GNC 250/GNC 250XL/GPS 150XL INSTALLATION MANUAL
GARMIN INTERNATIONAL, INC. 1200 E. 151st STREET OLATHE, KANSAS 66062-3426
PART NUMBER: 190-00067-62 REVISION E, 3 APRIL 1998
Av. Kit Install. Manual 190-00067-62 Rev. E Page 1
Copyright 1996-1998 Garmin Corporation All Rights Reserved This publication is the proprietary property of Garmin International Inc. It may not be reproduced or transmitted in any form whether printed or electronic, without the expressed written consent of Garmin International. Garmin International, Inc. 1200 E. 151st Street Olathe, KS 66062 U.S.A.

REVISION RECORD

ECO # Initial Rev. Rev. Rev. Rev. Rev. Rev. Date of Rev. Description FAA Approval A, 16 Dec 1996 B, 07 Mar 1997 C, 10 Dec 1997 D, 28 Jan 1998 E, 3 April 1998 Initial release Enhance Cooling Air Section Add ant note & STC; Chg btry GPN Chg to/from voltage, install dwg Corr to btry pk s/n & misc chgs
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TABLE OF CONTENTS

SECTION 1 1.1 1.2 1.2.1 1.2.2 1.2.3 1.3 SECTION 2 2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6 2.2 2.2.1 2.3 2.4 2.5 2.6 SECTION 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 SECTION 4 SECTION 5 SECTION 6 APPENDIX A APPENDIX B APPENDIX C GENERAL DESCRIPTION INTRODUCTION TECHNICAL CHARACTERISTICS PHYSICAL CHARACTERISTICS OPERATIONAL CHARACTERISTICS INTERFACES LICENCE REQUIREMENTS INSTALLATION CONSIDERATIONS ANTENNA CONSIDERATIONS GPS ANTENNA LOCATION COMM ANTENNA LOCATION (GNC 250/GNC 250XL only) ELECTRICAL BONDING ANTENNA LIMITATIONS VHF COMM INTERFERENCE OF GPS COMM ANTENNA INSTALLATION CONSIDERATIONS RACK CONSIDERATIONS ACCESSIBILITY CABLING AND WIRING COOLING AIR ANNUNCIATORS EXTERNAL ALTITUDE INPUT INSTALLATION PROCEDURE INSTALLATION ACCESSORIES ANTENNA INSTALLATION CABLE INSTALLATION RACK INSTALLATION UNIT INSTALLATION AND REMOVAL COMM ANTENNA INSTALLATION CHECK (GNC 250/GNC 250XL only) PLACARD POST INSTALLATION CONFIGURATION & CHECKOUT PROCEDURE CERTIFICATION CONTINUED AIRWORTHINESS CERTIFICATION DOCUMENTS CONNECTOR CHANGES STC PERMISSION
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LIST OF ILLUSTRATIONS

FIGURE 1-1 1-2 1-3 1-4 2-1 2-2 3-1 3-2 3-3 3-4 3-5 PINOUT DEFINITION, 37 PIN DSUB PINOUT DEFINITION, 26 PIN HD-DSUB (GNC 250/GNC 250XL only) INTERCONNECT SCHEMATIC INTERCONNECT SCHEMATIC NOTES GPS ANTENNA INSTALLATION CONSIDERATIONS UNIT INSTALLATION CONSIDERATIONS STUD MOUNT GA 56 INSTALLATION FLANGE MOUNT GA 56 INSTALLATION COAX CABLE INSTALLATION AVIATION RACK DIMENSIONS AVIATION RACK INSTALLATION
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SECTION 1 GENERAL DESCRIPTION
1.1 INTRODUCTION This manual describes the physical, mechanical, and electrical characteristics and the installation requirements for the GNC 250, GNC 250XL and GPS 150XL Aviation Kits. Unless stated otherwise, information found in this manual is applicable to the GNC 250, GNC 250XL and GPS 150XL. In this manual UNIT refers to any of the above units. 1.2 TECHNICAL CHARACTERISTICS
All UNITS offer the versatility of fixed installation in a panel mounted aviation rack as well as complete portability. For TSO Compliance, see Appendix A. The conditions and tests required for TSO approval of this article are minimum performance standards. It is the responsibility of those desiring to install this article on or within a specific type or class of aircraft to determine that the aircraft operating conditions are within the TSO standards. The article may be installed only if further evaluation by the user/installer documents an acceptable installation and is approved by the Administrator. 1.2.1 PHYSICAL CHARACTERISTICS Width: Height: Depth: Unit Weight: (See Figure 3-4) GA 56 Antenna Weight: Aviation Rack Weight: Max Air Speed: (Structural rating for antenna) 1.2.2 OPERATIONAL CHARACTERISTICS Operating Temperature Range: -20 oC to +55 oC Humidity: 95% non-condensing Altitude Range: -1,500 to 50,000 ft. Voltage Range: (GNC 250/GNC 250XL) 10 to 15.1V DC Voltage Range: (GPS 150XL) 10 to 33V DC Power Requirements:(GNC 250/GNC 250XL)1.35A @ 13.8v (not transmitting) 5.5A @ 13.8V (transmitting) Power Requirements: (GPS 150XL) 0.95A @ 13.8V
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6.25 inches 2 inches 5.65 inches 4 oz. 10 oz. Subsonic
1.2.3 INTERFACES The UNIT provides interfaces to various general aviation instruments. Figure 1-1 defines the function of each pin on the 37 pin DSUB connector located at the back of the rack. Figure 1-2 defines the function of each pin in the 26 pin HD-DSUB connector (J102) located above the 37 pin connector at the back of the rack. Figures 1-3 and 1-4 defines the interconnects between the rack and other instruments. The following interfaces are provided. 1.2.3.PIN CONNECTOR (J101) CDI: (Pins 1 and 4) To/From: (Pins 2 and 4) Capable of driving up to three 1000 ohm parallel loads, +150 millivolts full scale deflection with a maximum output of +300 millivolts. Capable of driving up to three 200 ohm parallel loads, +82 millivolts full scale deflection. Units with Mod Status 1: +190 millivolts full scale deflection. Capable of driving up to three 1000 ohm parallel loads, 375 millivolts for flag out-of-view, and +40 millivolts for flag in-view. Output providing bearing to waypoint data for a Bendix/King RMI (KI 229 or equivalent). Output capable of driving negative logic message annunciators by sinking up to 500mA.

