Narrative:

Controller cleared us to descend to 11000 ft (from FL250). Several mins later controller asked if we had traffic at 11 O'clock position in sight (we said no). Descending through 15500 ft controller said, 'where are you going, I told you to maintain 17000 ft.' captain and I are positive we never received the clearance to maintain 17000 ft, much less read the 'clearance' back to the controller. Supplemental information from acn 376117: next communication from controller was 'flight number confirm you are level at 17000 ft.' my response was 'negative, we are passing 15800 ft for 11000 ft. We were cleared to cross 40 NM northeast vulcan at 11000 ft.' the controller said that he had given us a stop at 17000 ft when we were issued the traffic. The first officer and I never heard any other altitude but the crossing restr nor did we acknowledge. I explained to controller and his response was that we had acknowledged when we acknowledged traffic. That was not the case. I point to controller error since I was required to read back the altitude cleared to by company policy and would have done so had I received it. The fact that I did not, should have indicated to controller that I did not receive such clearance.

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Original NASA ASRS Text

Title: AN ACR DC9 WAS GIVEN A DSCNT TO 11000 FT AND THEN LATER GIVEN TFC INFO AND AN AMENDED ALT OF 17000 FT. THE FLC ACKNOWLEDGED THE TFC INFO, BUT DID NOT HEAR THE NEW ALT ASSIGNMENT. THE ARTCC CTLR QUESTIONED THE ACFT'S ALT AT 15500 FT AND THE FLC SAID THEY DID NOT GET A NEW ALT ASSIGNMENT.

Narrative: CTLR CLRED US TO DSND TO 11000 FT (FROM FL250). SEVERAL MINS LATER CTLR ASKED IF WE HAD TFC AT 11 O'CLOCK POS IN SIGHT (WE SAID NO). DSNDING THROUGH 15500 FT CTLR SAID, 'WHERE ARE YOU GOING, I TOLD YOU TO MAINTAIN 17000 FT.' CAPT AND I ARE POSITIVE WE NEVER RECEIVED THE CLRNC TO MAINTAIN 17000 FT, MUCH LESS READ THE 'CLRNC' BACK TO THE CTLR. SUPPLEMENTAL INFO FROM ACN 376117: NEXT COM FROM CTLR WAS 'FLT NUMBER CONFIRM YOU ARE LEVEL AT 17000 FT.' MY RESPONSE WAS 'NEGATIVE, WE ARE PASSING 15800 FT FOR 11000 FT. WE WERE CLRED TO CROSS 40 NM NE VULCAN AT 11000 FT.' THE CTLR SAID THAT HE HAD GIVEN US A STOP AT 17000 FT WHEN WE WERE ISSUED THE TFC. THE FO AND I NEVER HEARD ANY OTHER ALT BUT THE XING RESTR NOR DID WE ACKNOWLEDGE. I EXPLAINED TO CTLR AND HIS RESPONSE WAS THAT WE HAD ACKNOWLEDGED WHEN WE ACKNOWLEDGED TFC. THAT WAS NOT THE CASE. I POINT TO CTLR ERROR SINCE I WAS REQUIRED TO READ BACK THE ALT CLRED TO BY COMPANY POLICY AND WOULD HAVE DONE SO HAD I RECEIVED IT. THE FACT THAT I DID NOT, SHOULD HAVE INDICATED TO CTLR THAT I DID NOT RECEIVE SUCH 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.