Narrative:

At cruise altitude; [we] got an 'unscheduled stab trim' EICAS with caution lights. After running the checklist; we were left with the 'left' stabilizer trim switch in cutoff position. All flight controls felt normal with no unusual control forces required while hand flying. [We] engaged right auto pilot. All controls and indicators appeared normal. After consulting with maintenance control; the decision was made to return to our departure airport. We declared an emergency in compliance with the overweight landing directive. The landing was normal and without incident.

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Original NASA ASRS Text

Title: Following receipt of an 'unscheduled stab trim' EICAS message; the flight crew of a B767-300ER ran the appropriate checklists; consulted with Maintenance; and elected to return to their departure airport for maintenance.

Narrative: At cruise altitude; [we] got an 'unscheduled stab trim' EICAS with caution lights. After running the checklist; we were left with the 'L' stabilizer trim switch in cutoff position. All flight controls felt normal with no unusual control forces required while hand flying. [We] engaged right auto pilot. All controls and indicators appeared normal. After consulting with Maintenance Control; the decision was made to return to our departure airport. We declared an emergency in compliance with the overweight landing directive. The landing was normal and without incident.

Data retrieved from NASA's ASRS site as of April 2012 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.