Nav Flag: (Pins 3 and 4) OBI data: (Pins 7, 8, and 23) Message annunciator: (Pin 20)
RS232 chan 1 output data: Output capable of driving devices as listed in Section 4. (Pin 24) Conforms to the EIA specification RS-232C. RS232 chan 2 output data: Output capable of driving devices as listed in Section 4. (Pin 19) Conforms to the EIA specification RS-232C. RS232 chan 1 input data: Input capable of receiving data from devices listed in (Pin 17) Section 4. Conforms to the EIA specification RS-232C. RS232 chan 2 input data: Input capable of receiving data from devices listed in (Pin 18) Section 4. Conforms to the EIA specification RS-232C. Arrival annunciator: (Pin 12) Output capable of driving negative logic annunciator by sinking up to 500mA.
ARINC 429 Output A & B: Output capable of interfacing with any device that has (Pins 15 and 16) an input conforming to the GAMA ARINC 429 specification.
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NAV Super Flag Output: (Pin 10)
Output capable of driving positive logic NAV Super Flag by sourcing up to 500mA for flag out of view (NAV valid).
Battery +,-, Charge Enable Connection for GARMIN remote battery accessory. (Pins 30, 34, 29) 1.2.3.PIN CONNECTOR (J102) (GNC 250/GNC 250XL only) MIC Audio Hi and Lo: (Pins 2 and 3) MIC Key: (Pin 4) COMM Audio Hi and Lo: (Pins 5 and 6) MIC Intercomm: (Pin 8) Remote Transfer: (Pin 10) TX Interlock: (Pin 12) Altimeter input: (Pins 14-24) Remote Enter: (Pin 26) Input requiring 275mV RMS into 470 ohm load. (Standard carbon or dynamic MIC containing transistorized pre-amp.) Input, when grounded, keys the transmitter. Output capable of driving a 500 ohm load with 100mW. Input requiring 125 mV RMS into 470 ohm load. (Standard carbon or dynamic MIC containing transistorized pre-amp.) Input, when grounded, swaps the active and standby COMM frequencies. Input, when grounded, reduces receiver sensitivity so squelch will not break when another transceiver is keyed. Capable of receiving encoded output data from any parallel altimeter device. Input, when ground, functions the same as the enter key on the UNIT front panel.

1.2.3.3 COMM Antenna Connector (J4) (GNC 250/GNC 250XL only) Capable of providing 5 watts, minimum at 13.8V. Sensitivity of 6 dB SNR, minimum, at 2 uV. The COMM antenna shall be approved to TSO C37( ) and C38( ). 1.3 LICENCE REQUIREMENTS
If any of these devices are used in home or in office, connected to a personal computer, then the below 4 paragraphs are applicable. These devices comply 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
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interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to other equipment, which can be determined by turning the equipment off and on, the user is encouraged to try and 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 service technician for additional help if these remedies do not correct the problem. These devices comply with Part 15 of the FCC rules. Operation 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. These units do not contain any user-serviceable parts. Repairs should only be made by an authorized GARMIN service center. Unauthorized repairs or modifications could void your warranty and your authority to operate this device under Part 15 Regulations. FCC requires GARMIN to inform users that these units meet the more stringent requirements For Home or Office Use. The following guidance is provided to help ensure the proper licensing of the GNC 250 and GNC 250XL COMM. 1) Telecommunications Act of 1996 effective February 8, 1996 provides the FCC discretion to eliminate radio station license requirements for aircraft. At present, and individual license to operate the GNC 250XL and GNC 250 aboard a private aircraft is not needed in many circumstances. Please see FCC Fact Sheet PR5000 or contact the FCC at 800 322-1117 for more information. 2) No license change is required for an aircraft which already has a station license per FCC 404 Instructions dated 1994. 3) If an aircraft license is required or desired contact the FCC at 800 322-1117 to request FCC form 404, Application for Aircraft Radio Station License to apply for FCC authorization. FCC also has a Fax on Demand service to provide forms by fax at 202-418-0177.

If the installation includes any electrical interface with other flight instruments, an annunciator may be required. Refer to current FAA directives. 2.6 EXTERNAL ALTITUDE INPUT
Pressure altitude input from an external source is not required but it may benefit the UNITS system performance during times of minimal satellite coverage or poor satellite geometry. Pressure altitude input from an external source may be derived from a RS-232 compatible serial altitude input or Parallel Greycode/Gillham Altitude (GNC 250/GNC 250XL only) as described in Section 4 of this manual. Gillham Altitude is not required when serial altitude is used.
SECTION 3 INSTALLATION PROCEDURE
3.1 INSTALLATION ACCESSORIES
The following installation accessories are available:
ANTENNA AND RACK OPTIONS 010-10040-01 GA 56 ANTENNA KIT, W/O CABLE Includes: 011-00134-00 GA56 ANTENNA SUB-ASSEMBLY 1 115-00031-00 BACKING PLATE 1 210-10004-09 NUT, SELF-LOCKING, #8-253-00002-00 ANTENNA GASKET 1 010-10040-02 GA 56 FLANGE MOUNT ANTENNA Includes: 011-00147-00 FLANGE MOUNT GA56 ANTENNA SUB-ASSEMBLY 1 115-00080-00 NUT PLATE 1 211-62212-14 SCREW, #10-32 X 5/253-00011-00 ANTENNA GASKET 1 320-00003-FT LOW-LOSS AVIATION ANT. EXTENSION CABLE WITH RIGHT ANGLE BNC CONNECTOR 320-00003-FT LOW-LOSS AVIATION ANT. EXTENSION CABLE WITH RIGHT ANGLE BNC CONNECTOR 330-00087-00 CONNECTOR, BNC, MALE, CLAMP Note: One cable assembly and one BNC connector are required to make the antenna cable, or it can be fabricated by the installer from materials meeting the requirements of paragraph 2.3. Av. Kit Install. Manual 190-00067-62 Rev. E Page 11
011-00154-00 MOUNTING RACK, (WITHOUT CONNECTORS) Note: A mounting rack is required for approved installations. The following hardware is required for installation of the mounting rack, but is not provided: #6-32 Flat Head Screw (4 ea.) #6-32 Self-locking Nut (4 ea.) 011-00313-00 CONNECTOR, (J1 and J2) Kit (GNC 250/GNC 250XL) 011-00313-01 CONNECTOR,(J1) Kit (GPS 150XL) DATA BASE OPTIONS 010-10038-00 MEMORY 010-10038-01 MEMORY 010-10038-02 MEMORY 010-10032-03 MEMORY CARD CARD CARD CARD - WORLDWIDE DATABASE - AMERICAS DATABASE - INTERNATIONAL DATABASE - USER
MISCELLANEOUS OPTIONS 010-10075-00 PC KIT 190-00067-50 GNC 250 PILOT'S GUIDE 190-00067-51 GNC 250 QUICK REFERENCE GUIDE 190-00067-56 GNC 250 IN MOONEY M20J DOCUMENTED INSTALLATION 190-00067-60 GNC 250XL PILOT'S GUIDE 190-00067-61 GNC 250XL QUICK REFERENCE GUIDE 190-00067-66 GNC 250XL IN MOONEY M20J DOCUMENTED INSTALLATION 190-00067-80 GPS 150XL PILOT'S GUIDE 190-00067-81 GPS 150XL QUICK REFERENCE GUIDE 190-00067-86 GPS 150XL IN MOONEY M20J DOCUMENTED INSTALLATION 330-00067-00 GPS 1.57542 GHZ NOTCH FILTER 362-00014-00 WALL ADAPTER - 110 VAC 010-10057-TO 14V CONVERTER (GNC 250/GNC 250XL ONLY) (Consists of 011-00181-00) 010-10074-00 REMOTE BATTERY PACK (Consists of 011-00182-00) THE FOLLOWING INSTALLATION ACCESSORIES ARE REQUIRED BUT NOT PROVIDED: (GNC 250/GNC 250XL ONLY) COMM ANTENNA: HEADPHONES: MICROPHONE BROAD BAND 50 OHM VERTICALLY POLARIZED WITH COAXIAL CABLE. 500 OHM NOMINAL IMPEDANCE LOW IMPEDANCE CARBON OR DYNAMIC WITH TRANSISTORIZED PRE-AMP.

