A Lockheed Martin (NYSE:LMT) F-35B Lightning II short takeoff/vertical landing (STOVL) stealth fighter today became the fifth F-35 to begin flight operations.

The jet, known as BF-3, departed the runway near Lockheed Martin's Fort Worth plant at 4:02 p.m. CST for its first flight. During the one-hour sortie, F-35 Chief Test Pilot Jon Beesley tested the aircraft's handling qualities, engine functionality, landing gear operation and basic subsystem performance.

BF-3 joins two other F-35Bs and one F-35A conventional takeoff and landing (CTOL) aircraft currently undergoing active flight test. The first CTOL F-35, AA-1, is now preparing for live-fire testing. The F-35 program continues to accelerate the time from flight line arrival to first flight.

BF-3 was built and instrumented to conduct flight sciences test work and will be used primarily to evaluate vehicle systems and expand the aircraft's aerodynamic and structural-loads envelope. It will deploy later this year to Naval Air Station Patuxent River, Md., where it will carry and release most of the weapons the F-35B will employ in combat.

BF-3 and all other Lightning II aircraft will be supported by the F-35 Autonomic Logistics Information System and monitored by the F-35 Autonomic Logistics Global Sustainment Operations Center in Fort Worth. F-35 sustainment is based upon the principles of Performance-Based Logistics, involving extensive partnering agreements between government and industry. The F-35 team has developed an advanced sustainment system capability with designed-in sustainability that will reduce overall life-cycle costs and ensure mission readiness.