The second Lockheed Martin F-35 Lightning II stealth fighter, known as AF-1 (photo), 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 November 14, 2009.

The F-35A flight test program has completed more than 43% 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.

Meanwhile, and for the first time, two Lockheed Martin F-35C Lightning II carrier variant test aircraft refueled together with a Lockheed Martin KC-130 Hercules in the sky above Patuxent River, Maryland, recently.

The CV aircraft, known as CF-1 and CF-2, completed the milestone as part of an F-35 flight test program that will accomplish more than 1,000 flights in 2013.

Later this year, Eglin AFB, Florida, will receive its first CV aircraft joining the F-35 pilot and maintainer training program there.