Garmin | GFC™ 600 Digital Autopilot | Garmin GFC™ 600 Digital Autopilot GFC 600 Pilot’s Guide

Garmin GFC™ 600 Digital Autopilot GFC 600 Pilot’s Guide
GFC 600 ™ Pilot’s Guide
Copyright © 2017 Garmin Ltd. or its subsidiaries. All rights reserved.
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used without the express permission of Garmin.
July, 2017
190-01488-00 Rev.B
Printed in the U.S.A.
Warnings, Cautions & Notes
WARNING: Perform a thorough preflight control check to verify that there
is no excessive friction, binding, or other anomalies that prevent smooth
movement throughout the intended range of motion in pitch, roll, and yaw
axis. Any discrepancies must be resolved prior to continued operation.
WARNING: For safety reasons, system operational procedures must be learned
on the ground.
WARNING: The Garmin system, as installed in this aircraft, has a very high
degree of functional integrity. However, the pilot must recognize that providing monitoring and/or self-test capability for all conceivable system failures
is not practical.
WARNING: To reduce the risk of unsafe operation, carefully review and
understand all aspects of the system, Pilot’s Guide documentation, the Pilot’s
Operating Handbook (POH), and the Aircraft Flight Manual Supplement
(AFMS). Thoroughly practice basic operation prior to actual use. During flight
operations, carefully compare the Flight Director commands and autopilot
response to all available navigation indications, attitude displays, and air data
information. For safety purposes, always resolve any discrepancies before
continued operation.
CAUTION: The system does not contain any user-serviceable parts. Repairs
should only be made by an authorized Garmin service center. Unauthorized
repairs or modifications could void both the warranty and the pilot’s authority
to operate this device under FAA/FCC regulations.
NOTE: All visual depictions contained within this document, including screen
images of the panel and displays, are subject to change and may not reflect
the most current system and aviation databases. Depictions of equipment
may differ slightly from the actual equipment.
NOTE: This device complies with part 15 of the FCC Rules. Operation is
subject to the following two 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.
Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
Part Number
190-01488-00
Rev
Date
A June, 2017
B
July, 2017
190-01488-00 Rev. B
Change Summary
Initial release
Description
Production Release
Removed software version number
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Garmin GFC 600 Pilot’s Guide
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Table of Contents
Section 1 System Overview................................................................................................... 1
1.1 Basic Functions................................................................................................................... 1
1.2 AFCS Equipment................................................................................................................. 2
GMC 605 Mode Controller.................................................................................................... 2
GSA 87 Servo........................................................................................................................ 4
GI 285 Annunciator Panel...................................................................................................... 4
1.3 Interfacing Equipment...................................................................................................... 5
G500/G600 Integrated Glass Panel System ........................................................................... 5
Aspen EFD1000.................................................................................................................... 6
GPS Navigators..................................................................................................................... 6
VHF Nav Radios ................................................................................................................... 7
Horizontal Situation Indicators (HSI)....................................................................................... 7
Directional Gyros (DG)........................................................................................................... 7
Audio Panel.......................................................................................................................... 8
GTX 335/345(R) with GPS Option.......................................................................................... 8
1.4 AFCS Controls...................................................................................................................... 9
GMC 605.............................................................................................................................. 9
External Controls................................................................................................................. 10
1.5 System Indications........................................................................................................... 11
GMC 605............................................................................................................................ 11
GI 285 Indications............................................................................................................... 12
Garmin PFD AFCS Indications.............................................................................................. 13
Section 2 Automatic Flight Control System............................................................... 15
2.1 AFCS Operation................................................................................................................. 15
AFCS Pre-Flight................................................................................................................... 15
Engaging the Autopilot........................................................................................................ 16
Flight Director Modes.......................................................................................................... 16
Disengaging the Autopilot................................................................................................... 17
2.2 Basic Autopilot Features................................................................................................. 17
Flight Director..................................................................................................................... 17
Control Wheel Steering........................................................................................................ 19
Yaw Damper....................................................................................................................... 20
Manual Trim........................................................................................................................ 21
Manual Electric Trim............................................................................................................ 22
Autotrim............................................................................................................................. 22
Overspeed Protection.......................................................................................................... 23
Underspeed Protection........................................................................................................ 24
2.3 Vertical Modes................................................................................................................... 27
Vertical Mode Controls and Annunciations........................................................................... 27
Pitch Hold Mode (PIT)......................................................................................................... 28
Level Mode (LVL)................................................................................................................. 30
Go Around Mode (GA)........................................................................................................ 31
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Table of Contents
Altitude Hold Mode (ALT).................................................................................................... 32
Selected Altitude Capture Mode (ALTS)................................................................................ 33
Vertical Speed Mode (VS).................................................................................................... 34
Indicated Airspeed Mode (IAS)............................................................................................. 36
Glidepath Mode (GP).......................................................................................................... 37
Glideslope Mode (GS)......................................................................................................... 39
2.4 Lateral Modes.................................................................................................................... 40
Lateral Mode Controls and Annunciations............................................................................ 40
Roll Hold Mode (ROL).......................................................................................................... 42
Heading Select Mode (HDG)................................................................................................ 43
Navigation Modes (GPS, VOR, LOC)..................................................................................... 45
Approach Modes (GPS, VOR, LOC)....................................................................................... 48
Flying A DME Arc With A GPS Navigator.............................................................................. 51
Backcourse Mode (BC)........................................................................................................ 52
2.5 Electronic Stability & Protection (ESP™).................................................................... 53
Roll Engagement................................................................................................................. 54
Pitch Engagement............................................................................................................... 56
Airspeed Protection............................................................................................................. 58
Section 3 Annunciations & Alerts..................................................................................... 59
3.1 Visual Annunciations and Alerts................................................................................... 59
3.2 Aural Alerts........................................................................................................................ 62
Voice Alerts......................................................................................................................... 62
Autopilot Disconnect Alert................................................................................................... 62
Section 4 Abnormal Operation.......................................................................................... 63
4.1 Suspected Autopilot Malfunction................................................................................ 63
4.2 Overpowering Autopilot Servos................................................................................... 63
Appendices..................................................................................................................................... 64
Appendix A: Feature/Equipment Matrix............................................................................ 64
Index....................................................................................................................................Index-2
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Garmin GFC 600 Pilot’s Guide
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System Overview
SECTION 1 SYSTEM OVERVIEW
The Garmin GFC 600 is a high-performance, attitude-based, Automatic Flight
Control System (AFCS) that supports an extensive set of operating modes and safety
features. The system design offers the flexibility to interface with a wide variety
of avionics equipment commonly found in general aviation aircraft. The specific
functions supported by the GFC 600 vary by installation. Refer to Appendix A for more
information.
CAUTION: This manual covers all functions and modes that the GFC
600 can support, however it is the responsibility of the user to become
familiar with the capabilities and limitations of a specific aircraft (per the
Airplane Flight Manual Supplement) which may not support all the features
described here.
1.1 BASIC FUNCTIONS
The GFC 600 AFCS provides the following main operating functions:
• Flight Director (FD) — The Flight Director function provides pitch and roll
commands needed to guide the aircraft toward the active reference selected by
the pilot. If a compatible Primary Flight Display (PFD) is installed these pitch and
rolls commands are displayed on the PFD as Command Bars. When the Flight
Director is active the pitch and roll commands can be hand-flown by the pilot.
When the Autopilot is engaged the autopilot servos drive the flight controls to
follow the commands issued by the Flight Director.
• Autopilot (AP) — The Autopilot function is provided by servo actuators which
move the flight control surfaces in response to Flight Director steering commands,
aircraft attitude, and airspeed. The optional pitch auto-trim function serves to
relieve any sustained effort required by the pitch servo to keep the aircraft in trim.
• Yaw Damper (YD) — The optional Yaw Damper function provides Dutch Roll
damping, assists in turn coordination, and provides a steady force to help maintain
directional trim. If installed the YD comes on when the autopilot is engaged. It
can be turned on/off independent of the autopilot and may be used during normal
hand-flying maneuvers.
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System Overview
• Manual Electric Trim (MET) — The optional Manual Electric Trim uses the same
servo as the auto-trim function and allows the pilot to command trim via a trim
switch when the autopilot is not engaged. The MET function does not preclude
the use of the aircraft’s basic mechanical trim system.
• Electronic Stability & Protection (ESP) — The ESP function provides a soft
barrier to keep the aircraft within the desired operating envelope when the autopilot
is not engaged. When the GFC 600 senses that the aircraft is near the defined
operating limit in pitch attitude, roll attitude, high airspeed, or low airspeed, the
ESP function will automatically engage one or more servos to nudge it back to the
nominal operating envelope. While ESP utilizes the same sensors, processors, and
actuators as the GFC 600 autopilot it is a separate mutually exclusive function.
ESP can be easily overpowered by the pilot and can be disabled using the AP
DISC / TRIM INT button.
1.2 AFCS EQUIPMENT
The basic GFC 600 system is comprised of the following equipment:
GMC 605 MODE CONTROLLER
The panel-mounted GMC 605 serves as the primary user interface for the GFC 600.
The GMC provides autopilot and Flight Director mode selection buttons and a wheel
for convenient adjustment of the pitch, airspeed, and vertical speed references. A
backlit monochrome LCD displays active and armed modes, reference values, alerts,
and messages.
The GMC 605 contains internal sensors which calculate the aircraft attitude, allowing
the GFC 600 to operate without relying on any external source of attitude. Flight
Director mode logic as well as some autopilot management functions are performed
within the GMC 605 main processor.
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System Overview
The GMC 605 has extensive I/O capabilities that support interfaces to a large variety
of equipment including Primary Flight Displays, Air Data Computers, GPS navigators,
VHF Nav radios, Audio Panels, HSIs, and Directional Gyros (DGs). The GMC requires
airspeed and altitude information, therefore if it does not have an interface to an Air
Data Computer, a small Air Data Module must be attached to the back of the GMC’s
mounting tray to provide basic air data information to the AFCS.
The GMC 605 features a covered USB port on the front face of the unit, allowing a
convenient means of updating software and downloading diagnostics information to
aid in troubleshooting.
CAUTION: The USB port is not designed to provide power or data to external
consumer devices such as smart phones, cameras, or tablet computers and
should not be used in flight.
GMC 605
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System Overview
GSA 87 SERVO
The GSA 87 servos provide control surface actuation as part of the autopilot, yaw
damper, electric trim, and ESP functions. The GSA 87 is a ‘smart’ servo which performs
most of the autopilot processing functions and offers many inherent safety features.
The brushless motor and electronic torque and speed sensing capabilities provide
smooth, reliable operation. The GSA 87 design incorporates an internal engagement
solenoid and a gear train that allows the motor to be backdriven by the pilot in case
the solenoid fails to disengage. This eliminates the need for a mechanical slip clutch
along with the associated performance limitations and maintenance requirements.
GSA 87
GI 285 ANNUNCIATOR PANEL
The GI 285 Annunciator Panel provides basic AFCS status and mode annunciation
for GFC 600 installations where the GMC 605 cannot be mounted within the pilot’s
primary field of view and there is no PFD capable of providing the annunciations.
