Air carrier flight crew responds to altitude change intended for another aircraft.

Attributes
ACN	440500
Time
Date	199906
Day	Fri
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : egkk.airport
State Reference	FO
Altitude	msl bound lower : 6600 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : egkk.tower
Operator	common carrier : air carrier
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude descent : approach
Route In Use	arrival : holding pattern
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
ASRS Report	440500
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

We were leaving the willow holding fix preparing for an approach to runway 26L. I heard approach control give us a descent from 7000 ft to 6000 ft. I read back the clearance and set 6000 ft in the altitude window and the captain confirmed 6000 ft. As we initiated the descent, we heard another air carrier read back the clearance and immediately reconfirmed with ATC if it was for us. ATC said it wasn't for us, and we immediately took corrective action to get back to 7000 ft. We got about 400 ft low. We were in clear VMC and under radar contact. No apparent conflict existed and ATC did not comment anymore. I feel this deviation resulted from less than good radio reception perhaps with someone stepping on his radio call causing it to be misinterped.

Original NASA ASRS Text

Title: ACR FLC RESPONDS TO ALT CHANGE INTENDED FOR ANOTHER ACFT.

Narrative: WE WERE LEAVING THE WILLOW HOLDING FIX PREPARING FOR AN APCH TO RWY 26L. I HEARD APCH CTL GIVE US A DSCNT FROM 7000 FT TO 6000 FT. I READ BACK THE CLRNC AND SET 6000 FT IN THE ALT WINDOW AND THE CAPT CONFIRMED 6000 FT. AS WE INITIATED THE DSCNT, WE HEARD ANOTHER ACR READ BACK THE CLRNC AND IMMEDIATELY RECONFIRMED WITH ATC IF IT WAS FOR US. ATC SAID IT WASN'T FOR US, AND WE IMMEDIATELY TOOK CORRECTIVE ACTION TO GET BACK TO 7000 FT. WE GOT ABOUT 400 FT LOW. WE WERE IN CLR VMC AND UNDER RADAR CONTACT. NO APPARENT CONFLICT EXISTED AND ATC DID NOT COMMENT ANYMORE. I FEEL THIS DEV RESULTED FROM LESS THAN GOOD RADIO RECEPTION PERHAPS WITH SOMEONE STEPPING ON HIS RADIO CALL CAUSING IT TO BE MISINTERPED.

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.