Pleasanton

A Cessna 208B struck a ridge line about 14 miles from the destination airport. The pilot reported to atc he had the airport in sight from 7,000 feet msl more than 30 miles away. A weather reporting station located 5 miles east of the accident site was reporting two cloud layers; a scattered layer at 1,500 feet agl, and a broken layer at 5,000 feet agl. The airplane was descending after the pilot was cleared for a visual approach. The airplane collided with a tree and the ground in a wings level attitude at an elevation of 1,500 feet msl. There was no evidence of mechanical failure or malfunction found with the airplane.

During arrival, the pilot was cleared for an ILS runway 27R approach to the metro Oakland Intl Airport. As she began the approach, the ATC controller noted the aircraft had descended thru 2,900 feet msl. He provided a low altitude alert to the pilot and warned her the aircraft should be at 3,300 feet. The pilot acknowledged by saying 'thank you.' The ATC controller suggested the pilot climb to 3,300 feet immediately, then he canceled the clearance and told the pilot to climb immediately to 3,300 feet. Subsequently, the aircraft crashed approximately 15 miles east of the airport. Impact occurred with a 1,500 feet ridge at about the 1,000 feet level. No preimpact part failure or malfunction of the aircraft was found. The pilot, sole on board, was killed.