Flight Tests of a General Aviation Envelope Protection and Stability Augmentation System

Abstract

This paper describes development of a means to reduce loss-of-control (LOC) accidents in the General Aviation fleet. A full-time stability augmentation and envelope protection system compatible for retrofit to existing cable-controlled aircraft, or forward-fit into new aircraft, was developed and flight tested in a Cessna R182 aircraft. Two particular features of the system were found to be of great potential value in eliminating LOC accidents: 1) stall warning and protection utilizing direct angle-of-attack measurement, including visual, auditory and tactile warnings; and 2) roll stability augmentation with or without overbank protection, including an always-on tendency to return to wings-level flight without compromising manual roll control feel. A full suite of envelope protection features was tested in addition to the above. Flight test results are reported in this paper.