The l(1)-optimal digital autopilot needed to control of the roll for an aircraft under an arbitrary unmeasured disturbances is addressed in this paper. This autopilot has to achieve a desired lateral motion control via minimizing the upper bound on the absolute value of the difference between the given and true roll angles. It is ensured by means of the two digital l(1)-optimal controllers of PI type The main result consists in establishing the fact that this controller can be robust in the presence of parametric and nonparametric uncertainties.