A detection device comprising a first data processing unit configured to determine a first trend of the control surface control order as a function of time, the first trend being defined according to a reference parameter, a second data processing unit configured to determine at least one second trend of the control surface position value as a function of time, the second trend being also defined according to the reference parameter, and a monitoring unit configured to compare the first and second trends in order to verify the existence of a correlation between these first and second trends so as to detect an oscillatory failure as soon as a loss of correlation between the first and second trends appears, if necessary.