Gulfstream G150 Technical specifications

Section VII
Systems
VII-22-1
AUTOPILOT SYSTEM
DESCRIPTION
The Flight Control system is an integrated 3-axis autopilot and flight
director, containing automatic elevator trim control. The system is
configured for dual flight directors and is certified for ILS Category 2
operations.
The system consists of the following:
Two FGC-3000 Flight Guidance Computer Module (2)
One FGP-3000 Flight Guidance Panel (1)
SVO-85C Primary Servo (2)
SMT-86C Servo Mount (2)
SVO-85B Primary Servo (1)
SMT-86B Servo Mount (1)
FGS MODES
Flight Guidance Mode Selection
The primary means of selecting and deselecting flight guidance modes
is by pressing the appropriate button on the FGP. pressing an FGP
button when the mode is not selected will select the mode. A
subsequent press of the FGP button deselects the mode. The FGS
defaults to the basic lateral and vertical flight guidance modes when no
modes are selected by the FGP.
10 Sep 2006

Section VII
Systems
VII-22-2
LATERAL MODES
Roll Hold Mode (Basic Roll)
The basic lateral mode of the FGS is roll hold. Roll hold consists of two
submodes - roll and heading hold. If the roll attitude of the aircraft is
less than 5° at mode activation, the system generates commands to
maintain the existing aircraft heading (wings level). If the roll attitude is
between 5° and 30° at mode activation, the system generates
commands to hold the aircraft's existing roll angle. If the roll attitude is
greater than 30° at mode activation, the system generates commands
to hold the roll angle at 30°.
Heading Select Mode (HDG)
When in heading select mode, the system generates commands to
capture and maintain the selected heading shown on the PFD and/or
MFD. The selected heading is set by the HDG knob on the FGP.
Heading mode is selected by pressing the HDG switch on the FGP.
Modes Activated by Control Functions
Roll Hold (Basic) - - - - Heading Hold, Roll Hold
Heading Select HDG Heading Select, Lateral
Navigation NAV FMS, Localizer, VOR
Approach APPR FMS, Localizer, VOR
Back Course B/C Localizer Go Around
Go Around GA (Control Wheel) Heading Hold
Half Bank 1/2 BANK Bank Command limited
to 12.5°
10 Sep 2006

Section VII
Systems
VII-22-3
Navigation Mode (NAV)
Navigation mode is selected by pressing the NAV button on the FGP.
When in navigation mode, the system generates commands to capture
and track the selected lateral navigation course (FMS, Localizer, and
VOR).
Approach Mode (Lateral)
Approach mode is selected by pressing the APPR button on the FGP.
When in lateral approach mode, the system generates commands to
capture and track the final approach course (FMS, localizer, and VOR).
Back Course Mode
Back course mode is selected by pressing the B/C button on the FGP
when a localizer is tuned. When in back course mode, the system
generates commands to capture and track the back course approach
(localizer).
Go Around Mode (Lateral)
Go around mode is selected by pressing the GA button. When in
lateral go around mode, the system generates commands in the lateral
axis to hold the heading existing when the GA button is pressed.
Activation of go around mode automatically disconnects the autopilot.
Half Bank
Half Bank is selected by pressing the ½ BANK button. Half Bank is
automatically selected when climbing through the half bank transition
altitude (30,000 ft). Half Bank reduces the maximum commanded roll
angle to 12.5°.
10 Sep 2006

Section VII
Systems
VII-22-4
VERTICAL MODES
Pitch Hold Mode (Basic Pitch)
The basic vertical mode of the system is pitch hold mode. When in
pitch hold mode, the system generates commands to hold the pitch
angle of the aircraft that exists when the mode is selected. When in
pitch hold mode, the VS/pitch wheel (down/up) is used to change the
pitch reference.
(Continued)
Modes Activated by Control Functions
Pitch Hold
(Basic) - - - - Pitch Hold
Altitude Hold ALT Altitude Hold (Pressure
Altitude)
AltitudePreselect - - - - Altitude Preselect (Baro
Altitude)
Vertical Speed VS Vertical Speed (fpm)
Flight Level
Change FLC IAS, Mach
Approach APPR FMS, Glideslope
Vertical
Navigation VNAV FMS
Go Around GA (control wheel) Go Around
Overspeed - - - - IAS, Mach
10 Sep 2006

