ZFW ARTCC controller did not hear incorrect readback by pilot.

Attributes
ACN	469354
Time
Date	200004
Day	Sat
Local Time Of Day	1801 To 2400
Place
State Reference	TX
Altitude	msl single value : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	general aviation : corporate
Make Model Name	Citation II S2/Bravo
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 3 controller time certified in position1 : 3
ASRS Report	469354
Person 2
Affiliation	government : faa
Function	controller : handoff position
Qualification	controller : radar
Experience	controller non radar : 3 controller radar : 5
ASRS Report	469351
Events
Anomaly	airspace violation : entry conflict : airborne critical non adherence : published procedure
Independent Detector	other controllera other controllerb
Miss Distance	horizontal : 9000 vertical : 0
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation Operational Error

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.

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.