We present Guidance and Control algorithms for a fixed wing aircraft under severe structural damage. We show that under damage that includes 25% and 50% asymmetric wing loss the aircraft is successful in maintaining stable autonomous flight and is capable of performing autonomous approach and landing. Key features of the presented algorithms are smart guidance techniques that ensure the aircraft maintains required flight speed to avoid stall and use the available control surfaces to maintain autonomous flight. Closed loop autonomous control is achieved using proportional-integral-derivative type control logic with gains scheduled according to the measured airspeed. Adaptive control methods for the attitude control loop are also presented. The presented methods have been tested on Georgia Institute of Technology's GT Twinstar fixed wing Unmanned Aerial Vehicle, the results are presented in the paper.