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AIM

10/12/17

5

−4−7

Arrival Procedures

Manhattan altimeter setting; when not available use
Salina altimeter setting and increase all MDAs
40 feet. When the altimeter must be obtained from a
source other than air traffic a note will indicate the
source; e.g., Obtain local altimeter setting on CTAF.
When the altimeter setting(s) on which the approach
is based is not available, the approach is not
authorized. Baro

−VNAV must be flown using the

local altimeter setting only. Where no local altimeter
is available, the LNAV/VNAV line will still be
published for use by WAAS receivers with a note that
Baro

−VNAV is not authorized. When a local and at

least one other altimeter setting source is authorized
and the local altimeter is not available Baro

−VNAV

is not authorized; however, the LNAV/VNAV
minima can still be used by WAAS receivers using the
alternate altimeter setting source.

NOTE

Barometric Vertical Navigation (baro

−VNAV).  An RNAV

system function which uses barometric altitude informa-
tion from the aircraft’s altimeter to compute and present
a vertical guidance path to the pilot. The specified vertical
path is computed as a geometric path, typically computed
between two waypoints or an angle based computation
from a single waypoint.  Further guidance may be found in
Advisory Circular 90

−105.

5.

A pilot adhering to the altitudes, flight paths,

and weather minimums depicted on the IAP chart or
vectors and altitudes issued by the radar controller, is
assured of terrain and obstruction clearance and
runway or airport alignment during approach for
landing.

6.

IAPs are designed to provide an IFR descent

from the en route environment to a point where a safe
landing can be made. They are prescribed and
approved by appropriate civil or military authority to
ensure a safe descent during instrument flight
conditions at a specific airport. It is important that
pilots understand these procedures and their use prior
to attempting to fly instrument approaches.

7.

TERPS criteria are provided for the following

types of instrument approach procedures:

(a)

Precision Approach (PA). An instrument

approach based on a navigation system that provides
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 k, 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

2/28/19

AIM