Garmin GPS 155XL User Manual

GPS 155XL

Pilot’s Guide and Reference

This manual is written for software version 2.04 or above, and is not suitable for
earlier software versions.

© 1999 GARMIN Corporation

GARMIN International, Inc., 1200 East 151st Street, Olathe, Kansas 66062 USA
Tel: [phone] Fax: [phone]

GARMIN (Europe) LTD, Unit 5, The Quadrangle, Abbey Park, Romsey, Hampshire S051 9AQ, UK
Tel: [phone] Fax: [phone]

GARMIN (Asia) Corp., 3rd Fl., No. 1, Lane 45, Pao-Hsing Road, Hsin Tien, Taipei, Taiwan R.O. C.

Tel: [phone]-3773 Fax: [phone]-1758

INTRODUCTION

Foreword

GARMIN, GPS 155XL, Spell’N’Find, AutoLocate,
PhaseTrac12, and AutoStore are trademarks of
GARMIN and may only be used with permission.

Web Site Address: www.garmin.com

All rights reserved. No part of this manual may be reproduced or transmitted in any
form or by any means, electronic or mechanical, including photocopying and recording,
for any purpose without the express written permission of GARMIN.

Information in this document is subject to change without notice. GARMIN reserves
the right to change or improve their products and to make changes in the content of this
material without obligation to notify any person or organization of such changes or
improvements.

January 1999 190-00067-20 Rev. B Printed in USA

NavData®is a registered trademark of
Jeppesen, Inc.

All rights reserved.

i

INTRODUCTION

Cautions

NOTE: This device complies with Part 15 of the FCC

limits for Class B digital devices. This equipment gener­ates, uses, and can radiate radio frequency energy and, if
not installed and used in accordance with the instruc­tions, may cause harmful interference to radio communi­cations. Furthermore, there is no guarantee that interfer­ence will not occur in a particular installation.

If this equipment does cause harmful interference, the
user is encouraged to try to correct the interference by relo­cating the equipment or connecting the equipment to a dif­ferent circuit than the affected equipment. Consult an
authorized dealer or other qualified avionics technician for
additional help if these remedies do not correct the problem.

CAUTION

The Global Positioning System is operated by the United States government,
which is solely responsible for its accuracy and maintenance. The system is subject to
changes which could affect the accuracy and performance of all GPS equipment.
Although the GARMIN GPS 155XL is a precision electronic NAVigation AID
(NAVAID), any NAVAID can be misused or misinterpreted and therefore become
unsafe.

Use the GPS 155XL at your own risk. To reduce the risk of unsafe operation,
carefully review and understand all aspects of this Owner’s Manual and the Flight
Manual Supplement, and thoroughly practice using the simulator mode prior to actu­al use. When in actual use, carefully compare indications from the GPS 155XL to all
available navigation sources, including the information from other NAVAIDS, visual
sightings, charts, etc. For safety, always resolve any discrepancies before continuing
navigation.

Operation of this device is subject to the following
conditions: (1) This device may not cause harmful inter­ference, and (2) this device must accept any interference
received, including interference that may cause undesired
operation.

The GARMIN GPS 155XL does not contain any user­serviceable parts. Repairs should only be made by an
authorized GARMIN service center. Unauthorized repairs
or modifications could void your warranty and authority
to operate this device under Part 15 regulations.

ii

The altitude calculated by the GPS 155XL is geometric height above mean sea

level and could vary significantly from altitude displayed by pressure altimeters in air­craft. Never use GPS altitude for vertical navigation.

The Jeppesen database incorporated in the GPS 155XL must be updated regularly
in order to ensure that its information is current. Updates are released every 28 days.
A database information packet is included in your GPS 155XL package.

Pilots using an out-of-date database do so entirely at their own risk.

Accessories & Packing List

Congratulations on choosing the finest, most advanced panel mount IFR
GPS receiver available. The GPS 155XL represents GARMIN’s commitment to provide
an accurate, easy-to-use GPS for all of your aviation needs.

Before installing and getting started with your unit, please check to see that your
package includes the following items. If any parts are missing or damaged, please see
your GARMIN dealer immediately.

Standard Package:

INTRODUCTION

Accessories and

Packing List

• GPS 155XL Unit & NavData® Card

• GPS Antenna

• Installation Rack & Connectors

• Pilot’s Guide & Quick Reference Guide

• Database Subscription Packet

• Warranty Registration Card

Optional Accessories:

• Remote Battery Pack

• AC Adapter

• PC Software/Interface Kit

• User Data Card

• 28 to 14 volt DC converter

• MD-41 External Switch/Annunciator

To obtain accessories for your GPS 155XL,
please contact your nearest GARMIN dealer.

iii

INTRODUCTION

Warranty

To obtain warranty service, see your local dealer
or call the GARMIN Customer Service department
for a returned merchandise tracking number. The
unit should be securely packaged with the tracking
number clearly marked on the outside of the
package, and sent freight prepaid and insured to a
GARMIN authorized warranty service facility.

GARMIN is fully committed to your satisfaction as
a customer. If you have any questions regarding
the GPS 155XL, please contact our customer ser­vice department at:

GARMIN International, Inc.
1200 East 151st Street
Olathe, KS 66062-3426
[phone]
FAX [phone]

Every GARMIN GPS is built to exacting standards to provide years of trouble-free
service. GARMIN warrants this product to be free from defects in materials and
workmanship for one year from the date of purchase.

GARMIN International, Inc. will at its sole option, repair or replace any
components which fail in normal use. Such repairs or replacement will be made at
no charge to the customer for parts or labor. The customer is, however, responsible
for any transportation costs. This warranty does not cover failures due to abuse,
misuse, accident or unauthorized alteration or repairs. GARMIN International, Inc.
assumes no responsibility for special, incidental, punitive or consequential damages,
or loss of use.

THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE,
AND IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED, INCLUD­ING ANY LIABILITY ARISING UNDER WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE, STATUTORY OR OTHERWISE. THIS
WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM
STATE TO STATE.

iv

PART ONE: INTRODUCTION

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i

Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ii

Accessories/Packing List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iv

Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v-vi

Key and Knob Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii-viii

GPS 155XL Takeoff Tour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-9

PART TWO: REFERENCE

Section 1: Navigation with the GPS 155XL ( Nkey) . . . . . . . . . . . . . . .10

Navigating and planning functions

Section 2: Waypoint and Database Information ( Wkey) . . . . . . . . . . . .32

Finding and using database and waypoint information

Section 3: Nearest Waypoints ( Tkey) . . . . . . . . . . . . . . . . . . . . . . . . .53

Finding nearest waypoints, SUAs and FSS/ARTCC frequencies

Section 4: Direct-to ( Dkey) & Route Navigation ( Rkey) . . . . . . . .58

Creating and using routes

Section 5: Approaches, SIDs and STARs ( Rkey) . . . . . . . . . . . . . . . . .74

Selecting and flying non-precision approaches

INTRODUCTION

Table of Contents

To quickly and easily locate information
on specific tasks, please refer to the Index
on page 130.

Section 6: Messages and Unit Settings ( Mkey) . . . . . . . . . . . . . . . . . .96

v

INTRODUCTION

Table of Contents

Appendix A: NavData®and User Data Card Use . . . . . . . . . . . . . . . .108

Appendix B: Installation and Maintenance of the GPS 155XL . . . . . . .110

Appendix C: Simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111

Appendix D: GPS 155XL Messages and Abbreviations . . . . . . . . . . . . .113

Appendix E: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121

Appendix F: Map Datums . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122

Appendix G: Troubleshooting Q & A . . . . . . . . . . . . . . . . . . . . . . . . .124

Appendix H: Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130

vi

B

b

a

T

R

W

Key and Knob Functions

The power/intensity knob controls unit power and display intensity.

The zoom-in key is used to zoom in to the next smaller scale setting when
viewing the map page.

The zoom-out key allows you to zoom out to the next larger scale setting
when viewing the map page.

The nearest key is used to obtain information on the 9 nearest airports,
VORs, NDBs, intersections, user waypoints and 2 nearest FSS/ARTCC
points of communication. The nearest key also accesses any active SUA
information. See Section 3 for more information on the nearest waypoints.

The route key enables you to create, edit, activate and invert routes, and
access approaches, SIDs and STARs. Search-and-rescue, parallel offset and
closest point of approach functions are also performed using the route key.
See Section 4 for more information on routes and Section 5 for more infor­mation on approaches, SIDs and STARs.

The waypoint key is used to view information such as runways, frequen­cies, position and comments on airports, VORs, NDBs, intersections and
user waypoints. See Section 2 for more waypoint information.

INTRODUCTION

Key and Knob

Functions

The GPS 155XL is designed to minimize
keystrokes when performing operations. There are
typically several ways to perform the same opera­tion. In general, using the knobs will decrease key­strokes and time spent using the GPS 155XL.
Experiment to find the most effective way to use
the GPS 155XL to your advantage.

N

The navigation key is used to view navigation and position information.
Planning operations are also performed using this key. See Section 1
for more information on navigation and planning operations.

vii

INTRODUCTION

Key and Knob

Functions

M

D

The message key is used to view system messages and to alert you to
important warnings and requirements. This key is also used to access the
GPS 155XL’s unit settings. See Section 6 for more information on messages
and unit settings.

The direct-to key performs an instant direct-to, allows you to enter a
waypoint, and sets a direct course to the destination. See Section 4.

viii

This manual will describe entering data using

the K and O knobs. Experiment with them and
become efficient in entering data with the concen­tric knobs. This will greatly reduce the amount of
time required to navigate with the GPS 155XL.

Whenever the GPS 155XL is displaying a list
of information that is too long for the display
screen, the scrolling arrow prompt will indicate
which direction to scroll to view additional infor­mation. To scroll through a list (with the cursor
active), simply rotate the outer knob. When the
cursor in not active, use the inner knob to view
additional information.

\

E

C

O

K

The clear key is used to erase information or cancel an entry.

The enter key is used to approve an operation or complete data entry.
It is also used to confirm information, such as during power on.

The cursor key is used to activate/deactivate the cursor on the GPS
155XL’s display. Pressing once will activate the cursor (indicated by high­lighted characters on a data field), which is used to highlight fields for data
entry, changing information or cycling through available options. Press a
second time to deactivate the cursor.

The outer knob is used to advance through pages, advance the cursor
or move through data fields.

The inner knob is used to change data or scroll through information that
cannot fit on the screen all at once.

The GARMIN GPS 155XL is a powerful navigational tool that provides pilots with accurate
navigational data, including non-precision approaches, SIDs and STARs. The Takeoff Tour is
designed to familiarize you with the operation of the GPS 155XL, including powering up the unit,
entering data and performing a simple direct-to, and provide a limited introduction to the
‘Nearest’ functions. In addition, this section also briefly covers the position, NAV summary, map
and frequency pages available from the NAV key. These pages will be used for most of your in­flight navigation.

The Takeoff Tour assumes that the receiver and antenna have been properly installed
and you have not changed any of the GPS 155XL’s default settings. If you have changed
any of the factory default settings (position format, units of measure, selectable fields, etc.),
the pictures shown here may not match your configuration. Prior to using your GPS
155XL for the first time, we recommend that you taxi to a location that is well away from
buildings and other aircraft so the unit can collect satellite data without interruption.

Powering up the GPS 155XL

The GPS 155XL’s power and display intensity are controlled using the Bknob at the

The welcome page appears when the GPS 155XL
is turned on. During the time this screen is
displayed, the GPS 155XL performs a self test to
ensure proper operation.

bottom left of the unit. Rotating it clockwise will turn unit power on and progressively
increase the display intensity. After turning the unit on, a welcome page will be displayed
while the unit performs a self test.

The database page will appear next, showing the current database information on the

NavData card, with the valid operating dates, cycle number and database type indicated. The
database is updated every 28 days, and must be current for approved approach and IFR opera­tions. Information on database subscriptions is available inside your GPS 155XL package.

To acknowledge the database information:

E key

1. Press the

.

The database confirmation page shows the
effective and expiration dates of the Jeppesen
database on the NavData Card.

TAKEOFF TOUR

Power On

1

TAKEOFF TOUR

Acquiring Satellites

The satellite status page shows the ID numbers for
the satellites and the relative signal strength of
each satellite received. Turn the K knob to view
additional satellites.

Once the database has been acknowledged, the satellite status page will appear,

and the GPS 155XL will begin to collect satellite information. An ‘Acquiring’ status
will be displayed on the satellite status page, and the signal values on the bottom line
of the page will begin displaying numeric values. This is a good indication that you
are receiving signals and satellite lock will occur. Following the first-time use of your
GPS 155XL, the time required for a position fix will vary — usually from one to two
minutes.

If the unit can only obtain enough satellites for 2D navigation (no altitude), the
unit will use the altitude provided by your altitude encoder, if one is connected and
working. If not, you will be prompted to enter the altitude with a ‘Need alt- Press
NAV’ message. If this message occurs, press the Nkey and use the Kand

O

knobs to enter the altitude shown on your altimeter. Press Ewhen finished.

If the GPS 155XL has not been operated for a period of six months or more, it
may have to ‘Search the Sky’ to collect new data. This means the unit is acquiring
satellite data to establish almanac and satellite orbit information, which can take 5 to
10 minutes. The satellite status page will display a ‘Search Sky’ status, and the
message annunciator (U), next to the Mkey, will also flash to alert you of a system
message — ‘Searching the Sky’.

To view a system message

1. Press M.

:

The message page will appear and display the status or warning information

‘Search Sky’ indicates that satellite almanac data
is not available or has expired (if the unit hasn’t
been used for six months or more). The data will
be recollected from the first available satellite.

2

applicable to the receiver’s current operating condition.

To return to the previous page after viewing a message

1. Press Magain.

:

After the GPS 155XL acquires satellites and computes a position, the position page

will appear automatically, and you’ll be informed with ‘Ready for navigation’ on the
message page.

Altitude, MSA or ESA

TAKEOFF TOUR

Position Page

Position (lat/lon)

Reference Waypoint Field

The position page displays your present latitude and longitude, altitude and a refer­ence waypoint field. The altitude and reference waypoint fields are also selectable (see
Section 1 for more information) to allow you to configure the unit to your own prefer­ences. The default settings are:

• Altitude— Your present GPS altitude

• Present Position— Latitude and longitude displayed in degrees/minutes

• Reference Waypoint— The bearing and distance to the nearest airport

The position page is one of seven pages available under the GPS 155XL’s Nkey:

• NAV summary page • Map page

• NAVCOM page • Position page

• Satellite status page • NAV menu 1

• NAV menu 2

During most flights, the position, NAV summary, map and NAVCOM pages will be the
primary pages used for navigation. The pages are accessible by pressing the Nkey and
rotating the outer knob, or by pressing the Nkey repeatedly.

{

The map page combines a moving map display
and navigation data for complete situational
awareness.

The navigation communications (NAVCOM) page
provides a complete list of airport frequencies at
your departure and arrival airports.

3

TAKEOFF TOUR

Direct-To Navigation

NAV Summary Page

The GPS 155XL uses direct point-to-point navigation to guide you from takeoff to
touchdown in the IFR environment. Once a destination is selected, the unit will provide
speed, course and distance data based upon a direct course from your present position
to your destination. A destination can be selected from any page using the D(direct-

to) key.

To select a direct-to destination:

D

1. Press the

key. The NAV summary page will appear with the destination field highlighted.

The NAV summary page without a direct-to
destination or active route appears blank, except
for ground speed (GS) and track (TRK) figures,
if displayed.

2. Rotate the
tion waypoint may be an airport, VOR, NDB, intersection or user waypoint, as long as it is in
the database or stored in memory as a user waypoint.

3. Rotate the

4. Repeat steps 2 and 3 to spell out the rest of the waypoint identifier.

5. Press

6. Press

K

knob to enter the first letter of the destination waypoint identifier. The destina-

O

knob to the right to move the cursor to the next character position.

E

to confirm the identifier. The direct-to confirmation page will appear.

E

to confirm the destination.

Once the direct-to destination is confirmed, the NAV summary page will appear

When a destination is selected, the direct-to
confirmation page appears to verify the
destination you selected.

with the destination indicated in the lower left hand corner of the screen. Your present
speed and track over the ground, and the distance and estimated time enroute to your
destination are also displayed. The graphical CDI (course deviation indicator), located at
the top of the screen, displays your position relative to the desired course and provides

4

turn anticipation and waypoint messages during route navigation.

In addition to the destination field and graphical CDI, the GPS 155XL NAV summa­ry page features five selectable fields for various navigation data so that the page may be
configured to your own preferences (see Section 1 for more information). The default
settings for the NAV summary page are:

• Distance (dis)— The distance to your destination in nautical miles

• Ground Speed (gs)— Your present speed over the ground in knots

• Bearing (brg)— The direction from present position to your destination

• Desired Track (dtk)— The course between the ‘from’ and ‘to’ waypoints

• Estimated Time Enroute (ete)— The time to your destination (in hours

and minutes) based upon your present speed and course

The next page available from the Nkey is the map page. The map page combines
the primary navigation information from the NAV summary page – distance to way­point, ground speed, bearing, desired track and ETE – with a moving map display. The
moving map display shows your current position (using an airplane symbol or a dia­mond symbol) relative to nearby airports, VORs, NDBs, intersections, user waypoints
and airspace boundaries. Notice that the graphical CDI does not appear on the map
page; the graphical CDI does appear on all other GPS 155XL pages.

The map page can be divided into two main sections:

Map Display

Data

Fields

{

TAKEOFF TOUR

NAV Summary &

Map Pages

NAV summary page with ‘trk’, ‘brg’ and ‘eta’
displayed.

NAV summary page with ‘dtk’, ‘brg’ and ‘trk’
displayed.

5

TAKEOFF TOUR

Map Page

The map display may be oriented along your
ground track (track up), course (desired track up)
or fixed at north up. Desired track up or north up
settings show your present position with a dia­mond symbol instead of the airplane symbol.

