An autonomous ﬂight controller must possess the most adaptive capability that can be imagined for any control system : robustness and failure tolerance.
1. Robustness of the control law:
b. Guaranteeing compliance with speciﬁcations (frequency and time) at a given probability,
c. Classic robustness/performance trade-oﬀ to be managed. 2. Failure tolerance
a. Can be ensured through sophisticated sensor redundancy and rapid detection/correction of actuator abnormal behavior,
b. Minimum capacity of algorithms to handle double failures in order to give the autonomous aircraft a chance.