Narrative:

On climb out; passing about 12;000 ft; the #1 engine N1 began fluctuating between 70% to over 100%. The a/T disengaged. The engine stabilized when retarded to idle. We leveled off at 14;000; declared an emergency; and coordinated our return. The engine limit surge/stall QRH was run as we descended for a single engine landing. The engine responded normally on final; allowing a more stable approach using power below 65%. An uneventful landing was accomplished; and we taxied to the gate.

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Original NASA ASRS Text

Title: B737 flight crew experiences the #1 engine surging between 70% and 100% N1 during initial climbout. The engine stabilizes below 70% but the crew elects to return to the departure airport.

Narrative: On climb out; passing about 12;000 FT; the #1 engine N1 began fluctuating between 70% to over 100%. The A/T disengaged. The engine stabilized when retarded to idle. We leveled off at 14;000; declared an emergency; and coordinated our return. The Engine Limit Surge/Stall QRH was run as we descended for a single engine landing. The engine responded normally on final; allowing a more stable approach using power below 65%. An uneventful landing was accomplished; and we taxied to the gate.

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.