GI 285
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Garmin GFC 600 Pilot’s Guide
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System Overview
1.3 INTERFACING EQUIPMENT
The GFC 600 is capable of interfacing with a wide variety of equipment including
the following:
G500/G600 INTEGRATED GLASS PANEL SYSTEM
The GDU 620 Primary Flight Display (part of the G500/G600 Glass Cockpit system)
can provide AFCS mode annunciation and alerts, Flight Director command bar display,
Altitude Preselect (ALTS) capability, Heading (HDG) reference selection, and bank limit
indications for the ESP function. The PFD displays AFCS reference values and bugs for
Vertical Speed (VS) and Indicated Airspeed (IAS) modes. Nav source selection can be
performed on the PFD and the GFC 600 will couple to the selected source for guidance.
The G500/G600 systems include an Air Data Computer which provides airspeed and
baro-corrected altitude to the AFCS. This is particularly beneficial when operating in
Altitude Hold (ALT) mode because the autopilot will automatically synchronize to small
changes resulting from an updated altimeter setting.
GDU 620
Reference the latest G500/G600 Pilot’s Guide for more detail about features related
to AFCS.
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System Overview
ASPEN EFD1000
The Aspen EFD1000 can provide Flight Director command bar display, Heading (HDG)
reference selection, and Nav source selection functions. The GFC 600 will couple to
the selected nav source for guidance including when the EFD1000 is operated in GPSS
mode.
Reference the Aspen EFD1000 Pilot’s Guide for operational details about features
related to autopilot interfaces.
GPS NAVIGATORS
The GFC 600 can accept guidance from a variety of panel mount GPS navigators
including those that provide Roll Steering and Glidepath commands and older models
that provide only basic lateral course deviation for guidance. The WAAS-enabled
Garmin GNS and GTN series navigators also provide an interface to the GMC 605 that
supports improved aircraft attitude computation, thereby enhancing AFCS performance
and increasing the availability of basic modes in the event of an air data failure.
The GTN 650 is an example of a compatible GPS Navigator:
GTN 650
Reference the applicable Pilot’s Guide for more information about operating the
GPS navigation equipment installed in an aircraft.
NOTE: If there is more than one navigation source (GPS and/or VHF Nav)
installed it is the responsibility of the user to understand the nav source
selection mechanism and ensure that the GFC 600 is coupled to the
intended source guidance.
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System Overview
VHF NAV RADIOS
The GFC 600 can accept VOR/Localizer and Glideslope guidance from a variety of
VHF Nav receivers including stand-alone radios and those that are included as part of
a Nav-Com or GPS-Nav-Com integrated navigator.
The GNC 255 is an example of a compatible VHF Nav receiver:
GNC 255
Reference the applicable Pilot’s Guide for more information about operating the VHF
Nav equipment installed in an aircraft.
HORIZONTAL SITUATION INDICATORS (HSI)
The GFC 600 can accept Heading commands and Course inputs from a variety of
HSIs including mechanical instruments such as the Bendix King KI 525A and Century
NSD360A and electronic HSI displays such as the Sandel SN3500/4500.
DIRECTIONAL GYROS (DG)
If GFC 600 is installed in an aircraft without an HSI, the system can accept Heading
commands from a variety of popular DGs that have a compatible interface. These
installations do not provide a Course input to the GFC 600, therefore whenever the
user selects a NAV or APR mode on the GMC 605 the Heading bug must be manually
set to align with the Course pointer on the CDI.
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System Overview
AUDIO PANEL
The GFC 600 can interface to a wide variety of audio panels to provide aural alerts
including the AP Disconnect tone and low Airspeed warning. The AFCS aural alerts
cannot be muted or deselected via the audio panel controls. In addition to the audio
panel interface, a Sonalert aural tone generator must be included with most GFC 600
installations to ensure the AP Disconnect aural is heard by the pilot if the audio panel
fails or suffers a loss of power.
The GMA 345 is an example of a compatible audio panel:
GMA 345
GTX 335/345(R) WITH GPS OPTION
The GTX 335/345(R) transponders with GPS Option can provide an interface to the
GMC 605 that supports improved aircraft attitude computation, thereby enhancing
AFCS performance and increasing the availability of basic modes in the event of an air
data failure.
GTX 345
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Garmin GFC 600 Pilot’s Guide
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System Overview
1.4 AFCS CONTROLS
GMC 605
NOTE: VNAV support is a future growth function.
1
4
5
2
6
14
3
7
8
9
10
11
12
13
GMC 605 AFCS Mode Controller
1
AP Key
Engages/disengages the autopilot
2
FD Key
3
YD Key
ctivates/deactivates the Flight Director only. Pressing once turns
A
on the director in the default vertical and lateral modes. Pressing
again deactivates the Flight Director and removes the Command
Bars. If the autopilot is engaged, the key is disabled.
Engages/disengages the yaw damper (if installed).
4
LCD Display Displays AFCS modes, references, and annunciations.
5
LVL Key
6
ALT Key
Engages the autopilot in Level Mode (or selects Level Mode if
autopilot is already engaged).
Selects/deselects Altitude Hold Mode
7
HDG Key
Selects/deselects Heading Select Mode
8
NAV Key
Selects/deselects Navigation Mode. Cancels GS Mode if LOC
Mode is either active or armed. Cancels GP Mode if GPS Mode is
either active or armed.
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System Overview
9
APR Key
Selects/deselects Approach Mode
10
BC Key
Selects/deselects Backcourse Mode
11
VNV Key
12
IAS Key
Selects/deselects Vertical Path Tracking Mode for Vertical
Navigation flight control (growth function)
Selects/deselects Indicated Airspeed Mode
13
VS Key
Selects/deselects Vertical Speed Mode
14
NOSE UP/DN Adjusts the vertical mode reference in Pitch Hold, Vertical Speed,
Wheel
Indicated Airspeed, and Altitude Hold modes
EXTERNAL CONTROLS
These controls are used for important Flight Director and autopilot functions but are
not found on the GMC 605.
Control
AP DISC/
TRIM INT
button
GA button
(optional)
MET switch
(optional)
CWS switch
(optional)
10
Common
Name
Autopilot
Disconnect
Typical
Location
Pilot control
yoke/stick
Go Around
Power lever
or instrument
panel
Manual
Pilot control
Electric Trim
yoke/stick
Control Wheel Pilot control
Steering
yoke/stick
Garmin GFC 600 Pilot’s Guide
Purpose
Disengages the autopilot, yaw
damper, and interrupts pitch trim
operation; or, acknowledges an
autopilot disconnect alert and mutes
the associated tone.
Holding the AP DISC / TRIM INT
button down for five seconds will
also disable Electronic Stability &
Protection.
Selects Go Around mode.
Commands manual electric pitch
trim.
Temporarily disengages the pitch
and roll servos. Upon releasing CWS
the servos re-engage and may be
synchronized to a new reference
(depending on mode).
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System Overview
Common
Typical
Control
Name
Location
Dimmer knob Panel Lighting Instrument
(optional)
Dimmer
Panel
Purpose
Adjusts the brightness of the GMC
605 LCD backlight, keypad, and
LED annunciators. If dimmer is not
connected the GMC lighting will
be adjusted automatically using its
photocell.
1.5 SYSTEM INDICATIONS
GMC 605
The GMC 605 provides indications to the pilot via a monochrome LCD combined
with three color LEDs that are located adjacent to the AP, FD, and YD keys.
The left side of the LCD displays lateral Flight Director modes, the center portion of
the display provides vertical modes and references, and the right side of the display
serves as a message area for status and alerts. Active modes and references are
depicted in large letters along the upper portion of the display, with armed modes
in a smaller font along the lower portion. The message area can display up to four
messages simultaneously.
Text can be flashed alternating between normal display and inverse video when
needed to get the pilot’s attention.
Active Lateral Active Vertical
Mode
Mode
Mode
Reference
Status Messages and
Alerts
Armed Lateral Armed Vertical
Mode
Mode
GMC 605 LCD Display
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System Overview
The LEDs adjacent the AP, FD, and YD keys are illuminated in conjunction with
other information on the LCD to provide status and alert information.
The AP, FD, and YD LEDs are illuminated in green to indicate that they are engaged.
Manual autopilot and yaw damper disconnect is indicated with flashing yellow AP
and YD annunciations, and red is used to indicate an abnormal disconnect or failure
condition.
The FD LED flashes yellow to indicate when an active mode is dropped automatically
by the AFCS.
The AP LED is illuminated in yellow when a trim failure has occurred or when a
mistrim condition has developed.
AP (Autopilot) LED
FD (Flight Director) LED
YD (Yaw Damper) LED
GMC 605 LEDs
Refer to section 3.1 for more information about specific GMC 605 messages and
LED annunciations.
GI 285 INDICATIONS
The GI 285 Mode Annunciator is required in installations where the GMC 605 is
located outside of the pilot’s primary field of view and there is no Garmin PFD to
provide mode annunciations and alerts. The left side of the GI 285 displays lateral
Flight Director modes, the center portion of the display provides status information for
the autopilot, yaw damper, and trim system, and the right side displays vertical modes.
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System Overview
The GI 285 can illuminate indications in multiple colors and also supports flashing
annunciations when needed to get the pilot’s attention. Active modes are depicted in
green and armed modes in white. Yellow is used to indicate when an active mode is
dropped automatically by the AFCS.
The AP and YD annunciations are illuminated in green to indicate that they are
engaged. Manual autopilot and yaw damper disconnect is indicated with flashing
yellow AP and YD annunciations, and red is used to indicate an abnormal disconnect
or failure condition.
The TRIM annunciation is illuminated in yellow when a trim failure has occurred or
when a mistrim condition has developed.
The pilot should reference the GMC 605 message area for more information
regarding failures and mistrim conditions.
GI 285 Annunciator
Refer to section 3.1 for more information about specific AP, YD, and TRIM
annunciations on the GI 285.
GARMIN PFD AFCS INDICATIONS
A Garmin PFD (if installed) can display Flight Director command bars, active and
armed mode annunciations, references, autopilot and yaw damper engagement
status, and AFCS alerts. Bugs are displayed along with digital references for Selected
Heading, Vertical Speed, Selected Altitude, and Indicated Airspeed (when GFC 600 is
in IAS mode).
Refer to the G500/G600 Pilot’s Guide for more detailed information.
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System Overview
Lateral Modes
Autopilot
Status
Yaw
Damper
Status
Vertical Modes
Active
Active
Armed
Armed
AFCS Status Annunciations
Selected
Altitude
Command
Bars
GPS is
Selected
Navigation
Source
Autopilot info on Garmin GDU 620 PFD
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Garmin GFC 600 Pilot’s Guide
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AFCS
SECTION 2 AUTOMATIC FLIGHT CONTROL
SYSTEM
NOTE: The approved Pilot’s Operating Handbook (POH) or Airplane Flight
Manual (AFM) always supersedes the information in this Pilot’s Guide.
NOTE: Refer to the approved Airplane Flight Manual Supplement (AFMS)
for GFC 600 specific emergency procedures.
2.1 AFCS OPERATION
AFCS PRE-FLIGHT
The pilot is expected to perform a standard pre-flight control check by moving the
flight controls through their full range of motion in pitch, roll, and yaw axis to verify
smooth and unrestricted operation. Any discrepancies must be resolved before flight.