Airspace

Boundaries

Airport Waypoint

Present

Position

The map display occupies the right side of the display. Your present position is indi­cated by a plane symbol (in track up mode) or a position diamond (in other orienta­tion modes), with your route displayed as a solid line. Nearby airports, navaids and
user waypoints may be depicted on the map—with unique identifying symbols for each
waypoint type. Boundaries for special use and controlled airspaces can also appear on
the map display. You may select which features are shown on the map using the map
setup page (see page 97).

Distance & Bearing

to Waypoint

Destination

Waypoint

GS

ETE

TRK

DTK

Map

Scale

The data fields on the map page indicate distance and bearing to destination way-

Distance and bearing to waypoint, destination
waypoint name and desired track are shown on
the left hand side of the map page. To remove the
data fields that border the map display, press \.

6

point, desired track, ground track, ground speed, time to waypoint and map scale. The
destination waypoint name, bearing to waypoint, distance to waypoint and desired track
appear on the left side of the page. The other data fields are located at the corners of the
map display, as shown in the illustration above, and may be removed by pressing

\.

The map display has 14 available scales from 0.5 to 300 (nautical miles, statute miles or
kilometers) representing the vertical height of the map. The map scale is controlled by
the aandbkeys, with the current scale displayed in the lower right corner.

To select a map scale:

1. Press

to increase the map scale and show a larger area (or turn Kto the right).

a

TAKEOFF TOUR

Map Scales

NAVCOM Page

2. Press

to decrease the map scale and show a smaller area (or turn Kto the left).

b

Another page available under the GPS 155XL’s Nkey is the navigation
communications (NAVCOM) page. It provides you with a complete list of airport fre-

quencies at your departure and arrival airports, allowing convenient selection of fre­quencies you’ll need along your flight path. If you do not have an active departure air­port, the navigation communications page will display the frequencies for the
airport nearest your departure position.

To view the NAVCOM page from the map page, rotate Oone stop to the right.

The NAVCOM page lists your departure and arrival airports on the left side of the
page, with all the database frequencies listed in a column down the right side of the
page. To scroll through the list of frequencies, simply rotate the inner knob (K) in the
direction of the arrow prompts at the bottom left of the page.

Once a direct-to is activated, the NAV summary page will provide navigation to the

destination until the direct-to is cancelled or another direct-to destination is activated.

To cancel a direct-to from the NAV summary page:

1. Press the

2. Press

3. Press

C

key to activate the cursor in the destination field.

\

.

E

.

To change the map scale press
scale or

The NAVCOM page lists the frequencies for your
departure (or nearest) and arrival airports.

to decrease the scale.

b

to increase the

a

7

TAKEOFF TOUR

Nearest Waypoints

The GPS 155XL’s Tkey provides the nine nearest airports, VORs, NDBs, inter­sections, user waypoints and any SUA (special use airspace) alerts, as well as the two
closest FSS (Flight Service Station) and center (ARTCC) frequencies for your present
position. The nearest waypoint feature is a handy safety feature that may be used to
execute a quick direct-to in case of an in-flight emergency or to review the closest facil­ities to your present position. The nearest feature can also be used to quickly find the
contact frequency of the nearest airport.

The nearest airport page shows up to nine
nearest airports from your present position.

To view the nine nearest airports

1. Press the Tkey. The nearest airport will be displayed, with the range and bearing from
your present position, along with elevation, frequency and runway data.

2. To review the rest of the nearest airport list, rotate the

To view the nearest list for other waypoint categories (VOR, NDB, etc.)

1. Rotate the Oknob to the right, or press the Tkey repeatedly.

2. Rotate Kto scroll through the list.

:

K

knob to the right.

:

Once the nearest airport (or any other nearest waypoint) page is displayed, the

selected waypoint can be quickly reviewed or selected as a direct-to destination.

To review the selected waypoint from the nearest waypoint list

1. Press Cto activate the waypoint field.

2. Press Eto display the waypoint identification page.

To view additional nearest airports, rotate the
K knob.

8

3. Rotate Oto view any additional waypoint information available.

4. Press Tto return to the nearest waypoint page.

:

To select a nearest waypoint as a direct-to destination

1. Press the Dkey. The direct-to confirmation page for the selected waypoint will appear.

2. Press Eto confirm.

:

Congratulations! You’ve covered the basic operation of the GPS 155XL. We
encourage you to experiment with your new GPS receiver to get to know all the
advanced navigation features it has to offer. If you’d like a little more practice, try
using the built-in simulator described in Appendix C. An optional AC adapter will
even let you plan and simulate flights in the comfort of your home or office.

TAKEOFF TOUR

Nearest Waypoints

Shutting Down

To turn the GPS 155XL off

1. Turn the Bknob to the left until the unit shuts off.

:

NOTE: The GPS 155XL is normally connected to power through the avionics master
switch. With the optional remote battery installed, the unit will display a power down
warning when the master switch is turned off. This warning page features a timer which
will count down from 30 seconds when the unit senses that power is off. After 30 sec­onds, the GPS 155XL will shut off. If you wish to

continue operating the unit, press
any key during the countdown period, and the GPS 155XL will continue operating
from the backup battery.

To review a nearest waypoint, highlight the identi­fier and press E.

To select a nearest waypoint as your direct-to
destination, press D and E.

9

SECTION

1

NAV KEY

Overview

Section 1

Navigation Key

The GPS 155XL features seven navigation pages to provide various position,
course, speed, status and planning information. The pages may be viewed by pressing
the Nkey and rotating the outer knob, or by pressing the Nkey repeatedly.

NAV Summary Page

Map Page

NAVCOM Page

NAV Menu 2

Remember! The NAV pages will only display infor­mation AFTER the position and navigational infor­mation has been calculated from the satellites. If you
are on the position page before the unit has calculat­ed a position, you will be able to enter an approxi­mate position and altitude. This is helpful in speeding
satellite acquisition if the unit has moved a great dis­tance with the power off.

If you are not sure the GPS is actively calculating
position, check the receiver status field for ‘2D NAV’
or ‘3D NAV’ by pressing the N key and rotating
the outer knob until the satellite status page appears.
The current receiver status is displayed at the top left
of the page.

10

The NAV summary, map, NAVCOM and position pages are the primary pages
used during in-flight navigation, while the nav menu and status pages offer access to
planning, calculation and status functions. Note that rotating the outer knob clock­wise will continuously cycle through all the nav pages, whereas turning the knob
counterclockwise will stop the page selection sequence at the NAV summary page.

Whenever the Nkey pages are in use, the indicator light (U) next to the
key will illuminate. If the GPS 155XL requires you to enter data on a navigation page,
a message prompt with specific instructions will appear and the indicator will flash. If
you leave the NAV page sequence for another set of pages, the last NAV page dis­played will reappear when you return to the nav sequence.

NAV Menu 1

Satellite Status Page

Position Page

N

The GPS 155XL’s NAV summary page provides you with the important informa-

tion needed to navigate directly to your destination. The destination field, located at
the bottom left of the page, displays the current destination waypoint or active route
leg being navigated. If no direct-to destination, route or approach is being navigated,
the destination field will remain blank.

Ground Speed

Messages

or CDI

NAV KEY

NAV Summary Page

SECTION

1

Distance

field

Direction

field

The graphical CDI (course deviation indicator) at the top of the page shows your

position relative to the desired course (the moving D-bar) to the destination way­point. The TO/FROM arrow in the center of the scale indicates whether you are
heading to (an up arrow) the waypoint or if you have passed the waypoint (a down
arrow). Note that the GPS 155XL always navigates TO a waypoint unless the GPS
SEQ switch is set to the HOLD position, or you have passed the last waypoint in a
route. The default setting of the CDI scale is ‘Auto’. If you are not navigating to a des­tination, the CDI field will display a ‘No active waypoint’ message, and only speed
and track data will be available. The CDI field is also used to display the GPS 155XL’s
turn anticipation and waypoint alert data during route and approach operations (see
sections 4 and 5).

In addition to displaying your active destination and the course deviation scale,
the NAV summary page features five selectable fields for various distance, direction,
speed and time options. This allows you to configure the NAV summary page to your
preferences. The default settings displayed are distance, ground speed, bearing,
desired track and estimated time enroute.

Destination Field

Time or Direction Field

Direction

field

The TO/FROM arrow indicates whether you are
heading to (an up arrow) the waypoint or if you’ve
passed the waypoint (a down arrow).

‘No Active Waypoint’ appears on the CDI field if
there is no destination waypoint selected using the
D key and no active route.

11

WPT 1

STR L

NORTH

NORTH

WPT 2

BRG

TRK

GS

DIS

AIRPLANE

DTK

The following functions may be displayed in the distance field:

SECTION

1

NAV KEY

Configuring the

NAV Summary Page

• dis— Distance from present position to the ‘active to’ waypoint.

• str— Steer direction and distance, or digital crosstrack error. An ‘L’ or ‘R’

indicates which direction to steer, while the distance value indi­cates how far you are off course.

The following functions may be displayed in the ground speed field:

• gs— Your present speed over the ground.

• str— Steer direction and distance, or digital crosstrack error. An ‘L’ or ‘R’

indicates which direction to steer, while the distance value indi­cates how far you are off course.

The following steering functions may be displayed in the direction fields:

• brg— Bearing, the direction from your present position to the waypoint.

• cts— Course to steer to reduce cross track error and re-intercept course.

• dtk— Desired track, the course between the active from and to waypoints.

• trk— Track, the direction of movement relative to the ground.

• trn— Turn, the direction and degrees to turn to get back on course.

The following information can be displayed in the time field:

• eta— Estimated time of arrival (at the active to waypoint).

• ete— Estimated time enroute (to the active to waypoint).

• trk— Track, or the direction of movement relative to the ground.

• vn— Vertical navigation, or VNAV. If VNAV has been activated, this field

indicates either the elapsed time before the VNAV maneuver is to

12

begin or the VNAV altitude (the suggested altitude you should be fly­ing in order to complete the maneuver).

OBS

TO

FR

N

33

30

W

24

21

S

15

12

E

6

3

To change any of the selectable fields on the NAV summary page:

1. Press Cto activate the cursor.

2. Rotate Oto highlight the field you would like to change.

3. Rotate Kto change the field to display the desired information.

4. Rotate Oto highlight another field, or Cto finish.

Destination

Selected

Course

The GPS 155XL’s course select feature allows the pilot to define the inbound course
to, or outbound course from, the ‘active’ waypoint, using an external HSI. Once the
course select function is activated, the selected course will be displayed next to the desti­nation waypoint identifier and the CDI will provide guidance relative to the desired
course. The course select feature is only available during route, approach or direct-to
navigation. For more information on the course select feature and the GPS SEQ switch,
see Section 5.

To set a desired inbound course:

1. Dial the desired course on the HSI.

2. Set the external GPS SEQ switch to the HOLD position.

3. To stop the course select function, set the GPS SEQ switch back to the AUTO position.

NAV KEY

SECTION

NAV Summary

& Course Select

1

GPS SEQ

AUTO HOLD

The GPS 155XL’s course select feature uses the
external GPS SEQ switch, allowing you to dial in
the desired course to or from your destination
directly from your HSI.

13

SECTION

NAV KEY

1

The map page, showing only airports and air­spaces on the map display.

The map page, showing airports, airspaces, VORs
and NDBs on the map display.

Map Page

Map Display

Data

Fields

{

The next page available from the GPS 155XL’s Nkey is the map page. The map
page displays your present position, using an airplane symbol (in track up mode) or a
position diamond (in other orientation modes), along with nearby airports, VORs,
NDBs, intersections, user waypoints and airspace boundaries. Note: If the GPS 155XL
is unable to determine a GPS position, the present position symbol will not appear on
the map page.

The map display occupies the right side of the display and shows your position
relative to nearby airports, navaids, user waypoints and airspaces. Different symbols
are used to distinguish between waypoint types. The identifiers for any on-screen
waypoints can also be displayed. Special-use and controlled airspace boundaries
appear on the map, showing the individual sectors in the case of Class B or Class C
airspace. The map display can be configured to display airports, navaids, user way­points, airspaces only at certain scales or these items may be disabled entirely (see page

95). This allows you to de-clutter the map display at larger scale settings.

The map display can be set to 14 different scale settings (from 0.5 to 300 nautical
miles, statute miles or kilometers) during en route operation; while in terminal or
approach mode 12 different scale settings are available (with the two highest en route
scales disabled). The scale represents the top-to-bottom distance covered by the map
display.

Present

Position

Map Scale

14

To select a map scale:

1. Press

2. Press

An autozoom feature is available which will automatically adjust from an en route
scale of 300 through each lower scale, stopping at a scale of 1 as you approach your
destination waypoint. The autozoom feature is turned on/off from the map setup page
described on page 97.

The orientation of the map may be fixed at ‘north up’ (nrthup), or set to ‘desired
track up’ (dtk up) or ‘track up’ (trk up). The ‘north up’ setting will keep the top of the
map display fixed on north. ‘Track up’ will cause the map to rotate so the top of the
map is the direction you are heading. ‘Desired track up’ keeps the map display fixed
along your desired course. Map orientation is changed on the map setup page
described on page 97.

Navigation data is also provided on the map page to guide you during your flight.
The destination waypoint name, distance & bearing to waypoint, and desired track
(dtk) appear on the left side of the page. Four additional data fields are located at the
corners of the map display (and may be removed by pressing \), as follows:

Ground speed (gs) - upper left corner
Ground track (trk) - lower left corner
Estimated time en route (ETE) - upper right corner
Map scale - lower right corner (cannot be removed)

to increase the map scale and show a larger area (or turn Kto the right).

a

to decrease the map scale and show a smaller area (or turn Kto the left).

b

NAV KEY

SECTION

Map Page

To change the map scale press theakey to
increase the scale or

To remove the North indicator and/or data fields
from the map display, press \.

to decrease the scale.

b

1

15

SECTION

NAV KEY

1

The NAVCOM page lists the frequencies for your
departure (or nearest) and arrival airports in the
following order:

Departure Arrival

• Unicom • ATIS

• ATIS • Approach

• Clearance Delivery • Arrival

• Clearance Pretaxi • TCA

• Ground • TMA

• Tower • CTA

• Multicom • ARSA

• Other • TRSA

• Departure • Tower

• TCA • Multicom

• TMA • Other

• CTA • Ground

• ARSA • Unicom

• TRSA

16

NAVCOM Page

The next page available from the GPS 155XL’s Nkey is the navigation communi-

cations (NAVCOM) page. The NAVCOM page provides a list of the airport frequencies

at your departure and arrival airports, allowing convenient selection of frequencies you’ll
need along your flight path. To scroll through the list of frequencies, rotate the inner
knob (K) in the direction of the arrow prompts at the bottom left of the page.

The frequencies displayed for the departure and arrival airports are listed in the
order you are most likely to use them (see left), with the available frequencies
displayed to the right of the airport identifier. If you do not have an active route with a
departure airport, the NAVCOM page will display the frequencies for the airport nearest
your departure position.

If a frequency has sector or altitude restrictions, the frequency will be followed by a
‘brg?’ indication.

To view restrictions on a frequency:

1. Press Cto activate the cursor.

2. Rotate Oto highlight the ‘brg?’ next to the frequency you wish to view.

E

3. Press

to begin viewing restrictions.

Once you begin viewing restrictions, you can view any additional frequencies for
the selected airport by rotating K. (Note: An arrow prompt displayed next to the air­port identifier indicates additional frequencies are available.) You can also view the
other airport information pages by rotating O. Information contained on these pages
is covered in Section 2. To return to the NAVCOM page, press N.

Some frequencies in the NAVCOM page have tags which designate their usage:

‘tx’ – transmit only ‘rx’ – receive only
‘pt’ – part time frequency

The GPS 155XL position page displays the graphical CDI along with your present
latitude and longitude, altitude and a reference waypoint field. The altitude and refer­ence waypoint fields are selectable to configure the page to your own preferences and
current navigation needs.

Altitude, MSA or ESA

Position (lat/lon)

Reference Waypoint Field

An altimeter setting field appears on the position page when you are within 30 nm
of a destination airport. The altimeter setting field allows you to define the current
barometric pressure, which is used by the integrity monitoring to crosscheck altitude.

The altitude field can display either the present altitude, minimum safe altitude
(MSA) or enroute safe altitude (ESA). MSA is the recommended minimum altitude
within a ten mile radius of your present position. ESA is the recommended minimum
altitude within ten miles of your course on an active route or direct-to. MSA and ESA
altitudes are calculated from information contained in the database and generally
include mountains, buildings and other permanent features (see following page).

{

Altimeter Setting

Field

(user-selectable)

NAV KEY

NAVCOM &

Position Pages

NAVCOM page with receive only (rx) frequency
and frequencies with restrictions (brg).

Frequency restrictions on 124.60, showing range
of applicable radials from 130º through 309º.

SECTION

1

17

To change the altitude field:

SECTION

NAV KEY

Position Page &

1

The position page displaying MSA. MSA and ESA
are based on data stored in the NavData card.
This information cannot be solely relied upon as
an absolute measure of safe altitude in your area.
Consult current charts and NOTAMS.

Position page displaying the ‘TOP’ VOR as the ref­erence waypoint. This configuration can be used to
help monitor your distance and radial from a
waypoint of your choice. (Note: the waypoint cate­gory is listed as ‘wpt’ rather than ‘VOR’ because

18

the GPS 155XL is not using the nearest VOR.)

Reference Waypoints

The position page also features a reference waypoint field, located at the bottom of

the page, to indicate your bearing and distance from a selected waypoint. The reference
waypoint field can display the following:

During DME arc approach operations, the reference field will automatically display

the DME reference as long as the ‘active to’ waypoint is part of the DME arc.

To change the reference waypoint field to display the nearest airport, VOR, NDB,
intersection, user waypoint or the range and bearing from a user selected waypoint:

If you have selected ‘wpt’:

This allows the distance and bearing from any waypoint to be displayed continuous-

ly, which may be useful when an approach reference is not the closest navaid.