insert/extract M81969/1-02 M81969/1-02 980-2000-426* 91067-2 M24308/1-02 M81969/1-02
positioner n/a 9502-11 see note n/a K774 see note
insert/extract M81969/1-02 M81969/1-02 274-7048-000* n/a M24308/1-02 M81969/1-02
positioner M22520/2-09 9502-3 995-0001-739 601966-6 K42 615724
insert/extract M81969/1-04 M81969/1-04 n/a 91067-1 M24308/18-1 M81969/1-04
* Insert/extract tools from ITT Cannon are all plastic, others are plastic with metal tip.
Non- GARMIN part numbers shown are not maintained by GARMIN and consequently are subject to change without notice. NOTE: Alternate contacts for 18 AWG wire: As an alternate to the Positronic contacts listed (and provided in the install kit), the installer may use contacts made by ITT Cannon as follows: Socket contact - ITT Cannon p/n: 031-10007-001, Pin contact ITT Cannon p/n: 330-5291-055. These contacts require the use of a different crimp tool positioner than that shown in the table, with part numbers as follows: Daniels p/n: K250, Astro p/n: 616245, or ITT Cannon p/n: 980-00005-722. See Appendix B for information regarding obsolete stamped type contacts.
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RACK INSTALLATION

A. Figure 3-4 shows outline dimensions for the aviation rack. Install the rack in a rectangular 6.320" x 2.000" hole in the instrument panel. Exercise caution when installing the rack into the instrument panel. The rack is designed to facilitate removal of the UNIT for portable use. Deformation of the rack may make it difficult to install and remove the UNIT. B. Install the rack in the aircraft panel using four #6-32 countersunk screws and four self-locking nuts or other FAA approved methods as per Advisory Circular 43.13-1A. The screws are inserted from the inside through the holes in the sides of the rack (see Figure 3-5). 3.5 UNIT INSTALLATION AND REMOVAL
The UNIT is installed in the rack by gently sliding it straight in until it rests against the back of the rack. A 3/32 inch hex drive tool is then inserted into the access hole at the bottom of the unit face. Rotate the hex tool clockwise while pressing on the left side of the Bezel until the unit is firmly seated in the rack. To remove the unit from the rack, insert the hex drive tool into the access hole on the unit face and rotate counter-clockwise until the mounting screw turns freely and the unit protrudes about 3/8 inch from the panel. Be sure not to over tighten the unit into the rack. The application of hex drive tool torque exceeding 15 in*lbs can damage the locking mechanism. 3.6 COMM ANTENNA INSTALLATION CHECK (GNC 250/GNC 250XL only)
Check for insertion loss and VSWR. VSWR should be checked with an in-line type wattmeter inserted in the coaxial transmission line between the transceiver and the antenna. Any problem with the antenna installation will most likely be seen as a high reflected power. A VSWR of 3:1 will result in a 25% loss in power. 3.7 PLACARD

After completing the installation, a placard stating that the UNIT is limited to VFR use must be installed on the panel in clear view of the pilot. The placard may be Garmin p/n 161-00024-00 as supplied with the unit, or a suitable equivalent.
SECTION 4 POST INSTALLATION CONFIGURATION & CHECKOUT PROCEDURE
Before starting the below operations, unit initialization must occur. Do this by first removing any data cards and then turning the unit on. Press enter in response to Select operating mode Normal ok?. Press enter in response to No Jeppesen database rte/prx limited to user wpts ok?. After the satellite status page is displayed for 5 seconds the unit may be turned off. Proceed with the following steps.
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TEST MODE OPERATIONS

With power applied to the aviation rack and the UNIT unit off, depress and hold the ENT key and turn the unit on (release the ENT key when the display activates). The first page displayed is the Display Test Page. While in TEST MODE, test pages can be selected by ensuring the flashing cursor is off and rotating the outer knob either direction. To change data on the displayed test page, depress the CRSR key and the cursor will highlight the standby COMM frequency for the GNC 250/GNC 250XL and the configuration selection for the GPS 150XL. In the GNC 250/GNC 250XL, press cursor again to move to the configuration selections. The inner knob will change the data on the selected field. The ENT key or the outer knob will advance to the next field on the page. Pressing the CRSR key again will stop the current field from flashing, allowing the outer knob to select the next test page. The ENT key is used to enter a new value into the OBI data field after selecting the desired value using the inner and outer knobs (see the appropriate chapter of the Pilot's Guide for more information on page and data selection). Note that some pages found in test mode are intended for bench testing and are not discussed here. 4.2 INSTALLATION CONFIGURATION
Note that the below pages are in the order found when rotating the outer knob clock-wise starting at the Display Test page. See Section 4.1 to get to this page. 4.2.1 DISPLAY ADJUSTMENT This page is called Display Intensity in the GNC 250 and called Lighting in the GNC 250XL and GPS 150XL. This page allows the setting of parameters that, in the automatic mode, affect the GNC 250 display and lighting brightness and the GNC 250XL/GPS 150XL display backlight and lighting brightness. response time sets the speed with which the brightness responds to ambient light changes. The higher the number the slower the display responds. min sets the minimum brightness of the display. The higher the number the brighter the minimum brightness. slope sets the sensitivity the brightness of the display has to changes in ambient light. The higher the number the brighter the display will be for a given increase in ambient lighting. For more information on the GNC 250 display setting, see the Display Intensity Page described in the Pilot's Guide (GPN 190-00067-50).

