Test pilots flying the F-35B, the short take-off and vertical landing variant of the Lightning II, successfully completed air start testing on 15 August 2012 at the Air Force Test Center at Edwards AFB, California. The test aircraft, designed BF-2, was ferried from NAS Patuxent River, Maryland, for these trials, which verified the ability of the F-35's propulsion system to be restarted during flight. Pilots used multiple restart methods during the tests, and BF-2’s engine successfully completed twenty-seven air starts at various altitudes. Verifying the F-35’s restart capability is a prerequisite for high angle of attack testing, which is scheduled to begin in 2013. Edwards has a unique testing range that provides controlled conditions for air start testing.