The directions and speed of development of plane avionics systems are determined by three factors: economical consideration, required safety levels, and optimized working conditions for the pilot. This article presents the concept of a system in which the automatic control and stabilization process is effected because of coordinated deflections of trimming surfaces: the rudder, the elevator, and the ailerons. In particular, this article presents the structure of the system in the longitudinal movement steering channel by way of deflection of the trimmer of the elevator. Furthermore, it discusses the results of numerical model simulations, which are compared to the results obtained during in-flight tests. Additionally, this article specifies general technical requirements for the servomechanisms intended for the system class discussed herein. Selection of sufficiently large amplification makes control the plane with relatively small deflections of the trimmer. In particular, relationship between the deflection of the elevator and the deflection of trimmer, view of a tail plane and dimensions of the elevator trimmer, the structure and results of the pitch angle control system and simulation are presented in the article.