Narrative:

We were descending for landing at narita, japan. Our original clearance was to an altitude of 10000' on a heading of 350 degrees. As we were descending through approximately 11700', the female controller told us to level at 11000' and issued a traffic advisory for a foreign air carrier widebody transport climbing to '9000'.' we acknowledged sighting the aircraft, and were then issued a heading of 060 degrees. Shortly thereafter, we were given 090 degrees in an apparent attempt to provide latitude sep. We were now flying away from the airport. We wondered why, as the widebody transport Z was supposed to be at 9000'. It appeared that widebody transport Z was at or very near our altitude (11000'). His position was at our 9:30 range, approximately 2 mi. My crew agreed that a descent was necessary in order to avoid the widebody transport Z. I exercised my emergency authority and descended to approximately 10600'. The widebody transport Z passed directly over us, approximately 400' above. It would have been a direct hit. A male approach controller then gave us a turn back toward the airport. When asked about the widebody transport Z's altitude, a female voice answered '9000'.' we questioned that with the response 'anyway, descend to 6000'.'

Related reports:

Google
 

Original NASA ASRS Text

Title: CLOSE PROX 2 ACR WDB'S OPPOSITE DIRECTION ARR DEP NRT.

Narrative: WE WERE DSNDING FOR LNDG AT NARITA, JAPAN. OUR ORIGINAL CLRNC WAS TO AN ALT OF 10000' ON A HDG OF 350 DEGS. AS WE WERE DSNDING THROUGH APPROX 11700', THE FEMALE CTLR TOLD US TO LEVEL AT 11000' AND ISSUED A TFC ADVISORY FOR A FOREIGN ACR WDB CLBING TO '9000'.' WE ACKNOWLEDGED SIGHTING THE ACFT, AND WERE THEN ISSUED A HDG OF 060 DEGS. SHORTLY THEREAFTER, WE WERE GIVEN 090 DEGS IN AN APPARENT ATTEMPT TO PROVIDE LAT SEP. WE WERE NOW FLYING AWAY FROM THE ARPT. WE WONDERED WHY, AS THE WDB Z WAS SUPPOSED TO BE AT 9000'. IT APPEARED THAT WDB Z WAS AT OR VERY NEAR OUR ALT (11000'). HIS POS WAS AT OUR 9:30 RANGE, APPROX 2 MI. MY CREW AGREED THAT A DSCNT WAS NECESSARY IN ORDER TO AVOID THE WDB Z. I EXERCISED MY EMER AUTHORITY AND DSNDED TO APPROX 10600'. THE WDB Z PASSED DIRECTLY OVER US, APPROX 400' ABOVE. IT WOULD HAVE BEEN A DIRECT HIT. A MALE APCH CTLR THEN GAVE US A TURN BACK TOWARD THE ARPT. WHEN ASKED ABOUT THE WDB Z'S ALT, A FEMALE VOICE ANSWERED '9000'.' WE QUESTIONED THAT WITH THE RESPONSE 'ANYWAY, DSND TO 6000'.'

Data retrieved from NASA's ASRS site as of August 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.