06 Flight Controls

PFC PFC

PFC

AutoPilot

PilotL1

ACECenterACE

L2ACE

RightACE

PCUFlight

ControlSurfaces

Airspeed Angle of Attack

InertialData

FlapPosition

Envelope Protection - Bank angle protection - Overspeed protection - Stall protection

PilotFSEU

FSEU

FSDHydraulic Motor

Electric Motor

Flap/SlatSurfaces

SecondaryMode

SLATS PRIMARY FAIL Slats are operating in the secondary mode.

FLAPS PRIMARY FAIL Flaps are operating in the secondary mode.

Alternate Mode FLAP/SLAT CONTROL Flap/slat electronics units are inoperative.

Unable ControlSLATS DRIVE Slat drive mechanism has failed.( Both hydraulic and electric drive motors fail )

FLAPS DRIVE Flap drive mechanism has failed.( Both hydraulic and electric drive motors fail )

B777 - 06 Flight Controls 1/11

PFC : Primary Flight Computers Analog electrical signals ACE : Actuator Control Electronics Digital signals PCU : Power Control Unit

- Fly-By-Wire : The flight controls are actuated hydraulically but controlled electrically.- If the indicated airspeed falls below 50kts due to unreliable airspeed, the flight control system

changes to the secondary mode, which does not depend on airspeed. - The forward control column force needed to maintain overspeed reduces at high bank angle.

F S D : Flap/Slat Drivers Primary ModeFSEU : Flap/Slat Electronics Unit Secondary Mode

Alternate Mode

MODE NORMAL SECONDARY DIRECT

PITCH

- Trim reference speed,- Elevator feel , displacement ,- Autopilot ,- Envelope protection, ( stall, overspeed )- Automatic pitch compensation, ( thrust, flap, gear )- The control wheel pitch trim switches are inhibited when the autopilot is engaged.

- No trim reference speed,- Both primary & alternate pitch trim levers moves the stabilizer directly.

- Elevator feel flap position : - Flaps down : less force, - Flaps up : greater force,

Inoperative Items

- Autopilot,- Automatic pitch compensation,

( thrust change, gear configuration, turbulence, flap / speedbrake configuration, turns to 30 bank angle )

ROLL

- Wheel to rudder cross-tie : 8 , ( In-flt, Eng Fail 210kts )- Aileron lockout : , , ( , lockout )- Spoiler 5, 10, high speed Lockout, ( depending on altitude and airspeed )- Auto Speedbrakes ,- Bank angle protection ( 30 ),- Aileron trim is inhibited when the autopilot is engaged.

- Aileron control : flap , ( flap up lockout )

- Spoiler 5, 10 always lockout,

- Speedbrake 4,5,10,11 lockout,

Inoperative Items

- Auto speedbrake,

YAW

- Pedal feel force : pedal displacement , ( ),- Rudder ratio changer deflection ,- TAC ( thrust 10% ),- Yaw damping, gust suppression ,

- Yaw damping degraded,( for some failures, it may be inoperative )

- Flap up, down rudder response .- Flap up, down rudder response .

Inoperative Items Inoperative Items

Gust suppression, TAC, Gust suppression, Manual rudder trim cancel switch,TAC, Yaw damping,

Primary Flight Control System

PITCH - Elevators,- A movable horizontal stabilizer : assists the elevators in controlling pitch.

ROLL

- 2 Ailerons : The ailerons are locked out at high speeds.- 2 Flaperons : The flaperons also provide added lift by drooping when the flaps extend. ( Flaperons Droop )- 14 Spoilers ( 7 on each wing ) : - assist the ailerons and flaperons in providing roll control, - serve as speedbrakes.

- Spoilers 4 and 11 are mechanically controlled through a cable from the control wheel. These spoilers are available for roll control until the speedbrake lever is moved to near the UP position, when they function as speedbrakes only. Spoilers 5 and 10 are locked out at high speed.