C

1. Press

2. Rotate

3. Rotate

• Range, bearing and identifier from the nearest airport (default), VOR, NDB,
intersection, or user waypoint

• Range, bearing and identifier from a user specified waypoint

1. Press

2. Rotate Oto highlight the category field after the fr.

3. Use Kto choose which waypoint type you would like displayed. (Choose ‘wpt’ if you would

like range and bearing from a specific waypoint to be displayed.)

4. Press

5. Rotate Oto advance the cursor to highlight the identifier field.

6. Use the
airport, VOR, NDB, intersection, or user waypoint.) Press

7. Press Cto confirm the selection.

to obtain a cursor.

O

until the ‘alt/esa/msa’ field is highlighted.

K

to display the desired data. Press Cto return to normal navigation.

C

to activate the cursor.

C

to remove the cursor, or:

K

and Oknobs to enter the identifier name. (This waypoint identifier can be an

E.

The GPS 155XL’s satellite status page provides satellite information to monitor

GPS coverage and receiver performance. This is helpful when you may be experienc­ing low signal levels due to poor coverage or installation problems.

To view the satellite status page:

1. Press Nand rotate Ountil the satellite status page appears.

NAV KEY

Satellite

Status Page

SECTION

1

CDI

Receiver Status

Satellites in view

Signal strength of

satellite being tracked (1-9)

The top lines of the status page display a graphical CDI, followed by the receiver

status and the current position accuracy in DOP or EPE. The default setting is DOP.

The following functions may be displayed in the DOP/EPE field:

• dop— Dilution of Precision, a measure of the satellite geometry quality

and relative accuracy of your position, with 1 indicating good
geometry and 10 meaning poor.

• epe— Estimated Position Error, an overall measure of your positional

accuracy in feet or meters using signal and data quality, receiver
tracking status and DOP.

Satellite in view

but not receiving signal

EPE/DOP

value

Satellite status page with ‘EPE’ displayed.
Estimated Position Error (EPE) gives an overall
measure of your position accuracy in feet or
meters.

Satellite status page with ‘DOP’ displayed.
Dilution of Precision (DOP) measures relative
accuracy from 1 to 10.

19

To change the DOP/EPE field:

SECTION

1

‘Acquiring’ satellites for navigation. In this case,
the satellites are being received, but the data is
still being collected before a position can be
determined.

‘Searching the Sky’ for satellites. No satellite
almanac data exists in the GPS 155XL. It must
be recollected from the first available satellite.

20

NAV KEY

Receiver

Status Field

1. PressNand rotate Oto display the satellite status page.

2. If the desired field (EPE or DOP) is not displayed, press C.

3. Use Kto change between ‘epe’ and ‘dop’. Press Cto finish.

The receiver status field, located on the second line (left side) of the page, will

display the following messages under the appropriate conditions:

Search Sky - The GPS 155XL is searching the sky for visible satellites. You

will be informed with the message ‘Searching the Sky’.

Acquiring - The GPS 155XL is acquiring satellites for navigation.
2D Nav - The GPS 155XL is in 2D navigation mode. If your installation

does not include an altitude serializer, you must enter the alti­tude manually (see page 2). ‘2D Dif Nav’ will appear when you
are receiving DGPS corrections in 2D mode.

3D Nav - The GPS 155XL is in 3D navigation mode and will compute

altitude. ‘3D Dif Nav’ will appear when you are receiving DGPS
corrections in 3D mode.

Simulator - The GPS 155XL is in simulator mode, which should only be

used for practice and trip planning. Never use simulator mode
for actual navigation.

Poor Cvrge - The GPS 155XL cannot acquire sufficient satellites for navigation.
Need Alt - The GPS 155XL needs altitude in order to start/continue naviga-

tion. Press Nto display the position page and enter altitude.

Not Usable - The GPS 155XL is unusable due to incorrect initialization or

abnormal satellite conditions. Turn the unit off and on again.

AutoLocate - The GPS 155XL is looking for any satellite whose almanac has

been collected. This process can take up to five minutes.

The third and fourth lines of the satellite status page provide the satellite number
and signal strength of each satellite in view. The satellite status page shows signal
strength for up to eight satellites at a time. If additional satellites are being received
an arrow on the ‘sat’ line will indicate additional data is available.

To view additional satellites:

1. Rotate

K

to view more satellites.

Additional information regarding each satellite’s azimuth, elevation and other data
is also available.

To view individual satellite information:

NAV KEY

Satellite Data Page

SECTION

1

1. Press Nand use Oto display the satellite status page.

2. Press Cto activate the cursor.

3. Use Oto highlight the satellite number you wish to view and press E.

This will display the satellite data page, showing the selected satellite’s number,
elevation angle, rise or fall indication, User Range Accuracy (URA, or the range
measurement accuracy as determined by the satellite), azimuth and signal strength.

To view other satellites:

4. Rotate Kto view information for the next satellite.

5. Rotate Oand press Con the satellite status page when you are finished.

Viewing individual satellite information.

21

SECTION

1

NAV KEY

NAV Menu 1

Trip Planning

NAV Menu 1

In addition to the five other navigation pages, the GPS 155XL features two menu

pages to perform a host of planning and navigation functions. NAV Menu 1 provides
access to the following functions:

• Trip Planning • Density altitude/true airspeed calc.

• Fuel Planning • Winds aloft calculations

• VNAV Planning • Checklists

To display NAV Menu 1:

1. Press N.

2. Rotate Ountil NAV Menu 1 is displayed.

Trip Plan is the first function listed on NAV Menu 1 and allows the pilot to view

distance, ESA, bearing and estimated time enroute (ETE) between any two waypoints,
and for programmed route legs. The ground speed can be varied manually to calcu­late several possible ETEs.

To use the trip planning function:

1. Press Nand rotate Ountil NAV Menu 1 is displayed.

2. Press C, then Eto access trip planning.

3. Rotate Kto select waypoint mode or desired route number and press E.

4. For direct-to navigation, use

E

to accept the waypoints. To use your present position as a waypoint, leave the way-

point field blank.

Trip planning with values calculated between two
waypoints.

22

5. For route calculations, choose either ‘cum’ for cumulative data (from beginning to end) or
the leg desired by rotating

6. Use

K

and Oto enter the ground speed. Press Eto calculate the values and

to finish.

K

and Oto enter the ‘to’ and ‘from’ waypoints. Press

K

.

C

The density altitude/true airspeed function is also accessed from NAV Menu 1.

Density altitude is the theoretical altitude at which your aircraft will perform depending
on several environmental conditions, including air pressure and total air temperature
(the temperature including the heating effect of speed, read on a standard outside tem­perature gauge on most aircraft). True airspeed considers the same factors.

To calculate the density altitude and true air speed:

1. Press Nand rotate Ountil NAV Menu 1 is displayed.

2. Press Cand rotate Oto highlight ‘Dalt/tas?’.

3. Press Eto access the density altitude page.

4. Use Kand Oto enter the indicated altitude (‘ialt’) and press E.

NAV KEY

Density Altitude &

True Airspeed

SECTION

1

5. Use Kand Oto enter the calibrated airspeed (‘cas’). Press E.

6. Use Kand Oto enter the air pressure (‘pres’) and press E.

7. Use Kand Oto enter the total air temperature (‘tat’).

8. Press Eand the density altitude and true airspeed will be calculated and displayed.

9. Press Cto remove the cursor.

If your installation includes components to provide any of the information

required on the density altitude page, they will be used as the defaults.

The fuel planning page will display fuel requirements for both direct-to naviga-

tion and programmed routes. The fuel planning function requires the pilot to enter
the initial amount of fuel on board and the flow rate. You may also enter different
ground speeds to view information based on different travel times. If your installation
is interfaced to a fuel flow sensor, the flow rate and other information will be sup­plied by the fuel flow sensor, and need not be entered manually.

Density altitude/true airspeed page

Fuel planning page showing calculation from pre­sent position to ‘KDAL’.

23

SECTION

1

NAV KEY

NAV Menu 1

Fuel Planning

To perform fuel planning operations:

1. Press Nand rotate Ountil NAV Menu 1 is displayed.

2. Press Cand rotate Ountil ‘Fuel Plan?’ is highlighted. Press E.

3. Rotate Kto select either ‘wpt’ for direct navigation or the desired route number. Press E.

4. For waypoint-waypoint navigation, use Kand Oto enter the ‘to’ and ‘from’ waypoints.
Press

E

to accept the waypoints. To use the present position as a waypoint, leave the

corresponding waypoint field blank.

5. For route calculations, choose either ‘cum’ for cumulative route fuel requirements
(from beginning to end) or the leg desired by rotating

If leg is selected, it displays the amount of fuel required to fly until that leg is complete.

K

K

.

Fuel planning page showing calculations between
two waypoints.

Fuel planning page with other information
indicating ‘endurance’ and ‘reserve’ times.

24

For example: The fuel required to complete leg 2 is leg 1 + leg 2.

Fuel required to complete leg 4 is leg 1 + leg 2 + leg 3 + leg 4.

6. Rotate Oto advance the cursor to ‘fob:’ or ‘gs:’ (depending on which is displayed).

7. Use Kand Oto enter the fuel on board or the ground speed. Press E.

8. Rotate Oback two positions to highlight the ‘fob:’ or ‘gs:’ field again.

9. Rotate Kto display the other information. Press E.

10. Use Kand Oto enter the remaining data. Press E.

11. Use Kand Oto enter the flow rate, in units per hour, if needed. Press E.

The GPS 155XL will calculate the range and endurance (i.e., how long the fuel
will last) of your aircraft. These are found in the first field on the bottom row of the
page. The amount of fuel left on board (lfob) and reserve time after the selected
direct-to, leg or route is flown are displayed in the second field on the bottom row.

The GPS 155XL’s winds aloft function is used to calculate the true direction and

speed of any winds, and indicates whether you are flying with a head wind or tail
wind, and the wind speed.

To calculate winds aloft:

1. Press Nand rotate Ountil NAV Menu 1 is displayed.

2. Press Cand rotate Ountil ‘Winds?’ is highlighted. Press E.

3. Use Kand Oto enter your present heading in the ‘hdg:’ field. If your installation
includes a fuel/air data computer, this will be displayed automatically. Press

4. Use Kand Oto enter your true airspeed (TAS) in the ‘tas:’ field. If you have previously

calculated it using the density altitude/true air speed function, it will be displayed as the
default. Press

E

. The wind direction and speed and head/tail wind will be displayed.

E

.

NAV KEY

Winds Aloft &

VNAV Functions

SECTION

1

The VNAV function calculates vertical speed requirements to reach a desired altitude before

or after a specified distance from a waypoint. This is helpful when you’d like to descend to a cer­tain altitude near an airport or climb to an altitude before reaching a route or direct-to waypoint.

To calculate vertical navigation parameters:

N

1. Press

2. Press

3. Use Kand Oto enter the initial (from) altitude. Your current GPS altitude will be dis-

played as the default. Press E.

4. Use Kand Oto enter the desired final (to) altitude. Press E.

5. Use Kand Oto enter the distance from the waypoint. Press E.

6. Use Kto select ‘before’ or ‘after’ the waypoint. Press E.

7. Use

or a direct-to waypoint). Press

and rotate Ountil NAV Menu 1 is displayed.

C

and rotate Ountil ‘Vnav Plan?’ is highlighted. Press

K

and Oto select the waypoint identifier (it must be a waypoint in the active route

E

.

E.

Winds aloft page

Vertical navigation page

25

SECTION

NAV KEY

NAV Menu 1

1

VNAV displayed on NAV summary page. The
VNAV altitude should be compared with the read­ing on the aircraft altimeter to ensure you are on
the proper climb/descent angle.

VNAV & Checklists

You will now notice that the vertical speed has been calculated, based on your

present speed. If you desire a more rapid climb or descent rate:

8. Use Kand Oto enter the new desired vertical speed, or press E to accept the
calculated value.

9. Press

E

to activate the vertical navigation function.

If you enter a value greater than the value computed by the GPS 155XL, the time
remaining before the maneuver is to begin will be displayed. When the countdown reaches
15 seconds, you will be informed with the message ‘Start altitude chng’. The VNAV func­tion will automatically be cancelled if the active direct-to or route is changed in any way,
and you will be informed with a ‘VNAV cancelled’ message.

The GPS 155XL will allow you to create up to nine checklists with 30 items each
to remind you of repetitive tasks (that can be called up at any time for review). The
checklist feature is useful for creating pre-flight checklists, landing checklists, emergency
procedures, etc. Each name or function can have up to 16 characters each.

To create a checklist:

N

1. Press

2. Press

3. Press
Press

4. Use

and rotate Ountil NAV Menu 1 is displayed.

C

and rotate Ountil ‘Chklist?’ is highlighted. Press E.

C

and use Oto highlight the checklist you would like to create or edit.

E

.

K

and Oto enter the title of the checklist. Press

E.

Checklist catalog page.

26

This will display the checklist items page. On this page you can enter each task,

such as ‘Check Fuel’.

5. Use Kand Oto enter the checklist item. Press E.

C

6. You may repeat step 5 to enter additional items, or press

to finish.

To execute a checklist:

1. Press Nand rotate Ountil NAV Menu 1 is displayed.

C

2. Press

3. Use

4. Press

To delete a checklist item or an entire checklist:

and rotate Ountil ‘Chklist?’ is highlighted. Press E.

O

to highlight the checklist you would like to see. Press E.

E

to check off list items.

NAV KEY

Checklists

Approach Timer

SECTION

1

1. To delete a checklist item, highlight the desired item and press

2. To delete an entire checklist, highlight the desired list and press \, followed by E.

The GPS 155XL’s NAV Menu 2 provides access to various timer and planning func-

tions, including:

• Approach timer • Clock (Date and time)

• Trip Timer • RAIM Prediction

• Scheduler messages • Sunrise and sunset calculations

The approach timer acts as either a count up or a count down timer that can be

set or reset at any time.

To activate/change/view the approach timer:

N

1. Press

2. Press

3. Rotate

4. Use

5. Rotate

and rotate Ountil NAV Menu 2 is displayed.

C

and rotate Ountil ‘Appr Time?’ is highlighted. Press E.

K

to select either ‘Count up’ or ‘Count down’. Press E.

K

and Oto set the time to begin counting from. Press E.

O

to select the desired function: ‘Start’, ‘Stop’, or ‘Reset’. Press Eto execute.

\

, followed by E.

Executing a checklist.

NAV Menu 2

27

SECTION

NAV KEY

Clock Function

1

Clock function set to display local time in the time
fields of all other GPS 155XL pages.

To reset the trip timer, highlight ‘Reset?’ and
press E.

Trip Timer

When the countdown timer reaches zero, you will be informed with a ‘Timer
expired’ message. The timer will then begin to count up, displaying the time since it
expired. The timer runs, if not altered, whenever the GPS 155XL is turned on.

The GPS 155XL clock function keeps track of both UTC time (Greenwich Mean
Time or Zulu Time calculated from the satellites) and local time, and allows you to
designate which format to use in all time displays. The local time and date can be set
without displaying local time on other GPS 155XL pages.

To set the local date/time:

1. Press Nand rotate Ountil NAV Menu 2 is displayed.

2. Press Cand rotate Ountil ‘Clock?’ is highlighted. Press E.

K

3. Use

4. Use

5. Use Kand Oto set the local time. Press E.

6. Press Cto complete.

The GPS 155XL’s trip timer will automatically keep track of the duration of your
current trip and can be configured to run when the GPS 155XL is on, or only when your
ground speed exceeds a specified value (see Section 6).

To view or reset the trip timer:

1. Press Nand rotate Ountil NAV Menu 2 is displayed.

2. Press Cand rotate Ountil ‘Trip Time?’ is highlighted. Press E. The current time of

to select either ‘utc’ or ’local’ time to be displayed in the time fields. Press E.

K

and Oto set the local date. Press E.

day, departure time and time enroute will be displayed.

3. To reset the timer, press E. To skip resetting the timer, press C.

28

The RAIM Prediction function allows you to confirm that GPS coverage is

available for your current location or at a specified waypoint any day of the year.
Receiver Autonomous Integrity Monitoring performs checks to ensure that the GPS
155XL will have adequate satellite geometry to work with during your flight. RAIM
availability will be near 100% in Oceanic, En route and Terminal phases of flight.
Because the FAA’s TSO requirements for non-precision approaches specify significant­ly better satellite coverage than other flight phases, RAIM may not be available when
flying some approaches. The GPS 155XL will automatically monitor RAIM during
approach operations and warn you if RAIM is not available. RAIM prediction will
help you plan for a pending flight to confirm GPS operation during an approach.

To predict RAIM availability:

N

1. Press

2. Press

3. Rotate

4. Use
position. Press

5. Use
you have selected from the clock display), and the day, month and year. The current date
will be displayed automatically. Press

6. Rotate

7. Press

When the computations are complete, the GPS 155XL will display whether or not
RAIM is available for the specified waypoint at the specified date and time, +/- 15
minutes of your ETA. Refer to the table on page 99 for specific RAIM protection
limits as they relate to CDI scale figures.

and rotate Ountil NAV Menu 2 is displayed.

C

and rotate Oto highlight ‘RAIM Prd?’. Press E.

O

to highlight the field which you would like to change.

K

and Oto enter the waypoint name, or leave it blank to use your current

E

to accept.

K

and Oto enter the ETA in hours and minutes (in local or UTC time, whichever

E

to accept.

O

to highlight ‘Compute RAIM?’.

E

to compute information.

NAV KEY

SECTION

RAIM Prediction

Enter the location, time and date for RAIM pre­diction.

RAIM available for the entered time, date and
waypoint location.

1

29

SECTION

NAV KEY

NAV Menu 2

1

The scrolling arrow prompt indicates which direc­tion to scroll to view additional listings.

Scheduler

The scheduler function will display reminder messages (such as ‘Change oil’, ‘Switch

fuel tanks’, ‘Overhaul’, etc) after a specified time has elapsed. For example, if you enter
‘Change oil’ to be displayed in 30 hours, the message ‘Change oil’ will be displayed after the
GPS 155XL has been running in Normal mode for 30 hours. After appearing, the message
will be displayed each time the GPS 155XL is turned on until it is changed or deleted.

