The absence of the F-35B from its highly anticipated international debut at two air shows in the U.K. was a public relations embarrassment for U.S. program leadership, prime contractor Lockheed Martin and, especially, engine manufacturer Pratt & Whitney, whose F135 caused the fire that grounded the entire Joint Strike Fighter fleet.

The disappointment and wisecracks circulating as a result will eventually subside, and the debut that wasn’t likely will be reduced to a footnote in the program’s storied history.

But the graver implications of a three-week full stand-down of test flights followed by a very restricted flight clearance are yet to be fully understood. Program Executive Officer U.S. Air Force Lt. Gen. Christopher Bogdan said on July 10, before the Royal International Air Tattoo (RIAT) at RAF Fairford, that about 50 test-flight opportunities had been missed as of that day; flights resumed six days later. While grounded, aircraft were updated with modifications slated for later in the test program, building extra margin that can be used for later flights, he said.

But the F-35’s return to the skies is very limited. Pilots are restricted to Mach 0.9, 18-deg. angle of attack, -1 to 3 gs and half a stick deflection for rolls. The overall impact on the program and its key milestones will depend on how long these limits are in place.

During the Farnborough air show, Bogdan said the U.S. Marine Corps’ initial operational capability, slated for July 1, 2015, is not yet in jeopardy. But weapons testing must be wrapped up before then, and this typically requires drops at various parts of the flight envelope. More pressing, however, are test points critical for maintaining plans for initial aircraft carrier trials this fall of the U.S. Navy’s F-35C, optimized for at-sea landings.

The cause of the F135 fire was traced to excessive friction between the third stage in the integrally bladed rotor and an abradable strip that lines the engine casing. Pentagon procurement chief Frank Kendall said the friction appears to be isolated to AF-27.

Nonetheless, the entire sequence of events leading up to the F-35 no-show announcement revealed chinks in the program’s communications with the public and allies.

Pentagon spokesman Rear Adm. John Kirby made the cancellation official late July 15 in Washington. “In concert with our partners in the U.K.—[the Defense Department] has decided not to send Marine Corps and U.K. F-35B aircraft across the Atlantic to participate in the Farnborough air show,” he told reporters at a Pentagon press briefing. “This decision was reached after consultation with operational commanders and airworthiness authorities, despite the decision by airworthiness authorities to clear the aircraft to return to flight.”

The decision came at 7 p.m. local time in Farnborough, after show crowds had left and only hours after Kirby and other officials—including Air Force Secretary Deborah Lee James—had expressed hope that the jets could perform a flying display once the Air Force and Navy lifted the grounding. “If I were a betting woman, I would say the odds just got better” that the F-35Bs would fly at the show, James said in a speech at the U.S. Pavilion that afternoon.

Although the U.S. armed services were willing to allow a return to flight, the risk-averse aviation authorities in London apparently nixed the deployment. Kirby insists it was a joint decision, but it was ultimately made by Marine Corps Commandant Gen. James Amos. British officials lay responsibility on the U.S. “There was no [Military Aviation Authority] involvement in this decision, which was made in the U.S. by the U.S.,” a U.K. defense ministry spokesman said.

Asked if the 2011 decision to terminate the General Electric/Rolls-Royce alternate F-35 engine program should be revisited, Kendall did not take the opportunity to put pressure on Pratt. He said the Pentagon remains confident in the F135 and its design.

Though the aircraft did not show, the Marine Corps has learned from the preparation work, says service spokesman Capt. Rich Ulsh. Marines arrived early for RIAT with what Lockheed Martin Aeronautics Executive Vice President Orlando Carvalho says was essentially a wartime spares package backed up by the F-35 logistics system.

Grp. Capt. Paul Godfrey, the U.K. Royal Air Force’s F-35 service entry team leader, says program officials are now targeting RIAT 2015 for the debut. “With the way the program is growing, and the amount of aircraft and people we’ll have by then, I do think it is a possibility,” he tells Aviation Week. 

 

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