Narrative:

On departure; we were climbing thru fl 320; when we felt a vibration in the aircraft. We continued to filed altitude of FL340. As the power was reduced at level off the vibrations abated some; but soon became more intense. They were cyclic in nature; and increasing in intensity. They are best described as the type of vibrations heard when the N1 rpms are not in sync; but these were more intense and could be felt in the airframe. The N1s were within .1; and the engine vibration monitor showed N1s at .8; the N2s at .6 throughout. We observed no flight control anomalies or airframe buffet. The vibrations directly increased with power increase; and decreased with power reduction. We decided to slow from .78M to .75 and descend back to 320. The vibrations decreased; but as we leveled at 320 and the power came up to hold airspeed; the vibrations returned; and over the next few minutes continued to increase in intensity. At that point we decided to divert. We set up a slow speed (250) descent; and the vibration was minimal until power was required to configure for approach; when they returned. Approach and landing were uneventful. Thanks for great support from ATC and the fire crews. The first officer also did a great job in coordinating the divert and support throughout the event. (We had deiced prior to departure; and considered whether ice had formed in the engine. However; we had used engine anti ice throughout the departure; were in the clear by 5;000 feet; and had no vibrations at all at climb power settings until FL320.)

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Original NASA ASRS Text

Title: An A300 Captain reported diverting because of an engine vibration which increased with increased thrust. The aircraft had been deiced prior to departure but was in VMC during cruise.

Narrative: On departure; we were climbing thru FL 320; when we felt a vibration in the aircraft. We continued to filed altitude of FL340. As the power was reduced at level off the vibrations abated some; but soon became more intense. They were cyclic in nature; and increasing in intensity. They are best described as the type of vibrations heard when the N1 rpms are not in sync; but these were more intense and could be felt in the airframe. The N1s were within .1; and the engine vibration monitor showed N1s at .8; the N2s at .6 throughout. We observed no flight control anomalies or airframe buffet. The vibrations directly increased with power increase; and decreased with power reduction. We decided to slow from .78M to .75 and descend back to 320. The vibrations decreased; but as we leveled at 320 and the power came up to hold airspeed; the vibrations returned; and over the next few minutes continued to increase in intensity. At that point we decided to divert. We set up a slow speed (250) descent; and the vibration was minimal until power was required to configure for approach; when they returned. Approach and landing were uneventful. Thanks for great support from ATC and the fire crews. The First Officer also did a great job in coordinating the divert and support throughout the event. (We had deiced prior to departure; and considered whether ice had formed in the engine. However; we had used engine anti ice throughout the departure; were in the clear by 5;000 feet; and had no vibrations at all at climb power settings until FL320.)

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.