Narrative:

In cruise at FL330, aircraft pitched up aggressively and 'autoplt trim' light illuminated. Disconnected autoplt and got a hard out of trim 'bump.' aircraft gained 700 ft before returning to altitude. Notified ATC, no conflict reported. Made logbook entry for maintenance. No further incident.

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Original NASA ASRS Text

Title: FLC OF AN MD88 EXPERIENCED AN AUTOPLT PROB WHEREIN DURING CRUISE FLT IT CAUSED THE ACFT TO CLB ABOVE ASSIGNED ALT UNTIL IT WAS DISCONNECTED. THE ACFT WAS IMMEDIATELY RETURNED TO ASSIGNED.

Narrative: IN CRUISE AT FL330, ACFT PITCHED UP AGGRESSIVELY AND 'AUTOPLT TRIM' LIGHT ILLUMINATED. DISCONNECTED AUTOPLT AND GOT A HARD OUT OF TRIM 'BUMP.' ACFT GAINED 700 FT BEFORE RETURNING TO ALT. NOTIFIED ATC, NO CONFLICT RPTED. MADE LOGBOOK ENTRY FOR MAINT. NO FURTHER INCIDENT.

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.