Source: Defense News
quote: "The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."
quote: You're probably not going to be able to just plain evade a SAM. They are much faster and more agile than any fighter jet could ever hope to be.
quote: The entire Lockheed Martin F-35 Lightning II fleet spent six days grounded after crack was discovered in an engine component of one aircraft.