Abstract: Aircraft altitude is visually displayed at a front panel of a flight instrument in analog form by a rotating pointer and in digital form by means of a rotary drum digital indicator. Barometric pressure is converted into rectilinear motion to drive a mechanical-to-electrical transducer providing a signal to a servo amplifier having an output coupled to a servomotor. The servomotor drives both the rotating pointer and the rotary drum digital indicator. Also coupled to the mechanical-to-electrical transducer is a manually adjustable set input signal to correct for atmospheric pressure along a given flight path with respect to sea level. Temperature and altitude error corrections are also coupled to the transducer to correct the servomotor drive signal to give a true indicated altitude display. Also driven by the servomotor is a pressure altitude encoder for providing absolute altitude digital signals for transmission to a ground station.

Abstract: A pressure altitude signal actuates a servomotor coupled through a gear train to an altimeter that includes a rotational shaft for repositioning an aneroid pickoff. Mounted on the rotational shaft is an encoding disc with seven code formations supported on one face of the disc. Each code formation has a generally circular configuration with the various formations juxtapositioned. Six brush pickoffs respond to the six outermost code formations to provide pulse trains related to altitude pressure. A seventh brush pickoff provides a reference code to encoder logic that generates three additional pulse trains related to altitude pressure. The pulse trains of the outer six code formations and the pulse trains from the encoder logic uniquely identify by means of a code bit pattern an altitude.

Abstract: Aircraft altitude is visually displayed at a front panel of a flight instrument in analog form by a rotating pointer and in digital form by means of a rotary drum digital indicator. Barometric pressure is converted into rectilinear motion to drive a mechanical-to-electrical transducer providing a signal to a servo amplifier having an output coupled to a servomotor. The servomotor drives both the rotating pointer and the rotary drum digital indicator. Also coupled to the mechanical-to-electrical transducer is a manually adjustable set input signal to correct for atmospheric pressure along a given flight path with respect to sea level. Temperature and altitude error corrections are also coupled to the transducer to correct the servomotor drive signal to give a true indicated altitude display. Also driven by the servomotor is a pressure altitude encoder for providing absolute altitude digital signals for transmission to a ground station.

Abstract: A system for electrically actuating the pitch trim of an aircraft in both autopilot and manual modes includes a primary pitch servomotor coupled to a primary control surface and a pitch trim servomotor for actuating a trim control surface. In the autopilot mode, an electrical signal applied to the primary pitch servomotor by the autopilot is also applied to two channels of a trim controller providing complementary output signals applied to the pitch trim servomotor. Each channel of the trim controller includes a voltage translator for providing a single ended voltage applied to an integrator that generates an output varying with the time average of the electrical signal applied to the primary pitch servomotor. This time average signal as generated in each channel is chopped into an alternating current signal for driving an output stage. The chopping duty cycle of each channel is varied in accordance with the absolute value of a time average of the electrical signal applied to the primary pitch servomotor.