An article of manufacture including a tangible, non-transitory computer-readable storage medium having instructions stored thereon for detecting a fault in a gas turbine engine that, in response to execution by a controller, cause the controller to perform operations comprising receiving, by the controller, a first data output from a first flight data source; receiving, by the controller, a second data output from a second flight data source; determining, by the controller, a first flight realm of the first data output based on the second data output; identifying, by the controller, a fault threshold using a first parameter of the first flight realm; and comparing, by the controller, the first data output to the fault threshold.