Narrative:

We departed atw on a 240 degree heading. During climb, I noticed a transponder only (no altitude) target displayed on TCASII approximately 8 mi at 11-11:30 O'clock position. I continued to monitor the display and look for the traffic visually. Departure control advised us of traffic at 11 O'clock with no altitude display. I believe this TA was for eastbound traffic at 3-5 mi. Both the first officer and myself were visually looking for the traffic in the 11 O'clock position. The TCASII sounded 'traffic, traffic' and displayed the TA as yellow in the 10-11 O'clock position moving past our left side inside the 3 mi ring. Several seconds later, a nice looking red and cream colored small aircraft Y appeared moving from right to left across our windscreen. I would estimate the distance as 100-200 ft horizontal and at same altitude of 5000-5500 ft, we were climbing. 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 traffic we were looking for existed but was not the same traffic with which we had a near-miss. The later traffic came from around 2 O'clock and was ssebound. Either this small aircraft Y did not have a transponder, or it was not turned on. In summary, the TCASII is an excellent device for improving traffic awareness. However, in our case, it caused us to focus our attention to a narrow sector and another intruder appeared from our unmonitored sector. I am suspicious that the small aircraft Y had a transponder, but was not in use. If he had seen us, I think he would safety wire the switch to on.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.