LTN-92 Pilots Guide

TP92-04138

Pilot's Guide

LTN - 92

Inertial

Navigation System

Basic/World Wide Data Base

Program 92-0413

June 1995

Revision 3: April 1998

Litton

Table of Contents

Section

Title

Page

Section 1 General System Description 1-1

Navigation Data Storage 1-4 Synthetic Magnetic Variation 1-4 Multiple System Operation 1-5 Mode Selector Unit 1-5 Mode Switch 1-5 MSU Annunciators 1-6 Control Display Unit 1-7

CDU Operational Summary 1-9

Operating Cautions 1-11

Section 2

Predeparture Procedures 2-1

INS Startup and Data Base Validity Check 2-1

Present Position Entry 2-4

Local Ident Entry of Present Position 2-5 Present Position Entry by Latitude

and Longitude 2-6 Present Position Entry by Range and

Bearing From a Reference 2-8 GMT and Date Entry 2-10 Position Page Normal Display During

Alignment 2-11 Alignment Status 2-12 Flight Plan Data Entry 2-15

Table of Contents

Section Me

_Page

Flight Plan Assembly by Waypoint to

Waypoint Entry 2-15 Duplicate Identifiers 2-17 Flight Plan Assembly by Route Entry 2-19

Crew Waypoint Entry or Correction 2-20

Latitude/Longitude Crew Waypoint

Entry 2-21

Bearing/Range Reference Crew

Waypoint Entry 2-23 Flight Plan Editing 2-26 Waypoint Substitution 2-26 Single Waypoint Deletion 2-28 Multiple Waypoint Deletion 2-30 Inserting a Waypoint or a Route

Between Existing Waypoints 2-32 Initial Track Selection 2-34 Default Leg Selection 2-34 Enter Leg by Identifier 2-35 Enter Leg by Waypoint Number 2-37 WPT.Page Flight Plan Verification 2-39

Section 3 Enroute Procedures 3-1

Leg Switching 3-1

Flight Plan Data 3-16

Table of Contents

Section Title

Page

EFIS "To" Waypoint Change 3-18

Course Data 3-19 Instrument Data 3-20 Remote Range 3-20

Section 4 Post Flight Procedures, Rapid

Realignment and Nay Update 4-1

Accuracy Test 4-1

Intermediate Stops 4-3

Post Flight Procedures 4-5

System Accuracy Removal Criteria 4-6

Rapid Realignment 4-6

Nav Update Mode 4-9

Section 5

Crossfill 5-1

Crossfill Procedures 5-2

Section 6 Position Updating 6-1 Easy On/Off Steering 6-1 Position Check 6-3 Automatic Position Updating 6-4 Radio Updating 6-6 Enabling Position Updating 6-9 RNAV Inhibit Functions 6-10 DME/VOR Related- Messages 6-11 DME Range Crossfill Related

Messages 6-12

Other Messages 6-13 STS/Update Page Summary 6-14

Table of`Contents

Section Title

_Page

Triple System Mixing. (TM IX) 6-16 Disabling Triple System Mixing 6-17 Triple System Mixing Related

Messages 6-18

STS/Update Page Description 6-19

Manual Position Update 6-21

Flush Updates 6-24

RNAV Approach Mode Characteristics 7-1 RNAV Approach Procedures 7-2 Missed Approach Point Entry 7-4

Section 8 Attitude Reference Mode 8-1

Section 9

Summary of Display Pages and

Function Keys 9-1

Position Page 9-3 Course Page 9-4 Leg Page 9-5 Waypoint Page 9-6 Flight Plan Page 9-7 Direct. to Page 9-8 Instrument Data Page 9-9 Catalog Page 9-10 Creating and Deleting Routes and

Waypoints in Permanent Memory 9-11

Storing a Custom Route 9-11

Clearing Custom Routes from the

ROUTES Catalog 9-12

Table of Contents

Section

Title

Page

Storing Waypoints , Stations and

Airports in Permanent Memory 9-13 Deleting a Waypoint or Station from

Permanent Memory 9-14 Remote Page 9-15 Status Page 9-16 Display Test 9-17 Accuracy Test 9-18 Dbase Type/Date 9-19 Autopilot/Flight Director Tests 9-20 HSI Operation 9-27

Section 10 Abnormal Operation 10-1

INS Warning Annunciations 10-1 Warning Annunciations 10-1 Action/Malfunction Messages 10-2

Section 11 Alphabetical Index 11-1

Section 12 Quick Reference Guide 12-1

Alignment (With Local Ident Stored in

Data Base) 12-2 Alignment (With Local Ident Not in Data

Base) (LAT/LON Procedure) 12-3 Display Test 12-4 Waypoint Entry by Route Definition 12-4 Waypoint Loading 12-5 Crossfill (Remoting) 12-6 Flight Plan Verification 12-7 Initial Track Selection 12-7 Route Change 12-8 Inserting a Waypoint Between Waypoints 12-8 Waypoint Substitution/Deletion 12-9

Table of Contents

Multiple Waypoint Deletion 12-9 Direct-To Mode (From Present Position

to a Waypoint)

Crosstrack (Offset) 12-10

VOR/DME Cross Check

12-11

Time, ETA, and WPT Distance Displays 12-11

Position Check _12-12

Manual Position Update

12-12

Remove All Position Updates

12-12

Remote Ranging 12-13

Use of Crew (Temporary) Catalog 12-13

Catalog Inspection

12-14

Accuracy Test - 12-14

Leg Change - Track Selection 12-15 Status Malfunction Messages 12-15

Attitude Mode 12-16

Automatic Updates , Disable/Re-Enablel2-16

List of Illustrations

Figure Title

Page

1-1 Inertial Navigation System 1-2

1-2 INS Typical Interface 1-3

1-3 Mode Selector Unit

1-5

1-4 Control Display Unit 1-7

1-5 Numeric Pushbuttons - Special Functions 1-10 3-1 Leg Switch Less Than 25 Degrees 3-2 3-2 Leg Switch Between 25 and 110 Degrees 3-2

3-3 Leg Switch Greater Than 110 Degrees

3-3

3-4 Direct To Modes 3-6

3-5 Crosstrack Offset Leg Change 3-13

3-6 Track Hold Mode 3-15

4-1 Radial Position Error 4-7

4-2 Drift Rate 4-8

9-1 Typical HSI Presentations 9-27

9-2 Summary 9-29

List of 111ustrations

List of Tables

A

Table. Title

Page

9-1

Synchro and Analog Test Output Values

to HSI and ADI

9-24

9-2

BCD Test Output Values (EFTS and WX Radar)

9-25

9-3

Annunciator Test

9-26

10-1

Action/Malfunction Messages

t

Section 1

General System

Description

NOTE:

This document contains all configurations

applica-ble to the LTN -92 navigation system. The user

may use any portion of this document that is

ap-propriate for a particular configuration.

