Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	166385
Time
Date	199012
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rjaa
State Reference	FO
Altitude	msl bound lower : 36000 msl bound upper : 36000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 4 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : pacific enroute airway : rjtg
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : pacific enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 9200 flight time type : 130
ASRS Report	166385
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X eastbound on R580 at FL360, according to our flight plan. I observed an aircraft at approximately our 12 O'clock position. He turned on his landing lights and I turned on ours. He passed by on our right side and appeared to be very near our altitude, but perhaps a little lower at a range of about 1/2 mi, we estimated. The first officer called ATC and inquired what his altitude was. When we were over oggmu we got a call from ATC. We were told that it was air carrier Y widebody transport that was westbound on R580 at FL360. The controller had tried twice to give us FL370 on clearance delivery, and later the controller had been concerned that we made a crossing restriction, level at FL360 by oatis. That should have made us question clearance.

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: ACR X EBND ON R580 AT FL360, ACCORDING TO OUR FLT PLAN. I OBSERVED AN ACFT AT APPROX OUR 12 O'CLOCK POS. HE TURNED ON HIS LNDG LIGHTS AND I TURNED ON OURS. HE PASSED BY ON OUR RIGHT SIDE AND APPEARED TO BE VERY NEAR OUR ALT, BUT PERHAPS A LITTLE LOWER AT A RANGE OF ABOUT 1/2 MI, WE ESTIMATED. THE F/O CALLED ATC AND INQUIRED WHAT HIS ALT WAS. WHEN WE WERE OVER OGGMU WE GOT A CALL FROM ATC. WE WERE TOLD THAT IT WAS ACR Y WDB THAT WAS WBND ON R580 AT FL360. THE CTLR HAD TRIED TWICE TO GIVE US FL370 ON CLRNC DELIVERY, AND LATER THE CTLR HAD BEEN CONCERNED THAT WE MADE A XING RESTRICTION, LEVEL AT FL360 BY OATIS. THAT SHOULD HAVE MADE US QUESTION CLRNC.

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.