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For more information on the GNC 250XL and GPS 150XL display setting see the Display Contrast and Mode Set page and the Backlight Set page described in its Pilot's Guide (GNC 250XL: 190-00067-60 and GPS 150XL: 190-00067-80) 4.2.2 I/O CHANNEL 1 Select the I/O CHANNEL 1 Test Page. Change the selectable input and output to match that of the installed equipment. The available options are: Description No units connected to Channel 1 input Serial altitude received from: Icarus, Model 3000, Mode C Serializer shadin-alt Serial altitude received from: Shadin 9000T Serializer System (Non-TSO'd) Shadin 9200T Series Serializer System (Non-TSO'd) Shadin 8800T Series Encoder System (TSO'd) shadin-fuel Fuel information received from: Shadin 91204XT Series Digital Fuel Management System (TSO'd) Shadin 91053XT Series Digital Fuel Management System (TSO'd) Fuel information received from: arnav/ei-fuel Arnav, Model FC-10, Fuel Computer (TSO'd) Arnav, Model FT-10, Fuel Totalizer (TSO'd) Electronics International, Model FP-5L, Fuel Flow Computer (Non-TSO'd) shadin-adc Air data information received from: Various models from the 9628XX-X family Fuel/Air data information received from: shadin-fadc Various models from the 9628XX-X family Note: Verify with manufacturer of data input device that unit supports GARMIN interface. Output: Field off aviation Description No units connected to Channel 1 output Serial position, velocity and navigation data to: Argus, Model 3000, Moving Map Argus, Model 5000, Moving Map Argus, Model 7000, Moving Map Stormscope, Series II with Navaid, Moving Map Shadin, 91204X[T] Digital Fuel Management System (TSO'd) Shadin, 91053X[T] Digital Fuel Management System Electronics International, Model FP-5L, Fuel Flow Computer (Non-TSO'd) Shadin, Model 9628XX-X Fuel/Airdata Computer (TSO'd) GARMIN, GPS 195 GARMIN, GPS III Input: Field off icarus-alt
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4.2.3 ARINC 429 CHANNEL Select the ARINC 429 Channel Test Page. Change the selectable output to match that of the installed equipment. The available options are: Input: No selection available Description No units connected to ARINC 429 output Collins Pro Line 2 EFIS connected (w/ GAMA) King Radio EFIS 40 or 50 connected (w/ GAMA) Any unit that receives standard 429 output

Output: Field off Collins PL2 EFS King EFS 40/50 w/o GAMA labels
Below is a list of labels output by the UNIT: Navigation/position data Label (octal) 313 147* 261* 275* 326* 351* 352* Description Selected course Desired track Bearing to waypoint Cross track error Horizontal command (to autopilot) Distance to go Time to go Present position latitude Present position longitude Ground speed Ground track Magnetic variation GPS navigation mode Navigation status Lateral scale factor Distance to destination Time to destination
Flight plan data Label (octal) 074* 075* 113* 300* 303* Description Flight plan header Active from/to waypoints Message checksum Station magnetic variation/type/class Message length/type/number
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304* 305* 306* 307*

Waypoint identifier characters 1-3 Waypoint identifier characters 4-6 Waypoint latitude Waypoint longitude
Identification data Label (octal) 377 371* Description Equipment identifier General Aviation equipment identifier
*These labels are formatted per the General Aviation Manufacturers Association (GAMA) definition. Note that the use of a 429 device w/o GAMA will cause the loss of the above asterisked labels. 4.2.4 CDI CALIBRATION Select the test page displaying CDI output calibration. Place the cursor on the alignment field by using the outer knob. Use the inner knob to adjust the CDI needle until it is centered. Once centered, turn the cursor off to complete the calibration process. 4.2.5 CONFIGURATION
Select the Configuration Test Page. Change the selectable Strap and Fuel selections to match that of the aircraft. The available options are: Fuel: av gas Using Aviation gas (5.8 lbs/gal) jet A Using Jet A/Jet A-1 fuel (6.7 lbs/gal) jet B Using Jet B (JP-4) fuel (6.5 lbs/gal) NOTE: The Fuel option is used to designate the type of fuel used so that the correct fuel density will be used in calculations. Remote Battery: none installed NOTE: If installed is selected when a battery is not installed erroneous voltages will be shown on the Power Test page and invalid battery messages will be issued in normal operating modes.
4.2.6 I/O CHANNEL 2 NOTE: This page is not found in the Test Pages but is included here to aid installation. For more information see SET Pages in the Pilot's Guide (GPN 190-00067-50). Select the I/O CHANNEL 2 Set Page. Change the selectable input and output to match that of the installed equipment. The available options are:
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Input:

Field off rtcm 104
Description RTCM SC-104 Compatible Differential GPS receiver.
NOTE: Below is a list of the RTCM SC-104 messages that the unit will receive. Message Message Message Message Output: Field off plotting type type type type Differential GPS correction Delta differential GPS corrections Reference station parameters High rate differential GPS corrections Description No units connected to Channel 2 output. Serial position, velocity, navigation and satellite data to: NMEA 0183 Version 2.0 compatible mapping device or GARMIN PC software.

NOTE: Below is a list of the NMEA 0183 sentences (with maximum number of characters) that the GNC 250 transmits. RMC -70 characters GGA -72 characters GSA -57 characters GSV -140 characters (70 characters x 2 sentences) RMB -70 characters BOD -35 characters WPL -38 characters *PGRME -35 characters *GARMIN proprietary accuracy error sentence that is not a part of the NMEA 0183 standard. 4.3 GROUND TEST
The UNIT ground test procedure incorporates a series of display pages to test CDI/ flag, OBI, annunciators, external switches, altitude inputs, and power functions of the unit. Note that the below pages are in the order found when rotating the outer knob counter-clockwise starting at the Display Test page. See Section 4.1 to get to this page. 4.3.1 POWER TEST Select the Power Test page. This page reports the status of the UNIT external power source, remote battery and internal memory battery. In the below voltage represents the voltage currently measured for that function.
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The first line of power information shows the source of external power as shown below: External Power voltage Battery Power Wall Adapter The presence of a Wall Adapter will overide the other two sources. Battery Power will not be shown unless on the Configuration Page the Remote Battery is selected as Installed. The higher voltage of External Power or Battery Power will determine which is shown. The next line shows the status of the Remote Battery as shown below: Rmt Pak none (If on the Configuration page Remote Battery is selected as none) Rmt Pak voltage mode auto status mode represents the mode of the charger enable to the remote battery pack and is selectable. On enables the charger. Off disables the charger. Auto enables the charger if the External Power is the current source and its voltage is high enough. When in Auto mode auto status will be either on or off reflecting whether the charger is enabled or disabled. The next line reports the status of the internal memory battery as shown below: Mem Batt ok/low. Note that the TX field will light on the display but the transmitter will not actually transmit when the UNIT is powered from the wall charger. 4.3.2 CDI AND FLAG TEST Select the the CDI Test Page. Using the controls on the UNIT front panel, make the selections indicated below and verify the interfaces as appropriate: CDI Full scale left Full scale right Centered Ensure the CDI is deflected full scale left (5 dots) Ensure the CDI is deflected full scale right (5 dots) Ensure the CDI is centered Ensure TO flag is visible Ensure FROM flag is visible Ensure TO and FROM are NOT visible Ensure CDI flag is in view Ensure CDI flag is out of view

