  Despite the advances in aircraft guidance and control systems technology,
Loss of Control remains as the main cause of the fatal accidents of large
transport aircraft. Loss of Control is defined as excursion beyond the
allowable flight envelope and is often a consequence of upset condition if
improper maneuver is implemented by the pilot. Hence, extensive research in
recent years has focused on improving the current fault tolerant control
systems and developing new strategies for loss of control prevention and
recovery systems. However, success of such systems requires the perception of
the damaged aircraft's dynamic behavior and performance, and understanding of
its new flight envelope. This paper provides a comprehensive understanding of
lateral control surfaces' failure effect on the NASA Generic Transport Model's
maneuvering flight envelope; which is a set of attainable steady state
maneuvers herein referred to as trim points. The study utilizes a massive
database of the Generic Transport Model's high-fidelity maneuvering flight
envelopes computed for the unimpaired case and wide ranges of aileron and
rudder failure cases at different flight conditions. Flight envelope boundary
is rigorously investigated and the key parameters confining the trim points at
different boundary sections are identified. Trend analysis of the impaired
flight envelopes and the corresponding limiting factors is performed which
demonstrates the effect of various failure degrees on the remaining feasible
trim points. Results of the post-failure analysis can be employed in emergency
path planning and have potential uses in the development of aircraft resilient
control and upset recovery systems.
