Narrative:

Had seen and just finished visually tracking other opposing traffic +2000 ft, 3-4 mi right off course. WX: dark, clear at altitude, low undercast. Over japan, cleared direct abets (from approximately lanat) at FL310. Radar contact with tokyo control on 124.1 heading ~110 magnetic. Saw TCAS symbol co-altitude approximately 11:30 O'clock 20 NM. Just before symbol turned yellow, tokyo called right turn to 180 degree, followed ~10 seconds later by 2 calls to turn left to 360 degrees heading. Captain (PF) responded with heading select, now approximately 12 NM separation. I saw other aircraft landing lights and turned ours on. About same time as second 360 degree heading call, got TCAS RA and climb annunciation. Captain disconnected autoplt and responded. We passed almost directly overhead other aircraft at ~31, 800 ft. When I reported 'climbing for TCAS RA' to tokyo, he cleared us to FL330. After we reported clear of traffic, he cleared us to maintain FL330. There was no radio conversation at all with the other airplane on our frequency, and no comments by way of explanation from tokyo after we called clear of the traffic. Other aircraft did not appear to maneuver at all. In the few seconds from TA to RA, we didn't have time to analyze lateral angle rates, and decide whether to disregard the turn reversal to the left (though it was tempting). We also didn't try to second guess the other airplane's next move (if any). I think we were waiting/hoping for those 3-5 seconds that the TCAS would tell us what to do, since we weren't at all confident of the controller's situational awareness when we called the turn reversal, but we had no better option at the time! In retrospect, we would have probably cleared him by a few hundred feet laterally if we had done nothing, more if we had continued the turn to 180 degrees, and hit him in the left turn to 360 degrees if we hadn't climbed. Don't know what restrictions or results would have been if we had no TCAS, I tend to think I would have tried a pushover when he got close, since we had little climb performance (comparatively speaking).

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Original NASA ASRS Text

Title: LOSS OF SEPARATION OCCURRED WHEN A U.S. B747 IN FOREIGN AIRSPACE AT FL310 RECEIVED A TCAS RA ALERT TO CLB. FLT WAS IN CONTACT WITH TOKYO CTL AT THE TIME.

Narrative: HAD SEEN AND JUST FINISHED VISUALLY TRACKING OTHER OPPOSING TFC +2000 FT, 3-4 MI RIGHT OFF COURSE. WX: DARK, CLEAR AT ALT, LOW UNDERCAST. OVER JAPAN, CLEARED DIRECT ABETS (FROM APPROX LANAT) AT FL310. RADAR CONTACT WITH TOKYO CTL ON 124.1 HDG ~110 MAG. SAW TCAS SYMBOL CO-ALT APPROX 11:30 O'CLOCK 20 NM. JUST BEFORE SYMBOL TURNED YELLOW, TOKYO CALLED R TURN TO 180 DEG, FOLLOWED ~10 SECONDS LATER BY 2 CALLS TO TURN L TO 360 DEGS HDG. CAPT (PF) RESPONDED WITH HDG SELECT, NOW APPROX 12 NM SEPARATION. I SAW OTHER ACFT LNDG LIGHTS AND TURNED OURS ON. ABOUT SAME TIME AS SECOND 360 DEG HDG CALL, GOT TCAS RA AND CLB ANNUNCIATION. CAPT DISCONNECTED AUTOPLT AND RESPONDED. WE PASSED ALMOST DIRECTLY OVERHEAD OTHER ACFT AT ~31, 800 FT. WHEN I RPTED 'CLBING FOR TCAS RA' TO TOKYO, HE CLRED US TO FL330. AFTER WE RPTED CLR OF TFC, HE CLRED US TO MAINTAIN FL330. THERE WAS NO RADIO CONVERSATION AT ALL WITH THE OTHER AIRPLANE ON OUR FREQ, AND NO COMMENTS BY WAY OF EXPLANATION FROM TOKYO AFTER WE CALLED CLEAR OF THE TFC. OTHER ACFT DID NOT APPEAR TO MANEUVER AT ALL. IN THE FEW SECONDS FROM TA TO RA, WE DIDN'T HAVE TIME TO ANALYZE LATERAL ANGLE RATES, AND DECIDE WHETHER TO DISREGARD THE TURN REVERSAL TO THE LEFT (THOUGH IT WAS TEMPTING). WE ALSO DIDN'T TRY TO SECOND GUESS THE OTHER AIRPLANE'S NEXT MOVE (IF ANY). I THINK WE WERE WAITING/HOPING FOR THOSE 3-5 SECONDS THAT THE TCAS WOULD TELL US WHAT TO DO, SINCE WE WEREN'T AT ALL CONFIDENT OF THE CTLR'S SITUATIONAL AWARENESS WHEN WE CALLED THE TURN REVERSAL, BUT WE HAD NO BETTER OPTION AT THE TIME! IN RETROSPECT, WE WOULD HAVE PROBABLY CLRED HIM BY A FEW HUNDRED FEET LATERALLY IF WE HAD DONE NOTHING, MORE IF WE HAD CONTINUED THE TURN TO 180 DEGS, AND HIT HIM IN THE L TURN TO 360 DEGS IF WE HADN'T CLBED. DON'T KNOW WHAT RESTRICTIONS OR RESULTS WOULD HAVE BEEN IF WE HAD NO TCAS, I TEND TO THINK I WOULD HAVE TRIED A PUSHOVER WHEN HE GOT CLOSE, SINCE WE HAD LITTLE CLB PERFORMANCE (COMPARATIVELY SPEAKING).

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.