TO/FROM/FLAG TO FROM FLAG CDI FLAG IN VIEW OUT OF VIEW
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SUPERFLAG IN VIEW OUT OF VIEW 4.3.3 ANNUNCIATOR TEST
Ensure superflag in view Ensure superflag out of view
Select the Annunicator Test Page. Using the controls on the UNIT front panel make the selections indicated below and verify the interfaces as appropriate: MSG Annunciator OFF ON Arrival Annunciator OFF ON Ensure the Message Annunciator is OFF Ensure the Message Annunciator is ON Ensure the Arrival Annunciator is OFF Ensure the Arrival Annunciator is ON
4.3.4 EXTERNAL SWITCH TEST (GNC 250/GNC 250XL only) Select the External COM Switches Page. For each of the following installed remote switches perform the following: Press Remote Enter and verify the Rmt ent field changes from off to on. Press PTT and verify the PTT field changes from off to on. Press Remote Transfer and verify the Rmt xfr field changes from off to on. 4.3.5 COMMUNICATIONS LOOPBACK TEST This page displays the results of communication loop back tests. Three channels are tested: RS232 channels 1 and 2 and Arinc 429. Results of the test are either OPEN or OK. Open means the channel's transmitter and receiver are not connected or the test failed. The tests are performed continuously while on this page except for RS232 channel 2. This channel is only tested at power on and the results displayed on this page. Therefore the unit must be turned off and the receiver/transmitter connected or disconnected and then turn the unit on to perform the test. The 429 channel may be connected to loop back to test the 429 transmitter. To test the channels: RS232 channel 1: Connect RS232 channel 1 receiver and transmitter RS232 channel 2: Connect RS232 channel 2 receiver and transmitter A429 : Connect Arinc 429 transmitter and receiver
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4.3.6 ALTITUDE INPUT TEST (GNC 250/GNC 250XL only) Select the Gray Code Altitude Test Page if this input is used. Verify that the altitude input is reading the correct altitude. NOTE: This does not display serial altitude. 4.3.7 OBI TEST Select the OBI Test Page. Using the controls on the UNIT front panel, make the selections indicated below and verify the interfaces as appropriate: OBI Data VALID INVALID OBI Value Ensure that the OBI indicates the proper value Ensure the OBI is invalid Ensure that the OBI displays the value entered when the VALID option is selected
NOTE: The 3 lines that make up the OBI interface may be toggled individually. This may be done from the Value field. Cycle this field to the desired line (either CLOCK, DATA or SYNC) and toggle the output to HIGH or LOW. 4.3.8 SIGNAL ACQUISITION TEST The Self Test Page will be displayed followed by the Data Base Page. Upon approval of the Data Base Page, the Satellite Status Page will be displayed. If unable to acquire satellites, relocate the aircraft away from obstructions which might be shading reception. If the situation does not improve, check the antenna installation. Once GPS position information is available, use the DIRECT-TO key to activate the navigation function to a nearby NAVAID, intersection, or airport. Ensure any connected equipment is transmitting data to and/or is receiving data from the UNIT and is functioning properly (see the Pilot's Guide for more information on the DIRECT-TO function). 4.3.9 OPTIONAL VHF COMM INTERFERENCE EVALUATION The below evaluation is included for installation information only. It can be used as a means to gauge VHF COMM interference and, in conjunction with Section 2.1.5, be used to improve an installation. Passing the below evaluation is not required. a) Go to the Satellite Status Page, verify that 7 to 8 satellites have been

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APPENDIX B

CONNECTOR CHANGES
STAMPED CONTACT CONNECTOR USAGE
Garmin panel mount GPS radios have previously been shipped with stamped crimp type contacts. All products are now being shipped with machined mil-spec contacts with color-coded barrels. The following figures can be used to identify which type contact you have:
Some contacts are pins as shown, while others are the socket type. The type used will vary with the installation. When working with the stamped crimp type contacts, the following tools should be used: Tools supplier Amp ITT Cannon Cinch 37 and 9 position connectors Crimp Tool Extraction Tool 58448-2 91067-22 995-2000-000 980-0008-124 HTD-544 CIET-20-HDB 26 position connector Crimp Tool Extraction Tool 90430-1 91285-1 995-2000-022 980-00004-804 HTD-544 HTD-520
Part numbers shown are not maintained by Garmin and consequently are subject to change without notice. When stamped contacts are used special considerations must be made for aircraft power and remote battery (optional) connections, as shown in the following diagram:
Av. Kit Install. Manual 190-00067-62 Rev. E Page 39
REMOTE BATTERY PIN ASSIGNMENTS
A change was made to the remote battery connectors starting with serial numbers 33050055. Units with lower serial numbers have pin contacts on the battery pack. Units 33050055 and up use socket contacts on the battery and the pin number assignments are different, however the individual contact locations are unchanged. The following table shows the pin assignments for the two different types of connectors:

Serial Number

remote batt. mating plug

below 33050055

Pins sockets

33050055 and up

sockets pins

function

battery + battery + charge enable aircraft power aircraft power no connection no connection ground ground

contact number

Av. Kit Install. Manual 190-00067-62 Rev. E Page 40
APPENDIX C STC PERMISSION
GNC 250: Consistent with N8110.69 or Order 8110.4, Aviation Authority approved installers are hereby granted permission to use STC# SA00336WI data to modify aircraft. GNC 250XL: Consistent with N8110.69 or Order 8110.4, Aviation Authority approved installers are hereby granted permission to use STC# SA00502WI data to modify aircraft. GNC 150XL: Consistent with N8110.69 or Order 8110.4, Aviation Authority approved installers are hereby granted permission to use STC# SA00503WI data to modify aircraft.
Av. Kit Install. Manual 190-00067-62 Rev. E Page 41
Av. Kit Install. Manual 190-00067-62 Rev. E Page 42
Av. Kit Install. Manual 190-00067-62 Rev. E Page 43
Av. Kit Install. Manual 190-00067-62 Rev. E Page 44

Page v

PART ONE: INTRODUCTION
Foreword.i Cautions.ii Accessories/Packing List.iii Warranty.iv Table of Contents.v-vi Key and Knob Functions.vii-viii GNC 250XL Takeoff Tour.1-10

Table of Contents

PART TWO: REFERENCE
Section 1: Navigation with the GNC 250XL ( N key).11 Navigating and planning functions Section 2: Communicating with the GNC 250XL.33 Using the GNC 250XLs radio Section 3: Waypoint and Database Information ( W key).37 Finding and using database and waypoint information Section 4: Nearest Waypoints ( T key).57 Finding nearest waypoints, SUAs and FSS/ARTCC frequencies Section 5: Direct-to ( D key) & Route Navigation ( R key).62 Creating and using routes
To quickly and easily locate information on specific tasks, please refer to the Index on page 103.

