Narrative:

We were IMC; being vectored for the ILS. The autopilot and autothrottles were engaged; and plane was descending out of 5000 for 4000 feet when we felt something hit the plane with a whump. Almost immediately; we smelled something burnt (not electrical); and the F/as called to report burnt smell and smoke in the cabin. All engine and system indications appeared normal at this time. Within moments; the plane began to level at 4000 feet; and the engines began to spool up. An increasing vibration/shaking of the plane was felt. I looked at the engine gauges and saw that the right engine was spooling up past 65% N1; but the left engine was stagnant at approx. 54% N1; with the trend arc indicating more thrust was being demanded. I realized we had an issue with the left engine; and immediately disconnected the autothrottles and retarded the left throttle. With the left throttle retarded to near idle; the vibration/shaking ceased. I attempted to spool up the left engine once again; but near 50% N1; the vibration/shaking would ensue. All other indications were normal. I retarded the throttle enough to prevent the vibration and left it there. Realizing we most likely had substantial damage to the left engine; I instructed the first officer to '[advise ATC]. I want to land immediately.' about this time; we had emerged from IMC into VMC conditions; and I acquired the airport visually off our right side. I disconnected the autopilot and began turning towards the airport; and transmitted to ATC that I had the field in sight and wanted visual approach clearance now. They immediately cleared us for the visual. The final approach and landing were otherwise uneventful. Since I didn't know the status of the left engine; I elected to use idle reverse and max autobrakes on landing. Emergency equipment visually inspected our aircraft; and then we taxied to the gate.

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Original NASA ASRS Text

Title: B737 Captain reported a bird strike that damaged the #1 engine while on approach in IMC .

Narrative: We were IMC; being vectored for the ILS. The autopilot and autothrottles were engaged; and plane was descending out of 5000 for 4000 feet when we felt something hit the plane with a WHUMP. Almost immediately; we smelled something burnt (not electrical); and the F/As called to report burnt smell and smoke in the cabin. All engine and system indications appeared normal at this time. Within moments; the plane began to level at 4000 feet; and the engines began to spool up. An increasing vibration/shaking of the plane was felt. I looked at the engine gauges and saw that the right engine was spooling up past 65% N1; but the left engine was stagnant at approx. 54% N1; with the trend arc indicating more thrust was being demanded. I realized we had an issue with the left engine; and immediately disconnected the autothrottles and retarded the left throttle. With the left throttle retarded to near idle; the vibration/shaking ceased. I attempted to spool up the left engine once again; but near 50% N1; the vibration/shaking would ensue. All other indications were normal. I retarded the throttle enough to prevent the vibration and left it there. Realizing we most likely had substantial damage to the left engine; I instructed the F/O to '[Advise ATC]. I want to land immediately.' About this time; we had emerged from IMC into VMC conditions; and I acquired the airport visually off our right side. I disconnected the autopilot and began turning towards the airport; and transmitted to ATC that I had the field in sight and wanted visual approach clearance now. They immediately cleared us for the visual. The final approach and landing were otherwise uneventful. Since I didn't know the status of the left engine; I elected to use idle reverse and max autobrakes on landing. Emergency equipment visually inspected our aircraft; and then we taxied to the gate.

Data retrieved from NASA's ASRS site 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.