Methods and systems for operating a gas turbine engine are provided. A health parameter for the gas turbine engine is monitored at a health evaluation device via a first instrument, the health evaluation device being communicatively coupled to a communication link established between a controller, associated with the gas turbine engine, and a second instrument which provides the controller with an operation parameter indicative of an operating condition of the gas turbine engine. The health parameter is compared to a predetermined threshold. When the health parameter is beyond the predetermined threshold, a signal is injected into the communication link to produce a predetermined value for the operation parameter to elicit a health response from the controller associated with the predetermined value.