Narrative:

Cruising at FL230, I was looking at charts and adjusting my HSI when I noticed a stabilizer out of trim light for autoplt was on. Looked at altimeter and aircraft was descending at 1500 FPM with the autoplt in altitude hold. It had descended approximately 500 ft. Autoplt was disconnected and aircraft was out of trim nose down. Retrimmed and climbed back to FL230. Was out of FL230 less than 15 seconds. Upon arrival at bos, maintenance put autoplt on mco. The autoplt had a previous write-up describing exact same scenario. Maintenance corrective action was ground checked ok.

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Original NASA ASRS Text

Title: STABILIZER OUT OF TRIM LIGHT ILLUMINATED ON B727 WITH AUTOPLT IN ATTITUDE HOLD COUPLED WITH A 1500 FPM DSCNT. RECURRENT PROB THAT GND CHKS OK.

Narrative: CRUISING AT FL230, I WAS LOOKING AT CHARTS AND ADJUSTING MY HSI WHEN I NOTICED A STABILIZER OUT OF TRIM LIGHT FOR AUTOPLT WAS ON. LOOKED AT ALTIMETER AND ACFT WAS DSNDING AT 1500 FPM WITH THE AUTOPLT IN ALT HOLD. IT HAD DSNDED APPROX 500 FT. AUTOPLT WAS DISCONNECTED AND ACFT WAS OUT OF TRIM NOSE DOWN. RETRIMMED AND CLBED BACK TO FL230. WAS OUT OF FL230 LESS THAN 15 SECONDS. UPON ARR AT BOS, MAINT PUT AUTOPLT ON MCO. THE AUTOPLT HAD A PREVIOUS WRITE-UP DESCRIBING EXACT SAME SCENARIO. MAINT CORRECTIVE ACTION WAS GND CHKED OK.

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.