An aircraft with electrical fly-by-wire controls is equipped with an automatic pilot having a navigation computer producing automatic pilot instructions that are sent directly to a flight control computer. The electric drive can be operated in both a partial load range as well as in a full load range, but always as a function of the timing of the PWM signal. The base wall and the top wall are parallel, the first side wall and the second side wall extend between both the base wall and the top wall such that the wale is of a trapezoidal cross-section. The selector circuit selectively drives one of the local oscillators in accordance with the numerical count data obtained in the detector circuit.