Narrative:

Airbus 320 (aircraft X) from ZZZ departed runway xxl and shortly after takeoff experienced high engine vibrations on the engine number ones N1 fan section. The vibration was in excess of 9.9 on the vib display and a very noticeable vibration was felt through the airframe. We notified ATC; leveled off at 10;000 feet; and referenced the QRH for troubleshooting and guidance. The captain was the flying pilot while I read through the QRH. The captain disconnected the auto thrust and reduced the power on the number one engine resulting in a decrease in vibration. All other engine parameters were operating in the normal range. We elected to keep the number one engine running at a reduced thrust level with the vibrations higher than usual; but within the normal range as indicated by the QRH.ATC vectored us back around to runway xxl where fire crash rescue was standing by in the event they may be needed. The approach and landing were non-issues and we landed about twenty minutes after departure; underweight at around 121;000 lbs. Fire crash rescue shadowed us back to the gate in the event they were needed. Once parked at the gate; a visual inspection of engine number one was conducted by the fire personnel; the flight crew; and maintenance; there were no obvious signs of damage or what may have caused the high vibrations.

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Original NASA ASRS Text

Title: A320 pilot reported high engine vibration and an air return.

Narrative: Airbus 320 (Aircraft X) from ZZZ departed runway XXL and shortly after takeoff experienced high engine vibrations on the engine number ones N1 fan section. The vibration was in excess of 9.9 on the vib display and a very noticeable vibration was felt through the airframe. We notified ATC; leveled off at 10;000 feet; and referenced the QRH for troubleshooting and guidance. The Captain was the flying pilot while I read through the QRH. The captain disconnected the auto thrust and reduced the power on the number one engine resulting in a decrease in vibration. All other engine parameters were operating in the normal range. We elected to keep the number one engine running at a reduced thrust level with the vibrations higher than usual; but within the normal range as indicated by the QRH.ATC vectored us back around to runway XXL where fire crash rescue was standing by in the event they may be needed. The approach and landing were non-issues and we landed about twenty minutes after departure; underweight at around 121;000 lbs. Fire crash rescue shadowed us back to the gate in the event they were needed. Once parked at the gate; a visual inspection of engine number one was conducted by the fire personnel; the flight crew; and maintenance; there were no obvious signs of damage or what may have caused the high vibrations.

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.