Narrative:

We had been cleared to FL280 several mins before. We were vectored off the jetway about 30 degrees right for our descent. We noticed, on our TCASII display, that there was an aircraft climbing up directly below us, and that his target was amber (a TA). At this moment the center controller handed us off to another sector. We tuned the new frequency, but before we could check in, we received a TCASII RA requiring us to climb. The first officer was flying and he asked me if I wanted him to follow the TCASII commands. I responded affirmative, and we started to climb. I called the new frequency stating that we were following a TCASII RA out of FL280, but received no answer. The TCASII had commanded a climb in excess of 3000 FPM, so it only took a few seconds until we passed FL290. At this point, another aircraft target appeared directly above us at FL310. Seeing that we were about to tangle with a second airplane, I instructed the first officer to stop his climb. It is important to note that TCASII was still calling for us to climb at this point. We topped out at FL295 and started back down. I now succeeded in contacting center and advised him of our situation. The aircraft below us had stopped his climb at FL270, and we were able to return to FL280. This incident is a classic chain of events. Had the second aircraft not been directly below us, or had he not been climbing at such a high rate, no problem. Had the third aircraft not been directly above us, no problem. Had we not been vectored off of J75, no problem. Had we been just 1 min earlier or later, no problem. If we hadn't been handed off at the precise moment that we were, we could have coordinated our avoidance maneuver with ATC. This incident also points out what I consider to be a major shortcoming of the present TCASII. The aircraft below us was only cleared to FL270. It is not unusual for targets climbing from below to be amber until they level off. However, this target was climbing so rapidly to altitude that they caused our TCASII to issue evasive action when they were still well below us. How far below? Good question. I don't know because the data block showing their distance below us was obscured by the symbol for our airplane on my navigation display. When the third airplane symbol appeared directly above, it blended with the other 2 making it impossible to tell exactly who was there. Which bring up another point. Since our TCASII only displays targets within 2000 ft vertically, we had no way of knowing the third aircraft was up there until we passed FL290. At that point, we had already violated the 200 ft vertical separation requirement, which just happens to start at FL290 (another link in the chain!). In conclusion, I don't see any way that we could have avoided this incident. We were compelled by far to honor the TCASII RA. Given the current state of TCASII technology, we could not have known that the other aircraft would level off below us. The controller did not mention his cleared altitude to us. Nor did ATC mention the other aircraft above us. And which controller was responsible for communicating that to us? Neither one I would imagine. In any event, it would have made no difference. We had to follow the RA.

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Original NASA ASRS Text

Title: ACR FLC RESPONDS TO TCASII RA, THEN ENCOUNTERS A SECOND ACFT DURING EVASIVE MANEUVER IN ZDC AIRSPACE.

