The second Lockheed Martin F-35 Lightning II stealth fighter, known as AF-1, joined the 500 flight hour club recently during its 272nd flight.

It joins AF-2 which passed the milestone June 26, 2012. The conventional takeoff and landing (CTOL) fighter began flight operations when it made its inaugural flight Nov. 14, 2009.

The F-35A flight test program has completed more than 43 percent of its overall test plan. Overall, the program's three variants have achieved nearly 5,900 flight hours by 55 aircraft in the System Development and Demonstration (SDD) and Low Rate Initial Production (LRIP) programs.