PHOENIX (AP) — An F-16 fighter flying out of Arizona's Luke Air Force Base crashed northwest of Phoenix on Friday during an air-to-air training exercise, Air Force officials said.

The status of the pilot, the only person on board, was unknown.

The aircraft went down around noon south of Alamo Lake, a remote area about 80 miles northwest of Phoenix, said Mary Jo May, a base spokeswoman.

A rescue helicopter was at the scene. The single-seat jet wasn't carrying any weapons, May said.

The cause of the crash of the F-16C was unknown.

Officials with a nearby state park and the La Paz County Sheriff's Office said they had no information to provide on the crash.

The pilot, whose identity hasn't been released, was part of the 62nd Fighter Squadron, one of eight squadrons at the base.

The base, located in the Phoenix suburb of Glendale, is the world's largest F-16 training base. It has about 185 F-16s.

In the last two years, the base has had at least two of its jets crash.

A pilot ejected safely from an F-16 in April 2006 after the lone engine on the jet exploded just after takeoff from the base. The aircraft came down in a cornfield.

Nearly nine months later, a two-seat F-16 that left the base crashed during a training mission at an Air Force bombing range in southwest Arizona. The pilot and instructor bailed out safely.