Abstract: The engine model identification using flight test signals is introduced. As the aircraft flights, the engine will be subjected to random disturbances, which will result in change of the engine performance. In this case, the engine model identification using flight text signals concerned with the engine performance will have practical meaning for adaptive control and condition monitoring of the engine.The flight tests are accomplished at the altitude H = 3km, flight speed v = 770km / h and at H= 13km, v= 1540km/h. The test signals are recorded by on-board signal sampling and recording equipment. The signal smoothing and filtering methods are introduced. Design and parameter selection of Butterworth filter are discussed.In order to obtain invariant estimation of the model parameters, the recursive generalized least square identification method is used the results are given.

Key words: flight test signal, engine model, identification