The INS consists of three units (figure 1-1): • a Mode Selector Unit (MSU)

• a Control Display Unit (CDU), and • an Inertial Navigation Unit (INU).

An optional Battery Unit (BU) is available as a backup power source.

0

The MSU and CDU are used for pilot control of the INS and are installed in the cockpit . The INU and BU are normally installed in the aircraft electronics bay.

The Litton LTN- 92 inertial navigation system (INS) is a

navi-gation system , with automatic GPS and radio update capabilities (VOR-DME, TACAN).

The INS may be operated as an Area Navigation System if

position is periodically updated using GPS or range and bearing from selected VOR -DME or TACAN stations.

Section 1 - General System Description

The system features a Control Display Unit (CDU) which

functions as an intelligent data terminal and incorporates a

Light- Emitting-Diode (LED) matrix display. The CDU

key-board has dual function pushbuttons for full alphanumeric

data entry. The displays provide navigation data, operating

status of the system, and formatted messages to assist the

pilot in data entry. I

f

MODE SELECTOR UNIT

CONTROL DISPLAY UNIT

Inertial Navigation System Figure 1-1

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Figure 1-2

Section 1 - General System Desc^tion

NAVIGATION DATA STORAGE

Crew Catalog (Temporary). Navigation data items (airports, waypoints , or stations) may be retrieved or entered at any time. This catalog can store a maximum of 120 data items. These data are lost when the system is turned off.

Custom Catalog (Permanent). Up to 2005 Navaids,

Way-points , and Airports, plus 100 routes of 98 wayWay-points can be stored in this memory. It remains unaffected by the cyclic database update. The facility exists to permanently store routes and other data entered via the CDU into this area of memory. The aircraft wiring determines whether the storage function is available.

World Wide Data Base (Permanent). Navigation data items

(airports, enroute waypoints, or stations) may be retrieved. This catalog can hold a maximum of 2 megabytes of data. Memory is consumed as follows:

• Each Navaid requires 32 bytes

• Each Waypoint/NDB requires 16 bytes

Each Airport requires 16 bytes.

Each route requires 16 bytes plus 4 bytes/waypoint

A large airline will typically store two complete databases (the current cycle plus the next cycle's worldwide Navaids), way-points/NDBs, airports, custom waypoints/ramp positions, 6000 routes, and airways with less than 50% of available memory used.

SYNTHETIC MAGNETIC VARIATION

The system can be used to display magnetic heading, track, and desired track independent of the aircraft compass sys-tem. When latitude is greater than 73° Nor 60°S, the system will automatically revert to True Heading and digital magnetic outputs will be NCD (no computed data).

4

r

Section 1 - General System Description

MULTIPLE SYSTEM OPERATION

Multiple systems may be integrated in dual or triple system

configurations. A crossfill feature allows the pilot to transfer

waypoint data, date, and time from one system to the

remain-ing systems.

A comparison warn feature alerts the pilot when a significant

difference in position or ground speed occurs between

sys-tems.

In e'triple system installation , the pilot may enable atriple

sys-tem mix feature which combines the present position of all

three systems for greater navigation accuracy.

MODE SELECTOR UNIT

The MSU controls the application of power to the INS and selects the Standby (STBY), Alignment (ALIGN), Navigation (NAV), and Attitude Reference (ATT REF) modes of opera-tion.

MODE BAIT FAIU ALIGN SWITCH ANNUNCIATOR ANNUNCIATOR

Y- ALIGN

r NAV

O

OFFS ATT_REF ALIGN

BATE

Mode Selector Unit Figure 1-3

c)

Mode Switch

OFF Turns INS power off; MSU and CDU panel lighting may remain on.

Section 1 - General System Description

STBYIALIGN Turns INS power on and selects Standby or Alignment mode. Pilot enters present posi-tion, GMT and date and display test may be performed. An automatic alignment sequence starts . The aircraft must remain stationary while the system is in Standby or Align.

NAV Selects Navigation mode. This is the normal flight operating mode and must be selected prior to moving the aircraft. Initial track mcy be entered at this time.

NAV may be selected directly from OFF, STBY, or ALIGN modes, but alignment must be completed prior to moving the aircraft. If NAV is selected before alignment is com-plete, the system will complete alignment before automatically sequencing to NAV. NOTE: The mode switch is detented in the NAV position to

prevent accidental INS shutdown. To deselect NAV, the knob must be pulled away from the panel and then turned.

ATT REF Selects Attitude Reference mode. In this

mode, the INS provides pitch, roll, and plat-form heading outputs only, and the CDU displays only status data. ATT REF mode disables INS navigation capabilities until a full alignment is performed on the ground. MSU Annunciators

ALIGN (amber) Comes on during alignment to indicate that

alignment sequence is in progress.. On com-pletion of a valid alignment and selection of NAV, ALIGN light goes out.

CAUTION: WHEN THE ALIGN LIGHT IS ON, THE AIR-CRAFT MUST REMAIN STATIONARY TO COMPLETE A NORMAL GROUND

ALIGN-MENT.

Section 1 - General System Description

BATT (FAIL)

(Battery fail) Comes on when DC backup

voltage is insufficient for INS operation. If the battery is discharged, this light will come on during the battery test at tum - on, and remain on until the next tum - on with a charged battery.

CONTROL DISPLAY UNIT

The CDU is used to enable the entry of data into the INU, to

selectflight plans; and to display datafrom the INU database.

UPDATING SOURCE INP TON (G. R. T E)

(NO UPDATE IN PROGRESS)

ALPHA OR NUMERIC

BRIGHTNESS MODE ALPHANUMERIC CONTROLS INDICATION PUSHBUTTON

CLEAR PUSH-BUTTON ENTER PUSH-BUTTON ALERT ANNUN-CIATOR OFFSET ANNUN-CIATOR DATA pE pN L^TTRR ^Y BUTTONS HOLD PUSH-BUTTON PUSHBUTTONS PUSHBUTTON

Control Display Unit Figure 1-4

The CDU LED alphanumeric display , annunciators, and

pushbuttons function as follows:

LED matrix display (display) - Displays five lines with 16

characters per line. When appropriate, lines can be slewed upward or downward by use of slew pushbuttons.

Section 1 - General System Description s

pressed , set brightness level of display . (Operable only in numeric mode).

