This Aerospace Standard (AS) specifies minimum performance requirements for primary pressure altimeter systems other than air data computers. This AS covers altimeter systems that measure and display altitude as a function of atmospheric pressure. The pressure transducer may be contained within the instrument display case or located remotely. Requirements for air data computers are specified in AS8002. Some requirements for nontransducing servoed altitude indicators are included in AS791. The instrument system specified herein does not include aircraft pressure lines. Unless otherwise specified, whenever the term "instrument" is used, it is to be understood to be the complete system of pressure transducer compponents, any auxiliary equipment, and display components. The test procedures specified herein apply specifically to analog type instruments. Digital instruments or automatic test instrumentation may require other test procedures. Such differing procedures shall be justified prior to use.