The work presented in this paper is undertaken within the European FP7 funded ADDSAFE project. The goal is to propose new fault diagnosis techniques that could significantly help developing environmentally-friendlier aircraft, by optimizing structural load design objectives. In this paper, a model-based fault detection scheme is proposed for robust and early detection of faults in aircraft control surfaces servo-loops. The proposed methodology is based on the H1/H− technique proposed in (Henry and Zolghadri, 2005a; Henry and Zolghadri, 2005b). The goal is to obtain a fault detection filter with enhanced fault transmission H− gain and large H1 nuisance attenuation. A complete Monte-Carlo campaign realized through a "high-fidelity" simulator provided by AIRBUS, demonstrates the potential of the proposed technique.