Altimeter tolerance range
Dear,
The ICAO document 8168 volume 1 Flight Procedures states the following note related to "Pre-flight operational test":
Note 2.— The tolerance of 20 m or 60 ft for altimeters with a test range of 0 to 9 000 m (0 to 30 000 ft) is considered acceptable for aerodromes having elevations up to 1 100 m (3 500 ft) (Standard atmospheric pressure). Table III-1-3-1 indicates the permissible range for aerodromes at different elevations when the atmospheric pressure at an aerodrome is lower than the standard, i.e. when the QNH setting is as low as 950 hPa.
When do we use the tolerance ranges in table III-1-3-1? Is it only when the elevation of the aerodrome is higher OR is it when the elevation is higher and the QNH is equal to or lower than 950 hPa?
Kind regards.