Upon power-up the GFC 600 will automatically perform a Pre Flight Test (PFT) to
check internal GMC 605 functions, interfaces, and servo status. While the test is in
progress the GMC displays the message PFT. The GMC’s three LEDs are illuminated
in yellow for 1 second and then in red for 1 second. The GI 285 (if installed) will
illuminate all lateral mode annunciations in yellow for 1 second, followed by the AP
YD/TRIM annunciations in yellow for 1 second, then the vertical modes in yellow for
1 second, and finally the AP/YD/TRIM annunciations in red for 1 second. Any failed
LED annunciators on the GMC 605 or GI 285 should be noted and addressed by the
operator.
When PFT is complete the AP Disconnect aural is played through the audio panel. If
everything passed the PFT message is removed from the GMC display. If there are any
failures detected the GMC displays PFT FAIL and illuminates the AP LED in red. The AP
annunciation on the GI 285 will also be illuminated red.
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AFCS
ENGAGING THE AUTOPILOT
The autopilot is engaged by pressing the AP key on the GMC 605. If the Flight
Director is already on the autopilot will begin following the active Flight Director
commands. If the Flight Director is not on when the AP key is pressed, the Flight
Director will come on with autopilot engagement in the default PIT and ROL modes.
Another way to engage the autopilot is by selecting the LVL key. This will engage
the autopilot in Level mode.
The aircraft must be within the GFC 600 engagement limits (+/-50 degrees pitch
and +/- 75 degrees roll attitude) in order to engage the autopilot.
FLIGHT DIRECTOR MODES
Flight Director modes are normally selected independently for the pitch and roll axes
using the keys on the GMC 605 bezel. Unless otherwise specified, all mode keys are
alternate action (i.e., press on, press off). In the absence of specific mode selection,
the Flight Director reverts to the default pitch and/or roll modes.
Active modes are annunciated on the GMC 605’s screen in large text. Armed modes
are annunciated in smaller text below the active modes and are queued to take effect
as soon as capture criteria is met. Automatic transition from armed to active mode is
indicated by the armed mode annunciation moving up to the active mode field and
flashing for 10 seconds.
If the information required to compute an active Flight Director mode (such as air data
or navigation data) becomes invalid or unavailable, the Flight Director automatically
reverts to the default mode for that axis. The affected mode annunciation on the GMC
605 flashes in conjunction with the FD LED in yellow. The affected GI 285 annunciation
also flashes in yellow. When such a loss occurs, the system automatically begins to
roll the wings level (enters Roll Hold mode) or maintain the pitch angle (enters Pitch
Hold mode), depending on the affected axis. The flashing annunciation stops when
the affected mode key is pressed or another mode for the axis is selected. If after 10
seconds no action is taken, the flashing annunciation stops.
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AFCS
The Flight Director is automatically disabled if the attitude information required to
compute the default Flight Director modes becomes invalid or unavailable.
DISENGAGING THE AUTOPILOT
The Autopilot is manually disengaged by pressing the AP key on the GMC 605 or by
pressing the autopilot disconnect button or MET switch on the control stick or yoke.
Manual disengagement is indicated by an aural alert and the AP LED on the GMC 605
flashing yellow for five seconds. The AP indication on the GI 285 also flashes yellow.
The aural alert and flashing annunciations can be canceled by an additional press of
the autopilot disconnect button.
Automatic disengagement is indicated by an aural alert and the AP LED on the GMC
605 flashing red. The AP indication on the GI 285 also flashes red. The aural alert
and flashing annunciations continue until acknowledged by pressing the AP key or
the autopilot disconnect button. Automatic disengagement may occur due to a failure
within the GFC 600 system, loss of both GPS and air data inputs, strong turbulence, or
exceeding the engagement attitude limits.
2.2 BASIC AUTOPILOT FEATURES
FLIGHT DIRECTOR
NOTE: Flight Director command bars may be displayed on a Garmin PFD or
an Aspen EFD 1000.
The Flight Director function provides pitch and roll commands to the autopilot and
displays them on the PFD. With the Flight Director active, the aircraft can be handflown to follow the path shown by the command bars or the autopilot can be engaged
to follow the commands.
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17
AFCS
ACTIVATING THE FLIGHT DIRECTOR
NOTE: In an installation that does not support display of command bars,
pressing the FD Key will result in a DISABLD KEY message and all active and
armed mode annunciations will be removed upon autopilot disconnect.
An initial press of the FD key on the GMC 605 or the GA button activates the
Flight Director and adds the command bars to the PFD. If the autopilot is disengaged,
an additional press of the FD key will turn off the Flight Director and remove the
command bars from the PFD.
NOTE: The FD Key is disabled when the autopilot is engaged.
COMMAND BARS ON GARMIN PFD
Upon activation of the Flight Director, Command Bars are displayed in magenta
on the PFD. If the aircraft is being flown by hand, the Command Bars are displayed
hollow. The Command Bars do not override the Aircraft Symbol. The Command Bars
move together vertically to indicate pitch commands and bank left or right to indicate
roll commands.
Hollow Command Bars (Pilot Hand Flying Aircraft, FD Only)
Solid Command Bars (Autopilot Engaged)
Aircraft Symbol
Command Bars
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AFCS
FLIGHT DIRECTOR LIMITATIONS
The maximum commanded pitch and roll attitudes are limited to values established
during AFCS certification. Maximum commanded pitch and roll rates are also limited.
Reference the AFMS for Flight Director command limits in a specific aircraft.
CONTROL WHEEL STEERING
During autopilot operation, the aircraft may be hand-flown without disengaging the
autopilot. Pressing and holding the CWS button (if installed) disengages the pitch and
roll servos from the flight control surfaces and allows the aircraft to be hand flown.
Releasing the CWS button reengages the servos. Depending on the active mode the
Flight Director may be synchronized to a new reference upon CWS release. Refer to
the descriptions of vertical and lateral modes for specific CWS behavior in each mode.
Control Wheel Steering is annunciated on the GMC 605 with a CWS ON message
and the AP LED flashing green. On the GI 285, the AP annunciation changes from
green to white while CWS is active.
GMC 605 Annunciating Control Wheel Steering
GI 285 Annunciating Control Wheel Steering
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19
AFCS
YAW DAMPER
NOTE: Yaw Damper is available in aircraft that have an autopilot servo
installed on the yaw axis.
The Yaw Damper reduces Dutch roll tendencies, coordinates turns, and provides a
steady force to help maintain directional trim. It can operate independently of the
autopilot and may be used during normal hand-flown maneuvers.
The Yaw Damper is engaged by pressing the YD key. It will also be engaged by pressing
the AP key to turn on the autopilot. If the autopilot is disengaged using the AP key or
the MET switch the Yaw Damper will remain engaged and can be separately turned off by
pressing the YD key. If the autopilot is disengaged using the AP DISC / TRIM INT button
on the control yoke/stick the Yaw Damper will also be disengaged.
NOTE: In an installation that does not have a Yaw Damper servo, pressing
the YD Key will result in a DISABLD KEY message on the GMC 605.
When the Yaw Damper is engaged it is annunciated on the GMC 605 with the YD LED
illuminated in green. On the GI 285 the YD annunciation is illuminated green.
GMC 605 Yaw Damper Indication
GI 285 Yaw Damper Indication
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Garmin GFC 600 Pilot’s Guide
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AFCS
When the Yaw Damper is disengaged it is annunciated by the YD LED on the GMC
605 and the YD annunciation on the GI 285 flashing yellow for five seconds and then
extinguished.
MANUAL TRIM
Aircraft that do not have a pitch trim servo must be manually trimmed by the pilot.
Manual trim may also be required in the event of pitch trim servo failure. Mistrim
indication is provided when the autopilot is engaged to inform the pilot when manual
trim is needed.
On the GMC 605 a mistrim condition is indicated by the AP LED flashing yellow for
five seconds and then steady illumination. A message is displayed indicating the trim
axis and the direction. ELE TRM UP indicates that the pitch servo is holding excessive
nose up force and the pilot must manually trim the aircraft in the nose up direction to
alleviate the load and restore the aircraft to an in-trim condition. Once the aircraft is
in-trim the yellow AP LED is extinguished and the message is removed.
The GI 285 indicates a mistrim condition by flashing the TRIM annunciation in yellow
for five seconds and then steady. The TRIM annunciation is extinguished once the
mistrim condition is resolved.
NOTE: The GI 285 does not provide any indication of mistrim axis or
direction. The pilot must look at the GMC 605 message for this information.
GMC 605 Mistrim Indication
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Garmin GFC 600 Pilot’s Guide
21
AFCS
GI 285 Mistrim Indication
MANUAL ELECTRIC TRIM
NOTE: Manual Electric Trim (MET) is available in aircraft that have an
autopilot servo connected to the pitch trim system. The same servo provides
both the MET and Autotrim functions.
NOTE: When the autopilot is engaged, moving the MET Switch will
disengage the AP.
When the autopilot is not engaged, the pitch trim servo may be used to provide
manual electric trim (MET). This allows the aircraft to be trimmed using a control stick
switch. The MET switch is split into two adjacent parts which must be moved together
to arm and activate the trim command.
AUTOTRIM
NOTE: Autotrim is available in aircraft that have an autopilot servo
connected to the pitch trim system. The same servo provides both the MET
and Autotrim functions.
Autotrim will automatically adjust the pitch trim to keep the aircraft trimmed while
the autopilot is engaged. Autotrim can be disabled by pressing the AP DISC / TRIM
INT or CWS button.
If pitch trim fails while the autopilot is engaged (as indicated by P TRIM FAIL
message and AP LED illuminated yellow) the pilot can continue to use the autopilot
and manually trim the aircraft in response to any mistrim messages.
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Garmin GFC 600 Pilot’s Guide
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AFCS
NOTE: After disengaging the autopilot it cannot be re-engaged until a trim
failure condition is corrected.
OVERSPEED PROTECTION
NOTE: Overspeed protection is not active in Altitude Hold (ALT), Glideslope
(GS), Glidepath (GP), or Go Around (GA) modes.
While Pitch Hold, Vertical Speed, Indicated Airspeed, or Selected Altitude Capture
mode is active, airspeed is monitored by the Flight Director. Overspeed protection is
provided in situations where the Flight Director cannot acquire and maintain the mode
reference for the selected vertical mode without exceeding the certified maximum
autopilot airspeed.
When an overspeed condition occurs, the Flight Director will deviate from the active
vertical reference and produce a pitch up command to slow the aircraft. Engine power
should be reduced and/or the NOSE UP/DN wheel moved in the UP direction to adjust
the PIT or VS reference.
When Overspeed Protection becomes active, the GMC 605 displays a MAXSPEED
message, the active vertical mode annunciation changes automatically to IAS, and the
previously active vertical mode becomes armed. The GI 285 displays IAS in green and
the previously active mode changes to white.
When the overspeed condition is resolved the MAXSPEED message is removed and
the armed vertical mode becomes active again.
NOTE: When the autopilot is outside normal operating limits, it uses more
aggressive commands to return to normal limits.
