Narrative:

I was PF, first officer called center and asked for FL210. We were previously cleared from maf departure to 12000 ft. I heard a 'roger,' but it was not for our aircraft. Center was swamped working several frequencys. Our initial call was blocked. We were not cleared to higher. I noticed that fact at 12500 ft. The aircraft was then descended to 12000 ft and never heard anything about it.

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Original NASA ASRS Text

Title: SMT FLC BEGAN CLBING WITHOUT AN ATC CLRNC.

Narrative: I WAS PF, FO CALLED CTR AND ASKED FOR FL210. WE WERE PREVIOUSLY CLRED FROM MAF DEP TO 12000 FT. I HEARD A 'ROGER,' BUT IT WAS NOT FOR OUR ACFT. CTR WAS SWAMPED WORKING SEVERAL FREQS. OUR INITIAL CALL WAS BLOCKED. WE WERE NOT CLRED TO HIGHER. I NOTICED THAT FACT AT 12500 FT. THE ACFT WAS THEN DSNDED TO 12000 FT AND NEVER HEARD ANYTHING ABOUT IT.

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.