Flight instrument

In a flight control system for an aircraft having an altitude responsive pressure transducer generating an altitude signal for a change in aircraft altitude from an established set point, the combination comprising:

• first circuit means for generating an indicated altitude signal,
• means for adjusting the set point of the pressure transducer and including means for generating a selected atmospheric pressure signal,
• second circuit means responsive to the indicated altitude signal and the pressure signal to generator a pressure altitude output signal,
• third circuit means responsive to the pressure altitude output signal for generating an altitude correction signal,
• means for generating two signals displaced 180 electrical degrees,
• a bridge circuit responsive to the ambient temperature of the pressure transducer and connected to the two signals to generate a temperature correction signal,
• means for summing the output of the third circuit means with the temperature correction signal to further modify the altitude correction signal, and
• control means responsive to the modified altitude varying signal and coupled to said means for adjusting to return the altitude varying signal to a set point level.

In a flight control system for an aircraft having an aneroid pressure transducer generating an altitude varying signal for a change in aircraft altitude from an established set point, the combination comprising:

• means for adjusting the set point of the aneroid of the pressure transducer,
• first circuit means responsive to the ambient temperature at the pressure transducer to generate a temperature correction signal,
• means for supplying an energizing voltage to the pressure transducer,
• second circuit means responsive to the energizing voltage for generating two signals displaced 180 electrical degrees,
• a bridge circuit including a temperature responsive element connected to the two signals for generating a temperature correction signal,
• means for connecting the temperature correction signal to the pressure transducer to modify the altitude varying signal, and
• control means responsive to the modified altitude varying signal and coupled to said means for adjusting to return the altitude varying signal to the set point level.

In a flight control system for an aircraft havng an aneroid pressure transducer generating an altitude varying signal for a change in aircraft altitude from an established set point, the combination comprising:

• means for supplying an energizing voltage to the pressure transducer,
• circuit means responsive to the energizing voltage for generating two signals displaced 180 electrical degrees,
• a bridge circuit including a temperature responsive element connected to the two signals and generating a temperature correction signal,
• means for connecting the temperature correction signal to the pressure transducer to modify the altitude varying signal, and
• control means responsive to the modified altitude varying signal and coupled to an indicated altitude display to present a visual reading of aircraft altitude.

In a flight control system for an aircraft having an altitude responsive pressure transducer generating an altitude signal for a change in aircraft altitude from an established set point, the combination comprising:

• first circuit means for generating an indicated altitude signal,
• means for adjusting the set point of the pressure transducer and for generating a selected atmospheric pressure signal,
• second circuit means responsive to the indicated altitude signal and the pressure signal to generate a pressure altitude signal,
• third circuit means responsive to the pressure altitude output signal for generating an altitude correction signal,
• fourth circuit means for generating two signals displaced 180 electrical degrees,
• a bridge circuit including a temperature responsive element connected to the two signals and generating a temperature correction signal,
• means for summing the altitude correction signal and the temperature correction signal into a temperature/altitude correction signal applied to the pressure transducer to modify the altitude varying signal, and
• control means responsive to the modified altitude varying signal and coupled to an indicated altitude display to present a visual reading of aircraft altitude.