Narrative: WE HAD BEEN CLRED TO FL280 SEVERAL MINS BEFORE. WE WERE VECTORED OFF THE JETWAY ABOUT 30 DEGS R FOR OUR DSCNT. WE NOTICED, ON OUR TCASII DISPLAY, THAT THERE WAS AN ACFT CLBING UP DIRECTLY BELOW US, AND THAT HIS TARGET WAS AMBER (A TA). AT THIS MOMENT THE CTR CTLR HANDED US OFF TO ANOTHER SECTOR. WE TUNED THE NEW FREQ, BUT BEFORE WE COULD CHK IN, WE RECEIVED A TCASII RA REQUIRING US TO CLB. THE FO WAS FLYING AND HE ASKED ME IF I WANTED HIM TO FOLLOW THE TCASII COMMANDS. I RESPONDED AFFIRMATIVE, AND WE STARTED TO CLB. I CALLED THE NEW FREQ STATING THAT WE WERE FOLLOWING A TCASII RA OUT OF FL280, BUT RECEIVED NO ANSWER. THE TCASII HAD COMMANDED A CLB IN EXCESS OF 3000 FPM, SO IT ONLY TOOK A FEW SECONDS UNTIL WE PASSED FL290. AT THIS POINT, ANOTHER ACFT TARGET APPEARED DIRECTLY ABOVE US AT FL310. SEEING THAT WE WERE ABOUT TO TANGLE WITH A SECOND AIRPLANE, I INSTRUCTED THE FO TO STOP HIS CLB. IT IS IMPORTANT TO NOTE THAT TCASII WAS STILL CALLING FOR US TO CLB AT THIS POINT. WE TOPPED OUT AT FL295 AND STARTED BACK DOWN. I NOW SUCCEEDED IN CONTACTING CTR AND ADVISED HIM OF OUR SIT. THE ACFT BELOW US HAD STOPPED HIS CLB AT FL270, AND WE WERE ABLE TO RETURN TO FL280. THIS INCIDENT IS A CLASSIC CHAIN OF EVENTS. HAD THE SECOND ACFT NOT BEEN DIRECTLY BELOW US, OR HAD HE NOT BEEN CLBING AT SUCH A HIGH RATE, NO PROB. HAD THE THIRD ACFT NOT BEEN DIRECTLY ABOVE US, NO PROB. HAD WE NOT BEEN VECTORED OFF OF J75, NO PROB. HAD WE BEEN JUST 1 MIN EARLIER OR LATER, NO PROB. IF WE HADN'T BEEN HANDED OFF AT THE PRECISE MOMENT THAT WE WERE, WE COULD HAVE COORDINATED OUR AVOIDANCE MANEUVER WITH ATC. THIS INCIDENT ALSO POINTS OUT WHAT I CONSIDER TO BE A MAJOR SHORTCOMING OF THE PRESENT TCASII. THE ACFT BELOW US WAS ONLY CLRED TO FL270. IT IS NOT UNUSUAL FOR TARGETS CLBING FROM BELOW TO BE AMBER UNTIL THEY LEVEL OFF. HOWEVER, THIS TARGET WAS CLBING SO RAPIDLY TO ALT THAT THEY CAUSED OUR TCASII TO ISSUE EVASIVE ACTION WHEN THEY WERE STILL WELL BELOW US. HOW FAR BELOW? GOOD QUESTION. I DON'T KNOW BECAUSE THE DATA BLOCK SHOWING THEIR DISTANCE BELOW US WAS OBSCURED BY THE SYMBOL FOR OUR AIRPLANE ON MY NAV DISPLAY. WHEN THE THIRD AIRPLANE SYMBOL APPEARED DIRECTLY ABOVE, IT BLENDED WITH THE OTHER 2 MAKING IT IMPOSSIBLE TO TELL EXACTLY WHO WAS THERE. WHICH BRING UP ANOTHER POINT. SINCE OUR TCASII ONLY DISPLAYS TARGETS WITHIN 2000 FT VERTLY, WE HAD NO WAY OF KNOWING THE THIRD ACFT WAS UP THERE UNTIL WE PASSED FL290. AT THAT POINT, WE HAD ALREADY VIOLATED THE 200 FT VERT SEPARATION REQUIREMENT, WHICH JUST HAPPENS TO START AT FL290 (ANOTHER LINK IN THE CHAIN!). IN CONCLUSION, I DON'T SEE ANY WAY THAT WE COULD HAVE AVOIDED THIS INCIDENT. WE WERE COMPELLED BY FAR TO HONOR THE TCASII RA. GIVEN THE CURRENT STATE OF TCASII TECHNOLOGY, WE COULD NOT HAVE KNOWN THAT THE OTHER ACFT WOULD LEVEL OFF BELOW US. THE CTLR DID NOT MENTION HIS CLRED ALT TO US. NOR DID ATC MENTION THE OTHER ACFT ABOVE US. AND WHICH CTLR WAS RESPONSIBLE FOR COMMUNICATING THAT TO US? NEITHER ONE I WOULD IMAGINE. IN ANY EVENT, IT WOULD HAVE MADE NO DIFFERENCE. WE HAD TO FOLLOW THE RA.

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.