aim-363

12/2/21

AIM

approach and missed approach, except that step down
waypoints may not be included in some TSO

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C129

receiver databases. Included in the database, in most
receivers, is coding that informs the navigation
system of which WPs are fly

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over (FO) or fly

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(FB). The navigation system may provide guidance
appropriately

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including leading the turn prior to a

fly

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by WP; or causing overflight of a fly

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over WP.

Where the navigation system does not provide such
guidance, the pilot must accomplish the turn lead or
waypoint overflight manually. Chart symbology for
the FB WP provides pilot awareness of expected
actions. Refer to the legend of the U.S. Terminal
Procedures books.

(e)

TAAs are described in paragraph 5

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5d,

Terminal Arrival Area (TAA). When published, the
RNAV chart depicts the TAA areas through the use of
“icons” representing each TAA area associated with
the RNAV procedure (See FIG 5

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6). These icons

are depicted in the plan view of the approach chart,
generally arranged on the chart in accordance with
their position relative to the aircraft’s arrival from the
en route structure. The WP, to which navigation is
appropriate and expected within each specific TAA
area, will be named and depicted on the associated
TAA icon. Each depicted named WP is the IAF for
arrivals from within that area. TAAs may not be used
on all RNAV procedures because of airspace
congestion or other reasons.

(f) Published Temperature Limitations.

There are currently two temperature limitations that
may be published in the notes box of the middle
briefing strip on an instrument approach procedure
(IAP). The two published temperature limitations
are:

(1)

A temperature range limitation associ

ated with the use of baro

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VNAV that may be

published on a United States PBN IAP titled RNAV
(GPS) or RNAV (RNP); and/or

(2)

A Cold Temperature Airport (CTA)

limitation designated by a snowflake ICON and
temperature in Celsius (C) that is published on every
IAP for the airfield.

REFERENCE

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AIM, Chapter 7, Section 3, Cold Temperature Barometric Altimeter
Errors, Setting Procedures and Cold Temperature Airports (CTA).

(g) WAAS Channel Number/Approach ID.

The WAAS Channel Number is an optional
equipment capability that allows the use of a 5

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digit

number to select a specific final approach segment
without using the menu method. The Approach ID is
an airport unique 4

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character combination for

verifying the selection and extraction of the correct
final approach segment information from the aircraft
database. It is similar to the ILS ident, but displayed
visually rather than aurally. The Approach ID
consists of the letter W for WAAS, the runway
number, and a letter other than L, C or R, which could
be confused with Left, Center and Right, e.g., W35A.
Approach IDs are assigned in the order that WAAS
approaches are built to that runway number at that
airport. The WAAS Channel Number and Approach
ID are displayed in the upper left corner of the
approach procedure pilot briefing.

(h)

At locations where outages of WAAS

vertical guidance may occur daily due to initial
system limitations, a negative W symbol ( ) will be
placed on RNAV (GPS) approach charts. Many of
these outages will be very short in duration, but may
result in the disruption of the vertical portion of the
approach. The

symbol indicates that NOTAMs or

Air Traffic advisories are not provided for outages
which occur in the WAAS LNAV/VNAV or LPV
vertical service. Use LNAV or circling minima for
flight planning at these locations, whether as a
destination or alternate. For flight operations at these
locations, when the WAAS avionics indicate that
LNAV/VNAV or LPV service is available, then
vertical guidance may be used to complete the
approach using the displayed level of service. Should
an outage occur during the procedure, reversion to
LNAV minima may be required. As the WAAS
coverage is expanded, the

will be removed.

NOTE

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Properly trained and approved, as required, TSO-C145()
and TSO-C146() equipped users (WAAS users) with and
using approved baro-VNAV equipment may plan for
LNAV/VNAV DA at an alternate airport. Specifically
authorized WAAS users with and using approved
baro-VNAV equipment may also plan for RNP 0.3 DA at the
alternate airport as long as the pilot has verified RNP
availability through an approved prediction program.

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6. Approach Clearance

An aircraft which has been cleared to a holding

fix and subsequently “cleared . . . approach” has not
received new routing. Even though clearance for the
approach may have been issued prior to the aircraft
reaching the holding fix, ATC would expect the pilot
to proceed via the holding fix (his/her last assigned

Arrival Procedures

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