The usage of an accurate mathematical model of a turbofan engine installed into an airplane is essential for flight simulation and controller design. However, the acquisition of the model is difficult because it consists of proprietary information. Thus, we proposed that the model was estimated by applying system identification techniques to arbitrarily accessible flight data. As a practical example, the relationship between the thrust lever angle and the rotation speed of the low-pressure axis of an airplane turbofan engine was estimated. The estimated model, whose structure was postulated to be linear, successfully simulated the actual data in at least 82.96% fitness.
