Está no campo de dados Altitude / Altitude Mínima:
5.30 Altitude/Minimum Altitude
Definition/Description: The Altitude/Minimum Altitude field indicates
the reference altitude associated with (1) Enroute Airways (MEA, MFA
or other minimum altitudes as defined by source), (2) holding pattern
path of Holding Pattern record, (3) altitudes at fixes in terminal
procedures and terminal procedure path termination defined by the Path
Terminator in the Airport or Heliport SID/STAR/Approach Record and (4)
lowest altitude of the blocked altitudes for a Preferred Route.
...
On Airport and Heliport SID, STAR and Approach Route records, the
first Altitude field will contain an altitude when Altitude
Description field contains a plus (+), a minus (-), or one of the
following characters: B, G, or V. The second Altitude field will
contain an altitude when the Altitude Description field contains one
of the following characters: B, C, D, G, or V. In approach procedure
coding, some fix Altitudes may be below sea level, in the case of
altitudes at runway fixes when the runway threshold elevation is below
sea level. In these cases, the Altitude will be expressed in feet with
a minus (-) sign in the first character of the five-character field,
see examples.
In Registros primários 4.1.9.1 SID / STAR / Approach você encontrará as colunas 85-89 e 90-94 são os dois campos de altitude mencionados no 5.30.
Os caracteres mencionados no 5.30 são definidos em:
5.29 Altitude Description (ALT DESC)
Definition/Description: The Altitude Description field will designate
whether a waypoint should be crossed at, at or above, at or below or
at or above to at or below specified altitudes. The field is also used
to designate recommended altitudes and cases where two distinct
altitudes are provided at a single fix.