Narrative:

We were IFR descending through 4000 ft to 3000 ft when ATC advised us that we had traffic ('pop-up') climbing out of 3200 ft and to level at 4000 ft. We climbed back to 4000 ft and leveled, and were told to make a turn of 50 degrees to the right to avoid the traffic. As we entered the turn, we got an RA on our TCASII ('climb'). I started a climbing turn and followed the TCASII commands. (We never got a TA first.) when we showed the turn rate and climb ('monitor vertical speed') a second RA appeared to overlay and obscure the first RA. When we looked out the windshield, I observed the first RA traffic approaching at about 300 ft below and 12 O'clock position. Just as the first aircraft started to become obscured by our aircraft's nose, I spotted a second aircraft at 12:30 O'clock position and appeared to be somewhat higher. (Our aircraft was rolling out of a turn and the horizon was obscured. Any bank angle would distort the actual relative position.) unable to positively identify relative altitude and closure rate, I made a split second decision to turn sharply back to the left (in the direction of original track). I was also influenced by the fact that the first aircraft had just disappeared below the nose of our aircraft and was still an RA target on our TCASII. (I was unable to descend). As the second aircraft disappeared below our aircraft, we received a TCASII message 'clear of conflict.' this was clearly a response to the conflict with the first aircraft, and not the second aircraft. Even though the TCASII displayed 2 red RA targets at the same time, it never gave commands to avoid a collision course with the second RA target, or that we were 'clear of (second) conflict.' the controller never advised us of the second aircraft's position or altitude, and by issuing the 50 degree turn to the right he positioned our aircraft directly between 2 aircraft that were converging vertically with us in the middle. I also believe that the turn caused the TCASII to become disoriented horizontally from the 2 targets.

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Original NASA ASRS Text

Title: FLC OF AN LTT WHILE DSNDING WERE REQUESTED BY APCH CTL TO HOLD ALT AND TURN. RIGHT AFTER WHICH THEY TOOK EVASIVE ACTION IN RESPONSE TO A TCASII RA AND THEN SUBSEQUENTLY A SECOND ACTION IN RESPONSE TO A SECOND TCASII RA.

Narrative: WE WERE IFR DSNDING THROUGH 4000 FT TO 3000 FT WHEN ATC ADVISED US THAT WE HAD TFC ('POP-UP') CLBING OUT OF 3200 FT AND TO LEVEL AT 4000 FT. WE CLBED BACK TO 4000 FT AND LEVELED, AND WERE TOLD TO MAKE A TURN OF 50 DEGS TO THE R TO AVOID THE TFC. AS WE ENTERED THE TURN, WE GOT AN RA ON OUR TCASII ('CLB'). I STARTED A CLBING TURN AND FOLLOWED THE TCASII COMMANDS. (WE NEVER GOT A TA FIRST.) WHEN WE SHOWED THE TURN RATE AND CLB ('MONITOR VERT SPD') A SECOND RA APPEARED TO OVERLAY AND OBSCURE THE FIRST RA. WHEN WE LOOKED OUT THE WINDSHIELD, I OBSERVED THE FIRST RA TFC APCHING AT ABOUT 300 FT BELOW AND 12 O'CLOCK POS. JUST AS THE FIRST ACFT STARTED TO BECOME OBSCURED BY OUR ACFT'S NOSE, I SPOTTED A SECOND ACFT AT 12:30 O'CLOCK POS AND APPEARED TO BE SOMEWHAT HIGHER. (OUR ACFT WAS ROLLING OUT OF A TURN AND THE HORIZON WAS OBSCURED. ANY BANK ANGLE WOULD DISTORT THE ACTUAL RELATIVE POS.) UNABLE TO POSITIVELY IDENT RELATIVE ALT AND CLOSURE RATE, I MADE A SPLIT SECOND DECISION TO TURN SHARPLY BACK TO THE L (IN THE DIRECTION OF ORIGINAL TRACK). I WAS ALSO INFLUENCED BY THE FACT THAT THE FIRST ACFT HAD JUST DISAPPEARED BELOW THE NOSE OF OUR ACFT AND WAS STILL AN RA TARGET ON OUR TCASII. (I WAS UNABLE TO DSND). AS THE SECOND ACFT DISAPPEARED BELOW OUR ACFT, WE RECEIVED A TCASII MESSAGE 'CLR OF CONFLICT.' THIS WAS CLRLY A RESPONSE TO THE CONFLICT WITH THE FIRST ACFT, AND NOT THE SECOND ACFT. EVEN THOUGH THE TCASII DISPLAYED 2 RED RA TARGETS AT THE SAME TIME, IT NEVER GAVE COMMANDS TO AVOID A COLLISION COURSE WITH THE SECOND RA TARGET, OR THAT WE WERE 'CLR OF (SECOND) CONFLICT.' THE CTLR NEVER ADVISED US OF THE SECOND ACFT'S POS OR ALT, AND BY ISSUING THE 50 DEG TURN TO THE R HE POSITIONED OUR ACFT DIRECTLY BTWN 2 ACFT THAT WERE CONVERGING VERTLY WITH US IN THE MIDDLE. I ALSO BELIEVE THAT THE TURN CAUSED THE TCASII TO BECOME DISORIENTED HORIZLY FROM THE 2 TARGETS.

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.