Electronic standby flight instrument

Claim 1

A single unit standby flight instrument for displaying turn rate, altitude, airspeed, pitch, roll, and heading of an aircraft to a pilot of the aircraft, said aircraft having an instrument panel with manual flight instrumentation, said instrument comprising sensor means for generating a plurality of sensor signals indicative of pitot pressure, static pressure, and angular displacement rates of the aircraft; display means for outputting display signals in a desired format; processor means for converting the sensor signals into a purality of display signals indicative of the turn rate, altitude, airspeed, pitch, roll and heading of the aircraft, said processor means comprising sampling means for periodically sampling said sensor signals, converter means for digitizing the sampled sensor signals, multiplexing means for applying the digitized sensor signals to an input bus in a predetermined input sequence, an input register responsive to the input bus and having a tri-state output for applying said digitized sensor signals to a program bus, an output register responsive to the program bus for outputting said display signals in a multiplexed format according to a predetermined output sequence, a microprocessor for controlling data flow on the program bus and updating the output register in accordance with current values of said digitized sensor signals in the input register, and demultiplexed means responsive to said output register for routing said display signals in accordance with the predetermined output sequence to appropriate inputs of said display means; power supply means for supplying electric power to said sensor means, processor means, and display means; and a single instrument housing mounted within view of the pilot and enclosing said sensor means, processor means, and power supply means, said display means being mounted on said housing so as to be visible to the pilot, said housing being rigidly mounted to the aircraft and located in an area on the instrument panel close to the standard flight instrumentation and within the vision limits of the pilot, thereby providing said pilot with an emergency source of airspeed, altitude, heading, attitude, and rate of turn information in a single compact unit.