Process and device for automatically controlling the thrust of at least one engine of an aircraft during a phase of horizontal flight at stabilized speed

A process of automatic control of the thrust of at least one engine (2) of an aircraft during a phase of horizontal flight at stabilized speed, according to which process the thrust of the engine (2) is controlled by applying a control value thereto which corresponds to the value of a predetermined control parameter representative of the rating of said engine (2), and according to which the following set of steps is carried out automatically and repeatedly:

• a) an actual speed corresponding to the actual value of the speed of the aircraft is measured;
• b) a preset reference speed corresponding to the speed of the aircraft, representative of the control value obtained from the previous set of steps, is determined;
• c) a first difference between said actual speed and said preset speed is calculated;
• d) an intermediate term dependent on said first difference is determined for said control parameter, said intermediate term making it possible to obtain a corrector term;
• e) the sum is computed of said corrector term and of an equilibrium term which produces an equilibrium rating of the engine (2) in the absence of disturbances so as to obtain said control value;
• and
• f) the control value thus obtained is applied to said engine,
• wherein in step d):
• a second difference between said intermediate term of the present set of steps and the corrector term of the previous set of steps is calculated;
• this second difference is compared with a predetermined threshold value;
• and
• one selects as corrector term for the present set of steps, that is used in particular in step e):
• said intermediate term of the present set of steps, if said second difference is greater than said threshold value;
• and
• said corrector term of the previous set of steps, if said second difference is less than or equal to said threshold value.