(Editor's note: This story has been updated to reflect additional information regarding a $591.9 million DOD contract with Pratt for the seventh lot of F135 propulsion systems to power the F-35.) A joint team investigating an engine fire onboard an Air Force Joint Strike Fighter this summer has validated the root cause of the incident and briefed its findings Oct. 10, according to a spokesman from the F-35 joint program office. The findings confirmed the root cause previously identified...