MD80 crew had altitude undershoot and altitude overshoot in D01 class B airspace.

Attributes
ACN	501300
Time
Date	200102
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl bound lower : 2800 msl bound upper : 3250
Environment
Flight Conditions	IMC
Weather Elements	Fog other
Light	Night
Aircraft 1
Controlling Facilities	tracon : d01.tracon
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 : 18r other other
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	501300
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
ASRS Report	501299
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : undershoot altitude deviation : overshoot inflight encounter : weather other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued alert controller : issued new clearance flight crew : returned to assigned altitude other
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Weather Aircraft
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Altitude alert. On base to final runway 18R dfw. WX 300 ft broken, RVR 6000 ft. First officer flying aircraft on autoplt. Given expedited descent to 3000 ft. Given speed reductions to 210 KTS then 180 KTS requiring several confign changes. Told to turn to 150 degree heading, maintain 3000 ft, cleared for ILS runway 18R approach, etc. Before reaching 3000 ft, given further speed reduction to 170 KTS. 170 KIAS hold is dialed into MCP. Descent stopped at approximately 3250 ft with aural altitude warning. Aircraft never captured and leveled at 3000 ft prior to altitude alert. ATC asked us if we were climbing. I responded our descent had stopped. ATC reasserted we were supposed to be level at 3000 ft. I replied that we were descending through 3100 ft. We were switched to tower 124.15. Autoplt failed to capture and level off at 3000 ft and aircraft descended to 2800 ft. First officer disengaged autoplt and returned aircraft to 3000 ft and re-engaged autoplt. Continued rest of approach and landing uneventfully.

Original NASA ASRS Text

Title: MD80 CREW HAD ALT UNDERSHOOT AND ALT OVERSHOOT IN D01 CLASS B AIRSPACE.

Narrative: ALT ALERT. ON BASE TO FINAL RWY 18R DFW. WX 300 FT BROKEN, RVR 6000 FT. FO FLYING ACFT ON AUTOPLT. GIVEN EXPEDITED DSCNT TO 3000 FT. GIVEN SPD REDUCTIONS TO 210 KTS THEN 180 KTS REQUIRING SEVERAL CONFIGN CHANGES. TOLD TO TURN TO 150 DEG HDG, MAINTAIN 3000 FT, CLRED FOR ILS RWY 18R APCH, ETC. BEFORE REACHING 3000 FT, GIVEN FURTHER SPD REDUCTION TO 170 KTS. 170 KIAS HOLD IS DIALED INTO MCP. DSCNT STOPPED AT APPROX 3250 FT WITH AURAL ALT WARNING. ACFT NEVER CAPTURED AND LEVELED AT 3000 FT PRIOR TO ALT ALERT. ATC ASKED US IF WE WERE CLBING. I RESPONDED OUR DSCNT HAD STOPPED. ATC REASSERTED WE WERE SUPPOSED TO BE LEVEL AT 3000 FT. I REPLIED THAT WE WERE DSNDING THROUGH 3100 FT. WE WERE SWITCHED TO TWR 124.15. AUTOPLT FAILED TO CAPTURE AND LEVEL OFF AT 3000 FT AND ACFT DSNDED TO 2800 FT. FO DISENGAGED AUTOPLT AND RETURNED ACFT TO 3000 FT AND RE-ENGAGED AUTOPLT. CONTINUED REST OF APCH AND LNDG UNEVENTFULLY.

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.