Flight Envelope Protection for Automatic and Augmented MAnual Control

Loss of Control (LOC) is currently the largest contributing category of catastrophic airplane accidents. A large percentage of the LOC accidents involve general aviation airplanes. The FAA is therefore has sponsored research to develop certification requirements for add-on envelope protection functions. This paper briefly discusses some of the LOC accidents and the deficiencies existing in many of the current GA and Transport airplane guidance and control systems that can lead to LOC. Next the paper discusses Envelope Protection (EP) design requirements, as well as functional, safety and performance objectives and design guidelines. Various approaches to designing envelope protection functions are discussed for airplanes under automatic or augmented manual Fly by Wire (FBW) control, to prevent stall, overspeed, excessive pitch and roll attitudes and excessive Normal Load Factor (NLF). Examples of simulation time history of what can be achieved are included.