LAX83FA034

After departing san jose, CA, the plt climbed to an alt of 4600 ft MSL & proceeded toward novato, CA. From 1528 to 1533 PST, radar data showed that the acft was level at 4600 ft on a heading of 330 deg at 180 fts ground speed. Radar info showed that the acft then entered a descent. During a 24 sec period, the acft descended to an alt of 4100 ft MSL & its heading changed 10 deg to the right. The last radar position, 12 sec later, revealed an additional heading change of 150 deg to the right, accompanied by a descent to 2300 (9000 frm descent). Witnesses saw the acft descending at high speed in a right turn with the engs at high power. Just prior to impact, the right bank angle & nose low attitude increased. The acft crashed in a steep nose down, right wing low, attitude. No preimpact,mechanical malfunction or failure was found. No autopsy was was made, only a gross exam of the plt's fragmented body was possible. Before departing san jose, the plt had remarked that he was bothered by a bad cold.