A • N (alphanumeric) pushbutton - An alternate action

switch enabling alphabetic or numeric data entry.

CLR (clear) pushbutton - When pressed before ENT is

pressed , removes entered data from display.

ENT (enter) pushbutton - When pressed, enters data input

via data entry pushbuttons into the computer.

ALR (alert) annunciator - Comes on at a preset time before

aircraft reaches each approaching To waypoint. When INS is in automatic mode , goes out to indicate that a leg change has been made automatically . When INS is in manual mode , flashes to indicate that a leg change must be made manually. Flashes when in track hold mode. OFS (offset) annunciator - On when INS is in the offset

. (parallel track mode).

Data entry pushbuttons - When pressed, enter data in the

display line indicated between entry line markers.

HLD (hold) pushbutton - When pressed, freezes present

position display (except in CARP mode).

EXP (expand) pushbutton - Expands selected display

cate-gories.

Slew pushbuttons - Enable slewing of appropriate lines of

display. Normally, display will advance one line each time pushbutton is pressed or when continuously pressed will continuously slew.

Data display select pushbuttons - Allow display of

particu-lar data category. (See Summary section).

•

Section 1 - General System Description

C

0

WRN (warn) annunciator - Comes on when a system

malfunction occurs . Flashes if ALIGN error occurs.

BAT (battery on) annunciator - Comes on when INS is

operating on-28 vdc backup power.

Entry line markers - Indicate display line into which

data may be entered (CDU line 3).

CDU OPERATIONAL SUMMARY

The CDU provides data entry and display based on pilot

call-up of various " pages " selected by the function pushbut-tons. The keyboard provides an alphabetic entry (shown on upper half of the pushbuttons ) when the alpha entry mode is selected . The system will automatically switch to the alpha

entry mode only when alpha entry is appropriate on a

partic-ular page. The alpha mode is annunciated by A in the upper right comer of the display. A return to the numeric mode may be selected at any time by pressing A • N.

The numeric entry pushbuttons on the right side of the

key-board are arranged in the same manner as standard numeric

keyboards. The normal data entries of North , South, East,

West, Left, and Right are made using these pushbuttons (fig-ure 1-5).

The following conditions apply for data entry:

1. All numeric data entries (latitude , longitude, etc.) and all

alphanumeric entries (flight plan , ident, etc.) are made

left to right.

2. Leading zeros are not required. 3. Trailing zeros must be entered.

4. A • N selection is not necessary when entering

posi-tion.

Section 1 - General System Description NORTH M 5 G 3 LEFT RIGHT z EXP HLD SOUTH

Numeric Pushbuttons - Special Functions Figure 1-5

Display pages are arranged to provide a primary display of

data. Where additional data relating to the primary page is available , the slew up or down pushbuttons are used. EXP

(Expand ) is used to provide information relating to an Item displayed on the entry line (example : latitude and longitude of a waypoint).

Refer to Section 12 for a summary of the CDU data pages.

i

Section 1 - General System Description

C

OPERATING CAUTIONS

1. UNLESS AN INS FAILURE OCCURS, THE MODE

SWITCH SHOULD NOT BE DESELECTED FROM NAV

ONCE NAV MODE IS ENABLED.

2. WHEN THE MSU ALIGN INDICATOR IS ON, THE

SYS-TEM IS PERFORMING AN ALIGNMENT. THE

AIRCRAFT SHOULD REMAIN STATIONARY DURING

THIS PERIOD.

3. IF CDU BAT ANNUNCIATOR COMES ON , THE INS IS

OPERATING ON DC BACKUP POWER.

NOTE: There is a 5 second battery test at tum on when the BAT annunciator will normally come on.

IF THE BACKUP POWER SOURCE IS A BATTERY UNIT, 15 TO 30 MINUTES OF OPERATION WILL BE AVAILABLE WITH A FULLY CHARGED BATTERY. IF PRIMARY POWER IS NOT RESTORED PROMPTLY, THE BATTERY VOLTAGE WILL FALL BELOW THE LEVEL REQUIRED TO OPERATE THE INS.

4. IF THE MSU BATT ANNUNCIATOR COMES ON, THE

DC BACKUP POWER IS INSUFFICIENT FOR INS

OP-ERATION.

5. IN A DUAL OR TRIPLE INSTALLATION, IF ONE OF THE SYSTEMS HAS A LARGE INERTIAL POSITION OR VELOCITY ERROR, THE FOLLOWING MESSAGE WILL BE DISPLAYED ON THE CDU:

"THIS SYS <I> POS OR G.S. DIFFERS FROM

OTHERS BY >35 N.M. OR 50 KT. CLR:RETURN"

THE PILOT HAS THE OPTION TO USE OR DISREGARD

THAT INS.

Section 1 - General System Description

6. IF AN ERROR IS DETECTED IN THE CUSTOM CATA-LOG DATA DURING FLIGHT, THE FOLLOWING MESSAGE WILL BE DISPLAYED ON THE CDU:

"DATA BASE COMMUNICATION FAILURE OR CUST/RTE CATALOG CHECKSUM FAIL: CUST FLIGHT PLAN DATA INVALID. CLR: RETURN" THE PILOT SHOULD VERIFY THE DATA IN THE FLIGHT PLAN IS CORRECT. THE PILOT HAS THE OPTION TO USE OR DISREGARD FLIGHT PLAN DATA FROM THAT INS. THE SYSTEM WILL INHIBIT FURTHER LOADING OF CUSTOM DATA INTO THE FLIGHT PLAN . HOWEVER , CREW CATALOG DATA, CROSSFILL DATA AND, EXTERNAL DATA BASE (NDB) DATA MAY STILL BE USED.

7. AFTER THE MSU HAS BEEN TURNED TO OFF, THERE

IS A 12 SECOND SHUTDOWN DELAY BEFORE THE

INS SHUTS DOWN . DURING THIS TIME THE SYSTEM

IS UPDATING MEMORY. DO NOT PULL CIRCUIT

BREAKERS TO THE INS UNTIL THE CDU BLANKS.

ATTI-TUDE (PITCH AND ROLL) AND ATTIATTI-TUDE FLAG ARE INVALID FOR ABOUT 29 SECONDS (NAV TO ATT REF) OR 60 SECONDS (OFF TO ATT REF). PRIOR TO SELECTING ATT REF, SELECT A BACKUP SOURCE OF ATTITUDE.

