Narrative:

We were wbound at FL380 (copilot at controls). In continuous light chop we requested a lower altitude from ZAB; and were cleared to descend to FL360. I observed a TCASII traffic target on my navigation display 10 NM in front of us; and 1000 ft below us. Initially; I thought the traffic was probably wbound also because normally 1) center won't allow descent through oncoming traffic; and 2) center allows descent through same direction traffic only with greater than or equal to 10 NM separation. My navigation display was in 160 NM range. Had I been in a shorter range; the closure of the oncoming traffic would have been more immediately apparent; and we probably wouldn't have descended. When I selected a shorter range on my navigation display; I saw apparent closure. I immediately told the copilot; 'level off!' at the same time I looked out the wind screen and saw the oncoming traffic directly in front and below us. We had descended approximately 200-300 ft. The copilot had grabbed the yoke to pull back (the autoplt was on) and right after I had said 'level off' we got a TCASII RA followed immediately by an RA commanding us to 'climb; climb.' the copilot disconnected the autoplt in accordance with RA procedure and climbed until the RA ceased at approximately FL384. After we were stabilized; I told the controller about the RA. She said somehow she had lost the traffic at FL370 before clearing us to descend. The MD10 had already switched to ZKC and his data block apparently had been dropped from the abq scopes. Lessons for me: clearing the flight path is paramount for safe rvsm operations! Closure may not be perceptible from TCASII with high ranges selected on navigation display. Situational awareness; visual lookout; and TCASII saved us from a certain collision. Center handoff glitches?

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Original NASA ASRS Text

Title: ZAB CTLR EXPERIENCED NEAR LOSS OF SEPARATION AT FL370; SAVED BY TCASII; AFTER HDOF OF CONFLICTING TFC TO ANOTHER SECTOR.

Narrative: WE WERE WBOUND AT FL380 (COPLT AT CTLS). IN CONTINUOUS LIGHT CHOP WE REQUESTED A LOWER ALT FROM ZAB; AND WERE CLRED TO DSND TO FL360. I OBSERVED A TCASII TFC TARGET ON MY NAV DISPLAY 10 NM IN FRONT OF US; AND 1000 FT BELOW US. INITIALLY; I THOUGHT THE TFC WAS PROBABLY WBOUND ALSO BECAUSE NORMALLY 1) CTR WON'T ALLOW DSCNT THROUGH ONCOMING TFC; AND 2) CTR ALLOWS DSCNT THROUGH SAME DIRECTION TFC ONLY WITH GREATER THAN OR EQUAL TO 10 NM SEPARATION. MY NAV DISPLAY WAS IN 160 NM RANGE. HAD I BEEN IN A SHORTER RANGE; THE CLOSURE OF THE ONCOMING TFC WOULD HAVE BEEN MORE IMMEDIATELY APPARENT; AND WE PROBABLY WOULDN'T HAVE DSNDED. WHEN I SELECTED A SHORTER RANGE ON MY NAV DISPLAY; I SAW APPARENT CLOSURE. I IMMEDIATELY TOLD THE COPLT; 'LEVEL OFF!' AT THE SAME TIME I LOOKED OUT THE WIND SCREEN AND SAW THE ONCOMING TFC DIRECTLY IN FRONT AND BELOW US. WE HAD DSNDED APPROX 200-300 FT. THE COPLT HAD GRABBED THE YOKE TO PULL BACK (THE AUTOPLT WAS ON) AND RIGHT AFTER I HAD SAID 'LEVEL OFF' WE GOT A TCASII RA FOLLOWED IMMEDIATELY BY AN RA COMMANDING US TO 'CLB; CLB.' THE COPLT DISCONNECTED THE AUTOPLT IN ACCORDANCE WITH RA PROC AND CLBED UNTIL THE RA CEASED AT APPROX FL384. AFTER WE WERE STABILIZED; I TOLD THE CTLR ABOUT THE RA. SHE SAID SOMEHOW SHE HAD LOST THE TFC AT FL370 BEFORE CLRING US TO DSND. THE MD10 HAD ALREADY SWITCHED TO ZKC AND HIS DATA BLOCK APPARENTLY HAD BEEN DROPPED FROM THE ABQ SCOPES. LESSONS FOR ME: CLRING THE FLT PATH IS PARAMOUNT FOR SAFE RVSM OPS! CLOSURE MAY NOT BE PERCEPTIBLE FROM TCASII WITH HIGH RANGES SELECTED ON NAV DISPLAY. SITUATIONAL AWARENESS; VISUAL LOOKOUT; AND TCASII SAVED US FROM A CERTAIN COLLISION. CTR HDOF GLITCHES?

Data retrieved from NASA's ASRS site as of January 2009 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.