Section VII
Systems
VII-22-5
Altitude Hold Mode (ALT)
Altitude hold mode is selected by pressing the ALT button on the FGP.
Additionally, altitude hold mode is automatically selected after altitude
capture has occurred and the aircraft has stabilized at the preselected
altitude. When in altitude hold mode, the system generates commands
to capture and maintain the pressure altitude that exists when the
mode is selected.
Preselect Altitude Mode
There is no manual selection of preselect altitude (PSA) mode, it is
armed continuously except in altitude hold, vertical approach
capture/track states. When in preselect altitude mode, the system
generates commands to capture the preselected (barometric) altitude.
Vertical Speed Mode (VS)
Vertical speed mode is selected by pressing the VS switch on the FGP
except in vertical approach capture/track and flight level change
overspeed modes. When in vertical speed mode, the system
generates commands to maintain the vertical speed that exists when
the mode is selected. In vertical speed mode, the VS/Pitch wheel is
used to slew the vertical speed reference.
Flight Level Change Mode (FLC)
Flight level change mode is selected by pressing the FLC button on the
FGP except when in vertical approach capture/track mode. Reference
airspeed is synchronized to the aircraft's current speed (IAS/Mach)
upon mode selection. The pilot controls the reference airspeed by
using the SPEED knob. When FLC mode is selected, a climb or
descend submode command is entered based on the difference
between the aircraft present altitude and the preselected altitude. If the
preselected altitude is higher than the current altitude, climb submode
is entered and visa versa. In either submode, a vertical speed floor is
implemented, forcing the aircraft toward the selected altitude if the
selected speed reference is inadequate.
10 Sep 2006

Section VII
Systems
VII-22-6
Approach Mode (Vertical)
Approach mode is selected by pressing the APPR button on the FGP.
The approach mode arms when selected and the system generates
commands to capture and track vertical guidance for precision
approaches (glideslope or GPS when approved) when the lateral
approach mode is in the track state and the vertical capture
requirements are met.
Vertical Navigation (VNAV)
The vertical navigation function enables the FMS to command various
FGS vertical modes and provide references for these modes. VNAV is
armed by pressing the VNAV button on the FGP except in ILS/MLS
vertical approach capture/track or when FLC overspeed mode is
active. Selection of VNAV does not automatically change the active
guidance mode. When VNAV is armed, the FMS can automatically
select the FGS vertical mode if required. The FGS generates
commands to follow the pitch command signal from the FMS when
coupled VNAV guidance is active in PATH and VGP modes. The pilot
can manually change any of the FCS mode selections made by the
FMS. Pilot action suspends the current FMS VNAV control of the FGS,
but does not preclude automatic reassertion of control by the FMS.
Go Around Mode (Vertical)
Go around mode is selected by pressing the GA button on control
wheel. When in vertical go around mode, the system generates a fixed
9° pitch up command.
Overspeed Mode
Overspeed mode is automatically selected when an overspeed occurs,
unless altitude hold mode or preselect altitude capture or track states
are active. When in overspeed mode, the system generates
commands to reduce the airspeed at 0.865 - 0.87 Mi. Airspeed bug
moves to 0.84 Mi.The system remains in overspeed mode until
changed by the pilot or an automatic mode change occurs.
10 Sep 2006

Section VII
Systems
VII-22-7
Malfunction Protection
The flight control system uses a multi-layered response to failures
which may occurs within the system and data from external sensors.
Malfunction protection and response are provided by a dual channel
main processor (Level II verified) and I/O processor (Level I verified)
architecture. The main processor provides protection against flight
guidance data failures and single channel attitude control failures. The
I/O processor provides additional limiters and monitors including
protection from possible generic software design errors in the main
processor program.
10 Sep 2006