GMC 605 Overspeed Indication
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Garmin GFC 600 Pilot’s Guide
23
AFCS
GI 285 Overspeed Indication
UNDERSPEED PROTECTION
NOTE: While underspeed protection is active, the aircraft will deviate from
the selected reference.
Underspeed Protection is designed to discourage aircraft operation below minimum
established airspeeds and is available when the autopilot is on.
When the aircraft is decelerating to within six seconds of reaching a predetermined
minimum airspeed (specified in the AFMS), the AIRSPEED aural will sound to alert the
pilot of the impending underspeed condition.
If the aircraft continues to decelerate, Underspeed Protection functionality depends
on which vertical mode is selected. For the purpose of this discussion, the vertical
modes can be divided into two categories: Those in which it is important to maintain
altitude for as long as possible (altitude-critical modes), and those in which maintaining
altitude is less crucial (non-altitude critical modes).
ALTITUDE-CRITICAL MODES (ALT, GS, GP, GA)
If the aircraft decelerates to stall warning for at least one second, the vertical and
lateral modes will change from active to armed. IAS and ROL will become the active
vertical and lateral modes and flash for five seconds, and the autopilot will provide
input causing the aircraft to pitch down and wings to level.
The AIRSPEED aural will sound every five seconds and a MINSPEED annunciation
will be displayed on the GMC 605.
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Garmin GFC 600 Pilot’s Guide
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AFCS
GMC 605 Underspeed Indication
(Altitude Critical Mode)
GI 285 Underspeed Indication
(Altitude Critical Mode)
The pilot must add power to increase airspeed. If the aircraft was in GA mode prior
to entering Underspeed Protection and full power has already been applied, the pilot
can move the NOSE UP/DN wheel in the DN direction to reduce the pitch attitude
reference. Moving the wheel will cause the vertical mode to revert to PIT mode after
exiting Underspeed Protection.
When airspeed increases to 5 KIAS above the minimum speed, the AIRSPEED aural
and MINSPEED message will be turned off, and the armed vertical and lateral Flight
Director modes will change back to active. The autopilot will resume tracking the
previously selected vertical and lateral references.
NON-ALTITUDE CRITICAL MODES (VS, LVL, PIT, IAS, ALTS,
VNAV)
If the aircraft decelerates to an IAS below the minimum commandable autopilot
airspeed, the vertical Flight Director mode will change from active to armed and IAS
will become the active vertical mode and flash for five seconds. MINSPEED will be
displayed on the GMC 605. The autopilot will cause the aircraft to pitch down.
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25
AFCS
GMC 605 Underspeed Indication
(Non-Altitude Critical Mode)
GI 285 Underspeed Indication
(Non-Altitude Critical Mode)
The pilot must add power to increase airspeed. If the aircraft was in PIT or VS mode
prior to entering Underspeed Protection and full power has already been applied,
the pilot can move the NOSE UP/DN wheel in the DN direction to reduce the pitch
attitude or vertical speed reference.
When airspeed increases to 5 KIAS above the minimum speed, the MINSPEED
message will be removed and the armed vertical Flight Director mode will change back
to active. The autopilot will resume tracking the previously selected vertical reference.
NOTE: When the AFCS is outside normal operating limits, it uses more
aggressive commands to return to normal limits.
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Garmin GFC 600 Pilot’s Guide
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AFCS
2.3 VERTICAL MODES
VERTICAL MODE CONTROLS AND ANNUNCIATIONS
The table below lists the vertical modes with their corresponding controls and
annunciations. The mode reference is displayed next to the active mode annunciation
on the GMC 605 for Altitude Hold, Vertical Speed, and Indicated Airspeed modes.
The NOSE UP/DN wheel can be used to change the vertical mode reference while
operating in Pitch Hold, Vertical Speed, Indicated Airspeed, or Altitude Hold modes.
Increments of change and acceptable ranges of values for each of these references
using the NOSE UP/DN wheel are also listed in the table.
Vertical
Mode
Description
Reference
Control Annunciation Change
Increment
Holds the current
aircraft pitch
attitude; may be
Pitch Hold
(default)
used to climb/
descend to the
Selected Altitude
Commands a pitch
attitude necessary to
establish a vertical
Level Mode speed of 0 fpm and
also commands
wings level (zero
bank angle)
Commands a
constant nose-up
GA
Go Around pitch attitude and
Button
also commands
zero bank angle
Altitude
Holds the current
ALT
Hold
Altitude
190-01488-00 Rev. B
PIT
0.5°
Ref
Range
Varies by
aircraft
type, see
AFMS
LVL
Varies by
aircraft
type, see
AFMS
GA
nnnnn ft
Garmin GFC 600 Pilot’s Guide
10 ft
± 150 ft
27
AFCS
Vertical
Mode
Selected
Altitude
Capture
Description
Reference
Control Annunciation Change
Increment
Captures the
Selected Altitude
Maintains the current
aircraft vertical
Vertical
speed; may be used
Speed
to climb/descend to
the Selected Altitude
Maintains the current
Indicated
aircraft airspeed;
Airspeed
may be used to
(IAS)
climb/descend to the
Selected Altitude
Captures and
tracks the SBAS
Glidepath
GPS glidepath
on approach
Captures and tracks
Glideslope the ILS glideslope
on approach
*
Ref
Range
ALTS
VS
IAS
nnnn fpm
nnn kt
100 fpm
Varies by
aircraft
type, see
AFMS
1 kt
Varies by
aircraft
type, see
AFMS
GP
GS
* When the GFC 600 is receiving a Selected Altitude value from a Garmin PFD, ALTS is armed
automatically when PIT, VS, IAS, or GA modes are active.
Autopilot Vertical Mode Summary
PITCH HOLD MODE (PIT)
When the autopilot or Flight Director is activated (AP or FD key is pressed), Pitch
Hold mode is selected by default. This mode may be used for climb or descent to
the Selected Altitude, since Selected Altitude Capture mode (with Garmin PFD) is
automatically armed when Pitch Hold mode is activated.
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AFCS
In Pitch Hold mode, the AFCS maintains a constant pitch attitude. The pitch
reference is set to the aircraft pitch attitude at the moment of mode selection, and
can be adjusted by using the NOSE UP/DN wheel. The wheel adjusts pitch attitude
in increments of 0.5 deg per click within the range defined in the AFMS. The pitch
reference can also be adjusted by pressing the CWS button, hand-flying the aircraft
to establish a new pitch reference, and then releasing the CWS button. If the aircraft
pitch attitude exceeds the autopilot pitch command limitations, the Flight Director
commands a pitch angle equal to the nose-up/down limit.
GMC 605 AND GI 285 ANNUNCIATIONS
Both the GMC 605 and GI 285 show the ‘PIT’ annunciation in their active vertical
mode sections. If the Selected Altitude Capture mode is available, the GMC 605 also
shows the ‘ALTS’ annunciation in the armed vertical mode section.
GMC 605 Annunciating Pitch Mode
GI 285 Annunciating Pitch Mode
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Garmin GFC 600 Pilot’s Guide
29
AFCS
LEVEL MODE (LVL)
Level mode is a coupled pitch and roll mode and is annunciated as both the vertical
and lateral modes when active. Pressing the LVL key engages the autopilot (if the
autopilot is disengaged) in level vertical and lateral modes. Level mode does not track
altitude or heading but instead uses a vertical reference of zero feet per minute and a
lateral reference of zero bank angle. When the LVL key is pressed all armed and active
modes are cancelled and the AFCS reverts to LVL mode for pitch and roll. While in level
mode, all other modes are available by pressing the corresponding button.
NOTE: The Level Mode may be helpful if the aircraft encounters strong
turbulence making it impractical to maintain normal references such as
Altitude Hold.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘LVL’ in both the vertical and lateral sections.
GMC 605 Annunciating Level Mode
GI 285 Annunciating Level Mode
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AFCS
GO AROUND MODE (GA)
Go Around mode is a coupled pitch and roll mode and is annunciated as both the
vertical and lateral modes when active. The GA button installed in the cockpit is used
to activate Go Around mode.
Go Around mode can also be activated while the aircraft is on the ground and used
to establish an attitude reference to follow immediately after takeoff.
WARNING: When GA mode is activated for takeoff the autopilot should
not be engaged until the aircraft has reached the Minimum Use Height
(MUH) specified in the Airplane Flight Manual Supplement (AFMS).
Pressing the GA button while in the air allows the execution of a missed approach
or a go around without disconnecting the autopilot (i.e. Coupled Go Around). Go
Around mode arms Selected Altitude Capture mode automatically, and any attempts
to modify the aircraft attitude (i.e., with the CWS button or the NOSE UP/DN wheel)
result in reversion to Pitch and Roll Hold modes.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘GA’ in both vertical and lateral sections. If
the Selected Altitude Capture mode is available, the GMC 605 also shows the ‘ALTS’
annunciation in the armed vertical mode section.
GMC 605 Annunciating Go Around Mode
GI 285 Annunciating Go Around Mode
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31
AFCS
ALTITUDE HOLD MODE (ALT)
Altitude Hold mode can be activated by pressing the ALT key; the AFCS maintains
the current aircraft altitude (to the nearest 10 feet) as the Altitude Reference.
With Garmin PFD:
Altitude Hold mode is automatically armed when in Selected Altitude Capture mode.
Selected Altitude Capture mode automatically transitions to Altitude Hold mode when
within 50 feet of the Selected Altitude. In this case, the Selected Altitude becomes
the Altitude Reference. The Altitude Reference is displayed on the GMC and the
autopilot will automatically compensate for small altitude changes introduced when
the altimeter setting is updated on the PFD.
When operating in Altitude Hold mode, the displayed altitude reference can be
adjusted by using the NOSE UP/DN wheel. The reference altitude can only be moved
a maximum of 150 ft from the current aircraft altitude; each click changes the reference
altitude by 10 ft. The altitude hold reference can also be adjusted by pressing the CWS
button, hand-flying the aircraft to a different altitude, and then releasing the CWS
button.
Without Garmin PFD:
When there is no Garmin PFD installed, the Altitude Reference is not displayed on
the GMC 605 and the autopilot cannot automatically compensate for small altitude
changes introduced when the altimeter setting is updated. The NOSE UP/DN wheel
may be used to adjust the Altitude Reference in increments of 10 ft per click up to +/150 ft from the current altitude.
When the wheel is moved the GMC will display the total adjustment the pilot has
selected. For example, clicking the wheel four times in the NOSE UP direction will
result in a display of ALT +40 FT. Three seconds after the last click, the adjustment
value will disappear and only ALT will be displayed. The autopilot will begin tracking
the new reference (in the example it would climb 40 feet). If the wheel is moved again
before the aircraft has reached the new reference altitude, the Altitude Reference will
synch to the current aircraft altitude and calculate a new adjustment from that altitude.
The altitude hold reference can also be adjusted by pressing the CWS button, handflying the aircraft to a different altitude, and then releasing the CWS button.
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AFCS
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and the GI 285 annunciate ‘ALT’ for Altitude Hold mode. If a Garmin
PFD is installed, the GMC also shows the reference altitude in the mode reference
section.