Page vi

Section 6: Messages and Unit Settings ( M key).75 Appendix A: NavData and User Data Card Use.87 Appendix B: Installation and Maintenance of the GNC 250XL.89 Appendix C: Simulator.90 Appendix D: GNC 250XL Messages and Abbreviations.92 Appendix E: Specifications.100 Appendix F: Map Datums.101 Appendix G: Index.103

Page vii

Key and Knob Functions B Q D T R W N
The power/volume knob controls unit power and radio volume. The squelch button activates automatic squelch control. The direct-to key performs an instant direct-to, allows you to enter a waypoint, and sets a direct course to the destination. 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 4 for more information on the nearest waypoints. The route key enables you to create, edit, activate and invert routes. Searchand-rescue, parallel offset and closest point of approach functions are also performed using the route key. See Section 5 for more route information. 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 3 for more waypoint information. 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.

Key and Knob Functions

The GNC 250XL 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 GNC 250XL. Experiment to find the most effective way to use the GNC 250XL to your advantage.

Page viii

The message key is used to view system messages. This key is also used to access the GNC 250XLs unit settings. See Section 6 for more information on messages and unit settings. The transfer key flip-flops the active and standby frequencies.
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 or deactivate the cursor in the separate areas of the GNC 250XL. Pressing once will activate the cursor in the comm window and enable the pilot to change frequencies. Pressing twice will activate the cursor in the GPS window (indicated by highlighted characters in a GPS window field). It is used to highlight fields for data entry, changing information or cycling through available options. 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.
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 GNC 250XL.

Page 1

The GARMIN GNC 250XL is a powerful navigational tool that provides pilots with accurate navigational data and communication capability, along with a host of database information at your fingertips. The Takeoff Tour is designed to familiarize you with the operation of the GNC 250XL, including powering up the unit, changing frequencies, entering data and performing a simple direct-to, and a limited introduction to the Nearest functions. In addition, this section also briefly covers the position, CDI and frequency pages available from the NAV key. These pages will be used for most of your in-flight navigation. The Takeoff Tour assumes that the GPSCOMTM and antennas have been properly installed and you have not changed any of the GNC 250XLs default settings. If you have changed any of the factory default settings (position format, units of measure, selectable fields, etc.), the pictures used may not match your configuration. Prior to using your GNC 250XL 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 GNC 250XL The GNC 250XLs power and volume are controlled using the B (power/volume) knob at the bottom left of the unit. Rotating it clockwise will turn the unit on and increase the radio volume. After turning the unit on, a welcome page will be displayed while the unit performs a self test. The database page will appear, 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 is available for one-time or subscription purchase.

To acknowledge the database information: 1. Press the E key.

TAKEOFF TOUR

Power On
The welcome page appears when the GNC 250XL is turned on. During the time this screen is displayed, the GNC 250XL performs a self test to ensure proper operation
The database confirmation page shows the effective date of the Jeppesen database on the NavData Card.

Page 2

Acquiring Satellites
Once the database has been acknowledged, the satellite status page will appear, and the GNC 250XL 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 GNC 250XL, the time required for a position fix will vary usually from two to five 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 N key and use the K and O knobs to enter the altitude shown on your altimeter. Press E when finished.
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.
If the GNC 250XL 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 M key, 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 applicable to the receivers current operating condition.

Comm Frequencies

CDI page with trk and eta displayed.

Map Display

Data Fields
CDI page with brg and trk displayed.
The communication frequencies are located in the upper left corner of the page, instead of across the top line as on other pages. The top frequency is the active frequency, with the standby frequency directly below.

Page 7

Airspace Boundaries Airport Waypoint Present Position

Map Page

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 76).
Distance to Waypoint GS TRK Map Scale
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.

Destination Waypoint

The data fields on the map page indicate distance to destination waypoint, desired track, ground track, ground speed and map scale. The destination waypoint name and desired track appear on the left side of the page, below the communication frequencies. 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 \.
Communication frequencies are shown in the top left corner of the map page, instead of across the top line as shown on other GNC 250XL screens.

Page 8

Map Scales NAVCOM Page
The map display has 14 available ranges 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 inner knob (K), with the current scale displayed in the lower right corner of the page.
To select a map scale: 1. Rotate the K knob clockwise to increase the map scale and show a larger area. 2. Rotate the K knob counterclockwise to decrease the map scale and show a smaller area.
To change the map scale rotate the K knob clockwise to increase the scale or counterclockwise to decrease the scale.
Another page available under the GNC 250XLs N key is the navigation communications (NAVCOM) page. It provides you with a complete list of airport frequencies at your departure and arrival airports, allowing convenient selection of frequencies youll 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 O one 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.
To place a frequency from the list in the standby field:
The NAVCOM page lists the frequencies for your departure and arrival airports. To place a frequency from this list on standby, highlight the desired frequency and press E.
1. Press the C key twice to activate the cursor in the GPS window. 2. Use the O knob to select the desired frequency. Press E to place the frequency in the standby field. The cursor will automatically advance to the next frequency on the list.

Page 9

Once a direct-to is activated, the CDI 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 CDI page: 1. Press the C key twice to activate the cursor in the destination field. 2. Press \. 3. Press E.
Cancelling a Direct-To Nearest Waypoints
The GNC 250XLs T key 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 and enter it in the standby field.
To view the nine nearest airports: 1. Press the T key. 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 K knob to the right. To place a nearest airport frequency in the standby field: 1. Press E. Press the @ key to place the frequency in the active field. To view the nearest list for other waypoint categories (VOR, NDB, etc.): 1. Rotate the O knob to the right, or press the T key repeatedly. 2. Rotate K to scroll through the list.
The nearest airport page shows up to nine nearest airports from your present position.
To place a nearest airport frequency in the standby field, press E.