To enter a scheduled message:

1. Press Nand rotate Oto display NAV Menu 2.

2. Press Cand rotate Ountil ‘Scheduler?’ is highlighted.

3. Press E.

4. Rotate

O

to highlight the message you would like to edit. To delete, press \,

then

E

.

5. Use Kand Oto enter the message. Press E.

6. Use Kand Oto set the time to elapse before the message is displayed, in hours and
minutes, up to 99 hours and 59 minutes (this time is cumulative and counts whenever
the GPS 155XL is on in Normal operating mode).

7. Press

E

.

You may edit another scheduled message by repeating steps 4, 5, 6 and 7 or if you

are finished, press C.

The scheduled message will appear after the timer
expires and reappear every time the GPS 155XL
is powered on until the message is changed.

30

The GPS 155XL’s sunrise/sunset planning function allows you to calculate the time

of sunrise or sunset at any waypoint or your present position for a specified date.

To calculate sunrise and sunset times at a waypoint or at your present location:

1. Press Nand rotate Ountil NAV Menu 2 is displayed.

2. Press Cand rotate Oto highlight ‘Sunrise?’. Press E.

3. Use Kand Oto enter the waypoint identifier, or leave blank to use current position.

E

Press

4. Press Eto accept the waypoint information.

5. Use Kand Oto enter the date desired.

6. Press
will be displayed in your local time or UTC time, whichever is specified from the clock
function on NAV Menu 2.

.

E

and the sunrise and sunset times will be calculated and displayed. The times

NAV KEY

SECTION

Sunrise/Sunset

Calculations

Sunrise/sunset planning page showing UTC (Zulu)
sunrise and sunset times for ‘KROG’.

1

31

SECTION

WPT KEY

2

Please note that your GPS 155XL uses ICAO
identifiers for all airports. All U.S. airport identifiers
which contain only letters use the prefix ‘K’. For
example, Los Angeles International is KLAX under
the ICAO standard. Other airports, such as Otten
Memorial (3VS), that contain numbers in the
identifier do not require the ‘K’ prefix. Many foreign
countries use two letter prefixes. For more
information on ICAO identifiers, contact:

Document Sales Unit
International Civil Aviation Organization
999 University Street
Montreal, Quebec
Canada H3C 5H7

32

Overview

Waypoint and Database Information

The GPS 155XL uses a Jeppesen NavData® card to provide position and facility
information for thousands of airports, VORs, NDBs and intersections. Each facility in the
database is stored as a waypoint with its own latitude/longitude, identifier (up to five let­ters and/or numbers), and other pertinent information. Up to 1,000 user waypoints may
also be created and stored in the GPS 155XL’s internal memory.

Waypoint Menu Page

Waypoints With Comments List

Waypoint information is available through four primary waypoint pages accessible
from the GPS 155XL’s Wkey. The waypoint pages may be scrolled through by pressing
the Wkey and rotating the outer knob until the desired page is displayed, or by press­ing the Wkey repeatedly.

Section 2

Proximity Waypoints Page

User Waypoint List

The GPS 155XL organizes waypoints into one of five waypoint categories for your
convenience. Each waypoint category provides different types of detailed information
for a selected facility:

• Airports - Identifier, city/state, country, facility name, position (lat/lon),

elevation, fuel services, control and approach information, IFR proce­dures, runways and communication frequencies.

• VORs - Identifier, city/state, country, facility name, position (lat/lon),

frequency, magnetic variation, co-located DME or TACAN and weather
broadcast indication.

• NDBs - Identifier, city/state, country, facility name, position (lat/lon),

frequency and weather broadcast indication.

• Intersections - Identifier, country, position (lat/lon) and nearest VOR.

• User - Identifier (name), position (lat/lon) and reference waypoint.

To view detailed waypoint information for a desired waypoint, select the appro­priate waypoint category from the waypoint menu page.

To choose a waypoint category (for viewing information):

1. Press

W

and rotate Oto display the waypoint menu page. (If pressing Wonce

does not display the waypoint menu page, press

2. Press Cand rotate Oto highlight the desired waypoint category.

3. Press

E

to accept the waypoint category. The waypoint identification or position page

for the selected category will appear with the waypoint identifier field ready for entry.

W

a second time.)

WPT KEY

SECTION

Waypoint Categories

& Menu Page

The waypoint menu page allows you to select the
desired waypoint type (or category).

The airport position page shows the position,
field elevation and available fuel types for the
selected airport.

2

33

SECTION

2

WPT KEY

Entering Waypoints

After a waypoint category is selected, information for a waypoint may be viewed
by entering the identifier or name of the desired waypoint. Airports, VORs and NDBs
may be entered by either the identifier, name or the location (city) of the facility.
Intersections and user waypoints must be entered by the identifier.

To enter a waypoint identifier:

1. With the cursor over the waypoint field, use
waypoint identifier.

As the identifier is entered, the GPS 155XL’s Spell’N’FindTMfeature will scroll
through the available database, displaying those waypoints matching the identifier let­ters you have entered to that point. When the desired waypoint is displayed, press

C

to remove the cursor.

Entering a waypoint by identifier.

Entering a waypoint by city. Note that punctua­tion marks are not used when entering locations
or names. Use spaces, where appropriate, to iden­tify these marks. For example, St. Louis would be

34

entered as “ST LOUIS” without a period.

To obtain waypoint information by entering the facility name of the airport or
navaid, or its location:

1. Press Wand rotate Oto display the waypoint menu page.

2. Press Cand rotate Oto highlight the desired waypoint category.

3. Press Eto accept the waypoint category.

4. Rotate Oto highlight the middle field to enter location (city) OR:

Rotate Oto highlight the bottom field to enter facility name or VOR/NDB name.

5. Use Kand Oto enter the location or the name, and press Cto finish.

As the information is entered, the GPS 155XL will display any entries in its data­base that match the letters you have entered. If duplicate entries exist for the entered
identifier, name or location, additional entries may be viewed by rotating K. Once
the desired waypoint is displayed, press Cto continue.

K

and Oto enter the

Once a waypoint category and identifier have been selected, the GPS 155XL will
provide extensive information through a set of waypoint pages for the selected cate­gory. The pages available for each waypoint category are presented here in the order
they appear on the waypoint menu page: airports, VORs, NDBs, intersections and
user waypoints.

Airport Information

Airport Identification Page

WPT KEY

Airport Information

SECTION

2

Airport Comments Page

Airport Runway Page

Airport Communication Page

To scroll through the airport pages:

1. Make sure the cursor is not present. If it is, press C.

2. Rotate Oin either direction to scroll through the available pages.

Airport Position Page

If the city or facility name information is too long
to fit the screen, the name will scroll across the
page every few seconds so the complete name can
be read.

Airport Procedures Page

The airport position page shows the position,
field elevation and available fuel types for the
selected airport.

35

SECTION

WPT KEY

2

Airport communication page. The down arrow
next to the identifier indicates additional frequen­cies may be displayed by rotating the K knob.

Airport Pages

The GPS 155XL features six airport pages:

airport identification— allows entry of desired airport by identifier,
facility name or city; displays region and/or country of facility.

airport position— allows entry of desired airport by identifier; displays
latitude, longitude and elevation; indicates usage and fuel availability;
displays available approaches and airport control/radar capability.

airport procedures— allows entry of desired airport by identifier; dis­plays all available approaches, SIDs and STARs at the selected facility.

airport communication— allows entry of desired airport by identifier;
displays radio frequencies/usage, and sector and altitude restrictions.

airport runway— allows entry of desired airport by identifier; indicates
runway designations, length, surface and lighting information; displays
ILS/localizer and/or pilot-controlled lighting frequencies.

airport comments— allows entry of desired airport by identifier; displays
user comments for the selected airport.

Waypoint Type

and Identifier

Location

(city/state)

CDI

Region/Country

Airport runway page. The down arrow next to
the identifier indicates additional runways may be
displayed by rotating the K knob.

36

The airport identification page displays a selected airport’s identifier, region and

country, city/state and facility name. The identification page is always the first airport
page available, allowing you to quickly review an airport facility or select another
facility by entering the identifier, facility name or city of the desired airport.

Facility Name

{

The airport position page displays the latitude, longitude and elevation of the
selected airport, as well as usage or fuel availability, available approaches and airport
control/radar capability. The following descriptions and abbreviations are used on the
airport position page:

Elevation— In feet or meters
Usage/Fuel— If the airport is for military use, it will display ‘military’.

If it is private, the GPS 155XL will display ‘private’. If it is a
public airport, it will display the fuel type(s) available:

• av gas— 80-87 octane, 100 LL, 100-130 octane, or mogas is

available

• jet— Jet A, Jet A-1 or Jet A+ fuel is available

• av/jet— Both av gas and jet fuel are available

Position— In degrees/minutes or degrees/minutes/seconds of latitude

and longitude

Approach Information— displays the airport approaches available

• no apr— No approach is available

• np-apr— Non-precision approach is available

• loc— Localizer approach is available

• ils— ILS approach is available

WPT KEY

Airport

Position Page

1 2 3

4

Airport Position Page

SECTION

2

65

Controlled Airspace Information— displays controlled airspace type

• class B • cta

• class C • tma

Radar— displays approach/departure radar capability

• radar— indicates radar is present

1. Identifier (selectable)

2. Elevation

3. Fuel Availability

4. Airport Position

5. Approach Information

6. Controlled Airspace/Radar Capability

37

SECTION

2

WPT KEY

Airport Procedures

Page

The airport procedures page displays all the available approaches, SIDs and

STARs at any selected airport in the database, without placing a specific approach,
SID or STAR in the active route. This allows the pilot to quickly scan the procedures
of any nearby airport in case of an emergency or help plan future flights. You may
view the available non-precision approaches, SIDs or STARs by selecting the desired
list from the procedure type field.

Airport Identifier

(selectable)

SID Procedures Page

STAR Procedures Page

38

Scrolling Arrow

Prompt

To view the available procedures for a selected airport:

W

1. Press

2. Press

3. Rotate

4. Press

Whenever there are more than two available procedures for a selected category,
the GPS 155XL will display a scrolling arrow prompt on the left side of the list. To
view additional procedures, simply rotate Kwith the cursor removed. As you scroll
through the list, the arrow prompt will point “down” to indicate additional listings
below the displayed procedures, “up” to indicate additional listings above, or a “dou­ble arrow” to indicate the list may be scrolled up or down.

and rotate Oto display the airport procedures page.

C

and rotate Oto highlight the procedure field.

K

to select the approach, SID or STAR list.

C

to remove the cursor.

CDI

Procedure Type

(selectable)

Available Procedures

The airport communication page displays the radio frequencies and usage for

the selected airport, as well as sector and altitude restrictions.

To view the communication page from any of the airport information pages:

1. Rotate Owith the cursor removed to display the communication page.

2. Rotate

K

in the direction of the arrow prompt to view additional frequencies. You may

also view additional frequencies with the cursor on the page by rotating the

The following descriptions and abbreviations are used on the communication page:

Frequencies without restriction information:

• ats - Automatic terminal information service (ATIS)

• ptx - Pre-taxi

• clr - Clearance delivery

• gnd - Ground

• twr - Tower

• uni - Unicom

• mul - Multicom

• atf - Aerodrome traffic frequency

• ctf - Common traffic advisory frequency (CTAF)

• mf - Mandatory frequency

• oth - Other frequencies

Frequencies with restriction information:

• dep - Departure • apr - Approach

• arv - Arrival • class B

• cta - ICAO control area • tma - ICAO terminal control area

• class C • trsa - Terminal radar service area

O

knob.

WPT KEY

Airport

Communications Page

Airport communications page for KCLT.

SECTION

2

‘Receive only’ frequencies will be followed by an ‘rx’ indicator, while ‘transmit
only’ frequencies will display a ‘tx’. If a frequency has sector and/or altitude restric­tions, they will also be displayed. Sector restrictions define a range of radials from the
facility, while altitude restrictions may describe an area above, below or between
altitudes. Additional instructions, if available, will be displayed on the bottom line.

Frequency page with sector restrictions.

39

SECTION

2

WPT KEY

Airport

Runway Page

The airport runway page displays runway designations, length, surface and

lighting for the selected airport, as well as ILS/localizer and/or pilot-controlled lighting
frequencies.

To view the runway page from any of the airport information pages:

1. Rotate Owith the cursor removed to display the runway page.

2. To view additional runway information, rotate
The scrolling arrow prompt, located beside the identifier field, indicates which direction to
scroll for additional runway information.

If a localizer and/or ILS are used on the same runway, rotating Kwill sequence

through both sets of information.

Airport runway page for KICT.

To view additional runways, rotate the K knob in
the direction of the arrow prompts.

40

The following descriptions and abbreviations are used on the airport runway page:

Runway surfaces:

• hard - Hard (concrete, asphalt, etc.) • turf - Turf (grass)

• seal - Sealed surface • grav - Gravel surface

• dirt - Dirt surface • soft - Unknown soft surface

• unkn -Unknown surface • watr - Water landing site

Runway lighting:

• pt lights - Part-time lights

• ft lights - Full-time lights

• pc - Pilot-controlled (with frequency) lights

• no lights - No runway lighting

K

with the cursor removed.

VOR Information

The GPS 155XL features three VOR waypoint pages:

VOR identification— allows entry of desired VOR by identifier,
facility name or city; displays region and/or country of facility.

VOR position— allows entry of desired VOR by identifier; displays
latitude, longitude and frequency; provides magnetic variation, weather
broadcasts and DME/TACAN information.

VOR comments— allows entry of desired VOR by identifier; displays user
comments for the selected facility.

WPT KEY

VOR Information

SECTION

2

VOR information is accessed by entering the desired facility by identifier, city or
facility name (see page 34) on any VOR waypoint page. The VOR identification and
comments pages are identical in form and function to their airport page counterparts.

To scroll through the VOR pages:

1. Make sure the cursor is not present. If it is, press C.

2. Rotate Oin either direction to scroll through the available pages.

In addition to displaying the VOR frequency, magnetic variation and position, the
VOR position page indicates if a DME or TACAN is co-located at the facility. The ‘wx
bdcst’ field indicates that the VOR also transmits weather information.

VOR identification page

VOR position page showing co-located TACAN
facility and weather broadcast.

41

SECTION

2

NDB Information

WPT KEY

NDB Information

NDB Position Page

The GPS 155XL also uses identification, position and comments pages for NDB
information. The NDB waypoint pages are used in the same manner as VOR pages:
NDB information is accessed by entering the desired facility’s identifier, city or name
(see page 34) on the NDB identification page.

NDB identification page

To scroll through the NDB pages:

1. Make sure the cursor is not present. If it is, press C.

2. Rotate Oin either direction to scroll through the available pages.

The NDB position page (see above) displays the selected facility’s identifier, fre­quency and position, as well as any weather broadcasts available. The NDB comment
page will display any user comments for the selected NDB (see page 50 for instruc­tions on entering user comments).

NDB comments page

42

Intersection Information

Intersection Position Page

The last database waypoint category available is intersections. Two intersection
pages are available: intersection position and intersection comments. Intersections
may be entered by identifier only (not city or name) on either intersection page.

WPT KEY

Intersection
Information

SECTION

2

To scroll through the intersection pages:

1. Make sure the cursor is not present. If it is, press C.

2. Rotate Oto toggle between the available pages.

The intersection position page displays the selected facility’s identifier, region and/or
country, latitude and longitude, and the identifier, distance and bearing to the nearest
VOR (not necessarily the VOR used to define the intersection). The intersection com­ment page will display any user comments for the selected intersection (see page 50).

Intersection comments page

43

SECTION

2

WPT KEY

User Waypoints

User Waypoint Information

In addition to the airport, VOR, NDB and intersection waypoints contained in your
NavData® card, the GPS 155XL allows you to store up to 1,000 user-defined way­points. Once a user waypoint is created, two user waypoint pages will display the fol­lowing information:

• Waypoint identifier

• Position in latitude and longitude

• Identifier, range and bearing from a reference waypoint

• User comments

User waypoint page

User waypoint comments page

44

To scroll between the user waypoint position page and the user comments page,
rotate O. User waypoints may be created or modified using the Wkey. After select-

ing the waypoint identifier, as shown on page 34, you will be prompted to enter infor­mation if the waypoint is new. There are three ways to create a user waypoint’s posi­tion from the Wkey:

1. Enter the exact position of the new waypoint.

2. Reference a known waypoint by range and bearing.

3. Enter a range and bearing from your current position.

To create or edit a user waypoint:

1. Press W.

2. Press Cand use Oto highlight the ‘user?’ field. Press E.

3. Use Kand Oto enter the waypoint identifier. Press E.

If the waypoint identifier entered does not exist, you will be prompted to select a
method to enter the new waypoint’s position into memory. If the waypoint exists (i.e.,
you’re just reviewing or editing a user waypoint), skip step 4 and move on to the next
set of instructions.

4. Select the desired waypoint entry method using Oand press E.

You will automatically be placed on the latitude and longitude field (if you
selected ‘enter posn?’), the ‘from’ field (if you select ‘ref wpt?’) or the ‘bearing’ field (if
you select ‘rng/brg from posn?’).

To enter/edit the position of the user waypoint:

1. Use

K

and Oto enter the latitude. You may select either north or south and enter a

latitude up to (but not including) 90°.

2. Press

E

.

3. Use

K

and Oto enter the longitude. You may select either east or west and enter a

longitude up to (but not including) 180°.

4. Press

E

.

Once the latitude and longitude have been entered, the cursor will move to the
reference waypoint field, where you may enter a reference waypoint to calculate a
bearing and distance to the new waypoint position. If you are not entering a reference
waypoint:

WPT KEY

SECTION

Creating

User Waypoints

Selecting a method to enter a new user waypoint.

