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Autoplt trim malfunction in cruise and aircraft descended 300 ft before reporter captain disconnected autoplt and returned to assigned altitude.
| Attributes | |
| ACN | 330901 |
| Time | |
| Date | 199603 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : hrv |
| State Reference | TX |
| Altitude | msl bound lower : 23700 msl bound upper : 24000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zhu |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 330901 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Autoplt started a descent, autoplt trim light came on. By the time a smooth return to FL240 could be made, a 300 ft descent below assigned altitude occurred and ZHU called 300 ft low. Returned to FL240 as soon as possible. First officer was in the head, so no help. Autoplt malfunction due to 2 altitude trim circuit breakers opened.
Original NASA ASRS Text
Title: AUTOPLT TRIM MALFUNCTION IN CRUISE AND ACFT DSNDED 300 FT BEFORE RPTR CAPT DISCONNECTED AUTOPLT AND RETURNED TO ASSIGNED ALT.
Narrative: AUTOPLT STARTED A DSCNT, AUTOPLT TRIM LIGHT CAME ON. BY THE TIME A SMOOTH RETURN TO FL240 COULD BE MADE, A 300 FT DSCNT BELOW ASSIGNED ALT OCCURRED AND ZHU CALLED 300 FT LOW. RETURNED TO FL240 ASAP. FO WAS IN THE HEAD, SO NO HELP. AUTOPLT MALFUNCTION DUE TO 2 ALT TRIM CIRCUIT BREAKERS OPENED.
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.