9. A STATIC INERTIAL ALIGNMENT CAN BE PER-FORMED AT LATITUDES UP TO 85 DEGREES; HOWEVER , STATIC INERTIAL ALIGNMENTS PER-FORMED AT LATITUDES ABOVE 80 DEGREES NORTH OR SOUTH, CANNOT GUARANTEE AN AC-CURACY OF 2NM/HR OR BETTER.

,I

Section 2

Predepa

rt

ure

Procedures

1. Ensure the MSU mode switch is set to OFF.

2: Set circuit breakers in (on).

3. Set mode switch to NAV for automatic 10 minute align-ment.

With WWDB

OFF ATT_REF

Without WWDB

page 2-1 February 1996 TP92-04-13-B

Section 2 - Predeparture Procedures

With WWDB

The CDU displays the INU program number on line 1.

Line 2 is the customer iden-tifier for the data base.

Lines 3 and 4 show the effectivity dates for the two stored World Wide data bases.

4. Slew to the proper date cycle. R

4

0

5. Press ENT.

Without WWDB .

The CDU displays the program number 92-04-13 on the top line.

4. After 3 seconds, display changes to custom data base title page where X's will identify the data base.

CUSTOM'OBAS'

If the Litton data base ser-vice is being used, the first two characters are the air-line code, the third and fourth are the month of expiration , and the fifth and sixth are the day of expiration . (LC0731 is Lockheed, expiring July 31.)

5. Press CLR to continue.

page 2-2

TP92-0413-B January 1997

Section 2 - Predeparture Procedures

I-6. The CDU changes to allow position entry (referto "Pres-ent Position Entry " in this section).

If an FMC is connected,

then position and time entry

is automatic.

N FMC input received

O

NOTE: If the INU data base is out of date, stored waypoint data, used in a route to be flown, should be cross checked against the current flight planning documents , and the accuracy of every Latitude and Longitude confirmed.

Additionally, when the data base is out of date, it is recommended that the stored VOR/DME data being used for RNAV position updating be cross checked for accuracy, or alternatively do not enable RNAV updating.

Section 2 - Predeparture Procedures

PRESENT POSITION ENTRY

Aircraft present position must be entered into each INS before alignment can be completed . If a compatible GPS or flight management computer (FMC) is connected to the INS, the position and time will automatically be displayed. The FMC position is automatically accepted . The GPS position is displayed and the pilot must accept or reject it.

Upon entry of present position , the system checks the entry to ensure that it is within 3+3t (t=time in NAV ) of the aircraft's last present position at time of shutdown on previous flight. If these comparison limits are exceeded , the CDU WRN annunciator will flash and the message "CHECK PPOS ENTRY" will be displayed on the POSITION page (STATUS page will display " ENTER PPOS "). Pressing ENT will accept the displayed position entry , pressing CLR will reject the entry and prompts for a new latitude and longitude entry will be displayed.

After 4.5 minutes of alignment, the system performs an

additional check of the entered latitude against an inertial estimate of the aircraft 's latitude. The two must agree to within 30 nautical miles for the alignment to proceed. If the comparison limit fails , the CDU WRN annunciator will flash and- the messages ENTER PPOS and ALN FAIL will be displayed on the STS page to alert the pilot.

Present position may be entered by: • Automatic download from FMS • Manual entry by IDENT

• Manual entry by LAT/LON

• Manual range and bearing to a known reference

i

Section 2 - Predeparture Procedures

LOCAL IDENT ENTRY OF PRESENT POSITION

POSITION page is displayed.

1. Slew LOC ID to entry

line.

2. Enter LOCAL (DENT for present position.

3. Press ENT

Section 2 - Predeparture Procedures

NOTE: If the LOCAL IDENT is not valid; "IDENT NOT

FOUND" will be displayed ; press CLR to return to

local (DENT entry. If duplicate idents are found, the

first one will be displayed . The pilot is prompted to

press ENT to accept the displayed ident, press SLEW

to display the other ident (s) or press CLR to return.

4. Enter GMT and date. Refer

to GMT ENTRY.

PRESENT POSITION ENTRY BY LATITUDE AND

LONGITUDE

POSITION page is displayed.

1. Select North (2N) or South (8S).

2. Enter latitude , including any trailing zeros.

F 2N or 3 3 5 6 5 2 T as page 2-6

Section 2 - Predeparture Procedures

n

3. Press ENT.

LAT flashes once; dis-play slews LON to entry line.

4. Select West (W4) or East

(6E).

5. Enter longitude , including

any trailing zeros.

6. Press ENT.

LON flashes once;

display slews GMT to

entry line.

7. Enter GMT HH:MM:SS, and

date. Refer to GMT ENTRY

ENT

P41 or

F

s

N

E

1182447

ENT

NOTE: Invalid present position coordinates (latitude greater than 90°, longitude greater than 180°, or arc-minutes greater than 59.9') will be rejected by the system . Line 3 will flash with the invalid data until CLR is pressed to clear the entry.

. Section 2 - Predeparture Procedures

PRESENT POSITION ENTRY BY RANGE AND

BEARING FROM A REFERENCE

POSITION page is

displayed.

1. Press AN key.

CDU displays:

2. Enter reference identifier.

3. Press ENT

4. Enter magnetic bearing

from the reference to

present position.

Section 2 - Predeparture Procedures

5. Press ENT.

6. Enter the range from the

reference to present

position.

7. Press ENT.

8. View data to ensure it is correct.

9. Press ENT to accept the data or CLR to reenter the data. The data may also be changed by slew-ing the desired parame-ter to the entry line and keying in new data.

ENT

R

ENT

or CLR

NOTE : If the reference cannot be found or distance is great-erthan 300 nmi or bearing is greatgreat-erthan 359.9 deg, line 3 will flash and the corresponding error mes-sage will be displayed.

Section 2 - Predeparture Procedures

GMT AND DATE ENTRY

NOTE :

Failure to enter GMT will invalidate INS

calcula-tions of ETA and Time initialize crossfill.

NOTE: If the aircraft is equipped with a compatible GPS, FMS or chronometer, the GMT and date will be automatically displayed . Time received from the GPS has priority and will overwrite manually entered time.

1. Enter GMT in hours, minutes , and seconds, 24 hour time.

e.g., 1 2 4 51 0

m ouT :r " ...a

LA7 4 32 ,r N .

2. Press ENT at instant preset time

matches actual GMT. ENT

NOTE : The INS will not accept afirst digit GMT entry other than 0, 1, or 2 . If invalid hours (greater than 23), minutes (greater than 59) or seconds (greater than 59) are entered , GMT line flashes and INVALID ENTRY is displayed . Press CLR and reenter GMT.