GMC 605 Annunciating Alt Hold Mode
GI 285 Annunciating Alt Hold Mode
SELECTED ALTITUDE CAPTURE MODE (ALTS)
NOTE: Selected Altitude Capture Mode is available in aircraft with a Garmin
PFD.
Selected Altitude Capture mode is a transitional mode used in conjunction with
other vertical modes. It is not directly selectable by the GMC 605 panel or other
equipment. Instead, Selected Altitude Capture (when supported by a GDU interface) is
automatically armed with activation of the following modes:
• Pitch Hold
• Indicated Airspeed
• Vertical Speed
• Go Around
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33
AFCS
The Altitude Preselect function on a Garmin PFD allows the pilot to adjust the altitude
bug to a target Selected Altitude for the AFCS to intercept, capture, and subsequently
track in Altitude Hold mode.
The GMC 605 will annunciate ‘ALTS’ as the armed vertical mode while the active
vertical mode is PIT, VS, IAS, or GA.
As the aircraft nears the Selected Altitude, the AFCS automatically transitions to
Selected Altitude Capture mode with Altitude Hold mode armed. This automatic
transition is indicated by the ‘ALTS’ annunciation flashing for up to 10 seconds and the
appearance of the ‘ALT’ annunciation. The Selected Altitude is shown as the Altitude
Reference.
At 50 feet from the Selected Altitude, the AFCS automatically transitions from
Selected Altitude Capture to Altitude Hold mode and holds the reference altitude. As
Altitude Hold mode becomes active, the ‘ALT’ annunciation moves to the active vertical
mode field and flashes for 10 seconds to indicate the automatic transition.
GMC 605 Annunciating Selected Altitude Capture Mode
Changing the Selected Altitude on the PFD while Selected Altitude Capture mode
is active causes the AFCS to revert to Pitch Hold mode with Selected Altitude Capture
mode armed for the new Selected Altitude.
VERTICAL SPEED MODE (VS)
Vertical Speed mode is selected by pressing the VS key. This mode acquires and
maintains a Vertical Speed Reference. The Vertical Speed Reference may be changed
by using the NOSE UP/DN wheel. The vertical speed reference can also be adjusted
by pressing the CWS button, hand-flying the aircraft to establish a new vertical speed,
and then releasing the CWS button. If the Selected Altitude Capture mode is available
in this aircraft, this mode may be used for climb or descent to the Selected Altitude
since Selected Altitude Capture mode is automatically armed when Vertical Speed
mode is selected.
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Garmin GFC 600 Pilot’s Guide
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AFCS
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘VS’ for Vertical Speed mode. Additionally, the
GMC 605 annunciates the Vertical Speed Reference in the mode reference section.
GMC 605 Annunciating Vertical Speed Mode
GI 285 Annunciating Vertical Speed Mode
GDU 620 ANNUNCIATIONS
The GDU 620 displays a Vertical Speed bug with a reference value (in FPM) and can
be adjusted via the controls on the GDU. When Vertical Speed mode is active, the GMC
605 also displays the Vertical Speed Reference and provides a means of adjustment
via the wheel.
The system will function as follows:
• With the Flight Director (FD) and Autopilot (AP) off, the Vertical Speed bug on the
PFD can be adjusted using the controls on the GDU.
• When the Flight Director (FD) is on (regardless of autopilot engagement status)
and Vertical Speed mode is selected on the GMC, the Vertical Speed Reference on
the GMC and the Vertical Speed bug on the PFD will sync to the current aircraft
vertical speed.
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Garmin GFC 600 Pilot’s Guide
35
AFCS
NOTE: When VS mode is selected on the GMC 605, the previous Vertical
Speed bug value on the Garmin PFD will be ignored (there is no Vertical
Speed preselect function).
• Subsequent changes to the Vertical Speed reference can be made with either the
GMC wheel or the PFD Knob and the value will remain in sync between the GMC
and PFD.
INDICATED AIRSPEED MODE (IAS)
Indicated Airspeed mode is selected by pressing the IAS key. This mode acquires and
maintains the Airspeed Reference (IAS). The Airspeed Reference is set to the current
airspeed upon mode activation. The IAS reference can be changed using the NOSE
UP/DN wheel. Moving the knob in the NOSE UP direction decreases the reference by
1 knot per click, and the NOSE DN direction increases the reference by 1 knot per click.
The airspeed reference can also be adjusted by pressing the CWS button, hand-flying
the aircraft to establish a new airspeed, and then releasing the CWS button.
Engine power must be adjusted to allow the autopilot to fly the aircraft at a pitch
attitude corresponding to the desired flight profile (climb or descent) while maintaining
the Airspeed Reference.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘IAS’ for Indicated Airspeed mode. Additionally,
the GMC 605 displays the Airspeed Reference value in the mode reference section.
GMC 605 Annunciating Indicated Airspeed Mode
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AFCS
GI 285 Annunciating Indicated Airspeed Mode
GLIDEPATH MODE (GP)
NOTE: Glidepath Mode is available in aircraft with an SBAS GPS-enabled
navigator. The GMC 605 may annunciate GP as an armed vertical mode
when the APR Key is selected even when interfaced to a GPS navigator that
is not capable of calculating a glidepath. In that case GP will never become
the active vertical mode.
Glidepath mode is used to track a glidepath generated by a GPS navigator with
WAAS or other Satellite Based Augmentation System (SBAS) capability.
Selecting Glidepath Mode:
1) EXTERNAL NAVIGATOR: Ensure a GPS approach with vertical guidance
(LPV, LNAV/VNAV, LNAV+V, LP+V) is loaded into the active flight plan. The
active waypoint must be part of the flight plan (cannot be a direct-to a
waypoint not in the flight plan).
2) Ensure that GPS is the selected navigation source.
3) GMC 605: Press the APR key. The AFCS maintains the current mode but
arms Glidepath mode.
4) Upon reaching the glidepath, the AFCS vertical mode transitions to
Glidepath Mode and begins to capture and track the glidepath.
NOTE: Some RNAV (GPS) approaches provide a vertical descent angle
as an aid in flying a stabilized approach. These approaches are NOT
considered Approaches with Vertical Guidance (APV). Approaches that are
annunciated on the HSI as LNAV or LNAV+V are considered Nonprecision
Approaches (NPA) and are flown to an MDA even though vertical glidepath
(GP) information may be provided.
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37
AFCS
WARNING: When flying an LNAV approach (with vertical descent angle)
with the autopilot coupled, the aircraft will not level off at the MDA even if
the MDA is set in the altitude preselect.
Once the following conditions have been met, the glidepath can be captured:
• GPS must be the active lateral mode.
• Vertical deviation is valid.
• The CDI is at less than full-scale deviation
• Automatic sequencing of waypoints has not been suspended (no ‘SUSP’
annunciation on the HSI)
NOTE: Pressing the CWS button while Glidepath mode is active does not
cancel the mode. Upon release of the CWS button the autopilot will guide
the aircraft back to the glidepath.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘GP’ for Glidepath mode. Since Glidepath
mode relies on GPS positioning, the ‘GPS’ lateral mode is also annunciated.
GMC 605 Annunciating Glidepath Mode
GI 285 Annunciating Glidepath Mode
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AFCS
GLIDESLOPE MODE (GS)
NOTE: Glideslope Mode is available in aircraft with a VHF Nav radio that
includes a glideslope receiver.
Glideslope mode is available for ILS approaches to capture and track the glideslope.
When Glideslope mode is armed, LOC Approach mode is armed as the lateral AFCS
mode.
Selecting Glideslope Mode:
1) EXTERNAL NAVIGATOR: Tune and activate the desired localizer frequency.
2) Ensure that LOC is the selected navigation source.
3) GMC 605: Press the APR key. This simultaneously arms LOC and GS
(Glideslope) modes.
Once the localizer has been captured (LOC is annunciated as the active lateral
mode), the glideslope can also be captured.
NOTE: Pressing the CWS button while Glideslope mode is active does not
cancel the mode. Upon release of the CWS button the autopilot will guide
the aircraft back to the glideslope.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 annunciate ‘GS’ for Glideslope mode. Since Glideslope
mode relies on LOC positioning, the ‘LOC’ lateral mode is also annunciated.
GMC 605 Annunciating Glideslope Mode
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Garmin GFC 600 Pilot’s Guide
39
AFCS
GI 285 Annunciating Glideslope Mode
2.4 LATERAL MODES
LATERAL MODE CONTROLS AND ANNUNCIATIONS
The table below lists the lateral modes with their corresponding controls and
annunciations. Refer to the Vertical modes section for a detailed description of Level
mode and Go Around mode.
Lateral Mode
Roll Hold
Level Mode
Go Around
Heading Select
40
Description
Holds the current aircraft roll
attitude or rolls the wings level,
depending on the bank angle at
the time of Roll mode activation
Commands wings level (zero bank
angle) and also commands a pitch
attitude necessary to establish a
vertical speed of 0 fpm
Commands zero bank angle and
also commands a constant noseup pitch attitude.
Captures and tracks the Selected
Heading
Garmin GFC 600 Pilot’s Guide
Control
Annunciation
(default)
ROL
LVL
GA Button
GA
HDG
190-01488-00 Rev. B
AFCS
Lateral Mode
Navigation, GPS
Navigation, VOR
Enroute Capture/
Track
Navigation, LOC
Capture/Track
(No Glideslope)
Navigation,
Backcourse
Capture/Track
Description
Control
VOR
Captures and tracks the selected
navigation source (GPS, VOR, LOC)
LOC
Captures and tracks a localizer
signal for backcourse approaches
Approach, GPS
Capture/Track
(Glidepath mode
automatically
armed)
Approach, VOR
Capture/Track
Annunciation
GPS
BC
GPS
Captures and tracks the selected
approach navigation source (GPS,
VOR, LOC)
Approach, LOC
Capture/Track
(Glideslope mode
automatically
armed)
VAPP*
LOC
The AFCS limits turn rate to 3 degrees per second (standard rate turn).
* The GMC 605 displays ‘VAPP’ for VOR Approach mode, however the GI 285 will display only
‘VOR’.
Autopilot Lateral Mode Summary
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Garmin GFC 600 Pilot’s Guide
41
AFCS
The CWS button (if equipped) does not change lateral references for Selected
Heading, Navigation, Backcourse, or Approach modes. The autopilot guides the aircraft
back to the Selected Heading/Course upon release of the CWS button.
ROLL HOLD MODE (ROL)
NOTE: If Roll Hold Mode is activated as a result of a mode reversion, the
Flight Director commands a wings level flight attitude.
When the Flight Director is activated Roll Hold mode is selected by default. The
current aircraft bank angle at the time of activation is held as the reference unless the
bank angle is greater than 20 deg or less than 6 deg as defined in the following table:
Bank Angle
< 6°
6 to 20°
>20°
Flight Director Response
Rolls wings level
Maintains current aircraft roll attitude
Limits bank to 20°
Roll Hold Mode Responses
When operating in Roll Hold mode, the roll reference can be adjusted in the following
ways:
• If the bank angle is less than 6°, the AFCS will roll the aircraft wings level.
• Hold the CWS button (if equipped), establish the desired bank angle, then release
the CWS button.
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and the GI 285 display the ROL annunciation when Roll Hold mode
is active.
