This paper is devoted to the detection of Oscillatory Failure Case (OFC) in the Electrical Flight Control System (EFCS). Such failures lead to a strong interaction between loads and aeroelasticity and must be quickly detected and passivated. This paper proposes a hybrid monitoring scheme for robust and early detection of such unauthorized oscillatory events. The proposed technique has been developed within ADDSAFE project (a collaborative project supported by the European Seventh Framework Program: Advanced Fault Diagnosis for Sustainable Flight Guidance and Control, http://addsafe.deimos-space.com). A robust finite-time differentiator is used to estimate derivatives in a noisy environment. Fault reconstruction is next achieved by solving on-line a nonlinear equation using a gradient descent method. Finally, fault detection and confirmation stage is based on the decision making rules currently used for in-service Airbus A380 airplane. Robustness and performance of the proposed fault detection scheme are tested using a high fidelity benchmark and intensive Monte Carlo simulations for several flight scenarios as specified within ADDSAFE project.