2

5. Press Eto advance the cursor to the ‘ok?’ prompt and press Eto save the new
waypoint in internal memory.

Entering the user waypoint’s exact position.

45

SECTION

2

WPT KEY

Reference

Waypoints

To enter/edit a user waypoint position from a reference waypoint:

K

1. Use

2. Press E. The waypoint’s position will appear.

3. Use Kand Oto enter the bearing from the reference waypoint.

4. Press E.

5. Use Kand Oto enter the distance from the reference waypoint.

6. Press E. The latitude and longitude will be calculated for the waypoint.

7. Press Eto confirm the ‘ok?’ prompt and save the waypoint position.

and Oto enter the reference waypoint’s identifier.

Creating a user waypoint by referencing another
waypoint.

To create a user waypoint from your present posi­tion, leave the reference waypoint field blank and
enter a bearing and distance from your present
position. The GPS 155XL will calculate the new

46

waypoint’s coordinates automatically.

If you have chosen to create a waypoint at a certain bearing and distance from
your current position, your current position will be displayed and you will enter the
bearing and distance at which you would like the new waypoint to be located.

To create a user waypoint offset from your present position:

1. Use Kand Oto enter the bearing from your position.

2. Press E.

3. Use Kand Oto enter the distance from your position.

4. Press E. The latitude and longitude will be calculated for the new waypoint.

5. Press Eto confirm the ‘ok?’ prompt and save the waypoint position.

The GPS 155XL’s AutoStoreTMfunction provides another method of creating user

waypoints. AutoStore is used to instantly capture your present position as a user way­point with a touch of a button and add the new waypoint to the end of a specified
route, if desired.

To perform an AutoStore:

1. Press Nand rotate Oto display the position page or map page.

2. Press E.

This will display the ‘Save waypoint’ screen, which will allow you to rename the
waypoint and choose the route to which it should be added. The GPS 155XL will
assign the next available three-digit number as the default waypoint name, preceded
by a ‘+’ sign. This will help you differentiate AutoStore waypoints from other user
waypoints.

To change the default name or route of an AutoStore waypoint:

1. Rotate Oto select the name or route number field.

2. Use

K

and Oto enter the name or route number. If you do not want to add the way-

point to a route, be sure to keep the route field blank.

3. Press

E

to accept.

4. Press Eto confirm the ‘ok?’ prompt.

WPT KEY

Creating Waypoints

with AutoStore

AutoStore waypoint with default name.

SECTION

2

If the waypoint name you entered is already assigned to another waypoint, you
will be informed with the message ‘WPT exists ______’. The default waypoint name
will be redisplayed, and you may enter a different name. The new waypoint will only
be added to a route if the desired route number is manually entered in the route field.

The default waypoint name may be changed
before saving the waypoint.

47

The second page available from the GPS 155XL’s Wkey is the proximity

SECTION

WPT KEY

Proximity

2

Proximity alarm message. Pressing N will
display the position page with the bearing and
distance from the proximity waypoint indicated
on the bottom line.

48

Waypoints

Proximity waypoints page

waypoints page. This page allows you to define an alarm circle around a selected
waypoint and is useful in defining alarm circles around towers or obstructions. Up to
nine proximity waypoints can be entered, each with an alarm radius of up to 99.9 nm.

To create or edit a proximity waypoint:

1. Press Wand use Oto display the ‘Proximity waypoints’ page.

2. Press Cand use Oto highlight the first available field.

3. Use

K

and Oto enter the identifier. It may be an airport, VOR, NDB, intersection or user

waypoint. Press

4. Use Kand Oto enter the radius of the alarm circle. Press E.

If two proximity waypoints are entered and their regions overlap, you will be

informed with the message ‘Proximity overlap’. This message will be displayed each
time you turn on the GPS 155XL for as long as the overlap remains. Warning: If you
enter the overlap area you will only be informed of the nearest proximity waypoint.

To remove a waypoint from the proximity waypoints page:

1. Press C, if necessary, to obtain a cursor.

2. Press \to erase the name, and then Eto delete.

To scroll through the proximity waypoints list:

1. Rotate
available proximity waypoints. The arrow prompt will indicate the direction to scroll to view
additional waypoints, if available.

E

.

K

with the cursor inactive (or use Owith the cursor active) to scroll through the

The third page available from the GPS 155XL’s Wkey is the user waypoint list,

which can be used to quickly scan, review, rename or delete user waypoints.

To display the user waypoint list:

1. Press Wand use Oto display the user waypoint list.

2. To scroll through the list, rotate K.

The total number of user waypoints is displayed at the top of the page, with the
individual user waypoints listed two at a time in alphabetical order below. The arrow
prompt, located at the top left of the page, will indicate which direction to scroll to
view additional waypoints. The status of each waypoint will be displayed to the right
of the identifier when it is the active-to waypoint, part of an active or stored route or
a proximity waypoint. To edit, rename or delete waypoints, the cursor must highlight
the desired waypoint.

To highlight a waypoint:

1. Press Cand use Oto highlight the desired waypoint.

To edit a highlighted waypoint’s position:

1. Press

E

to obtain the waypoint position page. Edit the waypoint position as described on

page 45. (Note: The active-to waypoint cannot be edited.)

To delete a waypoint from the list:

WPT KEY

SECTION

User Waypoint

List

User waypoint list showing the current active-to
waypoint and a proximity waypoint.

2

1. Highlight the desired waypoint and press

To rename a waypoint from the list:

1. Highlight the desired waypoint. Use
identifier for the waypoint.

2. Press

E

on the confirmation page to change the name, or press \to cancel.

\

. Press Eto confirm the deletion.

K

and Oto enter a new

Renaming a user waypoint.

49

SECTION

2

WPT KEY

Waypoint

Comments

The last page available through the GPS 155XL’s Wkey is the waypoints with

comments page, which lists all waypoints that have a user comment. User com-

ments may be added to 250 waypoints stored in the user or NavData®database, and
allow you to note two lines of special information concerning a particular waypoint.

To enter user comments:

1. Enter the waypoint identifier from any waypoint page (see page 34), and press
remove the cursor.

2. Rotate

O

to display the ‘comments’ page.

3. Press Cand use Oto highlight either the second or third line.

4. Use Kand Oto enter the comment.

Entering waypoint comments

with up to six waypoints at a time. The scrolling arrow prompt will indicate which
direction to scroll to view additional waypoints.

Waypoints with comments page

50

5. Press

E

to accept, and repeat steps 4 and 5, if necessary, to enter information on the

other line.

6. Press

C

to remove the cursor.

To view the ‘waypoints with comments’ list:

1. Press Wand use Oto display the ‘Wpts with comments’ page.

2. Use Kto scroll through the list.

The GPS 155XL will display the waypoints with comments in alphabetical order,

To view comments for a selected waypoint:

1. Highlight the desired waypoint and press E(or press \and Eto delete).

2. Rotate Oto display any other available pages for the selected waypoint.

C

to

The GPS 155XL’s extensive waypoint database makes it possible for several way-

points to share the same identifier. To ensure that you are selecting the waypoint
desired, the GPS 155XL will always offer the waypoint confirmation page (which
shows the waypoint’s position) when an identifier is entered for a particular function.

To accept the waypoint position:

1. Press Ewith the cursor over the ‘ok?’ prompt.

To reject the waypoint position:

1. Press

\

with the cursor over the ‘ok?’ prompt.

Once a waypoint has been accepted or rejected, the previous page will be dis­played. If there is more than one waypoint available for a selected identifier, the GPS
155XL will display a duplicate waypoint page for you to choose the desired waypoint.
The waypoint identifier and number of duplicates will be shown at the top of the
page, with the waypoint type and region of each duplicate indicated below. The way­points listed are sorted by the distance from your present position.

To scroll through additional duplicate waypoints:

1. Rotate Owith the cursor active, or Kwith the cursor inactive.

To select the desired waypoint from the duplicate list:

O

1. Activate the cursor and rotate

2. Press E. The waypoint confirmation page will appear.

3. Press

E

over the ‘ok?’ prompt to accept the waypoint or \to reject the waypoint

and return to the duplicate waypoints list.

to highlight the desired waypoint.

WPT KEY

Waypoint Confirmation

Duplicate Waypoints

Waypoint confirmation page

Duplicate waypoints page

SECTION

2

51

SECTION

WPT KEY

Locked Waypoints

2

Waypoint Scanning

Possible messages for locked waypoints.

Because the GPS 155XL relies on a NavData card for most waypoint information,

there may be instances when waypoint information is not available for use. Locked
waypoints exist when a waypoint contained in a route, used as a proximity waypoint
or with a comment, is not contained on the NavData card, or no card is inserted in
the unit. If this condition exists, you’ll be alerted with a ‘Proximity wpt locked’,
‘Route wpt locked’ or ‘Wpt comment locked’ message when the unit is powered up.
The identifier of a locked waypoint will be replaced with a ‘lockd’ message, which
indicates you cannot obtain waypoint information or navigate to the waypoint. The
identifier of a locked waypoint may be displayed by highlighting ‘lockd’ and pressing

E

. Locked waypoints may be deleted from routes, the proximity waypoints list or
waypoints with comments page by following the instructions in the appropriate
section of this manual.

The waypoint scanning feature provides a fast way to scan through airports,

VORs, NDBs and intersections in the database by identifier, facility name or city.
Waypoint scanning may be used from any blank waypoint identifier field.

To enter a waypoint by scanning the identifier, facility name or city:

1. With the cursor over a blank identifier field, press
highlight the field with the cursor and press

2. Use Oto highlight the waypoint category you wish to scan.

3. Press Eto activate the scanning mode.

4. Rotate

O

to place the cursor over the field you want to scan (identifier, facility or city

name).

To blank a waypoint field, highlight the field and
press the \ key.

52

5. Use

K

and Oto enter the letters of the identifier, city or facility name. The GPS 155XL

will scan the database and display the first waypoint that matches your entry.

6. Press

E

to accept the waypoint, and Eagain to confirm the waypoint for the

function being used.

W

. If the identifier field is not blank,

\

before pressing W.

Section 3

Nearest Waypoints

The GPS 155XL’s Tkey provides detailed information on the nine nearest airports,
VORs, NDBs, intersections and user waypoints within 200 nm of your current position. In
addition, it will display the two nearest Flight Service Station (FSS) and center (ARTCC/
FIR) points of communication, plus alert you to any Special Use Airspace (SUA) you may

be in or near. The Tkey can be used in conjunction with the GPS 155XL’s direct-to
function to quickly set a course to a nearby facility in case of an in-flight emergency.

To view the nearest waypoint information:

1. Press T.

This will display the airport nearest to your present position, subject to the runway

surface type and minimum runway length selected (see page 100).

To scroll through the next eight nearest airports, rotate K.

You may examine both the communication frequencies and the runway information

directly from the nearest airport page.

To view more comm/runway information:

1. Press Cand rotate Oto highlight the comm field or the runway field.

2. Rotate Kto scroll through more information, if available.

To perform a direct-to on any of the nearest waypoint pages:

D

1. Press

2. Press

. The waypoint confirmation page will appear.

E

to accept the waypoint or \to cancel.

Nearest airport with other frequency information.
If an airport has multiple frequencies available,
they may be quickly viewed without activating
the cursor by pressing the \ key repeatedly.

Nearest FSS page. To view additional frequencies
(if available), highlight the frequency and rotate
the O knob.

NRST KEY

Overview

SECTION

3

53

The nearest waypoints for other categories (VORs, NDBs, etc.) may be viewed

SECTION

NRST KEY

Special

3

Nearest SUA with controlling agency displayed.

NOTE: The GPS 155XL will flash the Unext to the Mkey
to inform you of SUA alerts. You do not have to repeatedly
check the Nearest Waypoint page for SUA information. It is
provided to supply more information on the SUA and its
boundaries. The GPS 155XL will not flash alerts, however, if
it has been turned off or if your altitude is such that you will
not enter the buffered airspace. Turning off SUA alerts and

54

setting the altitude buffer is described on page 105.

Use Airspace

Nearest SUA

by rotating O. Rotating Ocontinuously to the left will stop page selection on the
nearest airport category.

The next page available under the GPS 155XL’s Tkey is the SUA (special-use

airspace) alert page. The SUA alert page will alert you to as many as nine controlled or
restricted airspaces near or in your flight path, according to the following conditions:

• If your projected course will take you inside an SUA within the next 10

minutes, the message ‘SUA ahead < 10 min’ will be displayed.

• If you are within two nautical miles of an SUA and your current course will take

you inside, the message ‘SUA near & ahead’ will be displayed.

• If you are within two nautical miles of an SUA and your current course will not
take you inside, the message ‘Near SUA < 2nm’ will be displayed.

• If you have entered an SUA, the message ‘Inside SUA’ will be displayed.

Note that the GPS 155XL’s SUA alerts are based on three-dimensional data (latitude,
longitude and altitude) to avoid nuisance alerts. The alert boundaries for controlled air­space are also sectorized to provide complete information on any nearby airspace. Once
you have met one of the described conditions, the message annunciator will flash, alert­ing you of an SUA message.

To view an SUA message:

1. Press the Mkey.

2. Press Magain to return to the previous page.

Once you are notified of an SUA alert, detailed information concerning the specific
SUA is provided by the Tkey.

To view the SUA alert page:

1. Press the Tkey.

2. Rotate Oone stop to the right to view the SUA alert page.

The SUA alert page contains the following information:

NRST KEY

Special

Use Airspace

SECTION

3

SUA number

SUA Name or

controlling

agency

Controlling

airport identifier

The ‘SUA number’ field displays which SUA you are viewing (you may be alerted to up
to nine SUAs). SUAs are ranked with ‘sua1’ being the highest priority, and ‘sua9’ being the
lowest priority from your current position. The ‘SUA alert’ field displays the corresponding
alert message for this SUA, such as ‘near’, ‘near & ahead’, etc. (see page 54). The ETE (esti­mated time enroute), located at the top right of the page, will only be displayed if you are
projected to enter the airspace.

The second line of the SUA alert page displays the name or controlling agency of the

SUA, along with the type of SUA to which you are being alerted.

To toggle between the SUA name and controlling agency display:

K

1. Rotate

If the SUA name or controlling agency is too long to fit on the display, the GPS 155XL

will automatically scroll to display the rest of the information.

SUA Ceiling altitude

one stop in either direction.

Alert type

SUA Floor altitude

ETE

(if applicable)

SUA type

55

The following SUA types can appear in the SUA type field:

SECTION

NRST KEY

3

Frequency information for SUA. If the informa­tion is too long to fit on the display, the GPS
155XL will automatically scroll to display the rest
of the information.

56

SUA Messages

SUA alert page

and the ceiling and floor altitudes for the SUA alert. Controlling agency frequencies
may be viewed by highlighting the controlling airport identifier with the cursor and
pressing E. The following are examples of what can appear in the altitude fields:

Message Airspace Type

alrt - Alert
caut - Caution
cl B - Class B
cl C - Class C
cta - ICAO Control Area
dngr - Danger
moa - Military Operations Area
proh - Prohibited
rstc - Restricted
tma - ICAO Terminal Control Area
trng - Training
trsa - Terminal Radar Service Area
unsp - Unspecified
warn - Warning

The last line on the SUA alert page displays the SUA’s controlling airport identifier

Message Meaning

8000ftM - 8000 feet mean sea level (MSL)
3000ftA - 3000 feet above ground level (AGL)
ground - Ground level
msl - Mean sea level
notam - See Notice to Airmen (NOTAM)

for altitude restrictions
not sp - Altitude is not specified
unlmtd - Altitude is unlimited

SUA Settings Page

All SUA alert messages except for prohibited areas may be turned on or off

through the GPS 155XL’s unit settings options, found under the Mkey (see page

105). Alerts for prohibited areas will always be displayed, regardless of unit settings
or operating mode. SUA alerts may be turned off so the pilot can avoid continuous
alerts in areas with extensive special use airspace. SUA alerts are automatically dis­abled during approach operations.

Important: Turning off the SUA alerts only stops the display of SUA messages.
Any applicable SUA alert pages will still be available from the Tkey.

The GPS 155XL also features an altitude buffer which may be set to provide a
greater level of protection from penetrating an SUA. By specifying an altitude in the
buffer, you can effectively stretch an SUA’s altitude boundaries in both directions. This
allows the pilot to add an extra margin of prevention around controlled or restricted
airspace. For instructions on setting the altitude buffer, see page 105.

NRST KEY

SECTION

Special Use

Airspace

Altitude buffer set at 500 feet. This provides an
added 500 foot margin beyond the floor and ceil­ing limits for an airspace.

3

57

SECTION

ACTIVE LEG

EOS

KTUL

SGF

KSTL

'ACTIVE FROM' WAYPOINT

'ACTIVE TO' WAYPOINT

MAP

DIRECT-TO

Section 4

Direct-to & Route Navigation

4

ROUTE TERMINOLOGY

The diagram at the right shows a basic route
consisting of five waypoints and four legs.

The waypoint you are travelling to is called the
‘active to’ waypoint, and the waypoint immediately
behind you is called the ‘active from’ waypoint. The
course line between the active from and the active to
waypoint is called the ‘active leg’.

58

& ROUTE NAV

One of the many benefits of GPS navigation is the ability to fly directly to a way­point or fly a chain of waypoints without using ground-based navigation aids. To take
advantage of the convenience and efficiency provided by point-to-point GPS naviga­tion, the GPS 155XL provides two basic methods of selecting a destination for your
flight: direct-to and route navigation. The direct-to function provides a fast way to
set a course to a destination waypoint from your present position. The route function
allows the pilot to create a chain of waypoints to fly in sequence and provides access
to the GPS 155XL’s approach, SID and STAR capabilities.

As you pass each waypoint in the route, the GPS 155XL’s automatic leg sequenc­ing and turn anticipation features will automatically select the next waypoint as the
‘active to’ waypoint and provide smooth steering guidance around the turn. If you are
not currently navigating a particular route leg (e.g., your starting position is not a
route waypoint), the unit will select the appropriate leg as the active route segment.

