AIM

4/3/14

5−4−7

Arrival Procedures

course and glidepath deviation information meeting

the precision standards of ICAO Annex 10. For

example, PAR, ILS, and GLS are precision

approaches.

(b)

Approach with Vertical Guidance (APV).

An instrument approach based on a navigation

system that is not required to meet the precision

approach standards of ICAO Annex 10 but provides

course and glidepath deviation information. For

example, Baro−VNAV, LDA with glidepath,

LNAV/VNAV and LPV are APV approaches.

(c)

Nonprecision Approach (NPA). An in-

strument approach based on a navigation system

which provides course deviation information, but no

glidepath deviation information. For example, VOR,

NDB and LNAV. As noted in subparagraph i, Vertical

Descent Angle (VDA) on Nonprecision Approaches,

some approach procedures may provide a Vertical

Descent Angle as an aid in flying a stabilized

approach, without requiring its use in order to fly the

procedure. This does not make the approach an APV

procedure, since it must still be flown to an MDA and

has not been evaluated with a glidepath.

b.

The method used to depict prescribed altitudes

on instrument approach charts differs according to

techniques employed by different chart publishers.

Prescribed altitudes may be depicted in four different

configurations: minimum, maximum, mandatory,

and recommended. The U.S. Government distributes

charts produced by National Geospatial−Intelligence

Agency (NGA) and FAA. Altitudes are depicted on

these charts in the profile view with underscore,

overscore, both or none to identify them as minimum,

maximum, mandatory or recommended.

1.

Minimum altitude will be depicted with the

altitude value underscored. Aircraft are required to

maintain altitude at or above the depicted value,

e.g., 3000.

2.

Maximum altitude will be depicted with the

altitude value overscored. Aircraft are required to

maintain altitude at or below the depicted value,

e.g., 4000.

3.

Mandatory altitude will be depicted with the

altitude value both underscored and overscored.

Aircraft are required to maintain altitude at the

depicted value, e.g., 5000.

4.

Recommended altitude will be depicted with

no overscore or underscore. These altitudes are

depicted for descent planning, e.g., 6000.

NOTE

−

1. Pilots are cautioned to adhere to altitudes as prescribed
because, in certain instances, they may be used as the basis
for vertical separation of aircraft by ATC. When a depicted
altitude is specified in the ATC clearance, that altitude be-
comes mandatory as defined above.

2. The ILS glide slope is intended to be intercepted at the
published glide slope intercept altitude. This point marks
the PFAF and is depicted by the ”lightning bolt” symbol
on U.S. Government charts. Intercepting the glide slope
at this altitude marks the beginning of the final
approach segment and ensures required obstacle
clearance 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
complying with published altitudes for any preceding
stepdown fixes encountered during the subsequent
descent.

c. Minimum Safe/Sector Altitudes (MSA)

 are

published for emergency use on IAP charts. For

conventional navigation systems, the MSA is

normally based on the primary omnidirectional

facility on which the IAP is predicated. The MSA

depiction on the approach chart contains the facility

identifier of the NAVAID used to determine the MSA

altitudes. For RNAV approaches, the MSA is based

on the runway waypoint (RWY WP) for straight−in

approaches, or the airport waypoint (APT WP) for

circling approaches. For GPS approaches, the MSA

center will be the missed approach waypoint

(MAWP). MSAs are expressed in feet above mean

sea level and normally have a 25 NM radius;

however, this radius may be expanded to 30 NM if

necessary to encompass the airport landing surfaces.

Ideally, a single sector altitude is established and

depicted on the plan view of approach charts;

however, when necessary to obtain relief from

obstructions, the area may be further sectored and as

many as four MSAs established. When established,

sectors may be no less than 90

_ in spread. MSAs

provide 1,000 feet clearance over all obstructions but