SUMMARY. During a run down operation, a support of a turbogenerator rotor mounted on two symmetric tilting pad bearings exhibited a subsynchronous "flexural" vibration, consisting mainly in a rotation of the bearing in the vertical radial plane, at a frequency nearly half of the rotating speed of the shaft. Starting from this experimental evidence, this paper is aimed at illustrating how journal and bearing axis skewness can cause a form of oil film instability differing from the well known "radial" type. This instability form can be defined as "flexural", since it is characterized by the journal-bearing relative rotation in a certain radial plane.