The GPS 155XL’s direct-to function provides a quick method of setting a course

to a destination waypoint. Once a direct-to destination is activated, the GPS 155XL
will establish a point-to-point route line along the great circle from your present
position to the destination and provide steering guidance and navigation data to the
waypoint until it is cancelled. If you are navigating to a waypoint and get off course,
the direct-to function may also be used to re-center the d-bar to proceed to the same
waypoint.

To select a direct-to destination:

1. Press the Dkey. The NAV summary page appears with the destination field highlighted.

2. Use Kand Oto enter the identifier of the desired waypoint.

3. Press Eto confirm the identifier, and Eto accept the direct-to confirmation page.

To re-center the d-bar to the same active-to waypoint:

1. Press the

A direct-to may also be quickly activated from many pages that display a single
waypoint identifier (e.g., the nearest airport page) by simply pressing Dand E.
For pages that display a list of waypoints (e.g., the user waypoint list page), you must
highlight the desired waypoint with the cursor before pressing the Dkey. Once a
direct-to is activated, the GPS 155XL will provide navigation guidance until the
direct-to is cancelled or the unit is turned off.

To cancel a direct-to destination:

1. Place the cursor over the destination field on the NAV summary page.

2. Press \. The destination field will go blank.

D

key, followed by Etwice. NOTE: If you’re navigating an active approach

with the MAP as the active waypoint, the approach will be cancelled.

DIRECT-TO

SECTION

Selecting and

Cancelling a Direct-To

To select a direct-to destination, press the D key
and enter the waypoint identifier using K and O.

To quickly select a direct-to from any page that
displays a single waypoint identifier (e.g., the
nearest airport page), press D, followed by E.

4

3. Press E. The GPS 155XL will resume navigating Route 0 (the active route) if available.

59

SECTION

4

DIRECT-TO

Manually Selecting

A Course

Whenever you perform a direct-to, the GPS 155XL will set a point-to-point great

circle course to your destination. You can also manually define the course to your
destination with the GPS 155XL’s Course Select feature. The course select feature is
available from the bottom line of the direct-to confirmation page whenever the
external GPS SEQ switch is in the ‘Auto’ position.

Waypoint Position, Facility

Name or City/Region

(selectable)

The waypoint sequencing field, located at the
bottom left of the direct-to confirmation page, dis­plays the current status of the external GPS SEQ
switch.

To manually set your course from the course select
field, set the GPS SEQ switch to the ‘AUTO’ posi­tion and enter the selected course in the course
select field. NOTE: Whenever the GPS SEQ switch
is set to the ‘HOLD’ position, the selected course
will be determined by the external OBS/HSI.

When using the course select feature on the direct­to confirmation page or when the GPS SEQ switch
is set to the ‘HOLD’ position and external course
input is not present, you may also enter the
desired course from the NAV summary page using
the course field at the bottom of the page.

60

Waypoint

Sequencing Field

To manually set a course:

1. Set/confirm the GPS SEQ switch in the ‘AUTO’ position.

D

2. Press the

3. Rotate Oto place the cursor on the course select field.

4. Use

K

you have started editing the course select field).

5. Press

key. The direct-to confirmation page will appear.

to begin entry of the selected course (the Oand Kknobs may be used once

E

to accept the course, and Eagain to acknowledge the ‘ok?’ prompt.

The GPS 155XL will now use the selected course for your CDI and DTK steering
guidance. To reset the course to a GPS-calculated course from your present position,
simply press D, followed by E.

Waypoint Identifier Field

Course Select Field

The GPS 155XL lets you create up to 20 routes (numbered 0 through 19), with up

to 31 waypoints each. Routes are created, copied and edited through the Rkey,
which features five route pages selectable from the GPS 155XL’s outer knob.

Active Route Page

ROUTE NAV

Route Pages

SECTION

4

Route Catalog Page

SID Select Page

The five route pages can be divided into two types: active route pages and a

route catalog page. Active route pages provide information and editing functions for

route 0, which always serves as the route you are currently navigating. The route cata­log page serves as the main page for creating, editing, activating, deleting and copying
all routes.

Routes 1-19 are used as storage routes, which are stored in the GPS 155XL’s inter­nal memory. Once a storage route is ‘activated’, a copy is placed into route 0 for navi­gation until it is cancelled, overwritten by activating another route or erased when the
unit is turned off. If you want to save a route currently in route 0, be sure to copy it
to an open storage route (routes 1-19) before it is cancelled, overwritten or erased.

Approach Select Page

STAR Select Page

REMEMBER!

If you want to save the active route, be sure to
copy it to an empty storage route (1-19) before
turning the GPS 155XL off or activating a new
route (or direct-to destination). See page 65 for
instructions on copying routes.

61

SECTION

4

ROUTE NAV

Route Catalog Page

The GPS 155XL’s route catalog page is used to create, edit, delete or copy routes,

and serves as the main page for a host of functions. These include route activation,
determining the closest point of approach and search-and-rescue operations. It also
displays a summary of routes currently stored in memory, with the departure and
arrival route waypoints and total distance for the selected route number. To scroll
through the available routes, rotate K. A one-line user comment may be added to
any storage route, which will be displayed on the route catalog page.

To add user comments to any route (except route 0):

21

desired route operation. The following functions are available:

{

3

Route Catalog Page

1. Route selection field

2. Route action field

3. Departure/Arrival waypoints

4. Cumulative distance of route

5. Comments/Parallel track offset field

62

5

4

1. Rotate Kto display the route you would like to add comments to.

2. Press Cand use Oto highlight the bottom row.

3. Use Kand Oto enter comments, and press E. To erase press \, then E.

The route action field, located at the top right of the page, is used to select the

• Activate - activate the route for navigation

• Reverse - activate a route in reverse order

• Edit - create a new route, or edit an existing route

• Approach - select an approach for the route (see Section 5)

• Star - select a STAR for the route (see Section 5)

• Sid - select a SID for the route (see Section 5)

• Delete - delete a route

• Copy - copy the current route to an empty route

• CPA - calculate the closest point of approach

• Search - perform search-and-rescue ladder operations

• RAIM prd - evaluate enroute RAIM availability over the entire route

The route editing function allows you to create new routes and edit existing
routes. Creating routes before takeoff can help make route operations faster and easier
during your flight.

To create or edit a route from the route catalog page:

1. Use Kto display the route number you would like to edit.

2. Press C.

3. Use Kto select ‘edit?’. Press E. The route review page will appear.

To add a waypoint:

4. Rotate

O

to highlight the first blank waypoint field or the point where you want to enter
the new waypoint. The first waypoint field will already be highlighted if you’re creating a
new route.

5. Use

K

and Oto enter the waypoint’s identifier. Press E.

6. Press Eto confirm the ‘ok?’ prompt on the waypoint confirmation page.

7. Repeat steps 4 through 6 to add the next waypoint, or press Cto finish.

To delete a waypoint:

1. Rotate

O

to highlight the waypoint you wish to delete.

2. Press \to remove the name, then press Eto delete.

3. Repeat steps 1 and 2 to delete additional waypoints, or press Cto finish.

To delete an entire route:

1. Use

K

to display the route number you would like to delete (route 0 for the active route).

ROUTE NAV

Creating &

Editing Routes

Selecting the route edit function.

Adding a waypoint to route 1.

SECTION

4

2. Press Cand use Oto highlight the action field.

3. Use Kto select ‘delete?’. Press Eto delete.

63

SECTION

4

ROUTE NAV

Deleting &

Activating Routes

Once a route is defined through the route catalog page, it may be activated from the
route catalog page. Activating or reversing a route places the selected route into route 0
and overwrites the existing active route.

To activate a route:

1. Press Rand use Oto display the route catalog page.

2. Rotate Kto display the route you would like to activate.

3. Press Cand use Kto display ‘activate?’. Press E.

After travelling a route or creating a route with the GPS 155XL’s AutoStore™ feature,
the route activation field may be used to activate the route in reverse order.

To activate a route in reverse order:

Deleting route 0.

inal route will remain intact in its storage route location.

to another open storage route. The copy function can be used to save the contents of the
active route (route 0) to an open storage route.

Reversing route 0.

64

1. Press Rand use Oto display the route catalog page.

2. Use Kto display the route number you would like to reverse.

3. Press Cand use Kto display ‘reverse?’. Press E.

This will copy the reversed route to route 0 and display the active route page. The orig-

The route action field also features a copy function that permits you to copy any route

To copy a route:

1. Press Rand use Oto display the route catalog page.

2. Use Kto display the route to which you would like to copy. The route must be empty.

3. Press Cand rotate Kto select ‘copy?’. Press E.

4. Use

K

to enter the route you would like to copy. The departure/arrival identifiers will be

displayed for your reference. Press

The CPA function calculates the closest distance that a route will pass to a

reference waypoint, and helps when creating new route waypoints referenced to a
NAVAID.

To calculate the closest point of approach (CPA) from the route catalog page:

1. Use

K

to display the route you would like to use for the CPA function. The route must
consist of at least two waypoints, and the reference facility must fall between the
waypoints of a route leg.

2. Press

C

and rotate Kto select ‘cpa?’. Press E.

3. Use

K

and Oto enter the identifier of the reference waypoint.

E

4. Press

5. Press
waypoint to the route, it will be named based on the reference waypoint plus a number
(0-9) added to the end (e.g., KMCI3 for KMCI). If the waypoint does not fall between
waypoints on the route, the reference waypoint does not exist or a unique name cannot
be assigned to the CPA waypoint, you will be informed with the ‘Invald CPA wpt ____’
message.

. The bearing and distance of the closest point on the route will be displayed.

E

to add the cpa waypoint to the route, or \to finish. If you do add the cpa

E

to copy the route.

ROUTE NAV

SECTION

Copying Routes

CPA Function

Calculating closest point of approach.

Closest point of approach to ‘TXK’.

4

65

The GPS 155XL’s search-and-rescue function provides navigation guidance for

SECTION

ROUTE NAV

Search & Rescue

4

The map page will show the active leg of the
search and rescue pattern as a solid line with the
anchor waypoints joined together by a dashed line.

Performing a search-and-rescue operation.

66

Operations

search-and-rescue operations, navigating in a ladder pattern to maximize coverage and
efficiency. This is done in reference to two waypoints called ‘anchor waypoints’. The
first leg will be a specified distance from the line connecting the anchor waypoints.
This is called the ‘offset distance’. The ‘increment distance’ is the distance between each
subsequent leg. The ladder can be created on either side of the anchor waypoints.

To perform a search-and-rescue operation:

1. Create a route of only two waypoints.

2. Press Rand use Oto display the route catalog page.

3. Use Kto select the 2-waypoint route.

4. Press Cand use Kto display ‘search?’. Press E.

5. Use Kand Oto enter the leg increment value and R or L. Press E.

6. Rotate

O

to highlight the initial offset, and use Kand Oto enter the initial offset

value, and R or L.

7. Press

E

three times to accept the operation values and begin navigation.

After activating a search-and-rescue, you will be informed with an ‘Offset nav in
effect’ message each time you traverse the route offset from the anchor waypoints. The
NAV summary page will guide you along each leg of the ladder pattern. Note that
bearing and distance information are referenced to the anchor waypoints. Once you’ve
arrived at the destination waypoint, the leg increment will be added to your present
offset, and the route will be automatically reversed. If a search-and-rescue is interrupt­ed, note the parallel track direction (R or L) and distance on the catalog page for route

0. When you resume search-and-rescue operations, use this as the initial offset.

The GPS 155XL’s Route RAIM Prediction Function evaluates enroute RAIM availability
over the entire route that the pilot intends to fly. Route RAIM Prediction ensures that
satellite coverage will be sufficient to meet the protection limits defined by
BRNAV/RNP-5 (FAA Advisory Circular 90-96).

To use the Route RAIM Prediction Function:

1. From the Route Catalog Page (Figure 1), select the desired route for RAIM prediction (if the
route is empty, enter the route first).

ROUTE NAV

Route RAIM

Prediction

SECTION

4

2. Highlight the route action field by pressing
press

E

. The Route RAIM Prediction Page will be displayed (Figure 2).

3. Highlight and enter departure time, departure date, enroute altitude, and enroute ground
speed (valid enroute ground speed is “65 nm or greater”). Press

4. When all parameters are properly entered, move the cursor to the ‘Compute?’ field, and
press

E

. The unit will start to predict the RAIM availability over the entire route, and
will switch to ‘WAIT ->’, with the arrow sign continually rotating, indicating that the pre­diction computation is in progress.

5. If RAIM is available for the entire route ‘RAIM OK’ will appear on the Route RAIM
Prediction Page, as shown in Figure 3 (pg. 68).

C

, rotate Kto select ‘RAIM prd?’ and

E

to accept.

Figure 1

Figure 2

67

SECTION

4

ROUTE NAV

Route RAIM

Prediction

Figure 3

Figure 4

The time required for RAIM prediction computation depends on the route
distance (i.e., 1000 nautical miles = approximately 2 minutes) and the enroute speed.
The longer the route distance and the slower the enroute speed, the longer the time.
If RAIM unavailability is detected based on the associated requirement, the prediction
process will stop immediately and display ‘NO RAIM’ as shown in Figure 4.

‘NO RAIM’ does not mean RAIM is unavailable for the entire route. This
message results when RAIM unavailability is detected for more than 5 minutes at any
point along the intended flight (based on BRNAV requirements).

If a satellite is listed as ‘out of service’ by NOTAM, you may use the ‘rem
sat’ (remove satellite) field to prevent a particular satellite from being used in the
Route RAIM prediction (e.g., removing satellite 9 in Figure 4).

To exclude a satellite from the Route RAIM prediction:

1. Highlight the ‘rem sat’ field.

K

2. Rotate

3. Press

4. Press

to select the satellite to be excluded.

E

to accept.

E

again to begin Route RAIM Prediction without using the selected satellite.

68

During route navigation, it is sometimes desirable to navigate a specified distance

away from the ‘active leg’ to help avoid certain airspaces or regions. The GPS 155XL’s
parallel track feature will automatically guide you along a selected offset from the
active leg. Bearing and distance information will be to the waypoints along the original
course, with the CDI centered on the offset course.

To use offset navigation, or ‘parallel track’:

1. Press Rand use Oto display the route catalog page.

2. Use Kto display route 0 (parallel track can only be used on the active route).

3. Press Cand use Oto highlight the parallel track value field.

4. Use

K

and Oto enter the desired distance and direction (R or L) from the leg.

5. Press Eto accept. The Map Page will display the offset route as a solid line and the
original route as a dashed line.

It is important to note that offset navigation is only available on route navigation,
not direct-to navigation. If an approach is present in the active route, parallel offset
navigation is cancelled when entering the 30 nm terminal area. Offset navigation is
NOT valid for IFR approach procedures. “Approach not active” message will display if
parallel navigation is re-instated after approach navigation has been armed. When off­set navigation is activated, an ‘Offset nav in effect’ message will be displayed with the
distance and direction noted on the route catalog page for route 0. If you enter an off­set which causes a leg to be reversed, you’ll be informed with the message ‘Ofst too big
for rte’. If you change the active route in any way or perform a direct-to, you’ll be
informed with an ‘Offset nav cancelled’ message.

ROUTE NAV

SECTION

Parallel Track

Offset Navigation

Enter parallel track value after route activation.

4

Parallel Track

69

Flying and Modifying the Active Route

SECTION

4

USING THE ACTIVE ROUTE PAGE

The GPS 155XL’s active route page provides a
working list of all waypoints for the route you are
navigating, along with distance, timing or desired
track information. The scrolling arrow prompt to
the left of the route waypoint list indicates which
way to scroll to view additional route waypoints.

The active route page can also be used to manual­ly select your next ‘active-to’ destination (using
D), which allows you to fly directly to any way­point in the route without modifying the route
itself. The GPS 155XL will resume navigation of
the remainder of the route in sequence once you
arrive at the selected waypoint.

70

ROUTE NAV

Active Route

Page

Once a route has been created and activated, the GPS 155XL will provide naviga­tion to each route waypoint through the active route, NAV summary and map pages.
From the active route page, you may also create and modify the active route, and
insert an approach, SID or STAR. The NAV summary page will display detailed navi­gation data on your progress to each route waypoint, and provide turn anticipation,
waypoint arrival and next desired track information. By understanding the relation­ship between the active route and NAV summary pages and the role of the waypoint
sequencing (GPS SEQ) switch, you’ll be able to get the most out of the GPS 155XL’s
advanced route and approach features.

Whenever the GPS 155XL is navigating an approach, route or an on-route direct­to, the active route page will provide a list of the route waypoints in sequence,
along with distance, time and course information. You may also create and edit a
route directly from the active route page. If you want to save a route created from the
active route page (route 0), you must copy it to an open storage route (see page 65)
before turning the unit off or activating another route. The active route page may be
displayed by pressing the Rkey and rotating Oleft continuously. It will also
appear automatically whenever an approach, route, SID or STAR is activated.

To scroll through the active route waypoints:

1. Rotate Kwith the cursor inactive (or Owith the cursor active).

The active leg identifiers field, located at the top left of the page, displays the way­point identifiers of the route leg you are currently navigating. The first waypoint
identifier displayed is the ‘active from’ waypoint. The second waypoint is the ‘active
to’ waypoint. The line connecting these waypoints is known as the ‘active leg’. If
you are navigating a direct-to, the field will display the ‘goto’ destination only.

The distance field can be selected to display cumulative (‘cum’) distance or the dis­tance for each route leg (‘leg’). If cumulative is selected, the first leg’s distance will be
displayed. The second leg will represent the first leg’s distance plus the second leg, and
so on. The time field may be configured to display the estimated time enroute (ete),
estimated time of arrival (eta) or desired track (dtk) for each leg.

To change the distance and time fields:

O

1. With the cursor active, rotate

2. Rotate Kto select the desired setting and press C.

The active route page may also be used to create a new route or edit the route you
are currently navigating (approach, SID or STAR waypoints cannot be edited), and pro­vides a fast method of selecting any route waypoint as your next destination waypoint
without modifying the active route. If you are editing the active route and want to save
it in its original form, copy it to an open storage route before editing.

