Flight testing of F-35 Lightning II Joint Strike Fighters has been suspended after a U.S. Air Force aircraft experienced a dual generator failure and oil leak during a test sortie on March 9, prime contractor Lockheed Martin said March 11. THE MARCH 9 incident occurred at Edwards Air Force Base, Calif., which is the main Air Force flight test facility, on aircraft AF-4, pictured above. (Liz Kaszynski / Lockheed Martin) The plane, an F-35A, returned safely to base, but further test flights are being delayed while engineers figure out the cause of the problem. RELATED TOPICS Americas Air Warfare "As a routine safety precaution, the Joint Program Office (JPO) has temporarily suspended F-35 flight operations until a team of JPO and [Lockheed] technical experts determines the root cause of the generator failure and oil leak. Once the cause is known, the appropriate repairs and improvements will be made before flight operations resume," Lockheed spokesman John Kent said in an e...