Does an unexpected engine compressor surge event warrant the application of unscheduled engine maintenance?
Aircraft turbine engine operators are all familiar with the phenomenon of compressor surge (also frequently referred to as a compressor stall). A compressor surge is of special concern when engines with axial flow compressors are involved. Such engines may be equipped with up to 1 000 compressor blades, each of which can stall aerodynamically and start the onset of a compressor surge, with the possibility of various degrees of damage to an engine. Although the compressor blades in an axial flow compressor act like airfoils and experience changes in airflow, pressure and velocity similar to those felt on an airplane wing, these blades do not physically change their position with respect to the air flowing past them. This means that the stalling of compressor blades is not identical to the stalling of an airplane wing, where the gradual increase of the angle between the chord of the wing and the on-coming air flow (the angle of attack) causes the wing to stall. Instead, compressor blade
