"An Assessment of Planar Waves" provides background on some of the history of planar waves, which are time-dependent variations of inlet recovery, as well as establishing a hierarchy for categorizing various types of planar waves. It further identifies approaches for establishing compression-component and engine sensitivities to planar waves, and methods for accounting for the destabilizing effects of planar waves. This document contains an extensive list and categorization (see

Appendix A ) of references to aid both the newcomer and the practitioner on this subject.

The committee acknowledges that this document addresses only the impact of planar waves on compression-component stability and does not address the impact of planar waves on augmenter rumble, engine structural issues, and/or pilot discomfort.