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AIM

10/12/17

5−4−25

Arrival Procedures

approach and missed approach, except that step down

waypoints may not be included in some TSO−C129

receiver databases. Included in the database, in most

receivers, is coding that informs the navigation

system of which WPs are fly−over (FO) or fly−by

(FB). The navigation system may provide guidance

appropriately − including leading the turn prior to a

fly−by WP; or causing overflight of a fly−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 5−4−5d,

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 5−4−6). 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) Hot and Cold Temperature Limitations.

A minimum and maximum temperature limitation

is published on procedures which authorize Baro−

VNAV operation. These temperatures represent the

airport temperature above or below which Baro−

VNAV is not authorized to LNAV/VNAV minimums.

As an example, the limitation will read: “Uncom-

pensated Baro−VNAV NA below −8

C (+18F) or

above 47

C (117F).” This information will be found

in the upper left hand box of the pilot briefing. When

the temperature is above the high temperature or

below the low temperature limit, Baro−VNAV may

be used to provide a stabilized descent to the LNAV

MDA; however, extra caution should be used in the

visual segment to ensure a vertical correction is not

required. If the VGSI is aligned with the published

glidepath, and the aircraft instruments indicate on

glidepath, an above or below glidepath indication on

the VGSI may indicate that temperature error is

causing deviations to the glidepath. These deviations

should be considered if the approach is continued

below the MDA.

NOTE−

Many systems which apply Baro−VNAV temperature

compensation only correct for cold temperature. In this

case, the high temperature limitation still applies. Also,

temperature compensation may require activation by

maintenance personnel during installation in order to be

functional, even though the system has the feature. Some

systems may have a temperature correction capability, but

correct the Baro−altimeter all the time, rather than just on

the final, which would create conflicts with other aircraft

if the feature were activated. Pilots should be aware of

compensation capabilities of the system prior to

disregarding the temperature limitations.
NOTE−

Temperature limitations do not apply to flying the

LNAV/VNAV line of minima using approach certified

WAAS receivers when LPV or LNAV/VNAV are annunci-

ated to be available.

(g) WAAS Channel Number/Approach ID.

The WAAS Channel Number is an optional

equipment capability that allows the use of a 5−digit

number to select a specific final approach segment

without using the menu method. The Approach ID is

an airport unique 4−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

2/28/19

AIM