YAW - A dual surface hinged rudder,


Primary Flight Control System - Non Normal

NORMAL FLIGHT CONTROLS

- Multiple control surface failures, such as partial pitch control system loss, and, or partial roll control system loss, - Pitch and roll response reduced,

- Full control is retained by the flight crew.- With the FLIGHT CONTROLS caution message active, the landing is made with less than normal landing flaps.

SECONDARY FLIGHT CONTROL MODE

- displays when the flight control mode has degraded to the secondary mode.

Degraded Functions Inoperative Functions

- Elevator Feel,

- Aileron Lockout,

- Yaw Damping,

- Rudder Ratio,

- Autopilot, - Auto Speedbrakes, - Bank angle protection, - Overspeed protection, - Stall protection,

- Thrust asymmetry compensation, - Wheel-to-rudder crosstie, - Gust suppression,

DIRECT PRI FLIGHT COMPUTERS

- displays when the flight control mode automatically reverts to direct mode.- The ACEs no longer use the PFC commands and operate the flight controls directly from pilot inputs.- The primary flight computer disc switch is normally left in its guarded AUTO position. In AUTO position, normal, secondary or direct mode is automatically selected depending on the status of the system.


PITCH CONTROL 1/2

ELEVATORS

- The left elevator actuators are powered by the left and center hydraulic systems, and controlled by the left 1 and center ACEs.

- The right elevator actuators are powered by the left and right hydraulic systems, and controlled by the left 2 and right ACEs.

AHORIZONTALSTABILIZER

Pitch Trim

- The stabilizer is powered by the center and right hydraulic systems, and controlled by all 4 ACEs.

- On the ground, the stabilizer is positioned directly with the pitch trim switches on the control wheel, or the alternate pitch trim levers on the control stand.

- There are 2 stabilizer position indicators, 1 on each side of the control stand.- The illuminated green band is computed by the FMC.- The allowable range in which the stabilizer can be placed for takeoff is based on airplane weight, CG, and takeoff thrust.

- The green band is not displayed in flight.- If the stabilizer signal is not available, or is invalid, the greenband and pointer are not displayed.- During preflight, a nose gear oleo pressure switch provides an automatic cross-check of the CG to ensure the correct greenband is selected.- If the nose gear pressure switch disagrees with the FMC computed stabilizer greenband, the advisory message, STAB GREENBAND, displays.

Stabilizer Trim in Flight- Automatic trim with the autopilot engaged,

1. Pitch trim signals change the trim reference speed in the PFCs, 2. The PFCs then send signals through he ACEs to position the elevators,

3. The stabilizer moves to the position required by the new trim reference speed, 4. Then the elevators streamline with the stabilizer.

- The control wheel pitch trim switches are inhibited when the autopilot is engaged.- With the autopilot disengaged, manual trim is only necessary when changing airspeed.- The trim reference speed changes approximately 10kts for each second the trim switches are held.

- Trimming to compensate for thrust change, or for configuration change such as flap extension, is not necessary.

- Moving the control wheel in the opposite direction will override the pitch trim switches.


PITCH CONTROL 2/2

AHORIZONTALSTABILIZER

Alternate Pitch Trim Levers

- The levers are spring-loaded to neutral and must be moved together.

- In the normal mode changes trim reference airspeed and moves the stabilizer directly, In the secondary and direct modes, moves the stabilizer directly.

- The alternate pitch trim levers move a set of cables that control the stabilizer directly in all modes.

- The stabilizer moves at a reduced rate if 1 STCM is inoperative.

- Pitch trim commands from the alternate pitch trim levers will override autopilot pitch trim command, but will not disengage the autopilots.

- The levers should not be used with the autopilots engaged.

- The alternate pitch trim levers also have priority over the pitch trim switches.

Stabilizer Cutout Switches

- These switches control hydraulic power use for stabilizer positioning.

- If you have one switch in cutout and the other in NORM, only 1 stabilizer trim control module operates.


