Flight Controls Flashcards
Flight Controls
Which surfaces provide roll control ?
- 2 Ailerons
- 2 Flaperons
- 14 Spoilers
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Where are the flaperons located ?
Between the inboard and outboard flaps on both wings.
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Do the Ailerons and Spoilers droop with the trailing edge flaps to improve slow speed performance ?
Yes, they do.
Just like the Flaperons.
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Are the Ailerons ever locked in flight ?
YES, during high speed flight.
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At approximately which ground speed does the rudder become aerodynamically effective during take off ?
60 kts
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What is the flight control system powered by ?
- The Hydraulic system,
- The Electrical system
- The RAT
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What are individual flight surfaces controlled by ?
Individual flight surfaces are controlled by 4 Actuator Control Electronics (ACEs).
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How many Actuator Control Electronics (ACEs) are there ?
4
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What is the purpose of the 4 Actuator Control Electronics (ACEs) ?
They control individual flight surfaces.
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Can pitch and roll still be controlled in the event of the loss of ALL hydraulic power ?
YES, through the electrically actuated stabilizer and 2 spoiler pairs:
• Pitch control ➔ primary and alternate pitch trim switches
• Roll control ➔ control wheel
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Can pitch and roll still be controlled in the event of the complete loss of flight control signaling ?
YES, through direct wiring from the flight deck to the stabilizer and one spoiler pair.
• Pitch control ➔ alternate pitch trim switches
• Roll control ➔ control wheel
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Can flight control surfaces be LOCKED ?
YES, through 2 flight control lock switches on the overhead panel.
TAIL and WINGS.
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What does the FAIL light indicate on the flight control surfaces lock panel ?
A lock switch is in the lock position and one or more of the associated surfaces does not lock.
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Can flight control surfaces be locked in flight through the lock switches on the overhead panel ?
NO, flight control surfaces automatically unlock when ground speed > 40 kts.
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What happens if a jam occurs in the column, wheel or rudder pedals on one side ?
The pilots can maintain control by applying force to the other column, wheel or rudder pedals to overcome the jam.
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How many modes does the Primary Flight Control system have ?
3
- Normal
- Secondary
- Direct
All three modes use the same pilot controls and flight control surfaces.
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When are flight controls tested ?
1- After landing a 1st series of flight control self-tests are run when :
• Flaps and Speedbrakes are retracted,
• Ground speed is < 30 kts,
• Hydraulic power is on.
2- An additional series of flight control self-tests are run when:
• First series of tests are complete,
• All hydraulic systems are depressurized.
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What happens during each series of the flight control self-tests ?
- Various EICAS alert and status messages display
- the trim indication blinks
- various failures display on the flight controls synoptic page
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What happens if the flight control self-tests are not accomplished on two consecutive flights ?
A fault condition may be set.
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After landing, what are the conditions to be met for the first series of flight control self-tests to start ?
- Flaps and Speedbrakes are retracted,
- Ground speed < 30 kts,
- Hydraulic power is on.
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What are the conditions to be met for the second series of flight control self-tests to start ?
- The first series of tests are complete,
* All hydraulic systems are depressurized.
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Approximately how long does the first series of flight control self-tests take ?
90 seconds
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Approximately how long does the second series of flight control self-tests take ?
70 seconds
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When do the PFCs (Primary Flight Computers) automatically revert to secondary mode ?
- When Inertial or Air Data is insufficient to support normal mode or,
- When all Flap and Slat position data is unavailable.
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Can the secondary flight control mode be manually selected ?
NO
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What functions are lost in SECONDARY mode ?
- autopilot
- gust suppression
- auto speedbrakes
- envelope protection
- pitch compensation
- roll/yaw asymmetry compensation
- tail strike protection
(same as direct mode)
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When do the ACEs (Actuator Control Electronics ) automatically revert to direct mode ?
- they detect the failure of all three PFCs
- or they lose communication with the PFCs
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What functions are lost in DIRECT mode ?
- autopilot
- gust suppression
- auto speedbrakes
- envelope protection
- pitch compensation
- roll/yaw asymmetry compensation
- tail strike protection
(same as secondary mode)
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What is the main difference between secondary mode and direct mode ?
In secondary mode, the PFCs send simplified signals to the ACEs to be sent to the flight control surfaces.
In direct mode, the ACEs directly send signals to the flight control surfaces.
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Which automatic pitch compensation are lost in secondary and direct modes ?
- flap and speedbrake configuration changes
- gear configuration changes
- thrust changes
- turns to 30° bank angle
- turbulence
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How is the stabilizer moved ?
Using an electric control unit powered by the L2 and R2 AC buses
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When is the stabilizer position indication removed from EICAS ?
- gear up for 10 seconds
- or 60 seconds after liftoff
(Same as rudder indication)
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After landing, when is the stabilizer position indication automatically displayed on the EICAS ?
- any pair of pitch trim switches are used (primary or alternate)
- or ground speed is less than 40 kts
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Take off trim range :
What is the default green band range ?
A default green band is displayed from 4 to 9 units prior to performance data being entered into the FMC.
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On the ground, what provides actual airplane gross weight and CG information ?
2 nose gear pressure transducers.
