For the first time in the history of the Joint Strike Fighter program, a senior Pentagon appointee has raised the question of whether one of the three versions of the Lockheed Martin F-35 should be canceled to save money. The move comes as program leaders and Pentagon cost experts are trying to prepare for a long-delayed Defense Acquisition Board review of JSF, including a comprehensive effort to establish reliable predictions of acquisition and operating costs.

Navy Undersecretary Robert Work told the Navy and Marine Corps in July to provide lower-cost alternatives to the Navy's current tactical aviation plan, and to examine the consequences of terminating either the F-35B short-takeoff-and-vertical-landing (Stovl) version or the carrier-compatible F-35C. Work is seeking decisions in time for the 2013 budget submission.

He also directed service leaders to study whether the Navy and Marines could operate fewer than the 40 squadrons of JSFs currently planned (supported by 680 aircraft, divided equally between Bs and Cs) and to look at the possibility of accelerating development of unmanned alternative systems.

The instructions were included in a July 7 memo from Work to Navy acquisition chief Sean Stackley, Vice Chief of Naval Operations Adm. Jonathan Greenert and Assistant Marine Commandant Gen. Joseph Dunford. Work told the leaders to form a team to develop three alternative tactical aviation force structures, respectively representing cost savings of $5 billion, $7.5 billion and $10 billion across the future-years defense plan. Ultimately, Work expects to determine “the best value alternative, factoring in both cost and capability.”

“This relook must consider every plan and program,” Work wrote. “Even cuts to long-planned buys of JSF must be on the table.” The team was also tasked to define “the key performance differences between the Block II F/A-18E/F with all planned upgrades, F-35B and F-35C.”

The quick-look analysis was due to be completed three weeks after the memo date; that is, by July 28. That was also the date on which Marine leadership organized a high-profile demonstration of the F-35B's Stovl capability at the Navy's Patuxent River, Md., flight test center.

Under Work's leadership, the Marines and the Navy signed an agreement in March under which the Marines would operate 80 F-35Cs and 340 F-35Bs. Earlier, the Marines had argued that all 420 of their JSFs should be F-35Bs.

Work did not direct the team to assess the economic or operational impact of F-35 program changes on the Air Force or international partners. A reduction in Navy Department orders for both the F-35B and F-35C would increase unit costs. Canceling either version would eliminate some remaining development costs, mostly in flight test, and could lead to increased production of the surviving variant.

The largest international JSF partner, the U.K., changed its plans in October 2010, switching from the B to the C model. If the F-35C were to be canceled, the U.K. would withdraw from the program and “look for a European solution” to its requirement for a carrier fighter, a senior U.K. official said in Washington earlier this month. Italy is the only international partner that plans to operate the F-35B.

Lockheed Martin declined to comment on the memo, saying that it was an internal Navy document. The F-35 Joint Program Office (JPO) had no immediate comment.

As an analyst with the Center for Strategic and Budgetary Assessments, Work coauthored studies that supported the case for early development of a carrier-based unmanned combat air vehicle (UCAV) with greater range and better stealth characteristics than the F-35.

Currently, there is a debate in Washington about the characteristics of a future Navy UCAV system. General Atomics Aeronautical Systems Inc. is still proposing the 15,000-lb. weight class, moderately stealthy Avenger design, while Northrop Grumman confirmed earlier this month that it would be proposing a design similar to its larger and stealthier X-47B. The latter would potentially fill some of the deep-penetration missions that the F-35C is intended to perform.

Boeing, meanwhile, is continuing to work on an improved version of the F/A-18E/F Super Hornet, which would reduce capability and performance gaps between it and the F-35C. The company plans to conduct wind-tunnel tests, late this year or early next, of the conformal tanks, which add 3,000 lb. of fuel, and a centerline weapons pod. General Electric is also offering an Enhanced Performance Engine variant of the Super Hornet's F414, increasing thrust by as much as 25%.

The F-35B variant remains on probation, under a decree issued by then-Defense Secretary Robert Gates in January. Gates said at the time that problems affecting the aircraft—including the need for a redesigned lift-fan door, driveshaft and clutch mechanisms—would have to be solved without increases in cost or weight. The U.K. government said, in switching from the B to the C variant, that the Stovl aircraft cost more than either the F-35A or F-35C, and U.K. government reports repeatedly described the F-35B's “bring-back” performance—its ability to land vertically with fuel reserves and unused weapons—as marginal.

Last year, Work suggested in remarks to a Washington forum that forward basing and refueling on improvised airstrips—one of two pillars of the Marine case for the F-35B—would become much more hazardous in the presence of G-RAMM (guided rockets, artillery, mortars and missiles) threats.

The F-35B's basing flexibility is also being called into question by unresolved issues about the effects of the fighter's hot, high-velocity exhaust on ground and deck surfaces. Lockheed Martin and senior Marine leaders have downplayed these issues, stated that the environment under a landing F-35B is almost identical to that of an AV-8B Harrier, and claimed that early 2010 tests confirmed these characteristics.

Navy construction specifications continue to warn that the F-35B will impose temperatures as high as 1700F (several hundred degrees higher than a Harrier exhaust) on vertical-landing pads, with a transonic exhaust velocity. This is enough to cause standard concrete to “spall”—that is, shed surface flakes in a near-explosive manner—with a 50% chance of damage on the first landing.

Navy standards require F-35B landing pads to comprise 100 X 100-ft. slabs of special heat-resistant concrete, poured in one piece and continuously reinforced in two directions. At least one contract has been issued to these specifications since early 2010, when Lockheed Martin asserted that such measures were not necessary.

The Office of Naval Research still has an active program to develop a cooling system for the decks of LHD- and LHA-class ships that will carry F-35Bs, reflecting concerns that thermal expansion and contraction and consequent buckling will cause fatigue and premature failure.

The JPO has not responded to repeated inquiries about the discrepancies between Lockheed Martin's statements and Navy specifications. Navy engineering organizations have referred all queries to the JPO.

The Defense Acquisition Board review is required in order to renew Milestone B approval of the JSF development and low-rate initial production program—granted in 2001 but rescinded automatically after last year's critical breach of Nunn-McCurdy cost limits. In May, the review was expected in June, but it was abruptly delayed into the fall.

Any changes in the Navy's plans will also factor into the board's review. Among other factors being considered is a trend among international partners to delay deliveries, driven by last year's slip in the completion of development testing, which will have an impact on production rates, ramp-up plans and costs.

JSF test aircraft were cleared to return to flight on Aug. 18, after a two-week grounding caused by a failure in the integrated power pack (IPP). Production aircraft, including two at Eglin AFB, Fla., and F-35s being prepared for delivery at Fort Worth, remain grounded and restricted from engine and IPP runs.