Narrative:

Aircraft X, a citation jet inbound to dal, was issued a clearance to cross kagle at 12000 ft. Aircraft X read back kagle at 11000 ft and thus descended to that altitude. The sector at that time was very busy with numerous arrs to dallas love field and dfw airport.

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Original NASA ASRS Text

Title: ZFW ARTCC CTLR DID NOT HEAR INCORRECT READBACK BY PLT.

Narrative: ACFT X, A CITATION JET INBOUND TO DAL, WAS ISSUED A CLRNC TO CROSS KAGLE AT 12000 FT. ACFT X READ BACK KAGLE AT 11000 FT AND THUS DSNDED TO THAT ALT. THE SECTOR AT THAT TIME WAS VERY BUSY WITH NUMEROUS ARRS TO DALLAS LOVE FIELD AND DFW ARPT.

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.