Narrative:

During climb out at 12;000 ft MSL; the #1 engine failed to respond out of idle after a deceleration to avoid approaching weather. When a left climbing turn and power were added to continue departure; the left engine stayed in idle; airspeed/climb performance ceased and a return to [departure airport] was accomplished (single engine; full flap approach; landing). Remainder of flight [was] uneventful.

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Original NASA ASRS Text

Title: Airline flight crew reported #1 engine locked in idle thrust during climbout. Crew declared an emergency and returned to departure airport.

Narrative: During climb out at 12;000 FT MSL; the #1 engine failed to respond out of idle after a deceleration to avoid approaching weather. When a left climbing turn and power were added to continue departure; the left engine stayed in idle; airspeed/climb performance ceased and a return to [departure airport] was accomplished (single engine; full flap approach; landing). Remainder of flight [was] uneventful.

Data retrieved from NASA's ASRS site as of July 2013 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.