Flight Controls Flashcards
ACEs?
Actuator Control Electronics (4)
PFCs?
Primary Flight Computers (3)
Roll control is provided by what surfaces?
Ailerons, flaperons and assymetric spoilers
Ailerons?
Outboard of the flaps
Assist with roll control only in low speed flight
Locked out during high speed flight
Droop with flaps
How many PCUs on the rudder?
3
Each is powered by a different hydraulic system
How many slats are there?
12
Control Input path for manual flight?
Pilot inputs to ACEs
ACEs sends electronic signals to PFCs
PFCs calculate inputs and send them back to ACEs
ACEs then convert back to analog and send signals to PCUs
What are the inputs to the PFCs?
Air data
Inertial data
Flap and slat position
Engine thrust
Radio altitude
Control path for auto flight?
Pilot inputs to MCP
MCP signals to PFCs
PFC signals to ACEs
ACEs mechanical signals to PCUs
Why should the flight controls not be moved after landing?
After landing with the flaps retracted and speed below 30 knots, a series of flight control self-tests are run, and take approx. 90 seconds to complete
Moving the flight controls interrupt these tests
When are flight control self-tests performed?
After landing with speed less than 30 knots and flaps retracted
After shutdown with external power connected
Hydraulics should not be shut off
Controls should not be moved
Flaps and speed brake lever should not e moved
If two consecutive flights pass without uninterrupted self-tests, error message
What causes PFCs to revert to secondary mode?
Inertial or air data is insufficient
OR
All slat and flap position data is unavailable
FLIGHT CONTROL MODE EICAS?
Primary flight control system is in secondary mode
In which flight control modes is the autopilot available?
Only normal mode
How is secondary mode different from manual normal mode?
The PFCs use simplified computations to generate the flight control commands
What functions are not available in secondary mode, (nor in direct mode, for that matter)
Autopilot Auto speed brakes Pitch compensation Gust suppression Roll / yaw asymmetry compensation Tail strike protection Envelope protection
When do the ACEs automatically transition to direct mode?
ACEs detect failure of all three PFCs or lose communication with them
How do you manually select direct mode?
Move the PRIMARY FLIGHT COMPUTERS disconnect switch to disconnect
PRI FLIGHT COMPUTERS EICAS?
Flight control system is in direct mode
Flight control input path in direct mode?
Pilot inputs received by the ACEs are sent directly to the PCUs
For turns with bank angle less than ________ degrees, no back pressure on the column is required
30 degrees
When does the stab trim indication on the EICAS blank?
Gear is up for 10 seconds
OR
60 seconds after liftoff
When does stab trim pointer, box and digital readout display in white?
When outside of the green band
The stab trim pointer, the box and digital readout are all in amber (readout indicates “x”)
Stab trim is inoperative
The pointer will remain on the scale at the last known position
What is the magenta figure above the stab trim digital readout?
The FMC calculated units of trim
What is the function of the nose gear oleo transducers?
Provide actual gross weight and CG information
Compared to FMC calculated stab green band
STAB GREENBAND EICAS
Computed green band disagrees with transducer data
The transducers disagree
Either transducer has failed
Do the alternate pitch trim switches have priority over the primary trim?
Yes
What is Overspeed Protection?
As airspeed approaches Vmo or Mmo, the pilot must apply continuous forward column pressures twice the normal force to exceed the limit
Stall trim protection?
Lowest speed to which the aircraft can be trimmed is the minimum maneuvering speed
The pilot must apply continuous aft column pressure at twice the normal rate, to maintain airspeed below minimum maneuvering speed
If A/T armed but not engaged, and speed decreases near stick shaker….?
A/T automatically activates in speed mode and advances thrust to maintain minimum maneuvering speed
AIRSPEED LOW will be displayed
When will the A/T not automatically engage in autothrottle stall protection? (3)
Pitch mode in FLCH or TOGA
Airplane below 400 ft after takeoff
Airplane below 100 ft on approach
How does tail strike protection work?
The PFCs calculate if a tail strike is imminent
Elevator deflection is then automatically decreased
Pilot can override by increasing back force
Tail strike protection is not registered by the control column
What is LAM?
Landing Attitude Modifier
Improved approach attitudes
Increases nose wheel contact margin at overspeed approaches with FLAPS 20, 25 and 30
How does LAM work?
Undrooping the flaperons and extending inboard spoilers increases pitch attitude
When is LAM available?
In normal mode during both auto flight and manual flight
What calculates feel commands?
The PFCs, based on airspeed
What is the difference in pitch command between normal mode and both secondary and direct mode?
Normal pitch mode commands a rate of pitch change
Secondary and direct mode command a proportional elevator deflection
Secondary and direct modes do not provide pitch compensation for:
Flap and speed brake configuration
Gear configuration
Thrust changes
Turns at 30 degrees of bank
Turbulence
STABILIZER L2 or STABILIZER R2
EICAS?
