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 (20) that, in response to execution by a controller (208), cause the controller (208) to perform operations comprising receiving, by the controller (208), a first data output from a first flight data source (202); receiving, by the controller(208), a second data output from a second flight data source (202); determining, by the controller (208), a first flight realm of the first data output based on the second data output; identifying, by the controller (208), a fault threshold using a first parameter of the first flight realm; and comparing, by the controller (208), the first data output to the fault threshold.