GMC 605 Annunciating Roll Hold Mode
GI 285 Annunciating Roll Hold Mode
HEADING SELECT MODE (HDG)
NOTE: Heading Select Mode is available in aircraft with a Garmin PFD, an
Aspen EFD 1000 display unit, a compatible Horizontal Situation Indicator,
or a compatible Directional Gyro.
Heading Select mode is activated by pressing the HDG key. Heading Select mode
acquires and maintains the Selected Heading. Turn the HDG Knob on the HSI or DG to
set the Selected Heading.
When using a Garmin PFD, turns are commanded in the same direction as Selected
Heading Bug movement, even if the Bug is turned more than 180˚ from the present
heading (e.g., a 270˚ turn to the right). However, Selected Heading changes of more
than 330˚ at a time result in turn reversals.
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Garmin GFC 600 Pilot’s Guide
43
AFCS
For non-Garmin HSI or Directional Gyro interfaces, the turn is commanded in the
shortest direction toward the bug.
NOTE: For installations using a non-Garmin HSI or DG, rapid changes in
Selected Heading where the bug crosses the current aircraft heading or 180
deg to the current heading may result in the autopilot not turning in the
expected direction.
Holding the CWS button (if equipped) and hand-flying the aircraft does not change
the Selected Heading. The autopilot guides the aircraft back to the Selected Heading
upon release of the CWS button.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and the GI 285 display the HDG annunciation when Heading Select
mode is active.
GMC 605 Annunciating Heading Mode
GI 285 Annunciating Heading Mode
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
NAVIGATION MODES (GPS, VOR, LOC)
NOTE: Availability of Navigation Modes depends on the installed navigation
equipment capabilities and interfaces.
NOTE: The selected navigation receiver must have a valid VOR or LOC
signal or active GPS course for the Flight Director to enter Navigation Mode.
Pressing the NAV key selects Navigation mode. Navigation mode acquires and
tracks the selected navigation source (GPS, VOR, LOC) as provided by a GPS navigator
or VHF Nav radio.
When GPS is the selected navigation source the Flight Director will follow GPS Roll
Steering commands when available. Some older GPS navigators do not provide Roll
Steering commands to the AFCS in which case the Flight Director creates steering
commands using course and deviation inputs.
When the navigation source is VOR or LOC, the Flight Director creates roll steering
commands from the Selected Course and deviation. Navigation mode can also be used
to fly non-precision GPS and LOC approaches where vertical guidance is not required.
If the Course Deviation Indicator (CDI) shows greater than half scale when the NAV
key is pressed, the selected mode is armed.
GMC 605 Annunciating GPS Navigation Mode Armed
If the CDI is less than half scale, Navigation mode is automatically captured.
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
45
AFCS
When the AFCS is interfaced to a Directional Gyro (as opposed to an HSI), Navigation
mode cannot be armed. The pilot must align the aircraft to be on course with the CDI
displaying less than half scale of deviation and then press the NAV key to force capture
in Navigation mode. The GMC 605 will display a message ‘SET HDG=CRS’ while any
Navigation mode is active.
NOTE: When the AFCS is interfaced to a DG, set the Selected Heading on
the DG to the same value as the Selected Course when a Navigation Mode
is active.
Some navigators that combine both GPS and VHF Nav functions are capable of
automatically switching the CDI source from GPS to VOR/LOC when programmed to
transition from a GPS flight plan to a Localizer approach. The AFCS does not support
automatic transition from a Navigation mode to an Approach mode and will revert to
ROL mode if it senses that the navigation source has changed.
CAUTION: Navigators or PFDs with automatic CDI source switching
capability should be configured with automatic switching disabled.
If Navigation mode is active and any of the following occur, the AFCS reverts to Roll
Hold mode (wings rolled level):
• Different VHF Nav frequency tuned while in VOR or LOC Navigation mode (note
that in some installations Navigation mode may remain engaged if there is still
valid deviation after the frequency changes from VOR to VOR, or from LOC to LOC)
• Navigation source switched (e.g. GPS to VOR/LOC, or VOR to LOC)
Pressing the CWS button and hand-flying the aircraft does not change the selected
course while in Navigation mode. Upon release of the CWS button the autopilot will
guide the aircraft back to the selected course (or GPS flight plan).
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 will annunciate the appropriate lateral mode as GPS, VOR,
or LOC depending on the selected navigation source when the NAV key was pressed.
GMC 605 Annunciating Various NAV Modes
GI 285 Annunciating Various Nav Modes
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Garmin GFC 600 Pilot’s Guide
47
AFCS
APPROACH MODES (GPS, VOR, LOC)
NOTE: Availability of Approach Modes depends on the installed navigation
equipment capabilities and interfaces.
NOTE: The selected navigation receiver must have a valid VOR or LOC
signal or active GPS course for the Flight Director to enter Approach Mode.
Approach mode is selected by pressing the APR key. Approach mode acquires
and tracks the selected navigation source (GPS, VOR, or LOC), depending on
approach loaded in the navigator. This mode uses the selected navigation receiver
deviation and desired course inputs to fly the approach. Pressing the APR key
when the CDI deflection is greater than half scale arms the selected approach mode.
GMC 605 Annunciating GPS Approach Mode Armed
If the CDI deflection is less than half scale, the approach is automatically captured
when the APR key is pressed
When the AFCS is interfaced to a Directional Gyro (as opposed to an HSI), Approach
mode cannot be armed. The pilot must align the aircraft to be on course with the CDI
displaying less than half scale of deviation and then press the APR key to force capture
in Approach mode. The GMC 605 will display a message ‘SET HDG=CRS’ while any
Approach mode is active.
NOTE: When the AFCS is interfaced to a DG, set the Selected Heading on
the DG to the same value as the Selected Course when an Approach mode
is active.
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
Some navigators that combine both GPS and VHF Nav functions are capable of
automatically switching the CDI source from GPS to VOR/LOC when programmed to
transition from a GPS flight plan to an ILS approach. The AFCS does not support
automatic transition from a Navigation mode to an Approach mode and will revert to
ROL mode if it senses that the navigation source has changed.
CAUTION: Navigators or PFDs with automatic CDI source switching
capability should be configured with automatic switching disabled.
When GPS Approach mode is armed, Glidepath mode is also armed.
Selecting GPS Approach Mode:
1) EXTERNAL NAVIGATOR: Ensure a GPS approach is loaded into the active
flight plan. The active waypoint must be part of the flight plan (cannot be a
direct-to a waypoint not in the flight plan).
2) EXTERNAL NAVIGATOR: Ensure that GPS is the selected navigation source.
3) GMC 605: Press the APR key.
VOR Approach mode (VAPP) provides greater sensitivity for signal tracking than VOR
Navigation mode.
Selecting VOR Approach Mode:
1) EXTERNAL NAVIGATOR: Ensure a valid VOR frequency is tuned
2) EXTERNAL NAVIGATOR: Ensure that VOR is the selected navigation source.
3) GMC 605: Press the APR key.
LOC Approach mode allows the autopilot to fly an ILS approach with a glideslope.
When LOC Approach mode is armed, Glideslope mode is also armed automatically.
LOC captures are inhibited if the difference between aircraft heading and localizer
course exceeds 105°.
Selecting LOC Approach Mode:
1) EXTERNAL NAVIGATOR: Ensure a valid localizer frequency is tuned.
2) EXTERNAL NAVIGATOR: Ensure that LOC is the selected navigation source.
3) GMC 605: Press the APR key.
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Garmin GFC 600 Pilot’s Guide
49
AFCS
If Approach mode is active and any of the following occur, the AFCS reverts to Roll
Hold mode (wings rolled level):
• Different VHF Nav frequency tuned while in VOR or LOC Approach mode (note
that in some installations Approach mode may remain engaged if there is still
valid deviation after the frequency changes from VOR to VOR, or from LOC to LOC)
• Navigation source switched (e.g. GPS to VOR/LOC, or VOR to LOC)
Pressing the CWS button and hand-flying the aircraft does not change the selected
course while in Approach mode. Upon release of the CWS button the autopilot will
guide the aircraft back to the selected course (or GPS flight plan).
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 will annunciate VOR Approach mode as VAPP, LOC Approach mode as
LOC and GS, and GPS Approach mode as GPS and GP. The annunciation displayed is
based on the selected navigation source when the APR key is pressed.
The GI 285 provides the same annunciations as the GMC 605 with the exception of
VOR Approach mode which is annunciated VOR instead of VAPP.
GMC 605 Annunciating Various Approach Modes
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
GI 285 Annunciating Various Approach Modes
FLYING A DME ARC WITH A GPS NAVIGATOR
The AFCS will intercept and track a DME arc that is part of the active flight plan
provided that GPS Navigation mode is engaged, GPS is the active navigation source
on the CDI, and the DME arc segment is the active flight plan leg. It is important to
note that automatic navigation of DME arcs is based on GPS. If the final approach
segment will be flown as a VOR or Localizer approach the pilot must manually change
the navigation source from GPS to VOR/LOC when the arc segment is completed. The
Flight Director will revert to ROL mode and the pilot must press the APR key to capture
and track the VOR or Localizer approach.
If the pilot decides to intercept the arc at a location other than the published IAF
(i.e. ATC provides vectors to intercept the arc) and subsequently selects Heading mode
or Roll mode, the AFCS will not automatically intercept or track the arc unless the pilot
activates the arc leg of the flight plan and arms GPS Navigation mode. If at any point
while established on the DME arc the pilot deselects GPS Navigation mode, the AFCS
will no longer track the arc.
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Garmin GFC 600 Pilot’s Guide
51
AFCS
BACKCOURSE MODE (BC)
Pressing the BC key selects Backcourse mode. Backcourse mode captures and tracks
a localizer signal in the backcourse direction.
NOTE: When making a backcourse approach, set the Selected Course to the
localizer front course.
The Flight Director creates roll steering commands from the Selected Course and
deviation when in Backcourse mode. If the Course Deviation Indicator (CDI) shows
greater than half scale when the BC key is pressed, the mode is armed. If the CDI is
less than half scale, Backcourse mode is automatically captured.
NOTE: When the AFCS is interfaced to a DG, Backcourse mode cannot be
armed. Set the Selected Heading on the DG to the same value as the Selected
Course when Backcourse mode is active.
GMC 605 AND GI 285 ANNUNCIATIONS
The GMC 605 and GI 285 will annunciate ‘BC’ for Backcourse mode.
GMC 605 Annunciating Backcourse Mode
GI 285 Annunciating Backcourse Mode
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
2.5 ELECTRONIC STABILITY & PROTECTION (ESP™)
WARNING: Do not assume ESP will provide stability protection in all
circumstances. There are in-flight situations that can exceed the capabilities
of ESP technology.
Electronic Stability and Protection (ESP) feature is intended to monitor the aircraft
and provide control input feedback when necessary to discourage operating the aircraft
at potentially unsafe attitudes and/or airspeeds. This feature will only function when
the aircraft is above 200 feet AGL and the autopilot is not engaged.
CAUTION: In aircraft that do not have a Garmin PFD or a GTN 6XX/7XX
series navigator with a valid terrain database, Low Speed ESP is not
supported and all other ESP modes are functional at any altitude.
