Lockheed Martin’s grounded F-35 warplane still stands a chance of wowing crowds at the Farnborough Air Show in Great Britain as engineers work to restore its safety clearance before the end of the year’s biggest aviation expo.Military chiefs and the international consortium that built the jet are “hopeful” that four planes due to appear at the U.K. event will be able to cross the Atlantic this week, U.S. Defense Undersecretary Frank Kendall said at a briefing in Farnborough. The F-35, which is built in Fort Worth, was ordered to cease flying following an engine fire on June 23 thought to have been caused by friction between blades and the cowl around them. The jet has already missed an appearance at the naming of a U.K. aircraft carrier from which it will serve, as well as the weekend’s Royal International Air Tattoo and the first day of the Farnborough show, which runs until Sunday. “We’re all disappointed,” U.S. Air Force Lieutenant General Christopher Bogdan, the F-35 program manager, said at the briefing. “We’d planned for this over the past few months and it would have been a wonderful thing to have this plane here. But we’re not giving up yet. We still have a few days left.” The engine issue comes as a setback as the U.S. pushes to expand export sales of a model built to satisfy a domestic requirement from the Air Force, Navy and Marine Corps. Lockheed Martin and engine maker Pratt & Whitney took a week to strip back the stricken plane and uncover the fire’s cause, and it’s not clear if the damage can be repaired, the partners said.Four F-35 Lightning IIs were due to make the journey to the U.K., three from the U.S. Marine Corps and one from the RAF. The jet fighters are “perched” on a high state of readiness at an air force base in Maryland awaiting any lifting of the grounding order, Bogdan said, adding that any appearance at Farnborough southwest of London would need to involve a full display, with a “B52-style flyby” not under consideration.Given the time taken to reposition the aircraft, which need refueling to cross the ocean, the planes would need to leave the U.S. well before the weekend to make the trip worthwhile, he said. The F-35 has been plagued by a costly redesign, bulkhead cracks, excessive weight and delays in software. Building all 2,443 planes is projected to cost $398.6 billion, a 71 percent increase in inflation-adjusted dollars since the contract with Lockheed was signed in 2001. More than 6,000 people work directly on the F-35 program at Lockheed in Fort Worth, which employs about 13,300 overall. More than 100 F-35s have been delivered to the U.S. military. This article includes material from the Star-Telegram archives.