Aerospace Instrument-Making Annotation << Back One-step optimum control in a digital system. R.L. Leybov This paper presents an aircraft turbofan engine step by step control synthesis method. This method makes use of a multivariable linear model having uncertain matrices those describe the difference between nonlinear and linear models. Feedback coefficients for each step are calculated using quadratic programming. The results of step by step control synthesis method application for an aircraft turbofan engine are presented.