PITCH CONTROL - Non Normal

STABILIZER C ( R )

- displays if the respective stabilizer trim control module is inoperative,- due to auto shutdown signal, or

- respective switch in CUTOUT.

- With 1 stabilizer trim control module operational, pitch trim is still available at a reducedrate through the pitch trim switches and alternate pitch trim levers.

STABILIZER CUTOUT

- Both switches in CUTOUT,

- In normal mode with both switches in CUTOUT, pitch trim is still available. Pitch triminputs through the PFCs position the elevator to trim the airplane.

STABILIZER

- The warning message, STABILIZER, displays if uncommanded stabilizer motion is detected, or if the stabilizer is inoperative.

- Move both stabilizer cutout sw itches to CUTOUT. The STABILIZER warning message is replaced by the STABILIZER CUTOUT advisory message.

- To preserve elevator authority, do not exceed the airspeed at which the STABILIZER message occurred.

- The landing will be made with less than normal landing flaps.


ROLL CONTROL 1/2Ailerons and Flaperons

- The flaperons assists in roll control in high and low speed flight. The ailerons assist in roll control only during low speed flight. During high speed flight, the ailerons are locked in neutral.

- The flaperons droop to increase lift when flaps are extended to positions greater than 1. There is no flight deck indication for flaperon droop.

- Each aileron and flaperon is operated by 2 hydraulic systems, and 2 ACEs. Note that all 3 hydraulic systems power the ailerons and flaperons. If a single hydraulic system is lost, the ailerons and flaperons are still operational.

Spoilers

- When augmenting roll control, the spoilers work asymmetrically, and spoilers 5 and 10 are only available during low speed operations. Spoiler panels 5 and 10 are locked out during cruise, depending on altitude and airspeed.

- Spoiler 4 and 11 are also mechanically controlled through a cable from the control wheel. This insure operation of these 2 spoiler panels as long as the left hydraulic system is operational.

- When used as speed brakes, the spoilers work symmetrically in pairs. To achieve symmetrical speedbrake operation, each symmetrical spoiler pair is controlled by the same ACE, and operated by the same hydraulic system. If a hydraulic system or ACE is inoperative, the associated spoiler pair is inoperative.

- In the normal mode, when used as speedbrakes, spoilers 5 and 10 are available as ground speedbrakes only. In the secondary and direct modes, spoilers 4, 5, 10, and 11 are locked out.

- Autom atic speedbrakes are not available in the secondary and direct m odes.

- There is no lim itation for extension of speedbrakes in a landing configuration.


ROLL CONTROL 2/2Auto Speedbrake Operation

Takeoff - If the speedbrake lever is not in the DOWN detent when the thrust levers are advanced for takeoff, the speedbrake lever is automatically driven forward to the DOWN position.

Rejected Takeoff- If the pilot fails to extend the speedbrakes during a rejected takeoff, pulling either reverse thrust lever to the reverse idle detent automatically moves the speedbrake lever to the UP position, extending the spoilers.

Landing

- During approach with the speedbrake lever in the ARMED position, the lever automatically moves to full UP when the wheels touch the ground and both forward thrust levers are in idle.

- If the speedbrake lever is not ARMED upon landing, selecting reverse thrust moves the lever to full UP.

Auto speedbrakes are not available in secondary and direct modes.Spoiler 5 and 10 are not available in flight as speedbrakes.

Roll Protection Feature

Bank AngleProtection

- Bank angle protection aids in preventing excessively high bank angles during turn.

- Bank angle protection is complemented by the bank pointer on the PFD changing color to amber at bank angles exceeding 35 degrees.

- The aural " Bank Angle " also sounds as the bank angle passes 35, 40, and 45 degrees.

- If a 35 degree bank is exceeded, bank angle protection will create wheel forces to roll the airplane back within 30 degrees of bank. This roll command can be overridden by the pilot through the control wheel.

- Bank angle protection functions in both manual and autopilot operation.

