This British Standard specifies the general design and performance requirements for pressure altimeters having a combined counter and single pointer presentation in two forms as follows.
a) Type A. A panel-mounting indicator operating from any form of remote altitude transducer.
b) Type B. A panel-mounting indicator containing its own sensing mechanism inside the case.
The standard provides for instruments operating over
an indicated range of -1000 ft to +50 000 ft
(geopotential).
The design may include provision for applying
corrections to the aircraft static pressure system
error.