MD80 overshoots disputed altitude prior to final at dfw.

Attributes
ACN	427960
Time
Date	199902
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl bound lower : 3000 msl bound upper : 5000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon tower : ord.tower
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 13r
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	427960
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other
Independent Detector	atc equipment other atc equipment : mode c other controllera
Resolutory Action	controller : issued alert controller : issued new clearance
Consequence	Other
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Narrative:

While tracking inbound on the runway 13R localizer, we were cleared by approach to descend to 3000 ft and maintain until established on GS, 170 KTS to the marker cleared runway 13R ILS. In our descent, approach called and asked our altitude as we descended through 4000 ft. The controller said we were cleared 5000 ft and after we asked, she said we could maintain 4000 ft. We were subsequently descended to 3000 ft and cleared the approach. Factors involved that may have caused this error were aircraft on same frequency preceding us had similar call sign. We acknowledged the clearance as given and the controller did not reply to correct clearance if it was given in error because of their workload, and this is a typical clearance given for that segment of the approach.

Original NASA ASRS Text

Title: MD80 OVERSHOOTS DISPUTED ALT PRIOR TO FINAL AT DFW.

Narrative: WHILE TRACKING INBOUND ON THE RWY 13R LOC, WE WERE CLRED BY APCH TO DSND TO 3000 FT AND MAINTAIN UNTIL ESTABLISHED ON GS, 170 KTS TO THE MARKER CLRED RWY 13R ILS. IN OUR DSCNT, APCH CALLED AND ASKED OUR ALT AS WE DSNDED THROUGH 4000 FT. THE CTLR SAID WE WERE CLRED 5000 FT AND AFTER WE ASKED, SHE SAID WE COULD MAINTAIN 4000 FT. WE WERE SUBSEQUENTLY DSNDED TO 3000 FT AND CLRED THE APCH. FACTORS INVOLVED THAT MAY HAVE CAUSED THIS ERROR WERE ACFT ON SAME FREQ PRECEDING US HAD SIMILAR CALL SIGN. WE ACKNOWLEDGED THE CLRNC AS GIVEN AND THE CTLR DID NOT REPLY TO CORRECT CLRNC IF IT WAS GIVEN IN ERROR BECAUSE OF THEIR WORKLOAD, AND THIS IS A TYPICAL CLRNC GIVEN FOR THAT SEGMENT OF THE APCH.

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.