Page 10

Nearest Airports Shutting Down
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 C twice to activate the waypoint field. 2. Press E to display the waypoint identification page. 3. Rotate O to view any additional waypoint information available. 4. Press T to return to the nearest waypoint page. To select a nearest waypoint as a direct-to destination: 1. Press the D key. The direct-to confirmation page for the selected waypoint will appear.

Trip planning with values calculated between two waypoints.

Page 24

Density Altitude & True Airspeed
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 N and rotate O until NAV Menu 1 is displayed. 2. Press C twice and rotate O to highlight Dalt/tas?. 3. Press E to access the density altitude page. 4. Use K and O to enter the indicated altitude (ialt) and press E.
Density altitude/true airspeed page
5. Use K and O to enter the calibrated airspeed (cas). Press E. 6. Use K and O to enter the air pressure (pres) and press E. 7. Use K and O to enter the total air temperature (tat). 8. Press E and the density altitude and true airspeed will be calculated and displayed. 9. Press C to 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 navigation 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 various 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.
Fuel planning page showing calculation from present position to KDAL.

Page 25

To perform fuel planning operations: 1. Press N and rotate O until NAV Menu 1 is displayed. 2. Press C twice and rotate O until Fuel Plan? is highlighted. Press E. 3. Rotate K to select either wpt for direct navigation or the desired route number. Press E. 4. For waypoint-waypoint navigation, use K and O to 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 K.

Page 34

Overview Auto-Tuning
During the course of navigating with the GNC 250XL, there may be times when you need to quickly select a comm frequency while you are entering data in the GPS window. Whenever data entry in the GPS window is interrupted by activating the standby frequency field, the GPS field in use will become splatted, or blocked out.
To auto-tune from the nearest airport page, press E.
Once the standby frequency has been entered, you may return to data entry by pressing the C key. The cursor will return to the active GPS field at the point where data entry was interrupted. The GNC 250XLs auto-tune feature allows you to quickly select any database frequency in the GPS window as your standby frequency.
To select a frequency from a list, highlight the desired frequency and press E.
To auto-tune a single frequency displayed in the GPS window: 1. Press E with the cursor inactive. 2. To make the standby frequency the active frequency, press @.

Page 35

To auto-tune a frequency from a list displayed in the GPS window: 1. Press C twice to activate the cursor in the GPS window. 2. Rotate O to highlight the desired frequency. 3. Press E to make the selected frequency the standby frequency.
Auto-Tuning Volume & Squelch
Another useful feature integrating the GNC 250XLs navigation and communication capabilities is the Navigation Communications (NAVCOM) page, which is accessed using the N key. See pages 16-17 for more on the NAVCOM page. The GNC 250XLs automatic squelch and volume controls are located at the bottom left of the unit, near the NavData card slot.
To adjust the radio volume: 1. Rotate the B knob.
TX indicating radio transmission.
Whenever the GNC 250XL is powered up, the automatic squelch will be in the on position, allowing only transmissions which are powerful enough for clear broadcast to be received. Manual squelch control is not available.
To override the automatic squelch control: 1. Press the Q key. Press Q again to return to automatic squelch.
Whenever the GNC 250XL is transmitting, a tx icon will appear between the active and standby frequency fields. If the microphone is stuck or accidentally left in the keyed position, or if the headsets continue to transmit after the key is released, the radio will automatically timeout after 35 seconds of continuous broadcasting. Youll also receive a Stuck mic/Tx disabled message as long as the stuck condition exists.

Page 36

Emergency Channel Selection
The GNC 250XLs emergency channel select feature provides a quick method of selecting the 121.5 MHz frequency as the active frequency in the event of an in-flight emergency. The emergency channel select is available whenever the unit is on, regardless of GPS or cursor status, or loss of the display.
To automatically tune for emergency transmission: 1. Press and hold the @ key for more than two seconds.
The emergency channel (121.50) will appear in the active field by pressing @ for more than two seconds.

Page 37

Section 3 Waypoint and Database Information
The GNC 250XL 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 GNC 250XLs internal memory.
Waypoint Menu Page Proximity Waypoints Page

WPT KEY

Please note that your GNC 250XL 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
Waypoints with Comments List

User Waypoint List

Waypoint information is available through four primary waypoint pages accessible from the GNC 250XLs W key. The waypoint pages may be scrolled through by pressing the W key and rotating the outer knob until the desired page is displayed, or by pressing the W key repeatedly.

Page 38

Waypoint Categories & Menu Page
The GNC 250XL 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, runways, fuel services 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.
The waypoint menu page allows you to select the desired waypoint type (or category).
Intersections - Identifier, country, position (lat/lon), nearest VOR. User - Identifier (name), position (lat/lon), reference waypoint. To view the waypoint information for a desired waypoint, select the waypoint category from the waypoint menu page.

To enter a waypoint by scanning the identifier, facility name or city: 1. With the cursor over a blank identifier field, press W. If the identifier field is not blank, highlight the field with the cursor and press \ before pressing W. 2. Use O to highlight the waypoint category you wish to scan. 3. Press E to activate the scanning mode. 4. Rotate O to place the cursor over the field you want to scan (identifier, facility or city name).
Possible messages for locked waypoints.
To blank a waypoint field, highlight the field and press the \ key.
5. Use K and O to enter the letters of the identifier, city or facility name. The GNC 250XL will scan the database and display the first waypoint that matches your entry. 6. Press E to accept the waypoint, and E again to confirm the waypoint for the function being used.

Page 57

Section 4 Nearest Waypoints
The GNC 250XLs T key 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 T key can be used in conjunction with the GNC 250XLs 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.

NRST KEY

This will display the nearest airport to your present position, subject to the runway surface type and minimum runway length selected (see page 79).
To scroll through the next eight nearest airports, rotate K.
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.
You may examine both the communication frequencies and the runway information directly from the nearest airport page. You may also place the displayed frequency into the standby field by pressing E from the nearest airport page.
To view more comm/runway information: 1. Press C twice and rotate O to highlight the comm field or the runway field. 2. Rotate K to scroll through more information, if available. To perform a direct-to on any of the nearest waypoint pages: 1. Press D. The waypoint confirmation page will appear. 2. Press E to accept the waypoint or \ to cancel.
Nearest FSS page. To view additional frequencies (if available), highlight the frequency and rotate the O knob.

Page 58

Special Use Airspace
The nearest waypoints for other categories (VORs, NDBs, etc.) may be viewed by rotating O. Rotating O continuously to the left will stop page selection on the nearest airport category. The next page available under the GNC 250XLs T key 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.

Page 65

The GNC 250XL 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 R key, which features two route pages selectable from the GNC 250XLs outer knob: the active route page and the route catalog page. The active route page provides 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 GNC 250XLs internal memory. Once a storage route is activated, it is placed into route 0 for navigation until it is cancelled, overwritten by activating another route or erased when the GPS 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. The GNC 250XLs 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): 1. Rotate K to display the route you would like to add comments to. 2. Press C twice and use O to highlight the bottom row. 3. Use K and O to enter comments, and press E. To erase press \, then E.

