SMA PLT HAS A NMAC WITH A C172 IN THE TRAFFIC PATTERN AT CDW.

Narrative

CDW TWR CTLR INSTRUCTED ME TO ENTER A R DOWNWIND FOR RWY 22; TOLD ME I WAS #3 BEHIND AN ACFT TURNING 'BASE' AND TO RPT TFC IN SIGHT. AT THE TIME; I WAS ON A 45 DEG INTERCEPT ANGLE TO THE RWY 22 DOWNWIND AND STILL DSNDING FROM APPROX 2 SM W OF CDW. I COULD NOT IDENT THE ACFT ON BASE; AND RPTED THE ONLY ACFT I SAW WAS DEPARTING RWY 22 AND WAS CLBING ON UPWIND. TWR ABRUPTLY STATED 'THEN YOU'RE NOT LOOKING.' MY TCAS THEN ANNOUNCED A TFC CONFLICT TO MY R; AND AS I LOOKED R; I SAW A C172 THAT WAS TURNING FROM XWIND TO DOWNWIND (APPARENTLY DOING PATTERN WORK) AND ON A COLLISION COURSE WITH MY ACFT. I CONTINUED TO DSND BELOW TPA TO PASS UNDER THE C172'S FLT PATH AND ESTIMATE THAT WE GOT WITHIN 500 FT LATERALLY AND ABOUT 200 FT VERTICALLY. I RPTED THIS CONTACT TO THE TWR CTLR AND HE CLRED ME TO LAND ON RWY 22. I BELIEVE THE CONTRIBUTING CAUSES TO THIS NMAC WERE: 1) THE VISUAL APCH FROM CLOSE-IN AND HIGH; 2) MY NOT DSNDING TO TPA AT A FAST ENOUGH RATE; 3) THE RESULTING DIFFICULTY IN SEEING TFC ALREADY IN A BUSY PATTERN AS I APCHED; AND 4) MY CONCENTRATION ON THE AREA (BASE LEG) THAT I HEARD IN THE INSTRUCTIONS FROM TWR AND MY FAILURE TO SEE THE OTHER ACFT THAT WAS CLBING IN THE XWIND LEG TO MY R. TO PREVENT A RECURRENCE; I WOULD SLOW THE ACFT AND DSND FARTHER OUT USING S-TURNS AND/OR SLIP IF NECESSARY TO GET DOWN SO I HAVE THE TIME FOR A GOOD SCAN AND TIME TO SPOT TFC. I ALSO WOULD NOT ENTER THE PATTERN IF I COULD NOT SEE THE OTHER ACFT THAT WAS BEING CALLED OUT AND I WOULD REQUEST A 360 OR OTHER ATC ASSISTANCE TO AVOID A CONFLICT. I WOULD ALSO CONSIDER ASKING APCH FOR VECTORS TO BRING ME FARTHER W OF CDW BEFORE HANDING ME OFF TO THE TWR. THAT WOULD GIVE ME MORE TIME INBOUND TO MONITOR THE TWR AND IDENT WHERE THE TFC IS LIKELY TO BE.