Narrative:

Departure control reported traffic 1 O'clock. We were cleared to FL210 on departure from dfw (dallas 9). Looked at TCASII -- confirmed aircraft position 1 O'clock and above us. We were approximately FL195. We received TCASII alert 'traffic.' controller called traffic again and repeated altitude limit of FL210. We then received RA from TCASII of 3000 FPM up. I responded to TCASII as required, while IMC. Slowed climb approaching FL210 and TCASII gave audio 'monitor vertical speed' all lights red. I increased rate of climb to put vsi out red in excess of 4000 FPM, as red DOT on TCASII and TCASII aircraft symbol merged at 00 ft indicated. Our climb topped out at FL223 with 'clear of conflict.' we returned to FL210 assigned. We told center we were responding to TCASII RA at the beginning and end of the deviation. I believe the incident was created by the TCASII not having altitude limit information with respect to our level off. Until this information is added to the software, this can occur when 2 aircraft are passing the same vertical shaft of airspace when their respective rates of climb and descent command an RA. The immediate resolution is for center to give both aircraft horizontal separation under the above conditions. Supplemental information from acn 272280: very frightening experience. Apparently, the TCASII calculated the traffic conflict based on our rate of climb, and not knowing that we were going to level at FL210. I do not know what the opposing aircraft was doing. It would be a great feature for TCASII if pilots cold communication in some way to the TCASII computer that we intend to level off. This is especially important for sits such as this in which the opposing aircraft are changing altitudes as they approach one another. Over the last few yrs of TCASII experience, I have become a great fan of TCASII. I have received numerous TA's, most of the time in clear air. This incident was my first RA. It certainly erodes confidence in the TCASII, but I do not know what the opposing aircraft was doing.

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Original NASA ASRS Text

Title: ALT BUST.

Narrative: DEP CTL RPTED TFC 1 O'CLOCK. WE WERE CLRED TO FL210 ON DEP FROM DFW (DALLAS 9). LOOKED AT TCASII -- CONFIRMED ACFT POS 1 O'CLOCK AND ABOVE US. WE WERE APPROX FL195. WE RECEIVED TCASII ALERT 'TFC.' CTLR CALLED TFC AGAIN AND REPEATED ALT LIMIT OF FL210. WE THEN RECEIVED RA FROM TCASII OF 3000 FPM UP. I RESPONDED TO TCASII AS REQUIRED, WHILE IMC. SLOWED CLB APCHING FL210 AND TCASII GAVE AUDIO 'MONITOR VERT SPD' ALL LIGHTS RED. I INCREASED RATE OF CLB TO PUT VSI OUT RED IN EXCESS OF 4000 FPM, AS RED DOT ON TCASII AND TCASII ACFT SYMBOL MERGED AT 00 FT INDICATED. OUR CLB TOPPED OUT AT FL223 WITH 'CLR OF CONFLICT.' WE RETURNED TO FL210 ASSIGNED. WE TOLD CTR WE WERE RESPONDING TO TCASII RA AT THE BEGINNING AND END OF THE DEV. I BELIEVE THE INCIDENT WAS CREATED BY THE TCASII NOT HAVING ALT LIMIT INFO WITH RESPECT TO OUR LEVEL OFF. UNTIL THIS INFO IS ADDED TO THE SOFTWARE, THIS CAN OCCUR WHEN 2 ACFT ARE PASSING THE SAME VERT SHAFT OF AIRSPACE WHEN THEIR RESPECTIVE RATES OF CLB AND DSCNT COMMAND AN RA. THE IMMEDIATE RESOLUTION IS FOR CTR TO GIVE BOTH ACFT HORIZ SEPARATION UNDER THE ABOVE CONDITIONS. SUPPLEMENTAL INFO FROM ACN 272280: VERY FRIGHTENING EXPERIENCE. APPARENTLY, THE TCASII CALCULATED THE TFC CONFLICT BASED ON OUR RATE OF CLB, AND NOT KNOWING THAT WE WERE GOING TO LEVEL AT FL210. I DO NOT KNOW WHAT THE OPPOSING ACFT WAS DOING. IT WOULD BE A GREAT FEATURE FOR TCASII IF PLTS COLD COM IN SOME WAY TO THE TCASII COMPUTER THAT WE INTEND TO LEVEL OFF. THIS IS ESPECIALLY IMPORTANT FOR SITS SUCH AS THIS IN WHICH THE OPPOSING ACFT ARE CHANGING ALTS AS THEY APCH ONE ANOTHER. OVER THE LAST FEW YRS OF TCASII EXPERIENCE, I HAVE BECOME A GREAT FAN OF TCASII. I HAVE RECEIVED NUMEROUS TA'S, MOST OF THE TIME IN CLR AIR. THIS INCIDENT WAS MY FIRST RA. IT CERTAINLY ERODES CONFIDENCE IN THE TCASII, BUT I DO NOT KNOW WHAT THE OPPOSING ACFT WAS DOING.

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.