3. Enter date. e.g., 27 July 1993 enter as 270793

NOTE: Date entry is not required for navigation . It is

neces-sary when an external navigation base is installed on the aircraft.

NOTE : An entry of 00 will be read as year 2000. r

Section 2 - Predeparture Procedures

POSITION PAGE NORMAL DISPLAY DURING

ALIGNMENT

The POS page will display the entered latitude and longitude

and GMT (If entered). Position may be reentered at any time during ALIGN without affecting the ALIGN time. Once the system has sequenced into NAV, the inertial position cannot be changed.

Position page display

dur-ing alignment. Nearest

sta-tion range and bearing dis-played on line 4.

NOTE: Bearing is True or Magnetic depending upon

CDU selection of True or Magnetic data.

Section 2 - Predeparture Procedures

ALIGNMENT STATUS

1. Mode switch : STBY ALIGN or first 10 minutes of NAV.

On the MSU, the ALIGN an-nunciator comes on.

2. The alignment process can be observed by pressing STS on the CDU . SYS STS/TEST page is displayed . Refer to Alignment Status Table 2-1.

CDU displays SYS STS/TEST pages during alignment. STATUS 90 STATUS 80 60 50 10 2 ALIGN STBY^ NAV OFF ATT_REF

ALIGN STBY NAV OFF ATT REF

v

STS

Section 2 - Predeaarture Procedures

C

NOTE: The number (2 through 90) appearing on the

ALIGN line indicates alignment status . 90 is gen-erated at startup and decrements through 2 at completion of alignment (refer to Alignment

Status Table 2-1). The time remaining (minutes

and tenths) in align appears on the TIME line.

The time required to complete a normal align-ment is 10 minutes.

AUGN

3. Set mode switch to NAV. NAV

NOTE: The recommended operating procedure at turn-on is to switch the MSU from OFF directly to

NAV. The system will automatically sequence to NAV when the alignment is complete.

Alignment not complete : display remains in ALIGN until status 2 then shifts to NAV.

Alignment complete : ALIGN annunciator goes out; ALIGN line changes to NAV, status 1 , TIME line changes to time in NAV.

STATUS

1

CAUTION : DO NOT SET MODE SWITCH OUT OF NAV AFTER NAVIGATION MODE IS ENTERED.

NOTE: See Abnormal Operation Section for explanation

of action/malfunction messages.

NOTE:

INS alignment accuracy will continue to improve

even after entering NAV. No accuracy

improve-ment is gained by leaving the INS in STBY or

ALIGN.

Section 2 - Predeparture Procedures

Table 2 - 1. Alignment Status Table

Status

Description

90 System high voltage sequence is performed. Accelerometer coarse leveling is accomplished (complete 24 seconds after turn -on).

80 System continues leveling (complete 30 seconds

after turn -on).

70 Executed and displayed only if the system sensor block temperature is below 0°C.

Indicates extended align. The system will remain in status 70 until the block temperature is above - 15°C and align time is less than 9 minutes. When STS 70 is displayed , alignment time will be more than 10 minutes.

60 System performs fine leveling and gyro

compassing . System remains at status 60 until

5.5 minutes are remaining in align time.

50 Latitude is tested continually from 5 .5 minutes remaining in Align. If present position has not been entered the system remains at status 50. If the latitude test fails the system will reset to status 50 and position entry will be required. Otherwise, the system stays in status 50 for 10 seconds, then sequences to status 10. Fine leveling and gyro compassing continue in status 50.

4

10 System continues fine leveling and gyro compassing and remains in status 10 until the minimum align time has been completed. If NAV mode is selected, the system will automatically sequence into NAV mode.

2 The minimum align time has been completed. The system will cycle to NAV providing the MSU is set to NAV.

Section 2 - Predeparture Procedures

FLIGHT PLAN DATA ENTRY

The flight plan consists of a sequential waypoint list with up to 98 custom, crossflll, or pilot-entered waypoints (or a combination thereof) called up from various catalogs. Each waypoint is selected by entering an identifier (IDENT) which defines its coordinates. Refer to CATALOGS.

4

FLIGHT PLAN ASSEMBLY BY WAYPOINT TO

WAYPOINT ENTRY

1. Press WPT.

WPT SELECT page is

displayed.

NOTE: The <P> symbol represents present position.

NOTE:

If present position has not been entered when

the WPT key is pressed, the POS page is dis-played.

2. Press AN to display entry prompts.

CDU displays:

A•N

3. Assemble Flight Plan:

Waypoint Entry

a. Enter the waypoint IDENT by alpha-numeric entry, (e.g. VNY).

Section 2 - Predeparture Procedures

b. Press ENT.

VNY is added to waypoint list. Prompt line for next waypoint.

c. Continue flight plan assembly by entry of up to 98 way-points. Press CLR if no more waypoints to be entered.

NOTES : If the entered IDENT does not exist in any of the systems catalogs , prompts for entry of latitude and longitude will be displayed. Refer to CREW WAYPOINT SELECTION AND ENTRY section of the PREDEPARTURE PROCEDURES.

Use up and down slew keys to slew through the waypoints.

Pressing the A • N key on the waypoint page will advance to the first available blank waypoint and display the entry prompt line.

To jump to a particular waypoint, enter the way-point number (e.g., 27) and press ENT

Waypoints cannot be entered before present position is entered.

Waypoint zero <P> will hold the coordinates of the FROM waypoint whenever a DIRECT TO or

Section 2 - Predeparture Procedures

4

DUPLICATE IDENTIFIERS

When duplicate identifiers exist, the number of duplicates will

be displayed in the upper right comer of the CDU. The

country name will be displayed on line 4 . If the waypoint is a

CUSTOM waypoint, then CUST will be displayed . The pilot

must examine coordinates and country name of each

duplicate identifier.

1. During flight plan con-struction , enter an (D-ENT that is used for more than one set of coordinates.

2. Press EM.

Examine the

coordi-nates and country of the

first duplicate (DENT.

ENT

NOTE: The alpha character located at the center of

line 1 indicates the type of waypoint:

A Airports

S Stations

W Waypoints

Section 2 - Predeparture Procedures

3. If the displayed coordi-nates are not desired, slew up once; the num-ber in upper right comer increments by 1 and coordinates and country name change.

4. Repeat step 3 until the correct coordinates are found.

5. Press ENT.

Selected waypoint is en-tered into the waypoint list. The , prompt line is displayed to continue flight plan construction.

Section 2 - Predeparture Prgcedures

FLIGHT PLAN ASSEMBLY BY ROUTE ENTRY

1. Press WPT. H

WPT

WPT SELECT page is

displayed.