Uncommanded stabilizer motion sensed, and the stabilizer channel that caused the motion is shut down
STABILIZER warning message?
Both stabilizer channels automatically shut down or fail
STABILIZER CUTOUT warning message?
All power to the stabilizer switches has been removed by placing both STAB TRIM CUTOUT switches to CUTOUT
If control column force opposes pitch trim for more than two seconds?
Control cutout function will disable the trim commands until switch input indicates no trim input
If control column force opposes pitch trim input for more than 20 seconds?
STABILIZER L2/R2 EICAS
Flight controls revert to direct mode
System shutdown
What flight control modes is Control Column cutout function available in?
Normal and secondary
Describe roll control in normal flight control mode
PFCs position the ailerons, flaperons and spoilers to command a roll rate in proportion to wheel displacement
Flight control response to turbulence?
Aircraft roll response to turbulence is minimized by automatic control surface commands
Why is there no aileron trim?
Aileron trim is incorporated into the flight control laws
No pilot input required
Bank angle protection?
Reduces chance of exceeding bank angle boundaries due to:
External disturbances
System failures
Inappropriate pilot action
If 35 degrees exceeded, control wheel force rolls aircraft back to 30 degrees.
Can be overridden
What device disables bank angle protection?
The A/P DISENGAGE bar
When does bank angle indicator change to amber?
At bank angles exceeding 35 degrees
Is bank angle protection available in secondary or direct modes?
No, only in normal mode
If all hydraulic power lost, can pilot control pitch and roll?
Yes, using:
Primary pitch trim (stab)
Alternate pitch trim (stab)
Control Wheel (2 spoiler pairs)
Via direct wiring from flight deck to control surfaces
In normal mode, rudder pedals command what?
They command a sideslip maneuver depending on pedal displacement
Vertical gust suppression?
Enhances ride quality in vertical gusts and turbulence
Symmetric deflection of flaperons and elevators
Only with autopilot engaged in altitude hold or VNAV level flight
Lateral gust suppression?
Automatic application of discrete yaw commands
Manual rudder trim:
When is it zeroed?
When is it inhibited? (List 2 instances)
It is zeroes at 30 kts on takeoff
Also zeroes on landing
Further manual inputs are inhibited until airborne
Also inhibited on approach with autopilot yaw engaged (LAND3)
When is automatic rudder trim provided?
During normal flight mode
Does the automatic rudder trim displace the rudder pedals?
Yes, providing pilot awareness of the rudder commands
When does the rudder trim position blank on the EICAS?
Gear is up plus 10 seconds
OR
60 seconds after takeoff
When does EICAS RUDDER TRIM display automatically?
After landing, ground speed less than 40 kts
In the air with following EICAS messages:
PRI FLT COMPUTERS
FLIGHT CONTROL MODE
ENG SHUTDOWN
ENG FAIL
ENG THRUST
Describe rudder ratio operation
What is it based on?
The rudder ratio changer is based on flap position
When flaps are up, the rudder response to pedal deflection is less than when the flaps are extended
How many sets of spoilers are there?
There are seven sets of spoilers
Four outside of the flaperons
Three inside of the flaperons
How are the spoilers powered and controlled?
All three hydraulic systems supply five sets of spoilers
Each pair is controlled by the same ACE and hydraulic system
Two spoiler pairs (4+11 and 5+10) are individually powered by two electrical buses
SPOILERS EICAS?
Failure of one or two spoiler panels in the air
OR
Failure of one not down and locked spoiler panel on the ground
SPOILER PAIRS EICAS?
Failure of three or more spoiler panels
What is Autodrag?
Deflects the ailerons upward and raising the two most outboard spoilers, to assist in glideslope capture when above the glidepath
When is the Autodrag feature available?
Only in the landing configuration
Flaps 25 or 30
Thrust levers in idle
Only in normal mode
When is the Autodrag deflection removed?
At 500 feet AGL
PRIMARY FLIGHT CONTROLS switch to DISC?
Disconnects the PFCs and puts the flight control system in the direct mode
Putting back in AUTO may restore secondary of normal mode
PRIMARY FLIGHT COMPUTERS switch in AUTO?
Flight control system will operate in the normal mode
System faults will automatically cause the system to revert to secondary or direct mode
PRIMARY FLIGHT COMPUTERS DISC light?
PFCs are disconnected either automatically or manually, and the system is in the direct mode
What are the three modes of flap/slat operation?
Primary - hydraulic
Secondary - hydraulic or electric
Alternate - electric
Primary flap/slat mode
Flaps and slats are controlled together using center hydraulic system motors
Autogap and flap load relief available
How many flap positions on 787-8?
How many on 787-9?
Where are the gates?
7
10
Gates at 1 and 20 positions
When does the flap/slat indicator display?
When slats begin to extend
What is magenta figure on the flap/slat position indicator?
Flap lever position
When does flap lever position indication on indicator turn green?
When flaps reach commanded position
When is the flap/slat indicator removed from the EICAS?
