Narrative:

We were at 5000 ft and an assigned heading. The TCASII went off alerting us of traffic at our 10 O'clock position. About the same time, ATC called about the traffic. He was about 500 ft above us and 2 NM away. I looked up and spotted a small metallic balloon. I focused on the balloon and did not spot the traffic. My first officer said he had the traffic in sight. ATC was asking if we had the traffic. I was hesitant about calling out the traffic because I did not see him. Finally, the TCASII told us to descend and at the same time ATC was telling to turn to a heading that would parallel the traffic. I said we had the traffic and started to climb. I told ATC we were climbing to avoid the conflict. We then climbed up to 5500 ft. During this period, the traffic started to descend to our assigned altitude. I momentarily caught a glimpse of the traffic as he was passing our nose. My first officer saw the aircraft descending visually and had started to climb before the TCASII told us to descend. We then deviated from our assigned altitude of 5000 ft MSL up to 5500 ft MSL to avoid the conflict.the other aircraft did level-off at 5000 ft MSL. Because we were in the climb, my first officer decided that it would not be a good idea to descend. Also, when ATC gave us a heading, turning would have put us belly-up to the aircraft and we would have lost it visually. Plus, the aircraft was within a mi of us by then, and we would not have been able to turn in time to avoid the conflict. The other aircraft was a mooney, and we did not get an ample warning from ATC or the TCASII to avoid the situation entirely.

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Original NASA ASRS Text

Title: MDT HAS TCASII RA AND VECTOR FROM CTLR, DOES NOT COMPLY WITH EITHER.

Narrative: WE WERE AT 5000 FT AND AN ASSIGNED HDG. THE TCASII WENT OFF ALERTING US OF TFC AT OUR 10 O'CLOCK POS. ABOUT THE SAME TIME, ATC CALLED ABOUT THE TFC. HE WAS ABOUT 500 FT ABOVE US AND 2 NM AWAY. I LOOKED UP AND SPOTTED A SMALL METALLIC BALLOON. I FOCUSED ON THE BALLOON AND DID NOT SPOT THE TFC. MY FO SAID HE HAD THE TFC IN SIGHT. ATC WAS ASKING IF WE HAD THE TFC. I WAS HESITANT ABOUT CALLING OUT THE TFC BECAUSE I DID NOT SEE HIM. FINALLY, THE TCASII TOLD US TO DSND AND AT THE SAME TIME ATC WAS TELLING TO TURN TO A HDG THAT WOULD PARALLEL THE TFC. I SAID WE HAD THE TFC AND STARTED TO CLB. I TOLD ATC WE WERE CLBING TO AVOID THE CONFLICT. WE THEN CLBED UP TO 5500 FT. DURING THIS PERIOD, THE TFC STARTED TO DSND TO OUR ASSIGNED ALT. I MOMENTARILY CAUGHT A GLIMPSE OF THE TFC AS HE WAS PASSING OUR NOSE. MY FO SAW THE ACFT DSNDING VISUALLY AND HAD STARTED TO CLB BEFORE THE TCASII TOLD US TO DSND. WE THEN DEVIATED FROM OUR ASSIGNED ALT OF 5000 FT MSL UP TO 5500 FT MSL TO AVOID THE CONFLICT.THE OTHER ACFT DID LEVEL-OFF AT 5000 FT MSL. BECAUSE WE WERE IN THE CLB, MY FO DECIDED THAT IT WOULD NOT BE A GOOD IDEA TO DSND. ALSO, WHEN ATC GAVE US A HDG, TURNING WOULD HAVE PUT US BELLY-UP TO THE ACFT AND WE WOULD HAVE LOST IT VISUALLY. PLUS, THE ACFT WAS WITHIN A MI OF US BY THEN, AND WE WOULD NOT HAVE BEEN ABLE TO TURN IN TIME TO AVOID THE CONFLICT. THE OTHER ACFT WAS A MOONEY, AND WE DID NOT GET AN AMPLE WARNING FROM ATC OR THE TCASII TO AVOID THE SIT ENTIRELY.

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.