The industrial state-of-practice to diagnose Electrical Flight Control System (EFCS) faults and obtain full flight envelope protection at all times is to provide high levels of hardware redundancy to perform built-in-tests of various sophistication. Although not obvious at the first sight, there is a strong link between advanced Fault Detection and Diagnosis (FDD) and the future more sustainable aircraft. Indeed, it can be demonstrated that improving the fault diagnosis performance in EFCS enables to optimize the aircraft structural design (resulting in weight saving), which in turn helps improve aircraft performance and to decrease its environmental footprint (e.g. fuel consumption and noise). This paper exemplifies the contribution of advanced FDD techniques researched and developed by Airbus and the researchers from University of Bordeaux (France) for the future "greener" aircraft, through the results of some recent actions and projects. The actuator/sensor fault cases investigated in this paper are Oscillatory Failure Cases (OFC), jamming (a.k.a. lock-in-place failure) and runaway (a.k.a. hardover).