Narrative:

Clearance was from FL410 to maintain FL260, cross 20 north of ogd at 17000 ft. The large transport was equipped with TCASII and it was in use. Traffic was observed approaching northbound at approximately 30 NM range on the TCASII. Visual sighting at approximately 10 mi. We continued descent and at 28300 ft, ATC called and advised to 'maintain FL290'. At about this time the 'traffic' call was issued from the TCASII (no RA). The aircraft climbing out passed off our right wing at an estimated 2 mi lateral separation and altitude of 28500 ft. No evasive action was necessary. We did not climb back to FL290 as the traffic was just passing us and the clearance was obviously late in coming. ATC then cleared us to continue on down to 17000 ft. I suspect this incident violated ATC separation standards and in my opinion the instruction to 'maintain FL290' was late in coming. I was not aware of what altitude the northbound aircraft was cleared to. I did not at any time feel that there was any significant threat to safe operation since the traffic was in sight at all times and was also being observed on the TCASII. If anything, this certainly reinforced my belief that TCASII is one of the best safety enhancing items to be put on aircraft since radar.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT LTSS BTWN CLBING DSNDING TFC.

Narrative: CLRNC WAS FROM FL410 TO MAINTAIN FL260, CROSS 20 N OF OGD AT 17000 FT. THE LGT WAS EQUIPPED WITH TCASII AND IT WAS IN USE. TFC WAS OBSERVED APCHING NBOUND AT APPROX 30 NM RANGE ON THE TCASII. VISUAL SIGHTING AT APPROX 10 MI. WE CONTINUED DSCNT AND AT 28300 FT, ATC CALLED AND ADVISED TO 'MAINTAIN FL290'. AT ABOUT THIS TIME THE 'TFC' CALL WAS ISSUED FROM THE TCASII (NO RA). THE ACFT CLBING OUT PASSED OFF OUR R WING AT AN ESTIMATED 2 MI LATERAL SEPARATION AND ALT OF 28500 FT. NO EVASIVE ACTION WAS NECESSARY. WE DID NOT CLB BACK TO FL290 AS THE TFC WAS JUST PASSING US AND THE CLRNC WAS OBVIOUSLY LATE IN COMING. ATC THEN CLRED US TO CONTINUE ON DOWN TO 17000 FT. I SUSPECT THIS INCIDENT VIOLATED ATC SEPARATION STANDARDS AND IN MY OPINION THE INSTRUCTION TO 'MAINTAIN FL290' WAS LATE IN COMING. I WAS NOT AWARE OF WHAT ALT THE NBOUND ACFT WAS CLRED TO. I DID NOT AT ANY TIME FEEL THAT THERE WAS ANY SIGNIFICANT THREAT TO SAFE OP SINCE THE TFC WAS IN SIGHT AT ALL TIMES AND WAS ALSO BEING OBSERVED ON THE TCASII. IF ANYTHING, THIS CERTAINLY REINFORCED MY BELIEF THAT TCASII IS ONE OF THE BEST SAFETY ENHANCING ITEMS TO BE PUT ON ACFT SINCE RADAR.

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.