ROUTES

Overview 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

Route Catalog Page

7/17/98 1:28 PM

Page 66

Creating & Editing Routes
The route action field, located at the top right of the page, is used to select the desired route operation. The following functions are available: Activate Reverse Edit Delete Copy CPA Search activate the route for navigation activate a route in reverse order create a new route, or edit an existing route delete a route copy the current route to an empty route calculate the closest point of approach perform search and rescue ladder operations

Whenever waypoint sequencing is set to hold, the desired course is displayed at the bottom left of the CDI page. See page 64 for more details.

Page 74

Waypoint Sequencing
To hold on the active-to waypoint: 1. Press D and E. The direct-to confirmation page will appear. 2. Rotate O to highlight the waypoint sequencing field, and rotate K to select hold. 3. Press E. The cursor will advance to the course select field where you may manually enter the desired course to the hold waypoint. The default course is the GPS course calculated from your present position. 4. Press E to accept the course select field. 5. Press E to confirm the ok? prompt. The map page will display the inbound course as a solid line and the outbound course as a dashed line.
As you approach a route waypoint, the graphical CDI will be replaced by a flashing Next dtk xxx 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.
During route operations, the CDI page is used to provide turn anticipation, next desired track and waypoint arrival information to the pilot. The GNC 250XLs 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 aircrafts actual ground speed and the difference between the course angle of the two legs. The GNC 250XL 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 left of this page. As you approach a route waypoint, the graphical CDI on the CDI page will be replaced by a flashing Next dtk xxx prompt and the desired track readout on the map page will flash, both indicating the desired track of the next route leg. Turn anticipation will not be provided if you have set the waypoint sequencing field to hold or your current ground speed and the course angle between the two legs would require a bank angle greater than 25. If the leg transition is too short for a smooth transition, a Leg not smoothed message will appear, and the pilot should expect a rapid change in the CDI deflection.

5. To change the altitude buffer, highlight the buffer value, and use K and O to change the data. Press E to accept. 6. Press C to complete.

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The NavData card contains over 100 map datums for you to use when navigating. By default, your unit calculates positions using the WGS 84 map datum. If you are using charts based on another datum, you must set the GNC 250XL to use the same datum. Using a map datum that does not match the charts you are using can result in significant differences in position information. If you are using maps for reference only, the GNC 250XL will provide correct navigation guidance to the waypoints contained in the database, regardless of the datum selected.
To change the map datum to one listed in Appendix F: 1. Press and hold M, and use O to highlight the map datum page. 2. Press C twice. 3. Use O to highlight the current map datum. 4. Use K to change the datum. 5. Press C to complete. To create a user datum: 1. Press and hold M, and use O to highlight the map datum page. 2. Press C twice. 3. Use O to highlight Define user datum?. Press E. 4. Enter the five parameters of the map datum using K and O. Press E to accept a field. The signs of each value (+/-) should follow the convention: WGS84-local geodetic system. 5. Use O to highlight ok?, and press E. 6. To activate the user datum, select USER on the map datum page as described above.

Map Datums

Map datum page showing the default WGS 84 datum. This setting should be used unless your paper chart specifies a different datum.
User datum page. To use this function you must enter the parameters as differences from the WGS 84 default.

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I/O Settings
The last page available under the GNC 250XLs setup menu is the I/O setup page. The I/O setup page lets you configure the GNC 250XL to input RTCM SC-104 correction data, output to a RS-232 mapping device or a PC (with the optional GARMIN PC Kit or other mapping software) and select the appropriate baud rate. The I/O setup page only provides access to I/O channel 2 input/output. For information on using I/O channel 1, please see your GNC 250XL installation manual.
To change the output settings for I/O channel 2: 1. Press and hold M, and rotate O until the I/O setup page is displayed. 2. Press C twice, and rotate K to select off or plotting for output to an RS-232 device. 3. Rotate O to advance the cursor to the baud rate field.

Cannot chng actv wpt - An attempt has been made to modify the position of the active to or active from waypoint. The GNC 250XL will not allow the modifications. Cannot nav lockd rte - An attempt has been made to activate a route containing a locked waypoint. The GNC 250XL cannot perform navigation in this situation. Cannot ofst goto rte - An attempt has been made to engage the offset navigation feature while the GNC 250XL is navigating using a single waypoint route. The GNC 250XL will not allow offset navigation in this situation. Checklist is full - The selected checklist is full. No new items can be added until existing items are deleted. COM failed - The comm in the GNC 250XL has failed. Take the unit to an authorized GARMIN service center immediately. Comment memory full -The waypoint comment memory is full. You must delete existing waypoint comments before adding new ones.

Altitude input fail

Arrival at _____ Arrvl at offst _____

Battery low

Battery rqrs service
- The altitude serializer input is not available for the GNC 250XL. Check the I/O settings and/or the serializer installation. If enough satellites are available for a 3D position fix, no pilot action is required, providing no RAIM warnings are present. If only a 2D fix is possible, the pilot should enter an altitude within 1,000 feet of current indicated altitude. - Your craft has entered the arrival alarm circle for the indicated waypoint. - Your craft has entered the arrival alarm circle for the indicated waypoint offset by the parallel track distance. - The optional remote battery pack is low on power and limited operating time remains. The battery should be recharged for continued operation. - A problem has been detected in the optional remote battery pack. The battery should be serviced at an authorized GARMIN service center.

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Configuration reset

Data card failed

Data card write fail

Degraded accuracy

Do not use for nav EEPROM write fail

Final altitude alert

Fuel/Air input fail
- The GNC 250XL has detected a failure in its installation configuration memory. Data from the user memory has been used to reset the configuration. Check the installation settings for correctness. If the message persists, the unit is not usable and should be taken to an authorized service center for repair. - The GNC 250XL has detected a problem with the data card. The data is not usable and the card should be returned to Jeppesen or an authorized GARMIN service center. - The user data card failed to program. The card should be returned to an authorized GARMIN service center. - The GNC 250XL has detected poor satellite geometry while RAIM is not available. Additional cross-checking with a secondary navigation source should be performed to verify the integrity of the GPS position. - The GNC 250XL is in the simulator mode and must not be used for actual navigation. - The GNC 250XL has detected a failure while programming its installation configuration memory. The unit is not usable and should be taken to an authorized service center. - The suggested altitude is within 1000 feet of the final altitude entered on the VNAV Planning page. - The fuel and/or air data input is not available to the GNC 250XL. Check the I/O settings or fuel/air data system installation.