Boeing 757 Flight Controls

Front 1

What are the Primary Flight Controls

Back 1

Ailerons, Elevators, Rudder

Front 2

What are the Secondary Flight Controls

Back 2

-Spoilers/Speed brakes

-Flaps and Slats

-Horizontal Stabilizers

Front 3

Primary Flight Controls are powered by what

Back 3

Mechanical inputs, then fully powered by various hydraulic systems

Front 4

What powers the Spoilers/Speed brakes

Back 4

Fly by wire, individually powered by all the hydraulic system

Front 5

What powers the Flaps and Slats

Back 5

Mechanical input, hydraulically driven, with electric back up

Front 6

How are all of the Flight Controls configured

Back 6

To be Fail Safe, and utilise the redundancy made available by having multiple hydraulic system

Front 7

To the Flight Controls, full loss of hydraulic power, means what

Back 7

Full loss of hydraulic power means no more flight controls

Front 8

Why is Artificial Feel incorporated into the Primary Flight Controls

Back 8

Due to the full power nature of the primary Flight Controls, the pilots have no feel of the Air Loads acting on these surfaces

Front 9

What are the Flight Control Shut Off Valves

Back 9

Hydraulic Valves used to isolate individual hydraulic systems from the Aft Flight Controls

Front 10

Purpose of the Flight Control Shut Off Valves

Back 10

Used to enable some ground test's to be carried out and can be used as a simple safety precaution

Front 11

Where are the Flight Control Shut Off Valves located

Back 11

Aft bulkheads of the wheel wells

Front 12

What powers the Flight Control Shut Off Valves and where are the Switches located

Back 12

Battery, 28V DC, the switches are located on the P61 panel

Front 13

When will the Flight Control Shut Off Valves operate

Back 13

Only on the ground

Front 14

If the Flight Control Shut Off Valves are closed and the aircraft takes off what will the valves do

Back 14

Automatically open

Front 15

The primary Flight Controls and the Spoilers and speed brakes are all moved by what

Back 15

Power Controlled Actuators (PCA's)

Front 16

How many PCA's are there in total

Back 16

25

Front 17

The Rudder and Elevator PCA'S have a sensor included that does what

Back 17

It monitors the Differential across the actuator piston.

Front 18

What do the PCA's assy comprise of

Back 18

A linear piston type output actuator which responds hydraulically to a control valve

Front 19

All the primary PCA's include a feature that does what

Back 19

Ensures continued movement of the actuator piston should it's hydraulic system fails. This allows continued operation of the overall system

Front 20

Each aileron is controlled by how many PCA's

Back 20

2

Front 21

Quadrants located at the bottom of the pilots control columns are linked by what

Back 21

A bus rod that includes an override which given enough force will allow independent wheel movement

Front 22

What provides roll command signals to the spoilers system

Back 22

A Rotary Variable Transducer ( RVTD), located at the bottom of the pilots control columns

Front 23

Lateral feel, Centring and trim mechanism receives 2 inputs from what

Back 23

Human and 2 auto pilot lateral control servos

Front 24

Purpose of the Outboard Override and PCA's

Back 24

These are designed to guard against Jamming of their respective PCA input mechanism

Front 25

Purpose of the PCA Reaction Link

Back 25

To carry the pivotal loads

Front 26

Ailerons are constructed of what

Back 26

Composite material and mounted on a 5 point hinge

Front 27

EICAS status screen gets aileron surface position from what

Back 27

A Rotary Transducer

Front 28

2 Spoilers/Speed brake system purposes

Back 28

To provide Directional control in flight

To reduce lift and increase drag in flight and on the ground

Front 29

How many Spoiler control modules are there

Back 29

6

Front 30

SCM's receive inputs from what

Back 30

The pilots control columns RVDT

Front 31

The SCM received Feedback information from what

Back 31

The PCA'S RVTD

Front 32

Where are the SCM's located

Back 32

E3 & E4 racks in the main equipment center

Front 33

What other system has inputs to the SCM's

Back 33

The ground air sensing system

Front 34

What is a safety precaution when working on the Spoilers

Back 34

Control Locks should always be installed

Front 35

What conditions are required to operate the Auto Speed Brake

Back 35

-Speed Brake lever must be placed in the armed position prior to touchdown

-Both MLG must be on the ground

-Both MLG tilt Switches read high pressure

-Both thrust lever's below 50% total thrust

Front 36

The Yaw Damping Summing Assy receives inputs from what

Back 36

Thermal expansion rod

Pilots controls

Yaw damper servos

(No feedback to the Rudder pedals)