Section VII
Systems
VII-22-8
Flight Guidance Data Failures
When there is a failure detected in any sensor data used in the flight
guidance computations, the system internally reverts to the basic mode
for the affected axis, pitch attitude hold for vertical modes and roll
attitude hold for lateral modes. If the failure condition remains for a
period of time, typically four seconds, the flight director display
removes the steering command and annunciate the failure by placing a
red line through the active mode annunciation. The flight director
returns to normal operation if the data returns to a valid condition or
another operational mode is selected.
Response to flight guidance data is provided by pitch and roll attitude
and attitude rate limiters. These limiters limit the aircraft response to
those approaching normal maneuvering; 5 °/second of roll rate in the
lateral axis, and 0.2g in the vertical axis.
Aircraft response to failures which result in main processor servo
commands exceeding the maximum rate limit are limited by the I/O
processor cutout function and servo torque limiting. If the aircraft
exceeds predetermined attitudes, attitude rates, or accelerations, the
I/O processor will zero the command going to the servo control loop.
The servo drives the control surface toward the position it was in prior
to the malfunction. The cutout switch is activated only if the command
is in the opposite direction to arrest the malfunction.
In addition to the cutout function, servo torque is limited through direct
electronic limiting of servo motor current. By limiting the maximum rate
of change of the control surface, torque limiting limits the aircraft
response prior to cutout operation.
10 Sep 2006

Section VII
Systems
VII-22-9
Servo Control Failures
The dual channel analog servo control architecture provides fully fail
passive response to failures occurring within the servo control function.
The pilot's flight director commands are computed in one FGC-3000
module and the copilot's flight director commands are computed in the
other module. Using the CPL button on the FGP, the pilot selects which
flight director steering commands are displayed on both PFD’s with two
exceptions. In approach or go-around modes, left flight director
commands are displayed on the left PFD and right flight director
commands are displayed on the right PFD. The autopilot, if engaged,
is always coupled to the selected flight director. The selected flight
director commands are sent to the attitude loops in both computers
where identical computations are performed using redundant sensor
data for command limiting and feedback. The resulting servo
commands in each computer are fed to the analog servo loop where
they are voted before being applied to the servo.
10 Sep 2006

Section VII
Systems
VII-22-10
AUTOPILOT CONTROLS
The FGP-3000 flight guidance panel (Figure 7-22-1, page VII-22-15) is
a single unit that controls two independent flight guidance systems
using the following controls:
CRS knob (2) - Provides control of the pilot and copilot selected
courses. The knobs are continuously turning with no
mechanical or electrical stops. An integral button in center
of the knob provides a direct-to function.
ALT knob - Controls the altitude preselect display on the PFD. The
knob is continuously rotating with electrical stops at -1000
ft and 50,000 ft. Normally each “click” of this switch
changes the preselected altitude by 1000 foot increments.
The switch has a second position that is achieved by
pulling the knob away from the panel. The increment size
is changed to 100 ft per click. In either position, the full
range (-1000 to 50,000) is available. Movement of the
switch automatically arms altitude select, except when in
approach mode.
HDG knob/selector - Consists of a lower two-position selector, an
upper continuously turning knob, and an integral center
button. The selector sets the reference for pilot selected
angles - track or heading (track is only available when an
IRS is installed). The knob is used to select the desired
angle. The button provides a “sync” to current angle
function.
(Continued)
10 Sep 2006

Section VII
Systems
VII-22-11
Vertical Speed/Pitch Wheel - Has two separate functions. If vertical
speed mode is active, this wheel is used to change the
vertical speed reference proportionally to the rotation
angle. If vertical speed mode is not active, movement of
this wheel deselects any vertical mode that may be active
(except glideslope capture) and selects pitch mode. In
pitch mode, rotation of the wheel changes the pitch
reference proportionally to the rotation angle.
YD/AP DISC disconnect bar - Provides a positive means of
disconnecting the autopilot and yaw damper by directly
removing power from the servos. Once the autopilot and
yaw damper are disconnected using this means, the bar
must be restored to its normal position before
reengagement is possible.
FD button (2) - Selects and removes the steering commands on the
PFD. At power up, the steering commands are displayed
on the PFD. Steering commands are selected on both
PFD's by engaging the autopilot, selection of go around
mode, automatic selection of overspeed mode, or by
manual selection of a vertical or lateral mode, when
steering commands are not displayed on either PFD and
the autopilot is not engaged. Coupling to a flight director
selects the steering commands on the coupled side, if
steering commands are displayed on either side, or if the
autopilot is engaged.
AP button - Engages or disengages the autopilot. Note that there is
also an AP disconnect switch mounted on each pilot
control wheel. Engagement of the autopilot automatically
engages the yaw damper.
Activating the pitch trim switch on either pilot or copilot
control wheels disconnects the autopilot and leaves the
yaw damper operational.
(Continued)
10 Sep 2006

