This paper presents the design of an L1adaptive control augmentation for NASA’s Transport Class Model. The augmentation consists of separate augmentations of the longitudinal and the lateral-directional baseline controllers and is integrated into a partially implemented flight control system architecture aimed at preventing loss of control. The adaptive control augmentation recovers the nominal open-loop aircraft dynamics in off- nominal flight conditions. This way, the robust command tracking and the robust performance of a flight envelope protection module are improved. Preliminary verification of the design is conducted through pilot-off-the-loop simulations, by assessing the response of the augmented aircraft after a severe aft center of gravity shift. The results show that the augmentation is capable of restoring the nominal behavior and indicate that the developed augmentation assists in preventing loss of control accidents under specific circumstances.