Flight controls Flashcards
GVII uses fly-by-wire technology.
How does this work?
Pilot inputs are read by a computer that in
turn decides how to move control surfaces
to best achieve what the pilot wants.
How is trim accomplished?
Pitch and roll trim is accomplished by
actuating switch mounted on sidestick;
pedestal mounted PITCH TRIM switch is
also used to control pitch.
What’s the purpose of A/P DISC
switch?
It disengages autopilot and stops runaway
trim in all three axes.
What’s the function of FLT CTRL
RESET switch?
Used to reset flight control computers,
sidesticks, and control surface actuators
when directed by checklist
What effect does loss of one hydraulic
system have on flight controls?
Loss of one spoiler pair
What are control laws?
Software in FCCs that translate electrical
commands from cockpit control sensors
and aircraft motion sensors (inertial/air
data) into flight control surface commands
How many computers control the flyby-wire flight control system?
Three (3) computers: two (2) flight control
computers for normal operation and
Backup Flight Control Unit in case both
flight control computers fail.
What’s the minimum number of FCC
channels that can command all flight
control surfaces on the aircraft.
One.
What’s the purpose of Backup Flight
Control Unit (BFCU)?
It’s designed to provide what Gulfstream
calls “get home capability” if both primary
FCCs fail.
What happens once the BFCU
becomes active?
It communicates directly with EBHA
remote electronics units (REUs) on
separate backup data buses, and is active
for duration of flight.
Describe Electric Backup Hydraulic
Actuator (EBHA).
It’s a special actuator with self-contained
electric motor/pump and hydraulic
reservoir.
What type of sensor input is provided
to FCCs?
Input from IRSs, AHRS, ADSs and radio
altimeters
Describe AOA limiting feature.
In this mode, full stick input commands
maximum nose angle-of-attack of 0.95.
Which mode protects from surface
flutter and separation that would occur
greater than Vdive speed?
High speed protection
What’s the auto-retract feature?
It retracts speed brakes at high power
settings
Name the four (4) flight control
modes.
Normal, alternate, direct, and backup
When would flight control mode
change from normal to alternate?
Loss of multiple air data or inertial
sensors; may also revert to alternate mode
if FCCs lose communication with REUs
that control HS MCE.
What happens if all four (4) FCC
channels are invalid?
Flight control system reverts to direct
mode
What happens if all four (4) FCC
channels are unable to compute the
control law?
Backup Flight Control Unit (BFCU)
activates to provide “get home” capability
What term is used to describe the
amplification, attenuation, boosting,
or magnification that’s applied to
forward signal to achieve desired
aircraft response?
Gain
Normal mode has four (4) primary
operating sub modes. What are they?
On ground, In flight, AOA limiting, and
High speed protection
Describe how the flight control
system operates in alternate mode.
Pitch, roll, and rudder pedal inputs are
multiplied by set of fixed gains to
command elevator, ailerons, roll spoilers,
and rudder
How many sets of gains are associated
with degraded flight control modes?
Two: one set of generally smaller numbers
used when flap handle and gear handle are
up (and aircraft is presumed to be
traveling at higher speed – 340 kts), and a
set of generally larger numbers that are
used if flap handle or gear handle is down
(and aircraft is presumed to be traveling
slower – 250 kts).
What functions with ailerons to
improve roll response?
Mid and outboard spoiler panels extend to
a maximum of 55°
Name the two types of flight control
actuators.
Hydraulic Actuator (HA) and Electric
Backup Hydraulic Actuator (EBHA)
Describe HA operation.
It’s controlled electrically by its Remote
Electronics Unit (REU) and uses hydraulic
power to move control surface.
What’s the function of REU?
It’s averages FCC1 and FCC2 commands
and electrically controls a valve in
hydraulic manifold to control actuator
position to match FCC commands.
What additional features do EBHAs
have?
Able to operate in electric backup mode if
normal source of hydraulic pressure is lost
or operate in MCE direct control mode for
REU failure
Describe EB operation.
Within EB hydraulic manifold, an electric
motor turns a hydraulic pump that draws
fluid from self-contained reservoir: it acts
like third hydraulic system.
What does the color of HA or EBHA
status border indicate on flight control
synoptic page?
Green for active/healthy, gray for inactive,
and amber for failed
What pilot action is required for an
aileron, spoiler, or elevator surface
jam?
Both pilot and copilot side sticks remain
available to control the unrestricted
surfaces: fly normally and trim, and refer
to AFM.
Under what condition would pedestal
mounted PITCH TRIM switch have to
be used?
Backup mode: If this were to occur,
pedestal mounted PITCH TRIM switch
bypasses FCCs and controls horizontal
stabilizer directly at a constant, minimum
rate.
What’s the difference between active,
degraded active, and passive sidestick
modes?
Active mode features electronic linking
and electronic feel. In degraded active,
sidesticks remain linked but lose active
feel. In passive mode, there’s a loss of
both electronic linking and feel
What pilot action is required in the
unlikely event that rudder pedals
become mechanically jammed?
Pilots would have to use other flight
controls or differential power to control
the aircraft.
What component is responsible for
moving the stabilizer surface?
Horizontal Stab Trim Actuator (HSTA),
which is a dual electric motor
What kind of things can go wrong
with the horizontal stabilizer?
FCC loss of communication with
controlling REUs, failure of dual electric
motor, mechanical jam of jack screw, or
failure of both channels of Horizontal Stab
Motor Control Electronics (HS MCE)
What is elevator off-load feature?
Once elevator deflection exceeds preset
value for predetermined amount of time,
horizontal stabilizer and elevators move
simultaneously: horizontal stab moves to
new trim position as elevators move to
“faired” position (0 degrees relative to
horizontal stab surface). It’s controlled or
commanded from FCCs to reduce elevator
deflection.
Describe how the flaps operate.
Manually operated, electrically controlled,
hydraulically powered, and mechanically
actuated
What happens if there’s any sort of
malfunction (e.g., flap jam,
asymmetry, runaway, etc.) during flap
operation?
Flap motion is interrupted
What happens if you attempt to extend
the flaps at high rate of speed?
A load limiter device prevents the flaps
from extending
When do the spoilers function?
Six spoiler panels (three on each wing)
operate as speed brakes/air brakes and
ground spoilers; four operate as flight
spoilers (i.e., two outboard)
What is maximum spoiler deflection?
55°
What’s the maximum deflection with
full speed brake extension?
30° in-flight or 55° on ground with flap
handle not up
What indications would you get
during speed brake extension?
When moved left and aft out of forward
detent, a white Speed Brakes Extended
message displays.
How would the speed brake indications change
during level off with the speed brakes extended?
As power is increased during level off,
white Speed Brakes Extended message
changes to amber and you get the
associated two bong caution chime.
What happens if speed brakes are
extended and pilot advances the
throttles to high power setting?
Speed brakes automatically retract
although speed brake handle remains in
extended position, and amber Speed
Brakes Auto Retract message displays.
Ref: PAS
What function do ground spoilers
perform on touchdown or during
rejected takeoff?
All spoiler panels automatically deploy to
reduce lift and increase braking
effectiveness
What are the requirements for ground
spoiler deployment?
Throttles at idle and one of the following:
both main gear WOW, left WOW and
right wheel spin, right WOW and left
wheel spin, both main gear wheel spin and
radar altitude < 10 ft.