To add waypoints to the active route:

1. Press C, if necessary, to activate the cursor.

2. Use

O

to highlight the first blank waypoint field, orhighlight the waypoint before which

you would like to add the new waypoint.

3. Use

K

and Oto enter the new waypoint identifier. Press E.

to highlight the field you want to change.

ROUTE NAV

SECTION

Adding Active

Route Waypoints

Active route page with cumulative distance (cum)
and desired track (dtk) displayed.

4

4. Press

E

to accept or \to cancel. The cursor will automatically move to the next way­point field, and the remaining route waypoints (if any are present) will move down the list
accordingly.

Active route page with leg distance and estimated
time enroute displayed.

71

To delete a waypoint from the active route:

SECTION

ROUTE NAV

1. Press

C

, if necessary, to activate the cursor.

On-Route

2. Use

O

4

You can hold on a destination waypoint by setting
the GPS SEQ switch to the ‘HOLD’ position. The
GPS 155XL will hold on the current ‘active to’
waypoint as your navigation reference and pre­vents the unit from sequencing to the next way­point in the route. A user-defined course may also
be selected on the external HSI (OBS).

Whenever waypoint sequencing is set to ‘hold’, the
desired course is displayed at the bottom left of the
NAV summary page. See page 60 for more details.

72

Direct-To

3. Press

The active route page also allows you to select your next destination waypoint man-

ually from the active route waypoint list and resume the remainder of the route in
sequence. This procedure, referred to as an ‘on-route’ direct-to, allows the pilot to fly
directly to any waypoint in the active route without editing the active route, approach,
SID or STAR itself. For example, if you are flying a route with an armed approach, the
GPS 155XL will automatically provide the initial approach fix (IAF) for the selected
approach as your ‘active to’ waypoint. If you have been vectored directly to the final
approach fix (bypassing the IAF), you can manually “skip ahead” to the final approach
fix as your next active to waypoint.

To perform an on-route direct-to from the active route page:

1. Press

2. Press

The GPS 155XL will now provide guidance to the selected waypoint and resume

navigating the remainder of the route in sequence once you arrive at the next destina­tion waypoint. The waypoint sequencing field, located at the bottom left of the
direct-to confirmation page, indicates the current status of the waypoint sequencing
(GPS SEQ) switch. For more information on the waypoint sequencing switch and way­point ‘hold’ operations, see Section 5.

to highlight the waypoint you would like to delete from the active route.

\

, followed by E. The next route waypoint (if available) will move up to take

the position of the deleted waypoint.

C

and rotate Oto highlight the desired waypoint.

D

, followed by Eto confirm the ‘ok?’ prompt on the waypoint

confirmation page.

During route operations, the NAV summary page is used to provide turn anticipa-

tion, next desired track and waypoint arrival information to the pilot. The GPS
155XL’s turn anticipation feature will smooth out the transition between adjacent
route legs by providing CDI guidance along a curved path segment. This leg transi­tion is based on the aircraft’s actual ground speed and the difference between the
course angle of the two legs. The GPS 155XL will automatically sequence to the next
leg when you are abeam the ‘active to’ waypoint on the curved transition segment,
and the to/from indicator on the CDI will flip momentarily. During the transition, the
CDI display will be referenced to the dotted line illustrated at the right. Turn anticipa­tion will not be provided in the following scenarios:

• Waypoint/fix crossing is a requirement of the approach, SID or STAR
you’re navigating.

• The GPS SEQ switch is in the HOLD position.

• Your current ground speed and the course angle between the two legs
require a bank angle greater than 25º (see right).

As you approach a route waypoint, the GPS 155XL’s external waypoint annunciator
will flash 15 seconds before the turn anticipation point, and the graphical CDI will be
replaced by a flashing ‘Next dtk xxxº’ prompt (and the desired track readout on the
map page will flash), indicating the desired track of the next route leg.

To use the turn anticipation feature, note the ‘Next dtk’ heading when the external
waypoint annunciator begins to flash, and start the turn when the annunciator glows
steadily (approximately 2 seconds before the turn anticipation point). Once you’ve
reached the turn anticipation point, the desired track (dtk) field on the NAV summary
page will change to display the course for the next leg. If you have not adjusted your
HSI course selector before the turn, the ‘Next dtk’ will continue to flash until you
have reached the midpoint of the turn. Please refer to your aircraft flight manual sup­plement for specific turn anticipation instructions.

Since the approach select, STAR select and SID select pages relate to the GPS

155XL’s approach features, these pages and their functions are described in Section 5.

ROUTE NAV

SECTION

Turn Anticipation

As you approach a route waypoint, the graphical
CDI will be replaced by a flashing ‘Next dtk xxxº’
prompt indicating the desired track of the next leg.
When using the map page, the desired track read­out will flash and indicate the dtk for the next leg.

If the turn angle and your present speed will
require a bank angle that exceeds 25º, you’ll be
notified with a ‘Steep turn ahead’ message
approximately 90 seconds before arrival at the
active to waypoint.

4

73

SECTION

Section 5

APPROACH NAV

5

Once an approach is selected, the GPS 155XL will
replace the destination airport with the appropri­ate approach waypoints. The initial approach fix,
final approach fix and missed approach point
waypoints are indicated by an ‘if’, ‘ff’ and ‘mp’
designation to the immediate left of the waypoints.

In many instances, there may be approach way­points in the GPS approach that are not shown on
the approach plate. These approach waypoints are
usually intermediate fixes designed to help the
GPS provide smooth navigation along the
approach path.

74

Overview

The GPS 155XL’s approach navigation mode allows you to fly non-precision
approaches to airports with GPS and overlay procedures using information contained
on your Jeppesen NavData®card. GPS approaches are similar to existing IFR
approach procedures, but provide additional course and distance information for a
higher level of accuracy, efficiency and safety. The non-precision approaches available
in the GPS 155XL are executed using the GPS route features covered in Section 4, so
it’s important to understand routes before attempting approach navigation. A GPS
approach is a sequence of waypoints linked together as an approach route which
replaces your destination airport waypoint when selected. It may be based on an
existing RNAV, VOR or NDB approach procedure, or be an entirely new approach
created specifically for GPS. Regardless of the type of approach on which a GPS pro­cedure is based, the procedure is flown as a sequence of route legs in the active route.

The GPS 155XL’s auto-arming feature provides automatic control of the two
phases of approach operations: arm approach and active approach. The arm
approach phase consists of selecting an approach from the database and ensuring that
the receiver is ready to begin the tighter integrity monitoring and CDI adjustment
required for approach navigation. The active approach phase tightens the accuracy
requirements and sensitivity one step further to meet TSO standards for the non-pre­cision approach. Auto-arming of the approach will occur once you are within 30 nm
of the destination airport, and will be indicated by an ‘ARM’ message on the external
GPS APR switch. The approach will then transition to the active phase when the air­craft is within 2 nm of the FAF along the inbound course to the final approach fix.

Approaches, SIDs and STARs

The GPS 155XL works in conjunction with a set of external switches and your
HSI (OBS) to fly GPS approaches. The external switches are used to control GPS func­tions, and contain illuminated annunciators to indicate when functions are active.
Your installation must also have annunciators for waypoint arrival and GPS messages.

APPROACH NAV

GPS Approach

Switch

SECTION

5

NAV GPS

NAV ACTV

The NAV/GPS switch determines which data (GPS or NAV1) will be displayed on

the HSI and used by the autopilot/flight director. The current selection will be

indicated by an annunciator light. If power to the GPS 155XL is lost, the system

will automatically revert to NAV1.

GPS APR

CTV

The GPS APR switch is used to arm or deactivate an approach, and indicates the

current approach phase status (‘ARM’ or ‘ACTV’). The GPS 155XL will automati-

cally arm a selected approach 30 nm from the airport. If the pilot wishes to termi-

nate the approach or fly the missed approach, the GPS APR switch may be pressed

to disarm/deactivate the approach at any time and return the CDI scale sensitivity

to the 1.0 nm setting. The GPS APR switch may also be used to re-arm the

approach at any time before reaching the FAF. If the selected approach is disarmed

before the FAF, the unit will prompt you to re-arm the approach 3 nm before the

final approach fix.

GPS APR

ARM ACTV

NAV GPS

ARM GPS

GPS APR

ARM ACTV

Arm Approach Mode

The external GPS APR switch will automatically
be set to the ARM position 30 nm from the desti­nation airport. Once the approach is armed, the
unit will provide a smooth transistion from the 5.0
to 1.0 nautical mile CDI scale, and down to 0.3
nm within 2 nm inbound to the FAF. If the
approach is manually disarmed, it may be re­armed at any time (before reaching the FAF) by
pressing the GPS APR switch.

75

OBS

TO

FR

N

33

30

W

24

21

S

15

12

E

6

3

SECTION

APPROACH NAV

5

Always set the desired course on the HSI (OBS)
BEFORE returning the GPS SEQ switch to the
‘AUTO’ position.

76

GPS SEQ Switch

GPS SEQ

AUTO ACTV

The GPS SEQ switch is used to select manual or automatic waypoint sequencing

of waypoints. Setting the GPS SEQ switch to the HOLD position holds your current
‘active to’ waypoint as your navigation reference and prevents the GPS from sequenc­ing to the next waypoint. When the GPS SEQ switch is set to the AUTO position,
automatic waypoint sequencing is selected. Whenever the GPS SEQ switch is
engaged, the HOLD annunciator will illuminate and the GPS will continue navigating
to the active-to waypoint regardless of your position relative to other waypoints.

The GPS SEQ switch must be set to the HOLD position any time you are deviat­ing from the flight sequence of an approach (e.g., when you are flying radar vectors)
or when you must cross the same waypoint twice in succession (e.g., procedure turn,
IAF and FAF at the same waypoint). Whenever the GPS SEQ switch is set to the
HOLD position, the GPS 155XL allows you to select the desired course to/from a
waypoint using the HSI, much like a VOR.

Whenever the GPS SEQ switch is released from the HOLD position, the GPS
155XL will ‘capture’ the present HSI setting as your desired course. Always dial in
your next desired course before returning the GPS SEQ switch to the AUTO position.
The GPS SEQ switch may be released from the HOLD position 2 seconds after the
inbound course has been set. The GPS 155XL will continue navigation on the last
selected course
waypoint.

GPS SEQ

AUTO ACTV

through the active-to waypoint and sequence to the next approach

GPS SEQ

AUTO HOLD

Basic Rules of GPS Approaches

0.3 nm

30 nm

2nm

FAF

MAP

1 nm

1 nm

5 nm

1 minute

The GPS 155XL is the first GPS certified to meet the requirements of TSO
C-129a Category A1. When using the GPS 155XL for non-precision approaches,
you’ll encounter two types of approaches: overlay approaches (based on existing pro­cedures) and GPS approaches (new approaches designed specifically for GPS). The
FAA has approved a large number of overlay approaches, with plans to add as many
GPS approaches as possible to take advantage of the safety and convenience of GPS.

Flying a GPS approach is not difficult, and varies from conventional approaches
only in the operation of the equipment being used. Although you’ll often be following
the same flight path used in conventional approaches, the equipment operation pro­cedures will be different from typical NDB or VOR approaches.

The following definitions, guidelines and examples that follow will help you
understand the basic rules of GPS approaches, and guide you through some typical
approaches. Think through the approach examples— this will assist you in getting
the greatest benefit from the GPS 155XL. There are a few basic rules that apply to all
GPS approaches. Remembering these rules will assist you in understanding the
approach procedures and ensure the greatest margin of safety for your flight.

• The approach to be flown must be in the aviation database, and the database
must be current.

• You may select an approach any time after the destination airport is selected.
If the GPS APR switch does not indicate an ‘ARM’ status within 2 nm inbound
to the final approach fix, you run the risk of flying a non-approved approach.

• When performing an approach, the GPS SEQ switch must be set to the AUTO
position with the FAF as the active to waypoint for the approach to go active.
If the switch has not been set to the AUTO position 2 nm before the FAF, the
CDI scale transition will be compressed, making the CDI change more abrupt.

(continued on the next page...)

APPROACH NAV

SECTION

Basic Rules of

GPS Approaches

CDI Scale ramping during approach.

5

77

• If you cross the same waypoint twice in succession during an approach (e.g.,

5 nm5 nm 5 n m5 n m

2nm2

nm

SECTION

APPROACH NAV

Basic Rules of

5

Unlike a VOR, GPS CDI deflection is based on the
cross-track distance to the desired course, regard­less of how far away you are from the destination.

78

GPS Approaches

the IAF and FAF at the same waypoint, or radar vectors to the FAF), you must
set the GPS SEQ switch to the HOLD position prior to crossing the fix the
first time to prevent the GPS from sequencing to the next waypoint.

• During a GPS approach, keep in mind that your external HSI will display the
same CDI needle deflection and scale as the CDI on the GPS 155XL, which
will transition from 5.0 to 0.3 nm through the approach. Also note that unlike
a VOR CDI, the GPS CDI scale is based on the cross-track distance to the
desired course (the distance to the reference waypoint does not have an effect
on the CDI scale, see illustration left).

• The HSI course select should always be set 2 seconds before changing the
GPS SEQ from HOLD to AUTO to ensure the desired course to the next way­point is settled prior to use by the GPS and give the autopilot sufficient time
to react to the heading change.

• GPS always displays distance from the currently active waypoint. When deter­mining distance along the approach, use caution to determine the correct dis­tance from the approach chart.

• RAIM must be available (the GPS 155XL automatically monitors RAIM, and
will display a message if it is not available) from the FAF to the MAP. If RAIM
is not available or becomes unavailable during this leg, the HSI NAV flag will
appear, and you must fly the missed approach procedure.

• When flying a missed approach, SID or STAR, you must fly all published pro­cedures and ensure that all printed course and altitude restraints are achieved.

• If you are off course to the MAP waypoint and use a direct-to to re-center the
d-bar, the active approach will be cancelled.

• SUA alerts are disabled when an approach is selected and armed and the air­craft is less than 30 nm from the destination airport. SUA information is still
available from the NRST key at all times.

Flying A Typical Approach

The non-precision approaches available from the GPS 155XL will all follow the
same general flow of events described below. Specific details and instructions relating
to each step, along with several approach examples are provided later in this chapter.

1. Create a direct-to or route with an airport as the final destination

To save time during your flight, you may wish to create a route and select
an approach before takeoff using the route catalog page.

2. Select an approach for the destination airport

An approach may be selected at any time, but must be loaded before reach­ing the final approach fix. Once an approach is selected, the approach way­points will replace the destination airport and the GPS 155XL will provide
navigation to the Initial Approach Fix.

3. Transition to the Arm Approach Phase

The GPS 155XL will automatically arm the approach 30 nm from the
destination airport. The CDI scale will begin to ramp down from the 5.0 nm
to the 1.0 nm scale, and the GPS APR annunciator will indicate an ‘ARM’
status.

4. Establish yourself on the final approach course

a. No procedure turn approach– no special requirements
b. Radar vectors– requires use of GPS SEQ switch to hold on

designated approach waypoint

c. Procedure turn– requires use of GPS SEQ switch to hold on

active waypoint

d. DME arc– requires use of position page to monitor distance from

reference waypoint

(continued on the next page...)

APPROACH NAV

SECTION

Typical Approach

Procedures

Select the approach.

GPS APR

CTV

The GPS 155XL will automatically arm the
approach 30 nm from the destination airport.

GPS APR

ARM ACTV

5

79

5. Transition to Active Approach Phase

SECTION

APPROACH NAV

Typical Approach

5

GPS approaches must be in the current aviation
database to be approved.

TSO C-129a requires that satellite coverage and
navigational accuracy provided by the GPS system
meet minimum standards. A ‘No RAIM from FAF
to MAP’ message will appear if RAIM is predicted
to be unavailable for an approach. If you receive a
RAIM message, continue the approach ONLY if the
ACTV annunciator remains illuminated to the
MAP. If the ACTV annunciator does not stay illu-

80

minated, your HSI NAV flag will appear, and you
must fly the missed approach procedure.

Procedures

The approach will automatically transition to the active approach stage and
the GPS APR annunciator will indicate an ‘ACTV’ status if the following
conditions are met:

a. The approach is armed
b. The aircraft is 2 nm from the FAF on an inbound course
c. The GPS SEQ switch is set to the ‘AUTO’ position
d. The FAF is the active-to waypoint
e. The GPS 155XL confirms that integrity monitoring will be available to

complete the approach

Once the active approach phase begins, the CDI scale will begin to gradual­ly transition from the 1.0 nm scale to the 0.3 nm scale, and remain at the

0.3 nm scale from the FAF to the MAP unless the approach is cancelled by
pressing the external GPS APR switch, setting the GPS SEQ switch to
‘HOLD’ or by initiating a direct-to operation.

WARNING: You are not authorized to fly the final portion of the approach
unless the external GPS APR annunciator indicates an ‘ACTV’ status.

6. Missed Approach Procedure

The GPS 155XL’s automatic waypoint sequencing stops at the missed
approach point. Once you have crossed the MAP, the GPS 155XL will give
you the option of flying direct to the missed approach holding point:

a. Press the GPS APR switch to return the CDI to the 1.0 nm scale.
b. AFTER crossing the MAP, press D, followed by Eto fly directly to

the missed approach holding point.

WARNING! A direct course to the missed approach holding point may not
correspond to the published missed approach procedure. Always fly all
published procedures before selecting the holding fix on the GPS.

Selecting and Loading an Approach

When an arrival airport is selected with the direct-to key (or created and activated in

a route to the arrival airport), the approaches for your arrival airport become available
through the approach select page, which can be viewed by pressing Rand rotating

the outer knob. Remember that an airport must be the last waypoint in a route to select
an approach.

To select an approach:

APPROACH NAV

Selecting

Approaches

SECTION

5

1. Select the destination airport using the
to the destination airport (see Section 4).

2. Press

R

and rotate Oto display the approach select page.

