After years of suffering massive program delays and cost overruns, the U.K. Defense Ministry has set out an aggressive agenda to ensure procurement decisions are grounded in fiscal reality and based on program certainty.

However, in one of its first major modernization moves—choosing to buy the carrier variant of the Joint Strike Fighter instead of the F-35B short-takeoff-and-vertical-landing (Stovl) version—London acted without firmly grasping the associated operational and cost implications. It also appears to have committed to the procurement despite lacking the means to fully fund the program, violating another principle of its reform agenda.

The Defense Ministry has since tried to address some of those uncertainties, although it may take another year to define future plans completely.

For instance, the move to the carrier version (CV) has caused the Defense Ministry to explore air-to-air refueling capabilities in case of a disruption on the flight deck during recovery operations. The U.K. has asked Lockheed Martin to assess the feasibility of using the F-35C in a buddy-buddy refueling mode. Under rules of the JSF program, countries must themselves fund studies into unique capabilities they want for an aircraft. Since the U.S. can rely on F/A-18E/F Super Hornets as carrier-based refuelers, the U.K. has to finance the engineering assessment on its own.

A U.S. military official says the engineering details and cost estimate of the upgrade should be ready “later this year.” But the U.K. may take longer to decide on its course of action. Peter Luff, the U.K.'s minister for defense equipment, support and technology, tells legislators that the assessment of how to provide “the most cost-effective means of providing an embarked air-to-air refueling capability in support of the department's future Carrier Strike capability” should emerge around March 2012.

Also still unclear is the impact of the F-35C choice on broader carrier operations. Although increased operational capability is a main reason for the switch to the F-35C, which has greater range and payload capacity, that shift also has drawbacks. One of those was spelled out in a recent parliamentary hearing by Rear Adm. Amjad Hussein, the senior officer responsible for the carrier strike program. The ability to launch fixed-wing aircraft and at the same time carry out commando group amphibious operations “is where the focus of the risk is,” he told the public accounts committee.

In particular, Hussein said, “we may need to bring in a greater degree of timing separation between the launch of the aircraft and launch of the helicopters.” He further tells legislators that “there will be limitations on performance that will result from that.”

While the extent of those limitations is as yet unknown, Hussein insisted the ability to launch commando group amphibious ops will not be undermined. “Do I believe the concept, the proposition as a whole, will not work? No, it will not fail,” he said. However, the operational analysis to see exactly how it will work remains to be done.

Also still in process is an effort by the U.K. to switch one of three F-35s bought for the JSF test program from the “B” to the “C” model. The U.S. Congress must approve the move, as the U.S. would swap an F-35C to be bought in the sixth low-rate initial production (LRIP) lot for an F-35B the U.K. funded in LRIP 4.

The Pentagon says, “The proposed exchange would benefit both participants—the exchange would provide the U.S. with a Stovl aircraft 24 months earlier than planned to support maturity assessments and training needs; it would allow the U.K. to avoid the costs of a CV aircraft for operational test, and it would increase operational test capacity through the use of an instrumented CV aircraft in the LRIP 6 time frame.”

The move should come with no financial penalty to U.S. taxpayers. “The U.K. would bear the costs of upgrading and modifying the LRIP 4 Stovl aircraft to the more advanced LRIP 6 configuration. In addition, the U.K. would be responsible for bearing the costs of incorporating flight-test instrumentation of the CV aircraft as well as any other U.K.-unique CV aircraft requirements,” says the Pentagon. A U.K. defense official insists any costs associated with the change are already budgeted.

Last month, the U.K. government identified additional money for defense modernization. The £3 billion ($4.9 billion) to be spent after 2015, in exchange for force structure cuts, includes money to acquire an initial batch of F-35s. The budget represents a 1% increase in real terms in defense spending.

The money is not specifically targeted for the F-35, but Defense Secretary Liam Fox says it will go to make a down payment on the aircraft, as well as finance the planned purchase of 14 extra CH-47 Chinooks, three RC-135 Rivet Joint signals-intelligence aircraft and other assets. The number of JSFs to be bought during the time frame has not been disclosed. The funds also cover the configuration of a Queen Elizabeth carrier with catapult launch and arrestor gear.

The Defense Ministry promises to publish a 10-year equipment plan by September that is balanced.