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When is the EICAS advisory message STAB GREENBAND displayed ?
- Computed green band disagrees with pressure transducer data, or
- The two transducer values are not within the set tolerance, or
- Either transducer has failed.
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What do the stabilizer cutout switches do ?
They cut out the electric power to their respective stabilizer channels L2 or R2.
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If the stabilizer has failed or is shutdown while in normal mode, is pitch trim still available ?
YES, through the elevators.
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What does the column cutout function do ?
It is designed to stop the effects of uncommended pitch trim input from jammed or failed pitch trim switches.
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How does the column cutout function work ?
Pitch trim command from either primary or alternate trim switches is opposed by either control column for more than two seconds ➔ the column cutout function disables the specific pitch trim switch commands until the switch input indicates no trim input.
If that function remains active for more than 20 seconds :
- the flight control system reverts to direct mode
- the uncommanded input is removed by system shutdown
- The STABILIZER L2/R2 EICAS advisory is displayed.
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Is the Pitch Control cutout function ever deactivated ?
YES, on the ground to allow trimming nose down stabilizer with aft column input during a touch and go.
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Are the Primary pitch trim switches ever inhibited ?
YES : when the auto pilot is engaged.
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In normal mode, how do the Primary pitch trim switches operate on the ground ?
They move the stabilizer directly.
Alternate pitch trim switches operate the same way
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In normal mode, how do the Primary pitch trim switches operate in flight ?
They command the PFCs to change the trim reference speed.
They first move the elevators to achieve the trim change before moving to stabilizer to streamline the elevator.
(Alternate pitch trim switches operate the same way)
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In the secondary or direct modes how do the Primary pitch trim switches operate ?
They operate the same on the ground and in-flight, by directly moving the stabilizer.
(Alternate pitch trim switches operate the same way)
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Who has priority between Alternate and Primary pitch trim switches ?
Alternate pitch trim commands have priority over Primary pitch trim commands in all flight control modes.
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What does pitch envelope protection include ?
- Overspeed protection
- Stall protection
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Is tail strike protection activation apparent ?
NO, activation of tailstrike protection does not provide feedback to the control column.
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If tail strike protection is activated, will take off performance be affected ?
NO
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In normal mode, for roll control, what does a control wheel input command ?
Unlike conventional airplanes, it does not directly position the lateral surface in flight. Instead, it commands a rate of roll.
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For ROLL control, do forces change with airspeed changes ?
No, they don’t.
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In normal mode, do the rudder pedals position the rudder directly ?
No, they command a sideslip maneuver with the sideslip angle dependent on pedal displacement.
The flight control system will then position the rudder to generate the commanded maneuver.
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What automatically reduces the side-slip command, for a given pedal input, as airspeed increases ?
The rudder ratio changer.
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In secondary and direct modes, do the rudder pedals position to rudder directly ?
Yes, the rudder pedals command a proportional rudder deflection, with different response from pedal inputs when flaps are up or not.
(less response when flaps are up)
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Which flight control modes allow manual rudder trim operations ?
All three
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When is manual rudder trim inhibited ?
- With the auto pilot yaw (LAND3) engaged on approach,
* Above 30 kts during take-off roll until airborne.
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When does rudder position on EICAS normally blank ?
- Gear up for 10 seconds
- Or 60 seconds after liftoff
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In Primary (normal) mode, what hydraulic system powers the flaps and slats ?
CENTER
Positionned using the center hydraulic system motors.
They are controlled together.
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How many Spoilers are there ?
14, all symmetrically paired
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How are the Spoiler pairs powered ?
5 pairs are HYDRAULICALLY powered (1, 2, 3, 6 and 7)
2 pairs are ELECTRICALLY powered (4 and 5)
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What does the EICAS message “SPOILERS PAIRS” indicate ?
3 or more Spoiler panels failed.
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Will the Spoilers fully extend on landing even if they were NOT armed ?
Yes, they will under these conditions :
- On the ground,
- GS > 85 kts
- Either thrust lever was previously in the takeoff range before both are moved to the idle range (rejected takeoff)
OR
- On the ground,
- Both thrust reverse levers are moved to idle reverse detent.
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Do the Spoilers ever self-retract ?
YES :
- On the ground and either thrust lever is moved to the takeoff range
- On the ground and there is a transition to in the air
- In flight and either thrust lever is > 90 % full travel
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When is Autodrag used ?
To assist in glideslope/glidepath capture when the airplane is above the vertical path.
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Which surfaces are used by the Autodrag feature ?
Ailerons (upwards) and the 2 most outboard spoiler pairs.
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What are the conditions for Autodrag to function ?
- Landing configuration
- Flaps 25 or 30
- Thrust IDLE
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Can Ailerons be used in High Speed flight ?
NO, the Ailerons are locked out since the Flaperons and Spoilers provide sufficient roll control.
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In the ARMED position, when will the Spoilers extend on landing ?
- Main gear trucks un-tilt and
- Both thrust levers are not in the takeoff range.
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How is STALL protection provided?
Nose-UP TRIM is inhibited.
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What power source provides backup power for the Flight Control Electronics during temporary power interruptions ?
2 dedicated FCE batteries .
