Narrative:

Climbing out of ord, we were cleared to FL290. I (first officer) was hand flying the aircraft. Approaching FL280 we noticed a target on TCASII at FL280, 10 O'clock, about 6 mi and closing, followed shortly by a TCASII TA. At approximately FL282, chicago center called the traffic and directed a turn from 170 degrees to 260 degrees and 'expedite climb.' at the same time TCASII directed an RA descent at 2000 ft FPM. At this point the captain picked up the traffic visually and I elected to continue the climb, as we were already above the target (an large transport) the target did not appear to maneuver in altitude and the estimated miss distance (from TCASII) was about 1-2 NM horizontally. Later conversation with the controller revealed his radar showed a 4 NM miss. Not a reliable estimate, due to inherent inaccuracies in ATC radar. The point of this report is to bring to light the problems of TCASII directing 1 maneuver and the controller calling for the opposite. In this case I believe we made the proper decision, but all factors need to be considered. The target aircraft was not TCASII equipped. Had he been, the result might have been more exciting. Bottom line: TCASII may be a tool, but it is no substitute for human judgement! Supplemental information from acn 241826: air carrier X given an assigned heading for climb to FL280. Shortly after takeoff given direct bvt. After turning over bvt to fly the bvt 287 degree radial, I noted air carrier X in a hard right turn at approximately 2-3 NM. Check with company radio revealed that air carrier X had received a TCASII RA and took evasive action to preclude a near miss. We took no evasive action as we saw air carrier X after he had commenced his evasive maneuver and no threat existed to us. Our aircraft was not TCASII equipped and we received no advisory from ZID that air carrier X was in our vicinity. Although it is probable we would have seen each other visually, air carrier X TCASII RA kept an exciting situation from becoming a dangerous one as both aircraft were at FL280. Do not know why both aircraft were at FL280 on converging headings. We know of no crew omissions.

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Original NASA ASRS Text

Title: ACR X TCASII TA RA DSND NON COMPLIANCE WITH TCASII RA HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: CLBING OUT OF ORD, WE WERE CLRED TO FL290. I (FO) WAS HAND FLYING THE ACFT. APCHING FL280 WE NOTICED A TARGET ON TCASII AT FL280, 10 O'CLOCK, ABOUT 6 MI AND CLOSING, FOLLOWED SHORTLY BY A TCASII TA. AT APPROX FL282, CHICAGO CTR CALLED THE TFC AND DIRECTED A TURN FROM 170 DEGS TO 260 DEGS AND 'EXPEDITE CLB.' AT THE SAME TIME TCASII DIRECTED AN RA DSCNT AT 2000 FT FPM. AT THIS POINT THE CAPT PICKED UP THE TFC VISUALLY AND I ELECTED TO CONTINUE THE CLB, AS WE WERE ALREADY ABOVE THE TARGET (AN LGT) THE TARGET DID NOT APPEAR TO MANEUVER IN ALT AND THE ESTIMATED MISS DISTANCE (FROM TCASII) WAS ABOUT 1-2 NM HORIZLY. LATER CONVERSATION WITH THE CTLR REVEALED HIS RADAR SHOWED A 4 NM MISS. NOT A RELIABLE ESTIMATE, DUE TO INHERENT INACCURACIES IN ATC RADAR. THE POINT OF THIS RPT IS TO BRING TO LIGHT THE PROBS OF TCASII DIRECTING 1 MANEUVER AND THE CTLR CALLING FOR THE OPPOSITE. IN THIS CASE I BELIEVE WE MADE THE PROPER DECISION, BUT ALL FACTORS NEED TO BE CONSIDERED. THE TARGET ACFT WAS NOT TCASII EQUIPPED. HAD HE BEEN, THE RESULT MIGHT HAVE BEEN MORE EXCITING. BOTTOM LINE: TCASII MAY BE A TOOL, BUT IT IS NO SUBSTITUTE FOR HUMAN JUDGEMENT! SUPPLEMENTAL INFO FROM ACN 241826: ACR X GIVEN AN ASSIGNED HDG FOR CLB TO FL280. SHORTLY AFTER TKOF GIVEN DIRECT BVT. AFTER TURNING OVER BVT TO FLY THE BVT 287 DEG RADIAL, I NOTED ACR X IN A HARD R TURN AT APPROX 2-3 NM. CHK WITH COMPANY RADIO REVEALED THAT ACR X HAD RECEIVED A TCASII RA AND TOOK EVASIVE ACTION TO PRECLUDE A NEAR MISS. WE TOOK NO EVASIVE ACTION AS WE SAW ACR X AFTER HE HAD COMMENCED HIS EVASIVE MANEUVER AND NO THREAT EXISTED TO US. OUR ACFT WAS NOT TCASII EQUIPPED AND WE RECEIVED NO ADVISORY FROM ZID THAT ACR X WAS IN OUR VICINITY. ALTHOUGH IT IS PROBABLE WE WOULD HAVE SEEN EACH OTHER VISUALLY, ACR X TCASII RA KEPT AN EXCITING SIT FROM BECOMING A DANGEROUS ONE AS BOTH ACFT WERE AT FL280. DO NOT KNOW WHY BOTH ACFT WERE AT FL280 ON CONVERGING HDGS. WE KNOW OF NO CREW OMISSIONS.

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.