Section VII
Systems
VII-22-12
YD button - Engages or disengages the yaw damper. Manual
engagement/disengagement of the yaw damper is
completely independent of autopilot engagement.
CPL button - Controls the routing of flight guidance commands to the
autopilot and flight directors. The coupled side is indicated
by illumination of the appropriate arrow on the PFD AP
display. When the left arrow is on, the autopilot uses flight
guidance commands from the pilot channel. When the
right arrow is on, the autopilot uses guidance commands
from the copilot channel. Except when in ILS approach
submode or go-around modes, the CPL pushbutton
controls which flight guidance commands drive the flight
director command bars. In approach and go-around
modes, the flight directors operate independently.
The following buttons are momentary buttons used to select/deselect
modes. Unless the active mode is approach, selection of a lateral or
vertical mode respectively, automatically deselects any other lateral or
vertical mode. Unless the active mode is go-around, a second press
deselects the mode. Go-around is cleared by autopilot engagement or
selection of another mode:
HDG button - Automatically selects and clears either heading select
mode or track select mode, based upon the setting of the
HDG select knob. When in heading select mode, or track
select mode, changing the position of the HDG select
knob clears one mode and selects the other.
(Continued)
10 Sep 2006

Section VII
Systems
VII-22-13
1/2 BANK button - Allows the pilot to override the FCS automatic
transitions to/from half bank mode. Half bank limits the
maximum command bank angle to 12.5°. Half bank is
indicated by a white 1/2 BNK annunciation on the PFD.
Selection of half bank is inhibited when lateral go around
is active by onside localizer/azimuth capture/track, or by
onside FMS navigation capture/track.
NAV button - Selects/deselects the navigation mode. In NAV mode the
autopilot uses the active navigation source selected on
the display control panel (DCP).
APPR button - Selects/deselects approach mode.
B/C button - Selects/deselects back course mode. There is no
automatic selection of back course mode.
ALT button - Selects/deselects altitude hold mode.
VNAV button - Selects/deselects vertical navigation mode. In VNAV
mode, the autopilot follows pitch commands generated by
the FMS.
(Continued)
10 Sep 2006

Section VII
Systems
VII-22-14
FLC button - Selects/deselects flight level change mode. In FLC mode,
desired airspeed is synchronized to the aircraft's current
speed at the time of mode selection. This speed can then
be slewed up/down using the SPEED knob; turning the
knob increases or decreased speed setting in FLC mode.
Pressing the knob switches alternately between IAS and
Mach for display of airspeed on PFD. Automatic
changeover from IAS to Mach occurs at 35,000 ft in climb
and from Mach to IAS at 29,270 ft in descent. When FLC
mode is selected, a climb or descent submode is entered
automatically based on the difference between the aircraft
present altitude and the preselected altitude. If the
preselected altitude is higher than the current altitude, the
climb submode is entered. If the preselected altitude is
lower than the current altitude, the descend submode is
entered. In either case, a minimum vertical speed is
implemented, which forces the aircraft toward the
selected altitude with a certain minimum vertical speed.
VS button - Selects/deselects vertical speed mode.
There are two additional autopilot switches external to the panel. A
momentary button on the control wheel serves as the primary means to
disconnect the autopilot. Momentary button on the control wheel
engages the go-around mode.
Yaw damper remains engaged unless landing gear is down or with
flaps 40°
Caution Messages
A/P NOSE DOWN / UP - Excessive autopilot pitch trim
A/P NOSE LEFT / RIGHT - Excessive trim forces in the yaw axis
A/P PITCH TRIM FAIL - Autopilot pitch trim failure
A/P WING DOWN (L/R) - Excessive trim forces in the roll axis
MACH TRIM FAIL - Autopilot Mach trim failure
10 Sep 2006

Section VII
Systems
VII-22-15
Figure 7-22-1. FGP-3000 Flight Control Panel
10 Sep 2006

Section VII
Systems
VII-22-16
Figure 7-22-2. Autopilot Controls
10 Sep 2006