ESP engages automatically when the aircraft approaches or exceeds one or more
predetermined airspeed or attitude limitations. Stability protection for each flight
axis is provided by the autopilot servos, which apply force to the appropriate control
surface(s) to discourage pilot control inputs that would cause the aircraft to exceed
the normal or “protected” flight envelope. This is perceived by the pilot as resistance
to control movement in the undesired direction when the aircraft approaches a steep
attitude, and/or the airspeed is below the minimum or above the maximum configured
airspeed.
As the aircraft deviates further from the normal attitude and/or airspeed, the
force increases proportionally (up to an established maximum) to encourage control
movement in the direction necessary to return to the normal attitude and/or airspeed
range.
When ESP has been engaged for more than ten seconds (cumulative; not necessarily
consecutive seconds) of a 20-second interval, the autopilot will automatically engage
with the Flight Director in Level mode, bringing the aircraft into level flight. An aural
“Engaging Autopilot” alert is played and the Flight Director mode annunciation will
indicate ‘LVL’ for vertical and lateral modes.
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
53
AFCS
The pilot can interrupt ESP by pressing and holding the AP DISC / TRIM INT button.
If the AP DISC / TRIM INT button is held down for 5 seconds or more, ESP will be
disabled. ESP will be re-enabled when either of the AP or FD keys are selected on or
power is cycled on the GMC 605. ESP is always enabled by default on system powerup. If ESP has been disabled the GMC 605 will display the message ESP OFF and the
Roll Limit Indicators will be removed from the Garmin PFD (if installed).
The servo torque limit is configured such that when ESP is active the pilot can always
overpower the servo and hand-fly the aircraft.
ROLL ENGAGEMENT
NOTE: This section describes ESP indications displayed on a Garmin PFD. If
a Garmin PFD is not installed, the AFCS will still provide the same Roll ESP
function but without any displayed indications or annunciations.
Roll Limit Indicators are displayed on the roll scale of a Garmin PFD at 45 deg to
indicate where ESP will engage. As roll attitude exceeds the limit, ESP will engage and
the Roll Limit Indicator will move in to 30 deg to indicate where ESP will disengage as
roll attitude decreases.
AP
YD
BC
PIT
ALTS
141
RollGSLimit
Roll2400
Limit
Indicator ESP
170
Engage
(45°)
Indicator ESP
Engage
2500(45°)
160
240040
2 320
2300
00
80
2200
150 7
14 6
140 5
130
ESP Roll Engagement Indication (ESP NOT Engaged)
120
2100
123°
TAS 149 175°
KNOTS HDG
LOC2
21
Garmin GFC 600 Pilot’s Guide
30
33
7°c
W
OAT
24
N
3
6
S
HDG
54
30.19IN
15
NO GP
E
12
2
1
02
1
2
190-01488-00 Rev. B
AFCS
ESP Engage (45°) Aircraft
Roll Attitude = 44°
AP
BC
GS
YD
BC
141
GS
ESP Disengage (30°) Aircraft
Roll Attitude = 46°
PIT
ALTS
141 2400
AP
YD
PIT
ALTS
240
170
170
2500
2500
160
160
2400
24004
2 320
2300
8
2200
40
150 7
2 320
14 6 2300
00
140 5
80
150 7
14 6
140 5
130
2200
130
Before ESP Engage
After ESP Engage
Engagement
2100
120 to ESP2100
° Roll Increasing
°
123
123
°
°
175 IN
TAS 149 175
TAS 149 30.19
30.19IN
Once
engaged,
ESP
force
will
be
applied
between
HDG
12
12 of 30°
KNOTS
KNOTS HDG 2 bank angles
15
15 and 75°. The
2
force increases Eas roll attitude increases and decreases asE roll attitude decreases. The
applied force is intended to encourage pilot input1that returns the airplane to a more
1
LOC2
LOC2
normal roll attitude.
As roll attitude decreases, ESP will
disengage
at
30°.
02
0
120
6
3
6
3
N
N
33
PFD
30
7°c 2
0
W
OAT
Minimum
ESP Torque
(30º)
CDI
Configured
Bank Limit
(45º)
1-2
Maximum
ESP Torque
(60º)
W
30
33
ESP Roll Operating Range When Engaged
(Force Increases as Roll Increases & Decreases as Roll Decreases)
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
55
NO GP
1-2
1
24
24
CDI
Maximum
ESP Torque
(60º)
HDG
Bank Limit
(45º)
21
21
OAT Configured
7°c
S
NO GP
S
HDG
Minimum
ESP Torque
(30º)
1
2
0
PFD
AFCS
ESP™ is automatically disengaged if the aircraft reaches the autopilot roll engagement
attitude limit of 75°.
BC
GS
ESP Upper Disengage Limit (75°)
Aircraft Roll Attitude = 74°
AP
YD
PIT
ALTS
2400
141
170
2500
160
240040
2 320
2300
00
80
2200
150 7
14 6
140 5
130Roll Attitude Autopilot Engagement Limit (ESP Engaged)
2100
120
123°
°
175
PITCH ENGAGEMENT
TAS 149
30.19IN
6
3
21
NO GP
S
12 15
KNOTS HDG
2 Thresholds
ESP pitch engagement thresholdsE are configured
for each airframe type.
are established for both nose-up and nose-down attitudes. Most aircraft1 are configured
such that the torque applied by ESP LOC2
increases to its maximum value when pitch attitude
0 2The opposing
has exceeded the configured nose-up or nose-down pitch limits by 5º.
force increases or decreases depending on the pitch angle and the direction of pitch
1
travel. This force is intended to encourage movement in the pitch axis in the direction
OATattitude
7°c range for the aircraft. As the pitch attitude
2 moves back
of the normal pitch
0
toward the normal envelope the ESP force ramps down to zero and disengages when
1-2 pitchPFD
pitch is 5º less than the configured nose-upCDI
and nose-down
limits.
N
24
W
30
33
HDG
ESP will disengage if the aircraft exceeds the ESP engagement limits of 50 degrees
nose-up or nose-down.
There are no indications marking the pitch ESP™ engage and disengage limits in
these nose-up/nose-down conditions.
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
AFCS
ESP Pitch Operating Range When Engaged
(Force Increases as Pitch Increases & Decreases as Pitch Decreases)
NOTE: The Pitch ESP operating range may vary for each airframe type. The
specific values depicted in the figure above are only to illustrate the Pitch
ESP function. Reference the AFMS for the Pitch ESP limits for a specific
aircraft.
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Garmin GFC 600 Pilot’s Guide
57
AFCS
AIRSPEED PROTECTION
CAUTION: Low Speed ESP mode is available only in aircraft with a Garmin
PFD or a GTN 6XX/7XX series navigator with a valid terrain database.
LOW SPEED PROTECTION
When the stall warning system determines a stall condition is imminent, ESP will
engage and apply a force in the nose down direction. After stall warning becomes
inactive, the force will smoothly be reduced to zero and ESP will disengage.
Low Speed Protection is inhibited when the aircraft is below 200’ above ground
level. If the AFCS is not receiving height above ground information from an external
source, Low Speed Protection is not available.
HIGH AIRSPEED PROTECTION
Exceeding the airspeed limit (configured for each airframe type and usually set below
Vne) will result in ESP™ applying force to raise the nose of the aircraft. When the high
airspeed condition is remedied, ESP™ force is no longer applied.
Reference the AFMS for the High Airspeed ESP limits for a specific aircraft.
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Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
Annunciations & Alerts
SECTION 3 ANNUNCIATIONS & ALERTS
3.1 VISUAL ANNUNCIATIONS AND ALERTS
The GFC 600 provides visual annunciations and alerts to notify the pilot of system
status, failures, degraded operation, and conditions requiring specific pilot action. The
table below summarizes the messages that may appear on the GMC 605’s display
along with any associated LED illumination, GI 285 indications, and a brief description.
Refer to other parts of this Pilot’s Guide for more information about the functions and
modes associated with the annunciations and alerts.
NOTE: A Garmin PFD (when installed with GFC 600) will provide similar
annunciations and alerts to those listed below. Refer to the G500/G600 Pilot’s
Guide for a description of the PFD indications related to AFCS.
GMC 605
Message
GMC
605
LED
GI 285
Indication
PFT
PFT FAIL
AP FAIL
YD FAIL
P TRIM FAIL
ELE TRM UP
ELE TRM
DN
190-01488-00 Rev. B
Description
Preflight Test is in progress
•
•
•
•
•
•
AP
Preflight Test has failed
AP
Autopilot has failed
YD
TRIM
TRIM
TRIM
Yaw Damper has failed (on some aircraft
annunciation may be red)
Pitch Trim has failed. Autopilot may remain
engaged, but after disengagement it cannot be
re-engaged until problem is resolved.
Mistrim condition requiring Nose Up Elevator
trim
Mistrim condition requiring Nose Down
Elevator trim
Garmin GFC 600 Pilot’s Guide
59
Annunciations & Alerts
GMC 605
Message
AIL TRM LF
AIL TRM RT
RUD TRM LF
RUD TRM
RT
GMC
605
LED
•
•
•
•
GI 285
Indication
Description
TRIM
Mistrim condition requiring Roll trim to the Left
TRIM
TRIM
TRIM
Mistrim condition requiring Roll trim to the
Right
Mistrim condition requiring Rudder trim to the
Left
Mistrim condition requiring Rudder trim to the
Right
MAXSPEED
Overspeed Protection is active
MINSPEED
Underspeed Protection is active
AIRDAT
FAIL
ESP OFF
ESP FAIL
CWS ON
SET
HDG=CRS
DISABLD
KEY
AP KEY STK
60
•
AP
Air Data inputs to the GMC 605 have failed.
Functions dependent on air data (IAS, VS,
and ALT modes; Overspeed & Underspeed
Protection; and High Speed ESP) may not be
supported and AFCS performance may be
degraded.
Electronic Stability & Protection (ESP) has been
turned Off
Electronic Stability & Protection (ESP) function
has failed
Control Wheel Steering is active (the GMC
605's AP LED flashes green continuously
during CWS)
Pilot action required to set the Selected
Heading on the DG to the same value as the
Selected Course pointer on the CDI. Message
displayed continuously when NAV or APR
modes are active in a DG-equipped aircraft.
The GMC 605 key selected by the user is
disabled because the associated function is not
supported in a particular installation
The AP key on the GMC 605 is stuck in the
active state
Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
Annunciations & Alerts
GMC 605
Message
FD KEY STK
YD KEY STK
HDG KEY
STK
NAV KEY
STK
APR KEY
STK
BC KEY STK
VNV KEY
STK
IAS KEY STK
VS KEY STK
ALT KEY
STK
LVL KEY STK
GMC
605
LED
GI 285
Indication
Description
The FD key on the GMC 605 is stuck in the
active state
The YD key on the GMC 605 is stuck in the
active state
The HDG key on the GMC 605 is stuck in the
active state
The NAV key on the GMC 605 is stuck in the
active state
The APR key on the GMC 605 is stuck in the
active state
The BC key on the GMC 605 is stuck in the
active state
The VNV key on the GMC 605 is stuck in the
active state
The IAS key on the GMC 605 is stuck in the
active state
The VS key on the GMC 605 is stuck in the
active state
The ALT key on the GMC 605 is stuck in the
active state
The LVL key on the GMC 605 is stuck in the
active state
Visual Annunciations and Alerts
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Garmin GFC 600 Pilot’s Guide
61
Annunciations & Alerts
3.2 AURAL ALERTS
The GFC 600 outputs aural annunciations and alerts to provide enhanced awareness
to the pilot of several key AFCS conditions.
