Pentagon Says F-35 Joint Strike Fighters Can Fly Again

Were grounded after crack in engine blade was found

The Pentagon's fleet of next-generation F-35 Joint Strike Fighters has been cleared to resume flying, six days after the discovery of a half-inch crack in an engine blade led to the grounding all 50 or so training and test jets.

Engine-maker Pratt and Whitney said it is confident it has isolated the source of the crack in the F135 engine and can fix it. But the stealthy F-35?s propulsion problems are anything but fixed. Finicky motors are an inevitable side effect of the plane's design.