4/20/23 

AIM 

(d)  Waypoints. 

All RNAV or GPS stand

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alone IAPs are flown using data pertaining to the particular 

IAP obtained from an onboard database, including the sequence of all WPs used for the 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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by (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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4

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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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4

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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 associated 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. 

Arrival Procedures 

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4

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