3. Rotate K(or Owith the cursor active) to display the desired approach procedure.

4. Press Ctwice (if necessary) and rotate Ountil the desired approach is highlighted.

5. Press Eto select the approach.

If an approach procedure has more than one Initial Approach Fix (IAF), you’ll need

to select the desired IAF identifier for your approach.

To select an IAF:

1. Rotate Ountil the desired IAF is highlighted.

2. Press E.

Once the IAF is selected, the approach waypoints will be inserted into Route 0,
replacing the destination airport, and the active route page will be displayed. To review
the active route, rotate the Kknob. The scrolling arrow prompt will indicate which
direction to scroll to view additional waypoints, while the ‘if’, ‘ff’ and ‘mp’ designators
will indicate the IAF, FAF and MAP respectively.

D

key, or create and activate a route

Select the Initial Approach Fix.

Once the approach is loaded, the active route page
will appear.

81

When the aircraft is within 30 nautical miles of the destination airport, the GPS

SECTION

APPROACH NAV

Flying the

5

The GPS APR switch will indicate ‘ARM’ when the
approach is armed. This will begin automatic CDI
scale transitioning from 5.0 nm to 1.0 nm as you
make your way to the FAF.

The ‘Next dtk’ prompt will flash to indicate the
desired course for the leg of the approach route.
Set the HSI course select to the next dtk value
when the waypoint annunciator starts flashing.

82

Approach

155XL will automatically arm the approach, and the GPS APR switch will indicate an
‘ARM’ status.

To fly the GPS approach (without radar vectors):

1. Confirm that the GPS APR switch indicates an ‘ARM’ status. The CDI scale will begin a
steady transition from the 5.0 nm to the 1.0 nm scale as you make your way to the FAF. If
the approach has been disarmed and the aircraft is within 3 nm of the FAF, the GPS 155XL
will prompt you to re-arm the approach.

2. The GPS 155XL will automatically sequence to each waypoint in the approach, with CDI,
course and timing guidance to each waypoint. For each waypoint in the approach, the GPS
155XL’s turn anticipation and waypoint alerting features will provide three pilot cues:

a. The waypoint annunciator will flash approximately 15 seconds before reaching the

turning point for each approach waypoint, and glow steadily approximately 2 seconds
prior to the turn anticipation point.

b. The ‘Next dtk’ prompt will flash in the CDI field when the ‘WPT’ annunciator begins

flashing. Set the HSI course select to the next dtk value when the waypoint annuncia­tor starts flashing. Start the turn when the annunciator glows steadily.

c. The To/From indicator flag on the GPSCDI will flip momentarily to indicate you have

transitioned to the next approach leg.

For more information on turn anticipation and waypoint alerting, please refer to Section 4.

3. If a procedure turn is required:

a. 2 miles prior to crossing the waypoint outbound, set the GPS SEQ switch to HOLD.
b. At the waypoint, set the outbound course on the HSI.

c. Fly the procedure turn. After the procedure turn outbound, set the inbound course on

the HSI.

d. On the inbound intercept to the final course, fly to center the CDI.

(continued on next page)

e. Set the GPS SEQ switch to the AUTO position. The GPS 155XL will resume automatic

waypoint sequencing for the remaining approach waypoints.

4. Once the aircraft is within 2 nm of the FAF (and the approach is armed), the ‘ACTV’ annun­ciator will illuminate and the CDI scale will ramp down to 0.3 nm.

NOTE: If the ACTV annunciator does not illuminate, do not descend after crossing the FAF

and fly all published missed approach procedures.

5. Upon reaching the FAF, the GPS 155XL will automatically sequence to the MAP waypoint.

To fly a missed approach procedure:

If an approach is terminated, the GPS 155XL may be used to navigate to the missed approach
holding point using one of the following procedures.

APPROACH NAV

Flying the

Approach

SECTION

5

NOTE: To comply with TSO specifications, the GPS 155XL will not automatically sequence
to the missed approach holding point. The missed approach holding point will be displayed
as the next available waypoint, which the pilot may activate when authorized. You must
fly all published missed approach procedures before selecting the missed approach hold­ing point on the GPS. If you want to disarm the approach and return the CDI scale to the
1 nm sensitivity, press the GPS APR switch.

If the approach procedure permits navigation direct from the MAP to the missed
approach holding point:

1. After the MAP has been crossed, press the Dkey. The GPS 155XL will automatically
display the first waypoint of the missed approach as the next approach waypoint.

2. Press

E

to confirm the destination. The GPS 155XL will provide a direct navigation

course to the waypoint.

After crossing the MAP, press the D key to dis­play the missed approach holding point.

If you have clearance directly to the holding point,
press E. You must fly all published missed

approach procedures before navigating to the
holding point.

83

SECTION

5

APPROACH NAV

Missed Approach

If you’re not authorized to fly direct-to the missed approach holding point:

1. After the MAP has been crossed, press the Dkey. The GPS 155XL will automatically
display the first waypoint of the missed approach procedure as the next approach waypoint.

2. Press Eto confirm the destination.

3. Stop automatic waypoint sequencing by setting the GPS SEQ switch to the HOLD position.

4. Fly the missed approach procedure. Remember to select the desired inbound course to the
missed approach holding point before setting the GPS SEQ switch to the AUTO position.

5. Set the GPS SEQ switch to the AUTO position for navigation to the missed approach
holding point.

Select the waypoint to which you have been given
clearance on the active route page and press D.

Confirm the starting waypoint for the next
attempt by pressing E.

84

After a missed approach, the GPS 155XL will allow you to repeat the same
approach procedure and select the approach waypoint to which you have been
cleared as the next active to waypoint. Before reactivating the approach, make sure
you fly all published missed approach procedures.

To reactivate the same approach for another attempt:

1. Press the Rkey and rotate Oto select the active route page.

2. Press

C

and rotate Oto place the cursor over the identifier of the approach waypoint

to which you have been given clearance.

3. Press the

D

key, followed by E. The GPS 155XL will provide navigation for the

repeat approach, starting with the approach waypoint you have selected.

The GPS 155XL’s approach select page allows you to review the available approach pro-

cedures at the destination airport. From the procedures list, you may select and activate a new
procedure on the fly. The active approach is indicated by an on-screen asterisk, and the
scrolling arrow prompt indicates which direction to scroll to view additional procedures.

To select or replace a procedure from the approach select page:

R

1. Press the

2. To review all available procedures, rotate K. “Unkn” (unknown) is displayed on
the Approach Select Page when the unit software does not know how to display
a new approach type in the database. DO NOT USE THIS APPROACH TYPE.

3. To review all available procedures, rotate K.

key and rotate Ountil the approach select page appears.

APPROACH NAV

Approach Select

Page

SECTION

5

4. To select a procedure, press

5. Press

E

. If there are multiple IAFs for the selected approach, rotate Oto select the

desired IAF and press

You may also replace or delete the active approach from the route catalog page.

To replace or delete an approach from the route catalog page:

1. Press the

2. Press Cand rotate Kuntil the ‘approach?’ prompt appears. Press E.

3. To replace the active approach procedure, rotate

4. To delete the active approach (denoted by an asterisk), highlight the approach and press

R

key and rotate Ountil the route catalog page appears.

and press

E

. If there are multiple IAFs for the selected approach, rotate Oto select

the desired IAF and press

\

, followed by E.

E

C

and rotate Oto highlight the desired procedure.

.

O

to highlight the desired procedure

E

.

Approach Select Page

The Approach Select Page after deleting the
active approach. If direct-to navigation to a
SID/STAR/Approach waypoint is active when
the procedure is deleted, the direct-to waypoint
will be retained as an “off route” destination.

85

BAY CITY

IAF

344 BYY

307°

10 NM

082°

262°

MAGUS

307°

1800

116° (7.9)

n13hp

ff13

387

Ref: NDB RWY 13 approach
at Bay City TX (3R1)

SECTION

5

APPROACH NAV

GPS Approach

Examples

GPS APPROACH EXAMPLES

In the examples that follow, the GPS waypoints are shown along the approach
path. In some cases, intermediate database waypoints have been added to approaches.
These waypoints are named using lower case letters using the following convention
(the most common database waypoints are defined below). Note that these waypoints
are not charted on NOS approach plates. They do appear on current Jeppesen
approach charts.

• dyyyj— DME arc waypoint where yyy is the radial from the

reference facility (VOR) and j represents the arc
radius (e.g., “a”= 1 nm, “b”= 2 nm, etc.)

• cfxx or cfxxx— course fix for runway xx or radial xxx

• ffxx or ffxxx— final approach fix for runway xx or radial xxx

• rwxx— runway xx threshold

• nxxhp— NDB approach runway xx intermediate holding

pattern waypoint

• maxx or maxxx— missed approach point for runway xx or radial xxx

• vxxhp— VOR approach runway xx intermediate holding

pattern waypoint

86

EXAMPLE 1— GPS ONLY APPROACH

IAF

MARTINSBURG

3000

120°

(16.5)

SUSII

2700

048° (2.5)

2000

048° (2.5)

2.5 NM FROM BAKEE

(FAF)

BAKEE

(MAP)

MYRTA

048°

048°

228°

RUSSY

Example 1 uses the GPS approach into Frederick Municipal Airport (KFDK) and
illustrates the basic sequence of selecting and flying a GPS approach, and flying
directly to a missed approach holding point. Please refer to the previous sections of
this chapter for expanded keystroke instructions.

1. Select the destination airport (KFDK) using the Dkey, or create and activate a route
to the destination airport.

APPROACH NAV

GPS Only

Approach Example

SECTION

5

2. Select the desired approach (GPS RW05) from the approach select page. The GPS 155XL
will automatically select MRB as the IAF since it is the only IAF available.

3. Confirm that the GPS APR switch indicates an ‘ARM’ status 30 nm from the airport. The
CDI will automatically begin a smooth transition from the 5.0 nm to the 1.0 nm scale.

4. Fly the approach. The GPS will provide navigation to each approach waypoint in sequence:

• MRB (initial approach fix)

• SUSII

• BAKEE (final approach fix)

• MYRTA (missed approach point)

D

• RUSSY (missed approach holding point)

5. Set the HSI course to DTK at each waypoint. Confirm that the GPS APR switch indicates
an ‘ACTV’ status within 2 nm of the FAF (BAKEE). The CDI will automatically transition
from the 1.0 nm to 0.3 nm scale as you approach the FAF, and the unit will warn you if
RAIM is not available for your approach.

6. Complete the approach by landing or perform the missed approach procedure.

7. For direct navigation guidance to the missed approach holding point (RUSSY), press
followed by Eafter crossing the MAP (MYRTA).

GPS RWY 5

FREDERICK MUNI (FDK)

SUSII

3000

DO NOT USE FOR NAVIGATION

MISSED APPROACH

CLIMB TO 3000 DIRECT

2.5 NM FROM
BAKEE

2700

2.5 NM 2.5 NM 3.8 NM 1.2

RUSSY AND HOLD

BAKEE

2000

048°

3.10°

MYRTA

MAP

87

SECTION

5

APPROACH NAV

VOR/GPS

Overlay Example

EXAMPLE 2 – VOR/GPS OVERLAY APPROACH

Example 2 uses the VOR/GPS RWY 19 approach into Kansas City Downtown
Airport (KMKC) from the south and illustrates an approach with a procedure turn,
which requires the pilot to set the GPS SEQ switch to the HOLD position prior to
crossing the IAF the first time. This example also illustrates the procedures required
when direct navigation to the missed approach holding point is not available.

KANSAS CITY

RIVERSIDE

2600

154° (4.7)

VOR RWY 19

KANSAS CITY

DOWNTOWN (MKC)

R-013

238°

058°

193°

(IAF)

JAMES INT

RIS

5.3

R-281

193°

R-260

2600

281°

(21.2)

NAPOLEON

048°

228°

R-149

1. Select the VOR/GPS RW19 approach and confirm that the GPS APR switch indicates an
‘ARM’ approach status.

2. Fly towards the IAF (JAMES) of the approach.

3. Two nautical miles before crossing the IAF, set the GPS SEQ switch to the HOLD position.
This prevents the GPS 155XL from automatically sequencing to the MAP (Riverside) before
the required procedure turn is completed.

4. After crossing the IAF, set the 013º outbound course on the HSI.

5. Initiate the procedure turn and set the 193° inbound course on the HSI. As you turn to the
inbound intercept heading, set the GPS SEQ switch to the AUTO position. The GPS SEQ

1

E

N

R

O

U

T

E

F

0

N

M

A

C

I

L

I

T

I

E

S

MISSED APPROACH

CLIMB RIGHT TURN TO 3000

ON HEADING 240° THEN VIA

R-260 TO ANX VORTAC

AND HOLD.

VOR/DME

JAMES INT

RIS

7

REMAIN

WITHIN 10 NM

013°

2600

193°

2500

4.5 NM

switch must be set to the AUTO position for the approach to go active.

6. Confirm that the GPS APR switch indicates an ‘ACTV’ approach status within 2 nm of the
FAF. Complete the approach by landing, or follow the missed approach procedure.

7. To fly the missed approach procedure, cross the MAP (Riverside), climb to 3000 feet via
heading 240° and press

D

followed by E. This will select the missed approach

holding point (ANX) as your ‘active to’ waypoint.

8. Since direct navigation to the holding waypoint is not authorized, set the GPS SEQ switch
to the HOLD position to prevent automatic waypoint sequencing.

DO NOT USE FOR NAVIGATION

88

9. Set the HSI to the 080° heading and turn left to intercept the inbound course to the
holding point.

EXAMPLE 3 – VOR/DME ARC OVERLAY APPROACH

5 NM 7 NM

MISSED APPROACH

CLIMB TO 3000 VIA HEADING

240° AND TOP R-213 TO

ERASE 25 DME AND HOLD.

3000

2600

200°

12

7

TOP TOP

VORTAC

ONE MINUTE

HOLDING PATTERN

025°
205°

Airport (KFOE) and illustrates an approach based on a DME arc. Although DME arc
approaches are not based on a direct course, the GPS 155XL will still provide
approach navigation guidance through the arc by constantly displaying your distance
and bearing from the DME reference navaid on the position page. To fly the arc,
monitor the distance displayed on the position page and manually adjust your head­ing to maintain the course along the arc. When flying a DME arc, the GPS SEQ switch
must be set to the HOLD position to ensure proper CDI operation.

Example 3 uses the VOR/DME RWY 21 approach into Topeka/Forbes Field

1. Select the VOR RW21 approach and select the D094G initial approach fix to fly the left
hand arc from the 094° radial. Thirty nautical miles from the airport, confirm that the GPS
APR switch indicates an ‘ARM’ status.

2. Fly towards the IAF (D094G). The GPS WPT annunciator will flash 15 seconds before you
reach the waypoint.

3. After crossing the IAF, set the GPS SEQ switch to the HOLD position.

4. Set the desired inbound course (205º) on the CDI/HSI.

5. Press

N

and rotate Oto display the position page. The position page will display the
DME navaid as the reference waypoint (on the bottom line) as long as your ‘active to’
waypoint is part of the DME arc you are flying.

(continued on next page)

VOR/DME RWY 21

TOPEKA/

FORBES FIELD (FOE)

048°

228°

ERASE

TOP

25

MISSED APPROACH

CLIMB TO 3000 VIA HEADING

240° AND TOP R-213 TO

ERASE 25 DME AND HOLD.

DO NOT USE FOR NAVIGATION

APPROACH NAV

VOR/DME ARC

Example

NoPT

3000

Arc

7

3000

TOP

205° (7)

IAF

TOPEKA

205°

(IAF)

VORTAC

R-258

ONE MINUTE

HOLDING PATTERN

1 MIN

2600

(7)

200°

TOP

7

205°

205°

TOP

SECTION

5

3000

NoPT

7

Arc

R-094

(IAF)

89

SECTION

5 NM 7 NM

MISSED APPROACH

CLIMB TO 3000 VIA HEADING

240° AND TOP R-213 TO

ERASE 25 DME AND HOLD.

3000

2600

200°

12

7

TOP TOP

VORTAC

ONE MINUTE

HOLDING PATTERN

025°
205°

OBS

TO

FR

N

33

30

W

24

21

S

15

12

E

6

3

5

VOR/DME RWY 21

FORBES FIELD (FOE)

MISSED APPROACH

CLIMB TO 3000 VIA HEADING

90

240° AND TOP R-213 TO

ERASE 25 DME AND HOLD.

APPROACH NAV

VOR/DME Arc

Example

TOPEKA/

(IAF)

048°

228°

ERASE

TOP

25

VORTAC

DO NOT USE FOR NAVIGATION

NoPT

3000

7

TOP

IAF

TOPEKA

R-258

200°

TOP

7

ONE MINUTE

HOLDING PATTERN

6. Monitor your distance and bearing from the DME navaid along the arc.

7. The external CDI course deviation needle will begin to center as you approach the inbound
course. The GPS WPT annunciator will flash 15 seconds before reaching the course fix,
and the desired track for the final approach will appear in place of the graphic CDI.

GPS SEQ

Arc

3000

205°

205° (7)

205°

2600

(7)

1 MIN

3000

TOP

NoPT

7

Arc

205°

(IAF)

R-094

8. Dial in the final course (200º) on the HSI and set the GPS SEQ switch to the AUTO posi­tion. Automatic waypoint sequencing will resume for the rest of the approach. Locate the
step down fix by monitoring the distance to the MAP as shown on the profile view of the
approach plate. Confirm that the GPS APR switch indicates an ‘ACTV’ status 2 nm from
the FAF.

9. To fly the missed approach procedure, cross the MAP and climb to 3000 feet via
heading 240°.

10. Press

D

, followed by E. This will select the missed approach holding point

(ERASE) as your ‘active to’ waypoint.

11. Place the procedure on HOLD by pressing the GPS SEQ switch.

12. Set the HSI to the 213° course, fly until the CDI is centered and enter the holding

pattern.

AUTO ACTV