Aircraft instruments and parts therefore-namely, altimeters, airspeed indicators, rate of climb indicators, vertical velocity indicators, cabin pressure indicators, compasses, cabin altitude and differential pressure indicators, vacuum gauges, temperature gauges, oil temperature gauges, oil pressure indicators, turn and bank indicators, airspeed and mach indicators, maximum allowable airspeed indicators, servo pneumatic altimeters, altitude warning systems, namely, altimeters, encoding altimeters, blind encoders and transponders