Altitude deviation altitude overshot in descent.

Attributes
ACN	313760
Time
Date	199508
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mia
State Reference	FL
Altitude	msl bound lower : 2300 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : mia
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 75 flight time total : 21000 flight time type : 4000
ASRS Report	313760
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : became reoriented flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were on approach to mia runway 27R ILS, descending from 5000 ft to 3000 ft in a right turn to 240 degrees. The autoplt was on in #1 position, slats extended, heading select 240, IAS hold, altitude select 3000 ft. Airspeed was 230 KTS. Approach controller told us to slow to 200 KTS. I called for flaps 11 degrees and as the flaps started down I went from IAS hold to vertical speed 500 FPM and moved the airspeed select from 230 KTS to 200 KTS. I looked out the right front window to find the runway. When I looked back in the cockpit the autoplt 'out of trim' light was on and we were descending at 3000 FPM. I clicked off the autoplt as we descended through 3000 ft because the altitude didn't capture. We leveled off at 2300 ft. Approach told us remain at that altitude and cleared us for the approach. I flew the plane manually and the rest of the approach and landing were normal. After landing we tested the alternate motor that runs the autoplt and it tested normal.

Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT IN DSCNT.

Narrative: WE WERE ON APCH TO MIA RWY 27R ILS, DSNDING FROM 5000 FT TO 3000 FT IN A R TURN TO 240 DEGS. THE AUTOPLT WAS ON IN #1 POS, SLATS EXTENDED, HDG SELECT 240, IAS HOLD, ALT SELECT 3000 FT. AIRSPD WAS 230 KTS. APCH CTLR TOLD US TO SLOW TO 200 KTS. I CALLED FOR FLAPS 11 DEGS AND AS THE FLAPS STARTED DOWN I WENT FROM IAS HOLD TO VERT SPD 500 FPM AND MOVED THE AIRSPD SELECT FROM 230 KTS TO 200 KTS. I LOOKED OUT THE R FRONT WINDOW TO FIND THE RWY. WHEN I LOOKED BACK IN THE COCKPIT THE AUTOPLT 'OUT OF TRIM' LIGHT WAS ON AND WE WERE DSNDING AT 3000 FPM. I CLICKED OFF THE AUTOPLT AS WE DSNDED THROUGH 3000 FT BECAUSE THE ALT DIDN'T CAPTURE. WE LEVELED OFF AT 2300 FT. APCH TOLD US REMAIN AT THAT ALT AND CLRED US FOR THE APCH. I FLEW THE PLANE MANUALLY AND THE REST OF THE APCH AND LNDG WERE NORMAL. AFTER LNDG WE TESTED THE ALTERNATE MOTOR THAT RUNS THE AUTOPLT AND IT TESTED NORMAL.

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.