10 seconds after flaps and slats reach the UP position
When does the secondary flap/slat mode engage?
Center hydraulic system has failed
Flap or slat primary control failure
Primary mode fails to move flaps/slats to commanded position
Control surfaces move at less than 50% rate
Uncommanded motion detected
Flap or slat disagree detected
Describe flap and slat secondary mode
Slats and flaps are controlled separately
Positioned by hydraulic or electric motors
Pilot control is through flap lever, but procedures limit flap extension to flaps 20
What failures lead to the alternate flaps switch?
All 3 flight control modes in the Flight Control Electronics (FCE)
Primary and secondary modes
FLAP lever
What features are not available in the flap and slat alternate mode?
Asymmetry and uncommanded motion protection
Slat autogap and pregap
Flaps and slat load relief
What occurs when the ALTN FLAPS ARM switch is pressed?
ALTN appears in the switch
Each flap and slat position appears on EICAS
Alternate flap control is armed
Alternate flap selector is armed
Primary and secondary operation is disabled
Asymmetry, skew and uncommanded motion is disabled
Slat autogap disabled
Flap and slat load relief not available
Flap lever is inoperative
Three-position ALTN Flaps selector to EXT?
Flaps and slats extend simultaneously
Slats are limited to middle position
Flaps are limited to flaps 20
ALTN FLAPS selector to RET?
Slat retraction is inhibited until the FLAPS are UP
When is the expanded flap indication displayed automatically?
Flap/slat control in secondary or alternate mode
Any non-normal condition is detected
What colors are the outline and fill when in secondary mode?
White
When the outline and fill colors of the flap indication are amber, what EICAS message(s) will you see?
FLAPS DRIVE
OR
SLATS DRIVE
What does the magenta indication on the flap indicator signify?
Flaps or slats are in transit to the commanded position
What does the green color on the flaps indicator signify?
The flaps and slats are in the commanded position
Flap load relief?
Only available in the primary mode
Load relief prevents extension beyond 5-25
EICAS indication indicates in-transit condition, shows actual flap position
Flap lever does not move
Slat load relief?
Available in secondary mode
(Not required in primary or alt)
If slats fully extended and airspeed > 240 knots (B787-9) or 225 knots (B787-8),
the slats will retract to the middle position
LOAD RELIEF is displayed
What is Slat Autogap?
Primary mode only
If slats in middle position and high AOA, slats are fully extended to avoid stall condition
What is slat pregap?
Available only in secondary mode
Slats automatically move to full extend when flaps not UP and airspeed is less than 240 knots (787-9) or 225 knots (787-8)
Cruise flaps?
Automated function that improves aircraft performance by symmetrically moving the flaps, ailerons, flaperons and spoilers
Changes camber of the wing
Available above 25,000 feet between Mach .54 and .87
CRUISE FLAPS SYS EICAS?
The cruise flaps system has failed with the flaps in an increased drag condition
When are skew condition and asymmetric protection provided?
In primary and secondary modes
FLAPS PRIMARY FAIL or
SLATS PRIMARY FAIL EICAS
Uncommanded motion, system placed in secondary mode
If motion persists, the system will shut down and FLAPS DRIVE or SLATS DRIVE will be displayed
FLIGHT CONTROL SURFACES FAIL light?
Any of the control surfaces failed to lock
If the flight controls are LOCKED, when will they automatically lock?
When groundspeed exceeds 40 knots
What happens when you move the flap lever in the primary mode?
Sends a signal to the ACEs
ACEs send a signal to the Flight Control Module (FCM)
The FCM sends a position command back to ACEs
The position command is relayed to the PCUs
When do the flaps fully extend (both aircraft)?
At flaps 25
What are the flap and slat inhibit parameters?
Above 260 knots and above 20,000 feet
When does the aircraft attempt to maintain zero yaw rate?
During asymmetrical reverse thrust
Takeoff in gusty conditions
Takeoff in crosswind
What is the aircraft yaw response to an engine failure?
Above 60 knots groundspeed
The flight control system will command the rudder to counteract most of the yawing moment due to engine failure
Pilot will still recognize the engine failure as not all of the yaw will be counteracted
Rudder pedals will move with system
Moving speedbrake lever to UP positions which spoilers to which positions?
1, 2, 13, 14 - 60 degrees
3, 12 - 45 degrees
4, 11 - 35 degrees
All inboard spoilers - 10 degrees
With speedbrake lever in armed position, when will the spoilers extend?
Speedbrake lever is driven to UP position when the main gear trucks untilt and both thrust levers are not in the takeoff range
When will the speed brakes extend if the lever is not in the ARMED position?
On the ground with groundspeed above 85 knots if either thrust lever was in takeoff range then subsequently both thrust levers moved to idle
On the ground and both thrust levers are moved to reverse idle
When will speedbrakes automatically retract?
On ground, either thrust lever moved to takeoff range
On ground, if transition to the air
In the air, if either thrust lever is beyond 90% travel
