Narrative:

Cruising at FL280, talking to ZME (frequency 132.42, sector 21). Requested climb to FL350. Center cleared me to FL310. During climb, at approximately FL300, center asked us to 'descend to FL280, hurry down.' we began to descend, and received a TCASII RA to descend. We followed the RA, then visually acquired the other aircraft, which appeared to be at FL290. I hesitated to continue following the RA, as it appeared I would descend through the intruder's altitude at possibly very close range. As the distance/motion situation evolved, it appeared that the RA descent could be completed safely, and we expedited descent through FL290 to FL280. Intruder passed 1000 ft overhead, at approximately 1/2 mi lateral separation. Intruder asked ATC to verify 'cleared to FL310.' during descent, reached FL277 until 'clear of conflict' announced, then maintained FL280. My hesitation during the descent stems from a reluctance to descend through the altitude of a visually acquired aircraft in close proximity. If in fact the intruder was level at FL290, and hadn't started to climb to FL310, it seemed an unnecessary risk to descend through his altitude, rather than continue our climb through FL300 to FL310. The lesson here for me is that the TCASII guidance is invaluable, but is complicated when visual acquisition appears to conflict with TCASII guidance. Supplemental information from acn 436803: ATC provided inaccurate phone number to contact -- unable to determine fault or mistake. Another company flight requested confirmation that it was cleared to FL310.

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Original NASA ASRS Text

Title: AN ACR ACFT IS TOLD TO HURRY BACK DOWN TO FL280 WHEN AT FL300 CLBING DUE TO TFC AT FL290, OPPOSITE DIRECTION TFC.

Narrative: CRUISING AT FL280, TALKING TO ZME (FREQ 132.42, SECTOR 21). REQUESTED CLB TO FL350. CTR CLRED ME TO FL310. DURING CLB, AT APPROX FL300, CTR ASKED US TO 'DSND TO FL280, HURRY DOWN.' WE BEGAN TO DSND, AND RECEIVED A TCASII RA TO DSND. WE FOLLOWED THE RA, THEN VISUALLY ACQUIRED THE OTHER ACFT, WHICH APPEARED TO BE AT FL290. I HESITATED TO CONTINUE FOLLOWING THE RA, AS IT APPEARED I WOULD DSND THROUGH THE INTRUDER'S ALT AT POSSIBLY VERY CLOSE RANGE. AS THE DISTANCE/MOTION SIT EVOLVED, IT APPEARED THAT THE RA DSCNT COULD BE COMPLETED SAFELY, AND WE EXPEDITED DSCNT THROUGH FL290 TO FL280. INTRUDER PASSED 1000 FT OVERHEAD, AT APPROX 1/2 MI LATERAL SEPARATION. INTRUDER ASKED ATC TO VERIFY 'CLRED TO FL310.' DURING DSCNT, REACHED FL277 UNTIL 'CLR OF CONFLICT' ANNOUNCED, THEN MAINTAINED FL280. MY HESITATION DURING THE DSCNT STEMS FROM A RELUCTANCE TO DSND THROUGH THE ALT OF A VISUALLY ACQUIRED ACFT IN CLOSE PROX. IF IN FACT THE INTRUDER WAS LEVEL AT FL290, AND HADN'T STARTED TO CLB TO FL310, IT SEEMED AN UNNECESSARY RISK TO DSND THROUGH HIS ALT, RATHER THAN CONTINUE OUR CLB THROUGH FL300 TO FL310. THE LESSON HERE FOR ME IS THAT THE TCASII GUIDANCE IS INVALUABLE, BUT IS COMPLICATED WHEN VISUAL ACQUISITION APPEARS TO CONFLICT WITH TCASII GUIDANCE. SUPPLEMENTAL INFO FROM ACN 436803: ATC PROVIDED INACCURATE PHONE NUMBER TO CONTACT -- UNABLE TO DETERMINE FAULT OR MISTAKE. ANOTHER COMPANY FLT REQUESTED CONFIRMATION THAT IT WAS CLRED TO FL310.

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.