2. Pressing these four buttons will insert "-R" at the first WPT prompt. This will produce the Route prompt.

Prompt for route

name appears.

Insert route name then

press ENT.

AN

LI

4

J F K L A X 3

ENT

Route is now displayed.

NOTE: All routes can be listed by selecting the cata-log page and slewing to ROUTE.

Section 2 - Predeparture Procedures

CREW WAYPOINT ENTRY OR CORRECTION

The pilot may enter waypoint IDENTs not found in any catalog . These waypoints will be assigned by

latitude/longitude coordinates , and will be stored in the CREW (temporary) catalog.

If a mistake is made while entering waypoint data into the

CREW catalog , perform the following steps to rectify this

error:

1. Delete the waypoint from the flight plan and the CREW

catalog using the SINGLE WAYPOINT DELETION

procedure in this section.

2. Re-enter the waypoint using one of the following

CREW WAYPOINT ENTRY procedures.

0

Section 2 - Predeparture Procedures

LATITUDE/LONGITUDE CREW WAYPOINT ENTRY

1. Press WPT.

WPT SELECT page is displayed with the cur-rent flight plan.

2. Press AN to slew to first

unassigned waypoint

number.

3. Enter an ( DENT for the

waypoint (example

NYK).

4. Press ENT ,

Because NYK is not in memory, prompts appear for LAT/LONG entry to de-fine NYK' s position.

Section 2 - Pred

^

ture Procedures

5. Select North or South,

then enter waypoint

lati-tude, including trailing

zeros.

6. Press ENT; LAT stews to

line 2, LON prompt slews

to entry line.

7. Select East or West, then

enter waypoint longitude,

including trailing zeros.

8. Press ENT.

CDU displays:

(On some aircraft this

waypoint information will

be written into the INS

permanent memory)

9. Press DIP to USE way-point (crew wayway-point in temporary memory), or press CLR to REJECT waypoint and return to WPT entry mode. N 4 3 4 4 5 4 ENT W 1 1 8 3 5 6 0

z

Section 2 - Predeparture Procedures

BEARING/RANGE REFERENCE CREW WAYPOINT

ENTRY

NOTE: Bearing and range waypoints may be stored in the CREW CATALOG only.

1. Press WPT.

WPT SELECT page is

displayed with the

cur-rent flight plan.

H

WPT

2. Press A•N to slew to first unassigned waypoint number.

3. Enter an IDENT of the

form AAANNN. It must

be 3 alpha characters followed by 3 numeric characters.

(example: OLM234).

4. Press ENT. Waypoint IDENT appears on line 1 and the following prompt lines appear: DIST: line 2 , REF: entry line, BRG : line 4, CLR:RETURN, fine 5.

Section 2 - Predeparture Procedures

NOTE:

If an IDENT is found that matches the AAA entry,

the display will default to REFERENCE

WAY-POINT display with referenced waypoint

default-ing to the AAA entry.

5. Enter the referenced

waypoint IDENT. O L M

6. Press ENT.

Reference IDENT slews

to line 2, BRG prompt to

entry line.

7. Enter the magnetic bearing from referenced waypointto new way-point (0 to 359.9°).

8. Press ENT.

BRG stews to line 2, DIST prompt to entry line.

9. Enter range from

refer-enced waypoint to new

waypoint (0.1 to 300.0

nmi).

2 3 4 7

ENT

Section 2 - Predenarture Procedures

10. Press ENT

EXP:USE CLR:REJ

ap-pear on line 5.

a. Press EXP to USE

waypoint (crew

waypoint in

tempo-rary memory).

OR

b. Press CLFt to

RE-JECT waypoint

and return to the

WPT entry mode.

OR

cua

eparture Procedures

Section 2 - Prod

FLIGHT PLAN EDITING

The flight plan may be changed by waypoint substitution, insertion , or deletion.

CAUTION : WHEN AN ACTIVE FROM/TO WAYPOINT IS DELETED, ALL AUTOPILOT, FLIGHT

DIRECTOR AND HSI OUTPUTS ARE ZEROED; HSI FLAGS (NAV MODE) ARE

INVALID.

WAYPOINT SUBSTITUTION

1. Press WPT.

WPT SELECT page is displayed, with the cur-rent flight plan.

2. Slew desired waypoint to entry line . (DEN is to be replaced by KLA)q.

3. Press CLA.

R

Section 2 - Predeparture Procedures

(DENT is removed; prompt line is displayed.

4. Enter new IDENT.

5. Press ENT.

K L A X

ENT

NOTE: If FROM or TO waypoint # is changed , "FROM/ TO WAYPNT NO. WILL BE CHANGED " is dis-played . Press ENT to make change or CLR to reject the change.

Section 2 - Predeparture Procedures

SINGLE WAYPOINT DELETION

CAUTION: WHEN AN ACTIVE FROM/TO WAYPOINT IS DELETED, ALL AUTOPILOT, FLIGHT DIREC-TOR AND HSI OUTPUTS ARE ZEROED; HSI FLAGS (NAV MODE) ARE INVALID.

1. Press WPT.

WPT SELECT page is

displayed, with the

cur-rent flight plan.

2. Slew waypoint to entry

line. (DEN is to be

de-leted).

CDU displays:

3. Press CLR.

IDENT is removed ; 14, I I a

prompt line is displayed.

Section 2 - Predeaarture Procedures

4. Press CLR again.

Waypoint list closes up.

R

NOTE: If FROM or TO waypoint # is changed, "FROM/ TO WAYPNT NO. WILL BE CHANGED " is dis-played. Press ENT to make change or CLR to reject the change.

5. The following steps may be performed to delete the waypoint from the CREW catalog.

a. Press CAT.

b. Slew up until CREW is on the data entry line.

P

CAT

CDU displays:

Section 2 - Predeparture Procedures

d. Slew up until the waypoint for deletion is on the data entry line.

e. Press CLR to delete

the selected

way-point.

MULTIPLE WAYPOINT DELETION

1. Press WPT.

WPT SELECT page is

displayed.

2. Slew to first waypoint to

be deleted , (e.g., UBG

will be deleted).

FH

WPT

R

Section 2 - Predeparture Procedures

3. Press CLR.

CDU displays:

4. Press -, D, and ENT.

Display will change to request the last WPT number to be cleared.

5. Enter last WPT number to be deleted. (You can delete backward or for-ward).

6. Press ENT.

All waypoints between and Including the two entered numbers will be cleared and the way-point list will close up.

