to be acquired is reduced, and the B model is dropped in favor of the carrier variant (Defense Daily, Oct. 29).

Gates was briefed last November on new cost and schedule assessments for the troubled program. He was told at the time that delivery of the fighter could be delayed by another one to three years and cost $5 billion more than the most recently released estimates indicate (Defense Daily, Nov. 3). And, on Nov. 22, the Defense Department’s F-35 program manager, Vice Adm. David Venlet, presented the department’s Defense Acquisition Board with a new “technical baseline review” of the development and testing effort. Top Pentagon weapons buyer Ashton Carter has said the per-unit cost of the aircraft must be reduced going forward.