CRASH: Itscause under investigationFROM B1area surrounding Edwards Air Force Base in the Mojave Desert Both aircraft were flying under visual flight rules — meaning air traffic controllers were not directing the pilots, said Lt Eric Schnaible, a spokesman at EdwardsUnder Federal Aviation Administration rules, the pilots - not controllers — are responsible for avoiding collisions Schnaible said the weather was clear at the time of the collision, with good visibility and no heavy winds.Sorenson said he and other Pacific Aero Graphics employees went to the accident site Friday to confer with investigators.“From all we have been able to determine thus far, the aircraft was operating and following all F A A regulations,*’ he saidThe Talon jet was returning from a flight in which it was posing as a target for a new weapons-system radar being tested on an F-15 Eagle fighter jet, Schnaible said. When the collision occurred, the two jets had completed their test and were on their wav back to Ed-wards.The pilot of the F-15 was on final approach to Edwards and did not witness the crash, officials said. The Talon and the Cessna collided at an unknown altitude above the Cameron Canvon area about 15 orV20 miles northwest of the base, they said.The rugged scrub and ravine country is privately owned and dotted with hundreds of high-tech, electricity-generating windmills. The two planes fell to earth about one mile from one another, scattering Hames and wreckage amid the windmills without damaging any of them, said Lt. Col. Jerry Guess, an Air Force spokesman. Five to six acres of scrub burned before the flames were extinguished, officials said.Although the airspace Andelin was in is reserved for military flights, civilian aircraft are allowed to flv in the area under visu-mal flight rules, Guess said. Civilian pilots are not required to contact military air-traffic controllers, but they are warned by aviation charts to beware of the heavy military’ aircraft in the area. Guess said.The Air Force and the National Transporation Safety Board are conducting a joint investigation into the crash. Saturday, teams be-■rgan laying down a grid made of surveyors’ string as part of a painstaking search for all debris, officials said. Guess estimated pieces were spread over a three-mile area; the pattern in which they fell and an analysis of damage done to each part will help investigators determine the geometry’ of the collision and its probable causeMrs. Andelin said she and her husband moved to Irvine from Phoenix about eight years ago. Andelin had four children, all grown, and was a veteran of the Marine Corps.