Narrative:

The problem arose when air carrier X, a B727, was inbound to atlanta on the rome arrival. The second aircraft military Y, an F16, was flying from tys direct VU2 at FL260. Another controller descended Y to FL230. Realizing Y was in conflict with X, that controller climbed Y to FL250. At the same time, I descended X to 130. X acknowledged. Then asked if I had traffic for him. I responded affirmative that traffic was an F-16 and above him. Upon further conversation, X responded to a RA to climb. X went from approximately FL235 up to FL247 (approximately). Y apparently had gone from FL235 to FL250. X said at first, TCASII said to stay level showing target a FL235, then TCASII said to climb. It was a strange situation that TCASII did not interpret the data in the correct manner. Actually advising X to climb into the traffic. X did obtain visual contact of Y flying 'over the top of him. I think that the TCASII did not react quick enough, or was either unable to figure out what Y was doing. Supplemental information from acn 277961: in the vicinity of rmg 285 radial (we had been cleared to deviate) and about 3- NM west of rmg we reached our company descent profile and started down from FL240. We shortly received a 'traffic, traffic' alert from our TCASII and with the traffic altitude showing below us (about FL235) we started to decrease our rate of descent. At approximately FL235 we received a 'climb, climb' command from our TCASII, power was added and a climb was initiated. At about FL245 the first officer and so saw an F-16 pass overhead and to the left of our aircraft. We had not heard any radio xmissions to other aircraft in our vicinity and at no time received any traffic information about the F-16 from ZTL. We told ZTL about what had happened, and that we had responded to a TCASII RA. Atlanta said that the aircraft was at FL250 and later acknowledged a TCASII RA. Quality assurance was called monday and we were told that the F-16 had been on another frequency and under control of another controller. The F-16 had been cleared to FL230. When the controller noticed the conflict (the last transponder altitude recorded for the F-16 was FL250) the f- 16 was instructed to maintain FL250. The F-16 later reported that he had descended as far as FL235 and climbed back to FL250. With the F-16 being a military aircraft and not having TCASII for our TCASII to co-ordinate with, our TCASII could only use his latest transponder altitude received to calculate the best course of action.

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Original NASA ASRS Text

Title: ACR X TCASII RA CLBED INTO AND HAD LTSS FROM MIL Y. SYS ERROR PLTDEV.

Narrative: THE PROB AROSE WHEN ACR X, A B727, WAS INBOUND TO ATLANTA ON THE ROME ARR. THE SECOND ACFT MIL Y, AN F16, WAS FLYING FROM TYS DIRECT VU2 AT FL260. ANOTHER CTLR DSNDED Y TO FL230. REALIZING Y WAS IN CONFLICT WITH X, THAT CTLR CLBED Y TO FL250. AT THE SAME TIME, I DSNDED X TO 130. X ACKNOWLEDGED. THEN ASKED IF I HAD TFC FOR HIM. I RESPONDED AFFIRMATIVE THAT TFC WAS AN F-16 AND ABOVE HIM. UPON FURTHER CONVERSATION, X RESPONDED TO A RA TO CLB. X WENT FROM APPROX FL235 UP TO FL247 (APPROX). Y APPARENTLY HAD GONE FROM FL235 TO FL250. X SAID AT FIRST, TCASII SAID TO STAY LEVEL SHOWING TARGET A FL235, THEN TCASII SAID TO CLB. IT WAS A STRANGE SIT THAT TCASII DID NOT INTERPRET THE DATA IN THE CORRECT MANNER. ACTUALLY ADVISING X TO CLB INTO THE TFC. X DID OBTAIN VISUAL CONTACT OF Y FLYING 'OVER THE TOP OF HIM. I THINK THAT THE TCASII DID NOT REACT QUICK ENOUGH, OR WAS EITHER UNABLE TO FIGURE OUT WHAT Y WAS DOING. SUPPLEMENTAL INFO FROM ACN 277961: IN THE VICINITY OF RMG 285 RADIAL (WE HAD BEEN CLRED TO DEVIATE) AND ABOUT 3- NM W OF RMG WE REACHED OUR COMPANY DSCNT PROFILE AND STARTED DOWN FROM FL240. WE SHORTLY RECEIVED A 'TFC, TFC' ALERT FROM OUR TCASII AND WITH THE TFC ALT SHOWING BELOW US (ABOUT FL235) WE STARTED TO DECREASE OUR RATE OF DSCNT. AT APPROX FL235 WE RECEIVED A 'CLB, CLB' COMMAND FROM OUR TCASII, PWR WAS ADDED AND A CLB WAS INITIATED. AT ABOUT FL245 THE FO AND SO SAW AN F-16 PASS OVERHEAD AND TO THE L OF OUR ACFT. WE HAD NOT HEARD ANY RADIO XMISSIONS TO OTHER ACFT IN OUR VICINITY AND AT NO TIME RECEIVED ANY TFC INFO ABOUT THE F-16 FROM ZTL. WE TOLD ZTL ABOUT WHAT HAD HAPPENED, AND THAT WE HAD RESPONDED TO A TCASII RA. ATLANTA SAID THAT THE ACFT WAS AT FL250 AND LATER ACKNOWLEDGED A TCASII RA. QUALITY ASSURANCE WAS CALLED MONDAY AND WE WERE TOLD THAT THE F-16 HAD BEEN ON ANOTHER FREQ AND UNDER CTL OF ANOTHER CTLR. THE F-16 HAD BEEN CLRED TO FL230. WHEN THE CTLR NOTICED THE CONFLICT (THE LAST XPONDER ALT RECORDED FOR THE F-16 WAS FL250) THE F- 16 WAS INSTRUCTED TO MAINTAIN FL250. THE F-16 LATER RPTED THAT HE HAD DSNDED AS FAR AS FL235 AND CLBED BACK TO FL250. WITH THE F-16 BEING A MIL ACFT AND NOT HAVING TCASII FOR OUR TCASII TO CO-ORDINATE WITH, OUR TCASII COULD ONLY USE HIS LATEST XPONDER ALT RECEIVED TO CALCULATE THE BEST COURSE OF ACTION.

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.