Air carrier X descended into another sector's airspace without coordination. Operational deviation.

Attributes
ACN	130738
Time
Date	198912
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 10500 msl bound upper : 12000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	130738
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation

Narrative:

Working the tar-D position at atl approach, I was working several aircraft. Working air carrier X and air carrier Y inbound to atl, I instructed air carrier Y to descend to 10000' and instructed air carrier X to descend to 12000'. I, and the person working the north departure radar position observed air carrier X northeast of atl descending out of 10500'. I immediately advised air carrier X to climb back to his assigned altitude. No evasive action required. I believe like call signs was a contributing factor. Make sure of proper readback and advise aircraft of call signs on frequencys.

Original NASA ASRS Text

Title: ACR X DESCENDED INTO ANOTHER SECTOR'S AIRSPACE WITHOUT COORD. OPERATIONAL DEVIATION.

Narrative: WORKING THE TAR-D POS AT ATL APCH, I WAS WORKING SEVERAL ACFT. WORKING ACR X AND ACR Y INBND TO ATL, I INSTRUCTED ACR Y TO DSND TO 10000' AND INSTRUCTED ACR X TO DSND TO 12000'. I, AND THE PERSON WORKING THE N DEP RADAR POS OBSERVED ACR X NE OF ATL DSNDING OUT OF 10500'. I IMMEDIATELY ADVISED ACR X TO CLB BACK TO HIS ASSIGNED ALT. NO EVASIVE ACTION REQUIRED. I BELIEVE LIKE CALL SIGNS WAS A CONTRIBUTING FACTOR. MAKE SURE OF PROPER READBACK AND ADVISE ACFT OF CALL SIGNS ON FREQS.

Data retrieved from NASA's ASRS site as of August 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.