(Adds details on lessons learned)
FARNBOROUGH, England, July 14 (Reuters) - The U.S. and UK militaries are "not giving up" on bringing the Lockheed Martin F-35 Joint Strike Fighter to Britain for a high-profile air show this week after an engine fire prompted a fleetwide grounding and derailed the plane's international debut, a top U.S. official said Monday.
"We're not giving up yet. We still have a few more days left to try to get the airplane over here," Air Force Lieutenant General Chris Bogdan, the Pentagon's F-35 program chief, told reporters at the Farnborough Airshow.
U.S. Defense Undersecretary Frank Kendall said the United States and other countries involved in the $400 billion multinational F-35 Joint Strike Fighter remained committed to the program despite the June 23 failure of the Pratt & Whitney F135 engine on a U.S. Air Force jet that has grounded the entire F-35 fleet.
Kendall said he hoped the grounding order could be lifted in time to bring jets to the Farnborough air show that began Monday and runs through Sunday, but said no decision had been made.
Sources familiar with the situation said a key meeting had been set for later Monday to discuss the jet's flight status.
Kendall said there was growing evidence that the failure of the engine - triggered by excessive rubbing in the third stage of Pratt's F135 engine - was not a systemic design flaw affecting the whole fleet. But he said officials were still trying to understand why the engine broke up.
The United States' newest combat jet missed the Royal International Air Tattoo, the world's biggest military air show, last week where it was to make its international debut, and it remains unclear if it will still appear at the Farnborough show.
Industry executives thronged around a static display model of the F-35 at the air show on Monday to take turns sitting inside the jet, while a large electronic billboard displayed the three different models of the aircraft in flight.
Kendall and Bogdan were joined at a news conference at the show by top executives from the biggest contractors on the program - Lockheed, Pratt, Northrop Grumman Corp , and Britain's BAE Systems, as well as the acquisition chiefs of the U.S. Air Force and Navy.
Kendall said no similar problems had been found on any of the other 98 engines in service, and underscored that the program was still in the development stage when technical problems are meant to be found and fixed.
"It's unfortunate timing," he told the news conference, "but it's not a major setback."
U.S. officials said they expected to adopt a more streamlined process for the different military services and countries to report mishaps and accidents after early delays in sharing information about the June 23 incident.
Because the damaged jet belonged to the Air Force's education and training command, it took charge of the aircraft, quarantining it and going through its rigorous investigative process. But that left the other military services, Britain and the F-35 program office, in the dark, at least for a few days.
Bogdan said it took about a week before engineers were able to take the airplane and the engine apart for more detailed examinations of what went wrong.
Kendall acknowledged the delays in communication in this case, and said the Pentagon was learning from the experience. "We'll make sure we do a better job of that going forward."
Kendall said he was satisfied that Pratt and the other parties involved were providing information for investigators as they worked to understand and resolve the incident.
He said the F-35 program office was also working hard to keep the partners who helped fund the plane's development - Britain, Australia, Canada, Norway, the Netherlands, Italy, Turkey and Denmark - and Japan and Israel, which have ordered jets, up to date on the current situation. (Editing by Mark Potter and Jason Neely)