VOICE ALERTS
Voice alerts are played through the aircraft audio panel and are heard through the
headset and/or cockpit speaker depending on installation and audio panel selections.
The alerts cannot be muted. The voice alerts include:
• AIRSPEED - The AIRSPEED aural announces a low indicated airspeed condition and is
played in conjunction with the Underspeed Protection function.
• ENGAGING AUTOPILOT - When ESP has been active for 50% of a 20-second time
period, the autopilot engages automatically in Level Mode and the ENGAGING AUTOPILOT aural is played.
AUTOPILOT DISCONNECT ALERT
Autopilot disengagement is accompanied by an aural ‘bee-boop’ alert tone which
is played through the audio panel and also through a separate Sonalert device (when
installed). The Sonalert is a small speaker that plays a tone heard in the cockpit above
the ambient noise.
Manual autopilot disengagement plays the alert two times. After it is played once
the pilot may elect to press the AP DISC / TRIM INT button again to silence the alert.
Abnormal (automatic) disengagement results in the alert being played continuously
until silenced by the AP DISC / TRIM INT button.
The alert is also played at the end of Preflight Test to notify the pilot that PFT is
complete. The alert is played regardless of whether PFT passes or fails.
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Garmin GFC 600 Pilot’s Guide
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Abnormal Operation
SECTION 4 ABNORMAL OPERATION
4.1 SUSPECTED AUTOPILOT MALFUNCTION
If an autopilot failure or trim failure is suspected to have occurred, perform the
following steps:
1)
Firmly grasp the control wheel.
2)
Press and hold the AP DISC / TRIM INT button. The autopilot will
disconnect and power is removed from the trim motor. Power is also
removed from all primary servo motors and engaged solenoids. Note the
visual and aural alerting indicating autopilot disconnect.
3)
Retrim the aircraft as needed. Substantial trim adjustment may be needed.
4)
Pull the appropriate circuit breaker(s) to remove electrical power from the
GMC 605 and servos. The GMC 605 display may remain active for up to 10
seconds after power in removed.
5)
Release the AP DISC / TRIM INT button.
4.2 OVERPOWERING AUTOPILOT SERVOS
In the context of this discussion, “overpowering” refers to any pressure or force
applied to the controls when the autopilot is engaged. In an emergency the pilot can
forcibly overpower the servos and move the controls throughout their full range of
motion without disengaging the autopilot, however even a small amount of pressure
or force applied by the pilot in the pitch axis may cause the automatic trim to run.
If the action is prolonged this will result in an out-of-trim condition and significant
control forces upon autopilot disengagement. Therefore, any application of pressure
or force to the controls should be avoided when the autopilot is engaged.
NOTE: It is acceptable to engage the autopilot on the ground and overpower
the servos to verify proper operation and experience the forces required to
move the controls while backdriving the servo motors.
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
63
64
Garmin GFC 600 Pilot’s Guide
Low Speed Protection
Pitch/Roll
Engagement
High Speed Protection
Autotrim
Overspeed
Protection
Underspeed
Protection
Manual Electric Trim
Flight Director
Command Bar
Display
Control Wheel
Steering
Yaw Damper
OR
•
HSI
DG
•6
•
•7 OR •7
Electronic Stability and Protection (ESP) Features
•6
•6
•1
•
Basic Autopilot Features
Basic
WAAS
Aspen
GMC
Garmin
GPS
EFD
605
PFD
Nav
1000
Function
VHF
Nav
Radio
•2
•3, 4
•4
Add’l GSA
87 Servo
Appendix A
APPENDICES
APPENDIX A: FEATURE/EQUIPMENT MATRIX
190-01488-00 Rev. B
Appendix A
1.
2.
3.
4.
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
Glideslope
Glidepath
•6
Indicated Airspeed
Selected Altitude
Capture
•6
Vertical Speed
•
Pitch Hold
•6
•5
Go Around
Altitude Hold
•
Level Hold
•
•6
Vertical Autopilot Modes
6
Basic
WAAS
Aspen
GMC
Garmin
GPS
EFD
605
PFD
Nav
1000
Function
HSI
•9
VHF
DG Nav
Radio
Add’l GSA
87 Servo
5.
6.
7.
8.
9.
Also requires external CWS button.
Requires an additional Garmin GSA 87 servo installed on yaw axis.
Also requires external MET button.
Requires an additional Garmin GSA 87 servo to perform the Manual Electric Trim and
Autotrim functions.
Also requires external GA button.
Requires valid air data input to the GMC 605 via an Air Data Module or Air Data Computer.
Requires a Garmin GTN or PFD with a valid Terrain Database.
WAAS and Roll Steering not required for basic lateral GPS guidance.
Requires VHF Nav Radio that includes a glideslope receiver.
65
66
Garmin GFC 600 Pilot’s Guide
OR • OR •
OR • OR •
• OR •
• OR •
LOC Approach
•
VOR Approach
GPS Approach
OR • OR •
• OR •
BC Navigation
• OR •
OR • OR •
OR
• OR •
•
LOC Navigation
OR
OR • OR •
•8
•
DG
• OR •
•
HSI
VOR Navigation
GPS Navigation
Heading
Roll Hold
Lateral Autopilot Modes
Basic
WAAS
Aspen
GMC
Garmin
GPS
EFD
605
PFD
Nav
1000
Function
•
•
•
•
•
VHF
Nav
Radio
Add’l GSA
87 Servo
Appendix A
190-01488-00 Rev. B
Index
A
AFCS. See Automatic Flight Control
System
AIRSPEED aural 24
Airspeed Protection 58
Alerts 59
ALT 32
Altitude-Critical Modes 24
Altitude Hold Mode 32
Altitude Reference 34
ALT Key 9
ALTS 33
Annunciations 59. See also Vertical
Modes or Lateral Modes
AP. See Autopilot
AP DISC/TRIM INT 10
AP Key 9
Approach Mode 48
APR Key 10
Aspen EFD1000 6
Audio Panel 8
Aural Alerts 62
Automatic Flight Control System 15
Operation 15
Pre-Flight 15
Autopilot 1
Disengaging 17
Engaging 16
Features 17
Autotrim 22
Control Wheel Steering 19
Manual Electric Trim 22
Manual Trim 21
Overspeed Protection 23
Underspeed Protection 24
Yaw Damper 20
Flight Director 17
Malfunction 63
190-01488-00 Rev. B
Autopilot Disconnect Alert 62
Autotrim 22
B
Backcourse Mode 52
BC. See Backcourse Mode
BC Key 10
C
Command Bars 18
Control Wheel Steering 19
Control Wheel Steering (CWS) 19
CWS switch 10
D
DG. See Directional Gyros
Dimmer knob 11
Directional Gyros 7
DME Arc 51
E
Electronic Stability & Protection 2
Airspeed Protection 58
Disable ESP 54
High Airspeed Protection 58
Low Speed Protection 58
Pitch Engagement 56
Roll Engagement 54
ESP. See Electronic Stability & Protection
F
FD. See Flight Director
FD Key 9
Flight Director 1, 17
Activating 18
Command Bars 18
Limitations 19
Garmin GFC 600 Pilot’s Guide
Index-1
Index
I
Modes 16
Modes, vertical 17–31
G
G500/G600 5
GA 31
GA button 10
GA Mode 24
GI 285 4
Indications 12
Glidepath Mode 37, 49
Glideslope Mode 39
GMA 345 8
GMC 605 2, 9
Indications 11
Go Around 31
GP 37
GP Mode 24
GPS. See Navigation Modes or Approach
Modes
GPS Navigators 6
GS 39
GSA 87 Servo 4
GS Mode 24
GTX 335/345(R) 8
H
HDG. See Heading Select Mode
HDG Key 9
Heading Select Mode 43
High Airspeed Protection 58
Horizontal Situation Indicators 7
HSI. See Horizontal Situation Indicators
Index-2
IAS 36
IAS Key 10
Indicated Airspeed Mode 36
L
Lateral Modes 40
Approach, GPS 41
Approach, LOC 41
Approach Modes (GPS and LOC) 48
Approach, VOR 41
Backcourse Mode 52
Go Around 40
Heading Select Mode 43
Level Mode 40
Navigation, Backcourse 41
Navigation Modes (GPS, VOR, LOC)
45
Roll Hold Mode 42
LCD Display 9
Level Mode 30
Line Replaceable Unit (LRU) 1, 2, 5
LOC. See Navigation Modes or Approach
Modes
Low Speed Protection 58
LVL 30
LVL Key 9
M
Manual Electric Trim 2, 22
Manual Trim 21
MAXSPEED annunciation 23, 60
MET. See Manual Electric Trim
MET switch 10
MINSPEED annunciation 24
Garmin GFC 600 Pilot’s Guide
190-01488-00 Rev. B
Index
N
U
Navigation Modes (GPS, VOR, LOC) 45
NAV Key 9
Non-Altitude Critical Modes 25
ALTS 25
IAS 25
LVL 25
PIT 25
VNAV 25
VS 25
NOSE UP/DN Wheel 10
Underspeed Protection 24, 25
O
Overpowering Autopilot Servos 63
Overspeed Protection 23
P
PFD
Annunciations 59, 63
PFD AFCS Indications 13
PIT 28
Pitch Engagement 56
Pitch Hold Mode 28, 30
V
Vertical Modes 27
Altitude Hold 27
Glidepath 28
Glideslope 28
Go Around 27
Indicated Airspeed 28
Level Mode 27
Pitch Hold 27
Selected Altitude Capture 28
Vertical Speed 28
Vertical Speed Mode 33, 34
VHF Nav Radios 7
VNV Key 10
VOICE ALERTS 62
VOR. See Navigation Modes or
Approach Modes
VS 34
VS Key 10
Y
R
Yaw Damper 1, 20
YD. See Yaw Damper
YD Key 9
ROL. See Roll Hold Mode
Roll Engagement 54
Roll Hold Mode 42
S
Selected Altitude 28, 33
Selected Altitude Capture Mode 28,
31, 33
Selected Heading 43
System
Controls 9
190-01488-00 Rev. B
Garmin GFC 600 Pilot’s Guide
Index-3
Garmin International, Inc.
1200 East 151st Street
Olathe, Kansas, 66062, U.S.A.
Garmin AT Inc.
2345 Turner Road SE
Salem, OR 97302, U.S.A.
Garmin (Europe) Ltd.
Liberty House, Hounsdown Business Park
Southampton, Hampshire SO40 9LR U.K.
Garmin Corporation
No. 68, Zhangshu 2nd Road
Xizhi District, New Taipei City, Taiwan
Contact Garmin Product Support at www.flygarmin.com.
For warranty information refer to
https://fly.garmin.com/fly-garmin/support/warranty-information/
© 2017 Garmin Ltd. or its subsidiaries
190-01488-00 Rev. B
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