CAMARILLO, Calif. â€"  A privately owned jet contracted by the military to play the enemy in training exercises crashed Friday in a Southern California farm field, killing the civilian pilot, authorities said.

The Hawker Hunter jet trainer went down near Naval Base Ventura County, fire department spokesman Steve Swindle said. The pilot was the only person aboard.

The high-performance military-style aircraft took off from the base on a training sortie with another jet trainer and went down as it was returning, about two miles from the runway.

"He was on final approach. He went down," Swindle said. He said the sky in the area was "bright and crystal clear."

The farm field where the plane crashed is between Point Mugu State Park, Camarillo Airport, and the Naval base, some 50 miles northwest of downtown Los Angeles.

Debris from the crash covered an area about the size of a football field, Swindle said. There were no injuries on the ground and there was no fire, he said.

Sergio Mendoza, 23, was working in a nearby celery field when he saw the two planes flying together.

He told the Ventura County Star he saw one jet on fire and it began breaking apart in the sky as he lost sight of it.

Naval and fire personnel were at the crash site and investigators from the Federal Aviation Administration and the National Transportation Safety Board would take over the investigation, Swindle said.

The British-built, single-seat Hawker Hunter was owned by Airborne Tactical Advantage Co. of Newport News, Va., known as ATAC. It provides aerial training to the military, including the Navy's elite Fighter Weapons School.

Matt "Race" Bannon, director of business development for ATAC, confirmed that the pilot was also from the company but would not identify him or give any details until relatives were notified.

"Our concern right now is with the family," Bannon said.

The cause of the crash was not immediately known. "I won't even speculate as to anything," Bannon said.

Following company procedure after accidents, ATAC was immediately halting all its flights.

The Naval base uses ATAC planes and pilots to provide adversarial support for its fleet of ships out of San Diego, base spokesman Vance Vasquez said.

"They go out and play the bad guy, Vasquez said, "mimicking the enemy, jamming their radar, testing the fleet's defenses."

On March 6, one of the company's Israeli-built F-21 Kfir jets crashed into a building at Naval Air Station Fallon, Nev., killing the pilot. ATAC said at the time that although the investigation was continuing, there was no question that erratic and severe weather that had not been forecast contributed to the accident.

Friday's crash occurred on the anniversary of the crash of a commercial aerial refueling tanker during takeoff from the Ventura base's air station at Point Mugu. All three crewmembers escaped on May 18, 2011, before fire destroyed the Boeing 707 registered to Omega Air Inc. of San Antonio, Texas.