Altitude deviation. Replied to wrong call sign.

Attributes
ACN	313020
Time
Date	199508
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 6700 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	313020
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During radar vector descent to 7000 ft MSL was cleared to 5000 ft MSL. First officer repeated descent clearance to 5000 ft and controller acknowledged his readback. Passing 6700 first officer noted TCASII traffic below us passing right to left. Visual contact revealed oal aircraft below us at 5000 ft. Descent was immediately halted. A air carrier X also on the frequency. Then asked controller to verify his altitude and was told 5000 ft. Realizing something was not right we asked a very busy controller to confirm our assigned altitude and was told 7000 ft. We climbed back to 7000 ft and nothing else was said. Our altitude never went below 6700 ft.

Original NASA ASRS Text

Title: ALTDEV. REPLIED TO WRONG CALL SIGN.

Narrative: DURING RADAR VECTOR DSCNT TO 7000 FT MSL WAS CLRED TO 5000 FT MSL. FO REPEATED DSCNT CLRNC TO 5000 FT AND CTLR ACKNOWLEDGED HIS READBACK. PASSING 6700 FO NOTED TCASII TFC BELOW US PASSING R TO L. VISUAL CONTACT REVEALED OAL ACFT BELOW US AT 5000 FT. DSCNT WAS IMMEDIATELY HALTED. A ACR X ALSO ON THE FREQ. THEN ASKED CTLR TO VERIFY HIS ALT AND WAS TOLD 5000 FT. REALIZING SOMETHING WAS NOT RIGHT WE ASKED A VERY BUSY CTLR TO CONFIRM OUR ASSIGNED ALT AND WAS TOLD 7000 FT. WE CLBED BACK TO 7000 FT AND NOTHING ELSE WAS SAID. OUR ALT NEVER WENT BELOW 6700 FT.

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.