F-35 Lightning II flight test program milestones in August 2014 included: The 400th flight of F-35A test aircraft AF-1 came during a GBU-31 Joint Direct Attack Munition separation test on 13 August, which used the 2,000 pound Mk 84 bomb case for the first time. F-35B Mode 4 formation testing was completed on 9 August. In Mode 4, the aircraft’s STOVL propulsion system is engaged, with the lift fan, roll post nozzle, and the three-bearing-swivel nozzle operating. F-35B Block 2B software fleet release weapon separation requirements were completed with two successful instrumented AIM-120 Advanced Medium Range Air-to-Air Missile separation flights on 14 and 15 August. The F-35A test fleet reached the 4,000th flight hour mark on 14 August.