Front 37

Operation of the Horizontal Stabilizer Trim System initiated by the following ways

Back 37

-Both pilots control column Switches

-An alternative switch on P10 to left of the thrust reverser

-Automatically as a function of auto pilot

-Automatically by Mach/Speed trim system

Front 38

What is Mach/Speed trim

Back 38

When flaps are extended= Speed mode

When flaps are up = Mach mode

Front 39

What are 2 methods of stopping unwanted trim in the horizontal stabilizers

Back 39

Cut. Off Switches

Shut off Switches

Front 40

What are the primary stops for the horizontal stabilizers

Back 40

The Limit switches set the maximum limit of travel for the horizontal stabilizers

Front 41

What drives the Flaps

Back 41

The Power Drive Unit, located in the LH MLG wheel well

Front 42

What does the Flap PDU consist of

Back 42

-Input and follow up mechanism

-Control valve

-Hyd motor and torque limiter

-Electric motor and clutch assy

-Bypass valve

-Position resolver

Front 43

What type of pump is the flap hydraulic motor

Back 43

Constant displacement, bent access piston type driving thru a Torque Limiting device to protect the motor should a jam occur

Front 44

Purpose of the flap/Slat depressurisation module

Back 44

Shut off pressure to the Flaps and Slats in response to a number of situations

Front 45

What stops air loads moving the flaps

Back 45

A No Back Brake

Front 46

Where are the Flaps/Slats electronic units located

Back 46

E5 rack

Front 47

The Flaps Slats depressurisation module will stop hydraulic pressure due to

Back 47

Any drive fault is detected

Alternate Flap system is armed

Flap asymmetry is detected

Cruise mode

Front 48

Flap asymmetry is activated when what

Back 48

A detection of 4° difference between flaps is detected

Front 49

How would you know a flap asymmetry has occurred

Back 49

EICAS display TE FLAPS ASYM and a discrete light on the p3 panel illuminates

Front 50

With Flaps down and airspeed exceeds 170 knots, what will happen

Back 50

Flap load relief solenoid will retract the Flaps up from 30 unit to the 25 unit. Will return if speed drops below 165 knots

Front 51

Difference between normal and alternate flap control

Back 51

Normal uses hydraulics

Alternate uses electric motor.

Alternate has all protection services except Load Relief

Front 52

Where is Flap position shown in the flight deck

Back 52

A duel needle indicator gauge on the p3 panel

Front 53

What does the automatic feature of the Slats do

Back 53

The feature will extend the Slats should the Aircraft Stal Warning system be activated

Front 54

Where is the Slate PDU located

Back 54

In the leading edge shroud are, in the left wing root

Front 55

Purpose of the Slat bypass Valve

Back 55

Located in the forward wing to body fairing, when closed it removes hydraulic power and creates a run around circuit

Front 56

When is the Slat bypass Valve operated

Back 56

When using the alternate slat system

Front 57

Which Slats are monitored

Back 57

2, 5, 6, 9 EICAS message if any of them break away

Front 58

What inputs move the Aileron system

Back 58

Pilots control column

Auto pilot

Linear Electronic Actuator

Front 59

What provides Surface Position information to the EICAS screen

Back 59

A Rotary Transducer

Front 60

The Roll function of the spoilers is activated by what

Back 60

The pilot control column and a series of 6 RVDT's

Front 61

The Speed Brake function is activated by what

Back 61

A lever to the left of the throttles which drives a set of 6 linear variable differential transducers (LVDT)

