At 1116 Pacific time, a Lockheed P2V was destroyed when it collided with a hillside while maneuvering in mountainous terrain. The ATP-rated pilot and ATP-rated copilot were both killed. A VFR flight plan had been filed for the cross-country positioning flight from Prescott, Ariz. to San Bernardino, Calif. Instrument conditions prevailed at the accident site, about seven miles from the destination airport. Two witness in a forest lookout tower at about 7,900 feet elevation, one of whom was pilot-rated, described a cloud layer that extended south as far as they could see. They estimated the cloud tops at 5,000 feet. The witnesses observed the airplane flying northward up a canyon near the edge of the clouds. The airplane then made a 180-degree turn, leveled its wings and entered the cloud layer in an apparent descent. About two minutes later, the witnesses observed several dark bulges in the cloud layer and notified local authorities. Searchers reached the site about two hours later and reported that the wreckage and surrounding vegetation were on fire, and that visibility was low.