This paper addresses the problem of Oscillatory Failure Case (OFC) detection in the Electrical Flight Control System (EFCS) of the Airbus airplanes. The work describes the status of on going research activity undertaken within a collaborative project between Bordeaux University (France) and Airbus. A hydraulic actuator model is presented, which is currently used as the basis for a robust analytical redundancy-based technique implemented in A380 Flight Control Computer (FCC) for detecting unauthorized oscillatory events. The technique has been successfully validated and provides a complete OFC coverage without false alarms in the A380 EFCS. In the context of aircraft overall optimization, for upcoming and future programs, a need has emerged recently to improve the detection performance in case of less important amplitude OFC that may occur in the servo control loops of actuators. To meet this requirement, it becomes necessary to model more efficiently the dynamical behavior of actuators to get more sensitive fault indicating signals. It is shown that the model quality can be significantly improved by reliable estimating of some physical parameters. The fault indicating signals are compared to those obtained from A380 computers during flight tests. The results are quite encouraging and suggest that OFC with less important amplitude could be successfully detected by the new strategy.