MD80 crew had a runaway trim.

Attributes
ACN	426469
Time
Date	199901
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : msp
State Reference	MN
Altitude	msl bound lower : 3000 msl bound upper : 10000
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Flight Phase	other other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
ASRS Report	426469
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : overcame equipment problem other
Consequence	Other

Narrative:

Declaration of emergency. We were at 3000 ft MSL on an intercept heading of 090 degrees to msp ILS runway 12L. Just prior to localizer capture, first officer flying, CADC 2 in use, first officer localizer display failed with localizer/GS flags in view. Captain display remained normal. We retuned the 2 localizer and rearmed the localizer. At localizer capture the autoplt trim began a nose up trim until reaching the stop. The autoplt failed and manual control was assumed by the captain. We had full forward yoke control and still climbing, unable to level. We announced go around and declared an emergency with msp approach. The runaway trim checklist was accomplished and we regained control of the primary stabilizer and leveled at 10000 ft MSL. We requested vectors to dsm, our filed alternate, and landed uneventfully. We were unable to reach dispatch directly or commercial radio. We sent a diversion report via ACARS and requested ZMP contact dsm and relay our situation to all.

Original NASA ASRS Text

Title: MD80 CREW HAD A RUNAWAY TRIM.

Narrative: DECLARATION OF EMER. WE WERE AT 3000 FT MSL ON AN INTERCEPT HDG OF 090 DEGS TO MSP ILS RWY 12L. JUST PRIOR TO LOC CAPTURE, FO FLYING, CADC 2 IN USE, FO LOC DISPLAY FAILED WITH LOC/GS FLAGS IN VIEW. CAPT DISPLAY REMAINED NORMAL. WE RETUNED THE 2 LOC AND REARMED THE LOC. AT LOC CAPTURE THE AUTOPLT TRIM BEGAN A NOSE UP TRIM UNTIL REACHING THE STOP. THE AUTOPLT FAILED AND MANUAL CTL WAS ASSUMED BY THE CAPT. WE HAD FULL FORWARD YOKE CTL AND STILL CLBING, UNABLE TO LEVEL. WE ANNOUNCED GAR AND DECLARED AN EMER WITH MSP APCH. THE RUNAWAY TRIM CHKLIST WAS ACCOMPLISHED AND WE REGAINED CTL OF THE PRIMARY STABILIZER AND LEVELED AT 10000 FT MSL. WE REQUESTED VECTORS TO DSM, OUR FILED ALTERNATE, AND LANDED UNEVENTFULLY. WE WERE UNABLE TO REACH DISPATCH DIRECTLY OR COMMERCIAL RADIO. WE SENT A DIVERSION RPT VIA ACARS AND REQUESTED ZMP CONTACT DSM AND RELAY OUR SIT TO ALL.

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.