NMAC.

Narrative

WE DEPARTED ATW ON A 240 DEG HDG. DURING CLB; I NOTICED A XPONDER ONLY (NO ALT) TARGET DISPLAYED ON TCASII APPROX 8 MI AT 11-11:30 O'CLOCK POS. I CONTINUED TO MONITOR THE DISPLAY AND LOOK FOR THE TFC VISUALLY. DEP CTL ADVISED US OF TFC AT 11 O'CLOCK WITH NO ALT DISPLAY. I BELIEVE THIS TA WAS FOR EBOUND TFC AT 3-5 MI. BOTH THE FO AND MYSELF WERE VISUALLY LOOKING FOR THE TFC IN THE 11 O'CLOCK POS. THE TCASII SOUNDED 'TFC; TFC' AND DISPLAYED THE TA AS YELLOW IN THE 10-11 O'CLOCK POS MOVING PAST OUR L SIDE INSIDE THE 3 MI RING. SEVERAL SECONDS LATER; A NICE LOOKING RED AND CREAM COLORED SMA Y APPEARED MOVING FROM R TO L ACROSS OUR WINDSCREEN. I WOULD ESTIMATE THE DISTANCE AS 100-200 FT HORIZ AND AT SAME ALT OF 5000-5500 FT; WE WERE CLBING. HAD WE BEEN ON A COLLISION COURSE; WE PROBABLY WOULD NOT HAVE HAD ENOUGH TIME OR DISTANCE TO AVOID THE COLLISION. I BELIEVE THAT THE TFC WE WERE LOOKING FOR EXISTED BUT WAS NOT THE SAME TFC WITH WHICH WE HAD A NEAR-MISS. THE LATER TFC CAME FROM AROUND 2 O'CLOCK AND WAS SSEBOUND. EITHER THIS SMA Y DID NOT HAVE A XPONDER; OR IT WAS NOT TURNED ON. IN SUMMARY; THE TCASII IS AN EXCELLENT DEVICE FOR IMPROVING TFC AWARENESS. HOWEVER; IN OUR CASE; IT CAUSED US TO FOCUS OUR ATTN TO A NARROW SECTOR AND ANOTHER INTRUDER APPEARED FROM OUR UNMONITORED SECTOR. I AM SUSPICIOUS THAT THE SMA Y HAD A XPONDER; BUT WAS NOT IN USE. IF HE HAD SEEN US; I THINK HE WOULD SAFETY WIRE THE SWITCH TO ON.