An anonymous Slashdot reader quotes the Washington Post: Less than two months after declaring the controversial F-35 Joint Strike Fighter ready for combat, the Air Force on Friday announced that it was temporarily grounding 15 of the jets after it discovered that insulation was “peeling and crumbling” inside the fuel tanks. The setback is the latest for the $400 billion system, the most expensive in the history of the Pentagon. The problem comes as the program, which for years faced billions of dollars in cost overruns and significant schedule delays, had begun to make strides. The insulation problem affects a total of 57 aircraft, the Air Force said, 42 of which are still in production… In a statement, Lockheed Martin said that “the issue is confined to one supplier source and one batch of parts.” It emphasized that “this is not a technical or design issue; it is a supply chain manufacturing quality issue…” It is unclear how long the aircraft would be grounded, how long the problem would take to fix or what the larger affect on the program would be. âoeWhile nearing completion, the F-35 is still in development, and challenges are to be expected, ” said an Air Force spokeswoman, adding “The F-35 program has a proven track record of solving issues as they arise, and we’re confident we’ll continue to do so.” Read more of this story at Slashdot.