MD88 crew had an altitude overshoot in cvg class B airspace.

Attributes
ACN	519170
Time
Date	200107
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : cvg.airport
State Reference	KY
Altitude	msl bound lower : 6700 msl bound upper : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-88
Flight Phase	descent : approach descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 147 flight time total : 15000 flight time type : 1500
ASRS Report	519170
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance non adherence : published procedure non adherence : company policies non adherence : far
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During descent to 7000 ft controller gave a speed reduction from 250 KTS to 180 KTS. MD88 has IAS mode that works fine, but system has this anomaly. If in 'altitude capture' mode, any adjustment to flight control panel will cancel altitude capture. I did not notice altitude capture when speed adjustment was made because FMA is in a different place than flight control panel. I knew that, but it got me anyway. Aircraft did not capture 7000 ft, and we descended to about 6700 ft before climb was established. After returning to 7000 ft, we were given 5000 ft almost immediately. There were no conflicts that I am aware of.

Original NASA ASRS Text

Title: MD88 CREW HAD AN ALT OVERSHOOT IN CVG CLASS B AIRSPACE.

Narrative: DURING DSCNT TO 7000 FT CTLR GAVE A SPD REDUCTION FROM 250 KTS TO 180 KTS. MD88 HAS IAS MODE THAT WORKS FINE, BUT SYS HAS THIS ANOMALY. IF IN 'ALT CAPTURE' MODE, ANY ADJUSTMENT TO FLT CTL PANEL WILL CANCEL ALT CAPTURE. I DID NOT NOTICE ALT CAPTURE WHEN SPD ADJUSTMENT WAS MADE BECAUSE FMA IS IN A DIFFERENT PLACE THAN FLT CTL PANEL. I KNEW THAT, BUT IT GOT ME ANYWAY. ACFT DID NOT CAPTURE 7000 FT, AND WE DSNDED TO ABOUT 6700 FT BEFORE CLB WAS ESTABLISHED. AFTER RETURNING TO 7000 FT, WE WERE GIVEN 5000 FT ALMOST IMMEDIATELY. THERE WERE NO CONFLICTS THAT I AM AWARE OF.

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.