0

C

ENT

Section 2 - Predeparture Procedures

INSERTING A WAYPOINT OR A ROUTE BETWEEN

EXISTING WAYPOINTS

1. Press WPT.

WPT SELECT page is

displayed , with current

flight plan.

2. Slew the waypoint that will precede the added waypoint to entry line (waypoint AEL is to be inserted between KSTL and KFWA). PWPT

3. Press ENT

ENT

NOTE: If FROM or TO waypoint # is changed, " FROM/ TO WAYPNT NO.. WILL BE CHANGED " is dis-played . Press ENT to make change or CLR to reject the change.

C.

Section 2 - Predeparture Procedures

4. Enter new (DENT. A E L

5. Press ENT.

CDU displays:

ENT

NOTE: A route may be inserted by entering -R at step 4, then entering the route ident . Follow-ing waypoints are moved down in the flight plan to make room for all the route's way-points.

Section 2 - Predeparture Procedures

INITIAL TRACK SELECTION

A track leg must be selected to enable INS computations of steering and leg distances. Estimated . time enroute and ETA are zero until ground speed is greater than 100 knots. To select your present position as the FROM way, point, and the first waypoint listed in the flight plan as the TO waypoirt, simply press LEG then ENTer twice. If no waypoints have been entered in the flight plan, the message "ROUTE$7WPTS

NOT SELECTED" will be displayed.

Default Leg Selection

1. Press LEG.

LEG page is displayed,

with the ident of WPT 0

flashing over the

under-scores.

2. Press ENT.

The ident of the first waypoint in the flight plan will flash over the underscores.

C LEG

Section 2 - Predeparture Procedures

3. Press ENT again.

CDU displays:

CAUTION: PRESSING ENT ON THIS PAGE WILL SELECT THE MANUAL LEG SWITCH. BE AWARE OF INADVERTENT SELECTIONS.

The display will switch

to the CRS page after

five seconds.

Enter Leg by Identifier

1. Press LEG . (The flight

plan must contain

way-points).

LEG page is displayed.

c

Section 2 - Predeperture Procedures

2. Enter FROM waypoint IDENT.

NOTE: If the IDENT occurs more than once on the flight plan (waypoints 01-98), the pilot is given the option to press ENT to select the displayed WPT number, slew to select a different WPT number, or press CLR to reject the IDENT.

3. Press ENT.

CDU displays:

4. Enter TO waypoint IDENT. When the first character is en-tered, the software searches the WPT list for the first IDENT after the current TO that begins with that letter., If one is found it is displayed on line four. Pressing the <>/HLD key will place that IDENT on the entry line. The pilot may also continue entering characters and ignore the sug-gested prompt.

NOTE: If the IDENT assigned to this waypoint is a duplicate,

the pilot must examine the coordinates and country

of each duplicate and select the desired one.

number cannot be entered.

5. Press ENT.

CDU displays:

Section 2 - Predenarture Procedures

The display will switch

to the CRS page after

five seconds.

Enter Leg by Waypoint Number

1. Press LEG.

LEG page is displayed.

2. Press A.N. Slew way-point number line to the entry line.

CDU displays:

3. Enter FROM waypoint

number.

A•N

c

LEG

NOTE: If the waypoint number 00 is selected as the FROM waypoint, a DIRECT TO will be per-formed (see DIRECT TO MODE in the EN-ROUTE PROCEDURES section for more in-formation). The waypoint number must have a corresponding waypoint entered in the flight plan.

Section 2 - Prodeparture Procedures

4. Press ENT.

CDU displays:

ENT

5. Enter TO waypoint number.

NOTE: A FROM and TO waypoint with the same waypoint number cannot be entered. Also

waypoint 00 and blank waypoints are invalid.

6. Press ENT.

CDU displays:

The display will switch

to the CRS page after

five seconds or select

another page.

A

Section 2 - Predeparture Procedures

WPT PAGE FLIGHT PLAN VERIFICATION

Verify waypoint data as follows:

1. Press WPT.

CDU displays the active flight plan.

2. Press EXP.

CDU displays: Waypoint name and no., waypoint lat/long, course and distance from previous waypoint.

F HWPT

z

EXP

3. Verify the data.

NOTE: If the true mode has been chosen, True Course (TC) will be displayed in place of Magnetic Course (MC).

4. Press slew -up key to view next waypoint data.

R

4

5. Repeat steps 3 and 4 to verify the flight plan.

Section 2 - Predeparture Procedures

Section 3

Enroute

Procedures

LEG SWITCHING

Leg switching from one leg to the next is normally performed automatically by the INS; however, manual leg switching may

be selected if desired.

AUTOMATIC LEG SWITCHING

The annunciation of the automatic leg switching sequence varies between 1.5 and 3.0 minutes prior to reaching the next waypoint , and is determined by-the ground speed of the, aircraft and the change in the track angle between the new and the old track legs . When a leg change is to be made but no data for the next waypoint has been entered , the Alert lights will begin flashing 4 minutes prior to reaching the last entered waypoint. The alert lights will continue to flash until data is entered . The CDU will display the message "NO

NEXT WAYPOINT" on all CDU pages until the pilot presses CLR to acknowledge the message.

If the TO waypoint is overflown without a subsequent leg inputted , the system will revert to the MANUAL leg switch mode and continue on an extension of the previous track.

Section 3 - Enroute Procedures

LEG SWITCH LESS THAN 25 DEGREES

The alert light will come on 90 seconds before the leg switch occurs. The leg switch will occur 22 seconds before the TO waypoint is reached, i.e., at Time To Go (TTG) = 225.

ALERTLIGHT ON FLIGHT 90 SECONDS BEFORE PATH

WPT 6

LEG SWVTCH I^ LEG SWTICH < 25'

WPT 4 WPT 5

LEG SWITCH OCCURS ATTTG =

22 SECS

Leg Switch Less Than 25 Degrees

Figure 3-1

LEG SWITCH BETWEEN 25 AND 110 DEGREES

The alert light will come on 90 seconds before the leg switch occurs . The leg switch will occur between 22 and 93

seconds before the TO waypoint is reached, dependent on ground speed and angle change.

WPT 15 WPT 14 LEG SWITCH OCCURS ATTTG -22TO m SECS

•

Leg Switch Between 25 and 110 Degrees Figure 3-2

Section 3 - Enroute Procedures

LEG SWITCH GREATER THAN 110 DEGREES

The ALERT light will come on 90 seconds before the TO

waypoint is reached. The leg switch will occur when the TO

waypoint is reached.

