Estimation of the flight thrust increment changing the operation mode of the engine

The paper presents a new method for flight test identification of the thrust increment when changing engine operation mode. It is known that the problem of separate estimation of the engine thrust and the aerodynamic drag force from the aircraft flight data belongs to a class of ill-posed. The idea of the presented method is to come out of the ill-posed class by changing the original problem formulation. To achieve this purpose we give up the absolute values of the thrust and proceed to estimating the thrust increment resulting from the change of the aircraft engine operation mode. The accuracy of the solution is improved by introducing the special flight test maneuver. The algorithm requires only a few on-board measured parameters, such as longitudinal and normal overload, airspeed and altitude, and angle of attack. The complimentary use of the engine gas-dynamic model may improve the estimates but is not obligatory. The proposed method also does not require a-priory estimates of the aerodynamic drag force.