Front 62

What conditions are required to operate the Auto Speed Brake system

Back 62

-Speed brake lever must be placed in the armed position

-Both MLG must be on the ground

-Both MLG truck tilt pressure switches must indicate high pressure

-Both Thrust leavers must be below 50% of total travel

-Speed brakes will also deploy if thrust reversers are engaged

Front 63

What do the Spoiler PCA's have that the primary ones do not

Back 63

A manual override to allow panels to be moved by hand

Front 64

How many PCA'S move each Aileron

Back 64

2

Front 65

How are the Ailerons centered

Back 65

Mechanically, trim is achieved by adjusting this

Front 66

What links the control wheels

Back 66

Bus rod

Front 67

Where is feel introduced in the Aileron system

Back 67

Lateral feel, centering and trim mechanism

Front 68

How is trim achieved in the Aileron system

Back 68

By moving the neutral position

Front 69

What does the lateral control override mechanism do

Back 69

Allows independent operation of either aileron should one side jam

Front 70

Which speed brake panels are used on the ground only

Back 70

4 and 9

Front 71

Does the Yaw Damper system cause feedback through the pedals

Back 71

No, the Yaw Damper summing mechanism prevents this

Front 72

What prevents jamming if a rudder PCA assay fails

Back 72

Shear out features in the linkage's

Front 73

What forces is required for the override mechanism to activate

Back 73

65lbs

Front 74

What provides feel in the elevator system

Back 74

The Elevator feel and Centering mechanism

Front 75

What is the Elevator feel and Centering mechanism made of

Back 75

Feel computer and

Feel Actuator

Front 76

Which hydraulic system does the feel system use

Back 76

All three hydraulic systems

Front 77

What inputs does the feel computer use

Back 77

Air speed

Horizontal stabiliser position (Aircraft Attitude)

Front 78

What monitors feel pressure

Back 78

2 pressure switches monitor feel pressure, after 10 seconds sends an EICAS message if they differ by 25%

Front 79

What limit's the elevators being moved in opposite direction

Back 79

Asymmetry Limiters

Front 80

How many PCA'S control the elevator system

Back 80

3 PCA's, each powered by a hydraulic systems

Front 81

In the elevator PCA's system what reduces pressure

Back 81

Pressure reducing valves which reduce pressure from 3000psi to 2250psi

Front 82

Elevator system, if the right hydraulic systems fails what happens on the left hydraulic systems

Back 82

A pressure operated valve bypasses the reducer on the left to allow full pressure to operate the other PCA's

Front 83

What monitors elevator position

Back 83

Transmitters linked to each assembly, also sends EICAS messages and is used in the asymmetry limiting sys

Front 84

Horizontal stabiliser receives inputs from what

Back 84

Trim actuator assay

Air data computer

Manual trim switches

Flight control computer

Front 85

What does the PDU consist of

Back 85

Input and Follow up mechanism

Hydraulic motor and torque limiter

Electric motor and clutch assembly

Bypass valve

A position Resolver

Front 86

What protects the hydraulic flap drive motor in the event of a jammed flap

Back 86

A torque limiting device

Front 87

What type of motor is the flap drive motor

Back 87

Constant displacement bent axis piston type

Front 88

Purpose of the Trailing Edge Position Transmitters

Back 88

-6 position Resolvers

-Supply feedback information to FSEU's

-2 synchro transmitters for Duel Needle gauge in the flight deck

Front 89

Purpose of the Flap Load Relief system

Back 89

Will retract the flaps up from 30 unit position to 25 should the airspeed exceed 170knts

Front 90

How are the Leading Edge Slats driven

Back 90

Hydraulically driven, activated by an output from the Trailing Edge Follow up mechanism

Front 91

3 position's of the LE slats

Back 91

Up

Takeoff

Landing

Front 92

When will the slats automatically extend

Back 92

During an aircraft stall warning

Front 93

CSEU, Control System Electronic Unit's inputs

Back 93

-IRS

-FCC

-ADS

-LCS