Annotation of standard text SAE AS392D :
This Aeronautical Standard covers two (2) basic types of instruments as follows:
TYPE I - Range 35,000 feet. Barometric Pressure. Scale range at least 28.1 - 30.99 inches of mercury (946-1049 millibars). May include markers working in conjunction with the Barometric Pressure Scale to indicate pressure altitude.
TYPE II- Range 50,000 feet. Barometric Pressure. Scale range at least 28.1 - 30.99 inches of mercury (946-1049 millibars). May include markers working in conjunction with the Barometric Pressure Scale to indicate pressure altitude.
SUBFILE: Aerospace
TYPE OF DOCUMENT: Aerospace Standard
Stabilized: Sep 2025 