11.9

Question 1

Why are tabs less common on modern aircraft?

Answer 1

The flight surfaces are electrically or hydraulically moved and due to higher speed also have Mach trim

Question 2

How is lateral trim controlled?

Answer 2

A switch in the centre console controlled through the FCU and electrical wires to the servo

Question 3

How is yaw trim controlled?

Answer 3

-through a rotary knob on the centre console
-it is electrically controlled through the FCU and electrical wires to the servo

Question 4

Where is the trimmed position shown?

Answer 4

A mechanical command is inputed to the actuator control electronics through two pitch trim signals
There are two alternate pitch trim levers on the captains side

Question 5

What is active load alleviation?

Answer 5

Reduces the load of manoeuvring and turbulence

Question 6

What is manoeuvred load control?

Answer 6

It uses wing control surfaces to move the centre of lift inward and reduce wing bending as well as

Question 7

What is gust loading alleviation?

Answer 7

Deflects wing control surfaces to automatically counteract accelerations caused by wing gusts

Question 8

What are manually operated systems?

Answer 8

Unassisted controls operated by flight crew through chains, control cables, turnbuckles pulleys fairleads etc

Question 9

How are control cables set to allow for movements in both directions?

Answer 9

Bell cranks allow for pulling in both directions

Question 10

What is the purpose and function of the tension regulators?

Answer 10

Due to the change in shape and size of the aircraft because of temperature the cable can be stretched or slackened, the springs inside the machine maintain correct tension

Question 11

What is the function of a torque tube?

Answer 11

When angular or twisting motion is required they can be used to transmit tortional force

Question 12

What is a common application and the function of a screw jack?

Answer 12

-Moving surfaces that take high aerodynamic loads
-they transfer rotary to linear motion

Question 13

How can hydraulics safety be maintained?

Answer 13

-multiple hydraulic systems
-mechanical back ups
-multiple sources of pressurisation

Question 14

What is a hydraulic power control unit (PCU)?

Answer 14

A single assembly combining multiple hydraulic systems into one
-they position flight control surfaces
-they represent a principle structural element
-in damping mode the servo control unit is depressurised

Question 15

What is a servo control unit?

Answer 15

-A power section
-A distribution section

Question 16

What does the power section on a servo control unit do and what is its main component?

Answer 16

It changes hydraulic pressure into mechanical force
-cyllinder
-piston
-piston rod

Question 17

What are the main components on a distribution section of a servo control unit?

Answer 17

-control valve
-bypass valve

Question 18

What is control / active mode on a servo control unit?

Answer 18

In flight
-hydraulic supply is switched on
-servo control unit is pressurised
-bypass valve moves left against a spring
-if a mechanical lever is displaced right control valve is displaced left the rod retracts

Question 19

What is damping mode?

Answer 19

On ground
-servo control unit is depressurised
-used as a gust damper
-bypass allows movement

Question 20

What is power assisted control?

Answer 20

-hydraulic power assists the pilot in moving the control
-the pilot still receives feedback
-in hydraulic failure it still works

Question 21

What are manual and power assisted flying controls also known as?

Answer 21

Reversible flying controls

Question 22

What is a fully powered control system?

Answer 22

No mechanical controls and non reversible
No feedback given artificial feel is required

Question 23

What are pneumatic systems typically used for?

Answer 23

Back up systems

Question 24

How does an electrically actuated (PCU) differ from hydraulic ones?

Answer 24

The servo value is electronically controlled

Question 25

What are the three modes electrical power control units can position in?

Answer 25

Normal
Bypass
Blocked / dampened

Question 26

What are the (LAW’s) of fly by wire?

Answer 26

Normal
Alternate

Question 27

What is fly by wire law?

Answer 27

Computer software program which transfers input to movement

Question 28

When is fly by wire normal law used?

Answer 28

-stationary at gate
-taxiing
-beginning take off roll
-initial climb
-cruise climb and cruise flight
-final descent and landing

Question 29

What are the alternate laws of fly by wire?

Answer 29

-alternate law 1 & 2
-direct law
-mechanical law

Question 30

What is artificial feel?

Answer 30

In the case of hydro mechanical or electromechanical a false feel mechanism is required

Question 31

What devices are needed for artificial feel?

Answer 31

-a simple spring box with springs that can be compacted
-spring loaded roller fit into a v shape valley when input is increased the roller rides up the cam

Question 32

How does the Q pot feel system function?

Answer 32

A simple piston connected to a double linkage to the control column, the piston is pulled against pitot pressure.
The faster the air the higher the pitot pressure is pressing the diaphragm adjusting the valves on the pressure port and return port

Question 33

What are spring feel units adequate for?

Answer 33

Low speeds

Question 34

What is the purpose of a yaw damper and how does it work?

Answer 34

-To counter the rolling tendency of an aircraft
-the yawning damper provides input to the rudder in proportion to the yaw rate of the aircraft

Question 35

What is laws effect on flight control?

Answer 35

Adjusting the input effect on the flight control surface based on faults of the aircraft

Question 36

What is Mach trim system?

Answer 36

An automated system which trims the (THS) trimmable horizontal stabiliser to prevent uncontrolled nose down caused by Mach pressure waves

Question 37

What is the function of the rudder limiter?

Answer 37

It prevents large deflections of the rudder at high speeds
Full pedal movement is maintained

Question 38

How is gust lock structured?

Answer 38

-either separate or part of the system
-either on the control surface or the flight deck
-to be installed when parked or when maintenance is being performed

Question 39

What is static balance?

Answer 39

When a control surface is tendant to stay stationary when supported by its centre of gravity

Question 40

What is dynamic balance?

Answer 40

Where all of the rotating forces are balanced within themselves so that no vibration is preduced while the body is in motion

Question 41

When rebalancing what must be done?

Answer 41

-The trim tabs must be set to neutral
-when a control surface is mounted it must be free of air currents
-it must be able to rotate freely
A bubble protractor is used to establish a neutral position

Question 42

What is aircraft rigging?

Answer 42

Rigging is the process of setting cable tension, adjusting travel limits of flight controls and tabs as well as setting travel stops

Question 43

What system warns of an impending stall to the pilots?

Answer 43

Stick shaker

Question 44

What is the function of a stick nudger/ pusher?

Answer 44

To avoid a stall

Question 45

How is angle of attack measured?

Answer 45

AOA indicator

Question 46

What does angle of attack protection do?

Answer 46

Limits the pilots input effect to prevent a stall warning