Leg Switch Greater Than 110 Degrees Figure 3-3

Section 3 - Enroute Procedures

MANUAL LEG SWITCHES

In the manual leg switching mode , the alert lights will illumi-nate 1 . 5 to 3.0 minutes prior to reaching waypoints,

depending on ground speed and track angle change. Once the system calculates that a leg switch should take place, the alert lights will start flashing and the leg switch must be entered manually. The CDU will display the message

"SELECT NEXT WPT" until the pilot presses CLR. If the

autopilot is engaged and a switch is not made , the aircraft will continue on an extension of the previous track.

CDU displays:

1. Press CLR to delete the "SELECT NEXT WPT" message.

2. Press LEG.

The Leg Change page will be displayed with the ID-ENTs for the leg just flown on line 3 and the corre-sponding waypoint num-bers on line 2. Example assumes aircraft has just flown from ALO and passed over IRK. 3. Press A • N and slew

down one line to place the waypoint numerics on the entry line.

CLR c LEG Y

0

Section 3 - Enroute Procedures

4. Input the number for the waypoint that was just overflown in the flashing prompt on the left side of the entry line.

5. Press ENT. The new FROM waypoint is ac-cepted , and the next se-quential waypoint from the flight plan will flash on the right side of the entry line.

6. Input the desired way-point number in place of the flashing prompt (by-pass this step if the flashing prompt is cor-rect.)

7. Press ENT.

The IDENTS for the new leg will be displayed on line 2. The system will automatically revert to automatic leg switching, and after 5 seconds the display will revert to the Course Data page. If manual leg switching is still desired, it must be selected again.

NOTE: Manual leg switching may also be accom-plished by inputting then entering the (D-ENTS for the next leg instead of using their corresponding waypoint numbers.

Section 3 - Enroute Procedures

DIRECT TO MODE

When DIRECT TO mode is selected, the INS will fly the

aircraft directly from present position to any established waypoint. This is equivalent to a 00 to XX leg switch. If the

waypoint is not on the flight plan, it will automatically be

assigned waypoint number 99 (see figure 3-4). DIRECT TO can be performed using waypoint numbers or IDENTs.

NOTE: Performing a DIRECT TO will automatically select

Auto Leg Switch mode.

Direct Tb Modes

Section 3 - Enroute Procedures

To select DIRECT TO mode using waypoint IDENTs:

1. Press DIR.

DIRECT TO page is dis-played with DIRECT TO prompt on entry line, re-questing the waypoint ident.

J

DIR

NOTE: During ALPHA entry, the software will search the re-maining waypoint list after the TO waypoint for ID-ENTs having the same letters as those entered. If found , that IDENT is displayed on line four with a prompt indicating that the <> /HLD key may be used to select this IDENT as the DIRECT TO (DENT.

Character entry can continue up to the six character limit to allow easy reference waypoint entry.

2. Enter desired waypoint

(DENT.

Section 3 - Enroute Procedures

3. Press ENT.

Coordinates of Direct to

waypoint are displayed for acceptance.

ENT

After acceptance, the Direct to page displays for 5 seconds. Do not press ENT on this page unless you wish to ter-minate automatic leg switching.

After 5 seconds , the dis-play changes to the nor-mal CRS page. Line 1 confirms the system is in Automatic leg switch.

NOTE: If the IDENT assigned to this waypoint is a duplicate, the pilot must examine the coordinates and country of each duplicate and select the desired one.

NOTE: If the IDENT occurs more than once on the flight plan (waypoints 01-98), the pilot is given the option to press ENT to select the displayed WPT number, slew to select a different WPT number, or press CLR to reject the IDENT.

Section 3 - Enroute Procedures

To select DIRECT TO mode using waypoint numbers:

1. Press DIR. _DJ

2. Press A • N twice to select waypoint number only.

3. Enter the desired way-point number (leading zero is not required) or press ENT to accept the flashing default.

A•N

ENT

4. Press ENT. The coordi-nates of the Direct to waypoint are displayed for acceptance.

5. Press ENT to accept. ENT

Section 3 - Enroute Procedures

6. If MANUAL leg switch mode is desired, press

ENT. If no key is

pressed , the display will switch to the CRS page after five seconds. If the system was in MANUAL mode, it will change to AUTO.

NOTE: Invalid waypoint numbers include waypoint 00 or blank waypoints. If any of these are selected, error messages will result and no action will be taken by the system.

DIRECT TO STEERING

When a Direct To leg switch is entered , the INS establishes a pseudo FROM waypoint at the exit from the turn, (thus avoiding S turns), and will capture and maintain a track leg from this new FROM point to the DIRECT TO waypoint ( refer to Figure 3-4). The pseudo FROM waypoint coordinates are stored in

waypoint zero <P>.

WAYPOINT BYPASSING

Waypoints may be bypassed either by a waypoint to waypoint leg switch or by a Direct To leg switch (see figure 3-4).

r

Section 3 - Enroute Procedures

CROSSTRACK OFFSET MODE

To fly an offset track parallel to present track:

1. Press CRS.

CRS DATA page is

dis-played.

F

B

CRS

2. Press slew - up key and

EXP.

XTK OFFSET page is

displayed with XTK

OFFSET prompt on the

entry line.

z

EXP

3. Select left offset (L7) or s❑ _or u 9R right offset (9R). L7

Section 3 - Enroute Procedures

(5.3 nm) to nearest 1/10 nm, including trailing zeros.

(Maximum allowable val-ue is 399 .9 nm)...

5. Press ENT.

Display returns to

nor-mal CRS page except

XTK OFF is displayed in

place of XTK.

OFS annunciator comes

on.

i

NOTE: The XTK OFF value displayed on the CRS DATA page is the XTK from the original track. As the air-craft steers to the offset track, XTK OFF will increase.

6. To view the XTK

OFF-SET value entered,

press EXP. If the aircraft

is on the offset track, the

value won't change.

The aircraft will be steered to the offset track using up to 45' intercept to capture the offset track (ref. Figure 3-5). The time to go and distance displays refer to the time and distance to the offset waypoint . The leg switches will occur at or before the offset waypoint and the aircraft will maintain the offset track.

Section 3 - Enroute Procedures

7. To return to original leg:

Make a DIRECT TO leg change (see figure 3-4).

OR

Repeat steps 1 through 3 and press ENT to enter XTK OFFSET of 0.0 nm.

NOTE: Crosstrack offset is inhibited by:

Descent below 10,000 feet when RNAV or GPS is enabled (active or not).

APPROACH mode selected.

Track Hold mode selected.

DIR TO is performed.

When the FROM waypoint # is 00.

do0 TAN b„

Crosstrack Offset Leg Change