The objective of the project is the development of an on-board envelope estimation, protection and upset recovery tool to address loss of control incidents in commercial aircraft. Loss of control incidents can be attributed to variety of factors including environmental (icing, clear air turbulence, wakes, etc.), failure of aircraft components (stuck control surfaces, failure of hydraulic systems, broken cables, etc.), human factors (pilot error, insufficient training, crew distraction, etc.) or a combination of any of them. Usually the final catastrophic event is linked to nonlinear phenomenon (like stall) and there is a small time window of opportunity for the pilot (or the flight computer) to recover but the action they take are critical to any such recovery. In Phase I, we have demonstrated how nonlinear equilibrium analysis can be brought to bear upon this problem to understand the dynamic behavior of the aircraft outside of the nominal operating regime. We have also shown using NASA Generic Transport Model (GTM) how such tools may be used to dynamically estimate the operational envelope of the aircraft. In Phase II, we will extend the methodology to design an on-board envelope protection system and study upset recovery schemes. The analytical tools will be supported by the development of commercial grade software for on-board envelope estimation and upset recovery for unimpaired and impaired aircraft. We have already implemented symbolic tools for modeling and analysis, database management, numerical validation and visualization. These tools will be extended, improved and evaluated experimentally. Our goal is to provide verifiable software for commercial aircraft flight safety.