Narrative:

Kiak-kden approach den, initial descent clearance was given and acknowledged to FL240 (from FL350). As this happened a lot earlier then normal (180 mi from den), I questioned 'at pilots discretion?'. ARTCC responded 'no now!' 'roger leaving FL350'. As we passed FL260, ARTCC reported traffic 'small transport, 12 O'clock 5 mi, FL250, sebound', immediately followed by 'altitude excursion, turn right heading 360 degrees immediately, maintain FL260.' when we received the traffic report, the captain, realizing a conflict, spdily arrested the descent 'FL253' and climbed, we spotted and reported in-sight the small transport at 1 O'clock, +\- 4 mi and decided not to turn right to avoid his flight path. When clear of traffic, we were reclred direct to 10C-VOR and maintain FL240, and were asked to make phone contact with den-ARTCC on arrival at kden, which the captain did. He spoke with mr. Xx, shift supervisor, who claimed that in our descent we were reclred to FL260, something we never heard and therefore never acknowledged or complied with. Both mr. Xx and, later, system control shift supervisor mr. Y (per FAA request) asked to have the cvr tapes removed, but on the captain's statement that the 30 min tape by then had been automatically erased, the request was withdrawn. Captain further relayed to his flight crew, after a second conversation with mr. Xx, that ARTCC assumed an operational error on their part. I urge the expeditious completion of TCASII installation and activation in all our widebody transport!

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Original NASA ASRS Text

Title: ATC ISSUED DSCNT TO ACR, THEN REVISED CLRNC TO LEVEL OFF FOR TFC. FLC DID NOT RECEIVE CLRNC AND DSNDED TO OCCUPIED ALT. LTSS.

Narrative: KIAK-KDEN APCH DEN, INITIAL DSCNT CLRNC WAS GIVEN AND ACKNOWLEDGED TO FL240 (FROM FL350). AS THIS HAPPENED A LOT EARLIER THEN NORMAL (180 MI FROM DEN), I QUESTIONED 'AT PLTS DISCRETION?'. ARTCC RESPONDED 'NO NOW!' 'ROGER LEAVING FL350'. AS WE PASSED FL260, ARTCC RPTED TFC 'SMT, 12 O'CLOCK 5 MI, FL250, SEBOUND', IMMEDIATELY FOLLOWED BY 'ALT EXCURSION, TURN R HDG 360 DEGS IMMEDIATELY, MAINTAIN FL260.' WHEN WE RECEIVED THE TFC RPT, THE CAPT, REALIZING A CONFLICT, SPDILY ARRESTED THE DSCNT 'FL253' AND CLBED, WE SPOTTED AND RPTED IN-SIGHT THE SMT AT 1 O'CLOCK, +\- 4 MI AND DECIDED NOT TO TURN R TO AVOID HIS FLT PATH. WHEN CLR OF TFC, WE WERE RECLRED DIRECT TO 10C-VOR AND MAINTAIN FL240, AND WERE ASKED TO MAKE PHONE CONTACT WITH DEN-ARTCC ON ARR AT KDEN, WHICH THE CAPT DID. HE SPOKE WITH MR. XX, SHIFT SUPVR, WHO CLAIMED THAT IN OUR DSCNT WE WERE RECLRED TO FL260, SOMETHING WE NEVER HEARD AND THEREFORE NEVER ACKNOWLEDGED OR COMPLIED WITH. BOTH MR. XX AND, LATER, SYS CTL SHIFT SUPVR MR. Y (PER FAA REQUEST) ASKED TO HAVE THE CVR TAPES REMOVED, BUT ON THE CAPT'S STATEMENT THAT THE 30 MIN TAPE BY THEN HAD BEEN AUTOMATICALLY ERASED, THE REQUEST WAS WITHDRAWN. CAPT FURTHER RELAYED TO HIS FLC, AFTER A SECOND CONVERSATION WITH MR. XX, THAT ARTCC ASSUMED AN OPERROR ON THEIR PART. I URGE THE EXPEDITIOUS COMPLETION OF TCASII INSTALLATION AND ACTIVATION IN ALL OUR WDB!

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.