Engine fire triggers new turbulence for Lockheed's F-35 jet

By Andrea Shalal

RAF FAIRFORD, England, July 10 (Reuters) - Borne of the last downturn in U.S. military spending in the 1990s, Lockheed Martin Corp's F-35 Joint Strike Fighter was intended as a quick and affordable way for the United States and its allies to replace thousands of aging F-16s and other warplanes while avoiding the pitfalls of earlier programs.

Nearly two decades and a $166 billion jump in projected costs later, the world's largest arms program was poised for a high-profile international debut at two British air shows when the Pratt & Whitney engine on one of the jets broke apart and caught fire during a takeoff from a Florida air base.

The incident has grounded the existing fleet of 97 F-35 jets and triggered a fresh wave of criticism about the costly new warplane, although U.S. and British officials are underscoring their continued commitment to the program, which now has a revised price tag of $398.6 billion.

The latest engine issue came weeks after an in-flight oil leak that sparked a brief grounding in June, but U.S. officials remain hopeful the jet will at least fly at the bigger of the two UK events - the Farnborough Airshow that starts on July 14.

Lockheed's F-35 program manager Lorraine Martin told reporters that the planes would miss the first day of the Royal International Air Tattoo air show, but could still arrive in time to fly at the event, which continues through July 12. She said Lockheed had spare parts on hand at the air field in case they were needed.

British Defence Secretary Philip Hammond on Wednesday said the F-35 may miss the Air Tattoo given the grounding order, but said he was optimistic that the plane would fly at Farnborough.

It would be a huge embarrassment if it misses that show too, and could undermine export interest in the jet just as several countries including Canada and Denmark, both of which helped fund development of the jet, are weighing F-35 orders.

DEVELOPMENTAL TESTING

With three different models, supersonic speed and cutting-edge electronics, the F-35 was designed as a multi-service, multi-national program to lower development and production costs. Yet early technical challenges drove the cost of the program nearly 70 percent over initial estimates.

Pentagon officials say the F-35 is finally making progress after several major restructurings and years of delays, but also say the jet still has 40 percent of developmental testing to go.

The sheer complexity and scale of the program, which involves three U.S. military services and 9 other countries that have placed firm orders, also mean that grounding and technical issues have a far wider impact than on a single-service weapon.