ROLL CONTROL - Non Normal

SPOILERS- displays when 1 or more spoiler pairs fail to operate as signaled.- The message is for crew awareness. Spoiler capability for roll and speed control is reduced.- Auto speedbrakes remain operative, but the speedbrakes are less effective.

AUTOSPEEDBRAKE

- indicates a fault is detected in the automatic speedbrake system.- Do not arm the speedbrake lever, as arming may cause inadvertent speedbrake extension.- After landing, extend speedbrakes manually.

SPEEDBRAKEEXTENDED

- Landing flaps selected with speedbrakes extended.- Below 800ft RA w ith speedbrakes extended.- Speedbrakes extended and thrust levers not in idle.


YAW CONTROL- Yaw control is provided by the rudder pedals, the rudder trim system, the rudder ratio system, and the yaw dampers.

- There are 3 power control units, PCUs, which operate the rudder. Each PCU is powered by 1 of the 3 hydraulic systems, and controlled by right, center, and left 1 ACEs.

- There are no separate yaw dampers on the 777.

- In flight, the PFCs send command signals to the ACEs and to the PCUs for dutch roll damping and turn coordination.

- In secondary mode, yaw damping is available if inertial data is available.

- Yaw damping is not available in direct mode.

- The 777 has no separate rudder ratio unit. The PFCs calculate the amount of rudder deflection required based on airspeed.

- At low airspeeds, the rudder has full deflection. As airspeed increases, the PFCs gradually reduce rudder deflection. This assures structural protection for the rudder.

- In secondary and direct modes, rudder response defaults to 2 fixed rates. Flap position determines rudder response. With flaps up rudder response is less than with flaps down, - Flaps up : less rudder response,

- Flaps down : more rudder response.

- MANUAL TRIM CANCEL Switch : cancels manual rudder trim in the normal and secondary flight control system modes. The switch has no effect on rudder trim inputs from TAC.

Gust Suppression- Gust suppression increases passenger comfort.

- When a side gust hits the vertical tail, the gust suppression transducers send signals to the ACEs. The ACEs send this data to the PFCs to adjust PCU commands to dampen the force of the side gust.

Thrust Asymmetry Compensation ( TAC )- Thrust Asymmetric Compensation, or TAC, assists the pilot in maintaining directional control after an engine failure. TAC also assists the plot when thrust levers are split.

- TAC is armed above 70kts, and is operational during manual and autopilot flight.

- TAC is not operational during reverse thrust operations.

Wheel-to-Rudder Crosstie- A wheel-to-rudder crosstie is available below 210kts.

- Control wheel inputs deflect the rudder up to 8 degrees. This allows the pilot to control the initial effects of an engine failure by using control wheel inputs only.

- The wheel-to-rudder crosstie is available in normal mode only.

Turn Compensation- Turn Compensation is only available in normal mode.- Back pressure not required for banks of 30 degrees or less, Partial compensation for banks of 30 degrees to 60 degrees.

YAW CONTROL - Non NormalCONFIG RUDDER - Rudder trim greater than 2 units and takeoff thrust selected on either engine.


Secondary Flight Control System ( High Lift Control System )The high lift control system operates aerodynamic controls to increase lift at lower speeds for takeoff and landing.

SLATSslat

hydraulic moter

- 7 slats on the leading edge of each wing. ( 1 inboard and 6 outboard slats on each wing )

FLAPS

2 krueger flaps - The krueger flaps provide a seal between the inboard slat and engine nacelle, and are either up or down.- They extend with the slats at flaps 1.

2 inboard trailing edge flaps - When flaps 5 is selected, the inboard and outboard trailing edge flaps move to the 5 position.

2 outboard trailing edge flaps - Positions 5, 15, and 20 move the trailing edge flaps only. Any of these 3 positions can be used for takeoff.- Flap and slat extension is inhibited when airspeed is more than 275kts, or when above approximately 20,000ft altitude.

- This prevents deployment if the flap lever is inadvertently moved. If the flap handle is moved out of UP while the flaps are inhibited, LOAD RELIEF displays.

