Nine heavy hitters from the Lockheed Martin F-35 program fronted Tuesday’s media briefing here at Farnborough. But even three senior Pentagon officials, one Air Force general and five industry chiefs could not conjure the actual hardware–although the good news at the show yesterday was that the F-35 was given clearance to fly with “a restricted flight envelope.” The four F-35Bs slated to fly to the UK were have been grounded at NAS Patuxent River after a June 23 engine fire at Eglin AFB in Florida. With respect to the chances of an F-35 still making it to the show, Lockheed Martin stated yesterday that “no final decision has been made at this time.”

“We understand what happened, now we’re trying to figure out why,” said Lt. Gen. Chris Bogdan, head of the F-35 program office here on Tuesday. He said that borescope inspections of all 98 Pratt & Whitney F135 engines already delivered to the F-35 program has revealed nothing that would indicate a recurrence of the excessive rubbing of the inner cowl by the integral bladed rotor (IBR) in the third stage of the fan, that caused the failure in the F-35A. “Some blades are designed to rub, but this was more severe, leading to excessive temperatures, microcracking, and high-cycle fatigue, causing that part of the engine to come apart,” he explained.

A disappointed Frank Kendall, DoD under-secretary for acquisition, took comfort from the knowledge that “it’s not a systemic design problem.” He was still hopeful that the F-35 would appear here later this week. Bogdan said the impact of the grounding was “minor,” since scheduled maintenance and upgrades to the F-35 fleet had been brought forward.

Kendall said that more foreign sales of the F-35 were being negotiated. Israel, Japan and Korea have already joined the seven overseas nations that formed the original international partnership with the U.S. Some of those nations have since reduced their planned buys, Kendall admitted. “But they’re all still in–and there’s a good reason for that,” he added, citing the well-rehearsed advantages of fifth-generation combat aircraft.

These include stealth, of course–something you don’t hear much about in the F-35 program, despite all the government, congressional and media scrutiny. “There’s a reason for that,” Bogdan told AIN. “The aircraft is meeting or exceeding the low-observability requirements. The services are happy–and that includes the maintainability aspects of stealth.”

Kendall said the program was now meeting its cost projections, year by year. “It’s been a continuous learning experience. The problem in any sole-source procurement is incentivizing [the contractors],” he said. He cited the new so-called “Blueprint for Affordability” agreement with industry that was announced last week, and detailed in our Monday edition of AIN’s Farnborough Airshow News.

Bogdan said that the unit flyaway cost has come down 60 percent since the first low-rate initial production (LRIP) lot. The F-35As procured in the latest LRIP lot are costing $112 million, and the goal of achieving $80-85 million per unit by 2019, in then-year dollars, is achievable.

Marillyn Hewson, CEO of Lockheed Martin, said that ramping up the production rate would further lower the unit cost. But Kendall had potentially bad news for Hewson. Asked by AIN about sustainment costs for the F-35, the Pentagon’s chief buyer said he planned to inject significant competition into an area that accounts for 50 percent of the total cost of becoming an F-35 operator. “We’re aiming for performance based logistics (PBL),” he said. “We’re going to get the logistics system in place first. Then we’ll put it out to competition. We’re looking for innovative solutions, and the international partners can help provide them.”