AIM
11/3/22
on U.S. Government charts. Intercepting the glide slope
at this altitude marks the beginning of the final
approach segment and ensures required obstacle clear-
ance during descent from the glide slope intercept altitude
to the lowest published decision altitude for the approach.
Interception and tracking of the glide slope prior to the
published glide slope interception altitude does not
necessarily ensure that minimum, maximum, and/or
mandatory altitudes published for any preceding fixes
will be complied with during the descent. If the pilot
chooses to track the glide slope prior to the glide slope
interception altitude, they remain responsible for comply-
ing with published altitudes for any preceding stepdown
fixes encountered during the subsequent descent.
3.
Approaches used for simultaneous (parallel) independ-
ent and simultaneous close parallel operations
procedurally require descending on the glideslope from the
altitude at which the approach clearance is issued (refer to
5-4-15 and 5-4-16). For simultaneous close parallel
(PRM) approaches, the Attention All Users Page (AAUP)
may publish a note which indicates that descending on the
glideslope/glidepath meets all crossing restrictions.
However, if no such note is published, and for simultaneous
independent approaches (4300 and greater runway
separation) where an AAUP is not published, pilots are
cautioned to monitor their descent on the glideslope/path
outside of the PFAF to ensure compliance with published
crossing restrictions during simultaneous operations.
4.
When parallel approach courses are less than 2500 feet
apart and reduced in-trail spacing is authorized for
simultaneous dependent operations, a chart note will
indicate that simultaneous operations require use of
vertical guidance and that the pilot should maintain last
assigned altitude until established on glide slope. These
approaches procedurally require utilization of the ILS
glide slope for wake turbulence mitigation. Pilots should
not confuse these simultaneous dependent operations with
(SOIA) simultaneous close parallel PRM approaches,
where PRM appears in the approach title.
5.
Altitude restrictions depicted at stepdown
fixes within the final approach segment are
applicable only when flying a Non
−
Precision
Approach to a straight
−
in or circling line of minima
identified as an MDA (H). These altitude restrictions
may be annotated with a note “LOC only” or “LNAV
only.” Stepdown fix altitude restrictions within the
final approach segment do not apply to pilots using
Precision Approach (ILS) or Approach with Vertical
Guidance (LPV, LNAV/VNAV) lines of minima
identified as a DA(H), since obstacle clearance on
these approaches is based on the aircraft following
the applicable vertical guidance. Pilots are responsi-
ble for adherence to stepdown fix altitude restrictions
when outside the final approach segment (i.e., initial
or intermediate segment), regardless of which type of
procedure the pilot is flying. (See FIG 5
−
4
−
1.)
c.
The
Minimum Safe Altitudes (MSA)
is
published for emergency use on IAP or departure
procedure (DP) graphic charts. MSAs provide 1,000
feet of clearance over all obstacles, but do not
necessarily assure acceptable navigation signal
coverage. The MSA depiction on the plan view of an
approach chart or on a DP graphic chart contains the
identifier of the center point of the MSA, the
applicable radius of the MSA, a depiction of the
sector(s), and the minimum altitudes above mean sea
level which provide obstacle clearance. For conven-
tional navigation systems, the MSA is normally based
on the primary omnidirectional facility on which the
IAP or DP graphic chart is predicated, but may be
based on the airport reference point (ARP) if no
suitable facility is available. For RNAV approaches
or DP graphic charts, the MSA is based on an RNAV
waypoint. MSAs normally have a 25 NM radius;
however, for conventional navigation systems, this
radius may be expanded to 30 NM if necessary to
encompass the airport landing surfaces. A single
sector altitude is normally established, however when
the MSA is based on a facility and it is necessary to
obtain relief from obstacles, an MSA with up to four
sectors may be established.
Arrival Procedures
5
−
4
−
8