PRIMARY

- Hydraulic - center system,- Autoslat, ( flap position 1,5,15,20 stall signal slat fully extended position ) There is no flight deck indication during autoslat operation.

- Slat load relief .- Flap load relief operates for flaps 15 to 30 ( Flap 5 relief ), The flap lever does not move during flap load relief operation.- Asymmetry protection and uncommanded motion protection are available.

SECONDARY

- Electric - automatically engaged, ( The slats and flaps are positioned electrically at a slower speed )- Because autoslats are unavailable, the slats are fully extended at all flap positions (if airspeed is less than 256 knots) to improve stall handling characteristics. If airspeed exceeds 256 knots, the slats retract to the midrange position ( the midrange index on the slat position indicator ), or will not extend beyond the midrange position.- Slat load relief is available. ( The slats retract to midrange and LOAD RELIEF displays )- If the slats are UP when secondary mode engages, the slats extend to the down, or gapped position when selecting flaps 1. This improves stall handling characteristics. However, if the slats are in the midrange position when secondary mode engages, they remain in that position until flaps are retracted to UP, or extended beyond 20.- F lap load re lie f .- Asymmetry protection and uncommanded motion protection are available.

- Once engaged, the secondary m ode remains engaged until the flaps and slats are fully retracted, or until hydraulic control is restored.- On the ground, secondary electric mode extension or retraction is inhibited when groundspeed is less than 40 knots, center hydraulic system pressure is low, and two of the following three items are true : - left engine N2 is less than 50 percent, - right engine N2 is less than 50 percent, - primary external power is available.

ALTERNATE

- Electric - Manually engaged, ( Alternate mode must be selected manually )- F lap / S lat extension , retraction F lap ,- Slat mid range, Flap 20 - . ( )- When selected, the alternate mode overrides flap lever inputs.- Autoslat, Flap / Slat Load relief, Asymmetry protection, uncommanded motion protection .


Secondary Flight Control System - Non Normals

Mode EICASIndicationEICAS

Messages Reasons Results

Secondary

SLATSPRIMARY FAIL Slats are operating in the secondary mode.

- Expanded flap and slat position indication,

- Slats driven electrically at slower speed,

FLAPSPRIMARY FAIL Flaps are operating in the secondary mode.

- Expanded flap and slat position indication,

- Flaps driven electrically at slower speed,

Alternate FLAP/SLATCONTROL Flap / slat electronics units are inoperative.

- Alternate mode must be selected manually,- When selected, the alternate mode overrides flap lever inputs,- disables primary and secondary flap / slat mode operation,- Maximum flap extension in alternate mode is flaps 20, and slats remain at midrange,- Automatic flap and slat sequencing does not occur. however, during retraction, slat retraction is inhibited until the flaps are up.- It is your responsibility to monitor the alternate flap and slat indication, and move the alternate flap selector to OFF when the correct flap position is reached.

- Asymmetry / skew and uncommanded motion protection, autoslat, and flap / slat load relief are not available

UnableControl

SLATS DRIVE - Slat asymmetry detected,

- Hydraulic and electric drive motors fail, - Uncommanded motion,

- Slat drive mechanism has failed. ( Both hydraulic and electric drive motors fail ) - The slat position indication on EICAS turns amber.

- The slats cannot be repositioned from this failed position. - Do not use alternate mode.

FLAPS DRIVE - Flap asymmetry detected,

- Hydraulic and electric drive motors fail, - Uncommanded motion,

- Flap drive mechanism has failed. ( Both hydraulic and electric drive motors fail ) - The flap position indication on EICAS turns amber.

- The flaps cannot be repositioned from this failed position. - Do not use alternate mode.


01 Overview02 Primary Flight Control System03 Primary Flight Control System - Non Normal04 Pitch Control 105 Pitch Control 206 Pitch Control - Non Normal07 Roll Control 108 Roll Control 209 Yaw Control10 Secondary Flight Control11 Secondary Flight Control System - Non Normals

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06 Flight Controls