PVT PLT OF AN SMA SEL TOOK EVASIVE ACTION TO AVOID ANOTHER ACFT AT APPROX THE SAME ALT XING THROUGH HIS FLT PATH WHILE DSNDING IN CLASS C AIRSPACE. NMAC.

Narrative

WHILE DSNDING THROUGH 3500 FT ON V334 APPROX 10 NM NE OF THE SAN JOSE VOR I SUDDENLY SAW A LIGHT TWIN ACFT; LIGHT BLUE AND WHITE IN COLOR; PROBABLY A BEECH DUTCHESS; XING IN MY 10-11 O'CLOCK POS; AT MY ALT L TO R AND AT A DISTANCE OF ABOUT 1000 FT. I MADE AN IMMEDIATE DSNDING SHARP L TURN AS AN EVASIVE MANEUVER. I PASSED BEHIND AND UNDER THE TWIN AT A MINIMUM DISTANCE OF ABOUT 300 FT. I WAS IN RADAR FLT FOLLOWING AND HAD BEEN ADVISED OF TFC AT 12 O'CLOCK 4500 FT; 1 MI; SAME DIRECTION MOMENTS PRIOR TO THIS. AFTER RPTING THE NEAR MISS; I WAS TOLD BY THE CTLR THAT HE SAW NO TFC AT MY ALT. I ASSURED HIM THAT THERE INDEED WAS TFC. FACTS/OPINIONS: HAD I NOT MADE THE IMMEDIATE MANEUVER I AM CONVINCED WE WOULD HAVE COLLIDED. I AM VERY COMMITTED TO CONTINUOUS SCANNING FOR TFC AND WAS DISTRACTED BY THE ADVISORY I WAS GIVEN AND SO FAILED TO LOOK L AT THAT TIME IN PARTICULAR. I WOULD GUESS THE TWIN WAS 'SNEAKING THROUGH' THE CLASS C AND MAYBE NEARBY CLASS B AIRSPACE BY NOT ACTIVATING HIS XPONDER. ONLY OTHER EXPLANATION IS CTLR MISSED RETURN OR THERE IS A RADAR BLIND SPOT IN THIS AREA AND ALT UNLESS TWIN WAS REPLYING WITH ALT 1000 FT IN ERROR.