The ALT-3 is a 3 1/8” instrument that contains a precision altimeter and a wide range vertical speed indicator. The altimeter conforms to ANSI standard atmosphere rules from –700 ft up to a maximum of 30,000 ft. The altimeter can display altitude in feet or meters, local pressure can be set in millibars or inches of mercury
The onboard VSI indicator is altitude compensated and can be displayed in either feet/minute (ft/min) or meters/second (m/s). It also offers a digital readout with a wide range from +/-20 ft/min to as high as +/-10 000 ft/min, it also offers a logarithmic analog display with a +/-2000 ft range. The VSI can be calibrated by the user once the instrument has been installed in the aircraft.