Narrative:

Receiving vectors from ZFW for general sequencing into dfw off of acton 3 arrival. Descent issued by center to FL250 on easterly heading. During descent through FL252 got a 'TA' on TCASII with traffic at 12 O'clock/7 mi and approximately minus 1400 ft in a climb. 'TA' followed by 'RA' calling for a descent. Copilot (PF) called out traffic in sight to crew, and leveled off at assigned altitude (FL250). TCASII issued a second RA -- 'increase descent, increase descent.' PF ignored all TCASII advisories and instructions. Other aircraft was observed in a climbing right turn and eventually passed by 9-10 O'clock, 3- 4 mi and minus 600 ft (from TCASII) (FL244). Center later asked for other aircraft to call ZFW for possible violation. At no time did center call out either aircraft as traffic. Note: other aircraft was climbing to level off at FL240. ATC never called out traffic to either aircraft with opposite direction, head-on vectors with 1 aircraft descending to FL250 and other aircraft climbing to FL240. 'TA' was first indication of possible conflict. Confusion in cockpit as to responsibilities for following 'RA,' with other aircraft in sight. Apparently, other aircraft did not have us in sight and was following his TCASII RA to climb. TCASII apparently assumed a 'crossing climb' situation and attempted to direct aircraft through each other's altitude for resolution, when aircraft would not have crossed normally. TCASII directed 2 instructions which would have caused 2 deviations from assigned altitudes and, in fact, did cause one, and also created a conflict. Center could have avoided confusion by identifying aircraft to each other with altitude assignments. Supplemental information from acn 275507: radar vectored by ZFW for a 'metering delay' into dfw. Since we were not in visual contact with other traffic, TCASII directions were followed and aircraft altitude reached FL244 before the captain located offending traffic above and to our left. ATC had erroneously stated that 'he didn't' know why we got the TCASII alert since both aircraft had been level for some time.' supplemental information from acn 275690: we had been level at 24000 ft for some time and taken several heading changes. ATC came right back and requested that we stop climbing, that we had traffic at 25000 ft. Flight stopped climb at 24500 and returned back to 24000 ft. ATC then said aircraft had been level 25000 ft and that there should not have been TCASII RA. I spoke with the captain of conflicting traffic later on the ground. He informed me that they had descended to 25000 ft at a pretty good rate of descent. Our delay was over 15 mins in various vectors, we should have been put into holding where we all have a good picture where aircraft are! Maybe ATC should have held us on the ground until having a slot without excessive delays into dfw. There is too much traffic in the dfw area to be radar vectoring that many aircraft just to delay for (gate/fix) time in the air.

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Original NASA ASRS Text

Title: TCASII RA SENDS ACR Y A CLB MESSAGE FOR A CLB TOWARDS OCCUPIED ALT. ACR X GETS TCASII RA FOR DSND MESSAGE TOWARDS OCCUPIED ALT. FLC DEV FROM ATC CLRNC.

Narrative: RECEIVING VECTORS FROM ZFW FOR GENERAL SEQUENCING INTO DFW OFF OF ACTON 3 ARR. DSCNT ISSUED BY CTR TO FL250 ON EASTERLY HDG. DURING DSCNT THROUGH FL252 GOT A 'TA' ON TCASII WITH TFC AT 12 O'CLOCK/7 MI AND APPROX MINUS 1400 FT IN A CLB. 'TA' FOLLOWED BY 'RA' CALLING FOR A DSCNT. COPLT (PF) CALLED OUT TFC IN SIGHT TO CREW, AND LEVELED OFF AT ASSIGNED ALT (FL250). TCASII ISSUED A SECOND RA -- 'INCREASE DSCNT, INCREASE DSCNT.' PF IGNORED ALL TCASII ADVISORIES AND INSTRUCTIONS. OTHER ACFT WAS OBSERVED IN A CLBING R TURN AND EVENTUALLY PASSED BY 9-10 O'CLOCK, 3- 4 MI AND MINUS 600 FT (FROM TCASII) (FL244). CTR LATER ASKED FOR OTHER ACFT TO CALL ZFW FOR POSSIBLE VIOLATION. AT NO TIME DID CTR CALL OUT EITHER ACFT AS TFC. NOTE: OTHER ACFT WAS CLBING TO LEVEL OFF AT FL240. ATC NEVER CALLED OUT TFC TO EITHER ACFT WITH OPPOSITE DIRECTION, HEAD-ON VECTORS WITH 1 ACFT DSNDING TO FL250 AND OTHER ACFT CLBING TO FL240. 'TA' WAS FIRST INDICATION OF POSSIBLE CONFLICT. CONFUSION IN COCKPIT AS TO RESPONSIBILITIES FOR FOLLOWING 'RA,' WITH OTHER ACFT IN SIGHT. APPARENTLY, OTHER ACFT DID NOT HAVE US IN SIGHT AND WAS FOLLOWING HIS TCASII RA TO CLB. TCASII APPARENTLY ASSUMED A 'XING CLB' SIT AND ATTEMPTED TO DIRECT ACFT THROUGH EACH OTHER'S ALT FOR RESOLUTION, WHEN ACFT WOULD NOT HAVE CROSSED NORMALLY. TCASII DIRECTED 2 INSTRUCTIONS WHICH WOULD HAVE CAUSED 2 DEVS FROM ASSIGNED ALTS AND, IN FACT, DID CAUSE ONE, AND ALSO CREATED A CONFLICT. CTR COULD HAVE AVOIDED CONFUSION BY IDENTIFYING ACFT TO EACH OTHER WITH ALT ASSIGNMENTS. SUPPLEMENTAL INFO FROM ACN 275507: RADAR VECTORED BY ZFW FOR A 'METERING DELAY' INTO DFW. SINCE WE WERE NOT IN VISUAL CONTACT WITH OTHER TFC, TCASII DIRECTIONS WERE FOLLOWED AND ACFT ALT REACHED FL244 BEFORE THE CAPT LOCATED OFFENDING TFC ABOVE AND TO OUR L. ATC HAD ERRONEOUSLY STATED THAT 'HE DIDN'T' KNOW WHY WE GOT THE TCASII ALERT SINCE BOTH ACFT HAD BEEN LEVEL FOR SOME TIME.' SUPPLEMENTAL INFO FROM ACN 275690: WE HAD BEEN LEVEL AT 24000 FT FOR SOME TIME AND TAKEN SEVERAL HDG CHANGES. ATC CAME RIGHT BACK AND REQUESTED THAT WE STOP CLBING, THAT WE HAD TFC AT 25000 FT. FLT STOPPED CLB AT 24500 AND RETURNED BACK TO 24000 FT. ATC THEN SAID ACFT HAD BEEN LEVEL 25000 FT AND THAT THERE SHOULD NOT HAVE BEEN TCASII RA. I SPOKE WITH THE CAPT OF CONFLICTING TFC LATER ON THE GND. HE INFORMED ME THAT THEY HAD DSNDED TO 25000 FT AT A PRETTY GOOD RATE OF DSCNT. OUR DELAY WAS OVER 15 MINS IN VARIOUS VECTORS, WE SHOULD HAVE BEEN PUT INTO HOLDING WHERE WE ALL HAVE A GOOD PICTURE WHERE ACFT ARE! MAYBE ATC SHOULD HAVE HELD US ON THE GND UNTIL HAVING A SLOT WITHOUT EXCESSIVE DELAYS INTO DFW. THERE IS TOO MUCH TFC IN THE DFW AREA TO BE RADAR VECTORING THAT MANY ACFT JUST TO DELAY FOR (GATE/FIX) TIME IN THE AIR.

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.