11.9 FLIGHT CONTROLS

Question 1

What are the primary flight control surfaces

Answer 1

• ailerons
• elevators
• rudder

Question 2

Explain balance tab

Answer 2

• tab moves opposite to flight control
• just for aerodynamic reasons

Question 3

Explain servo tab

Answer 3

• opposite deflection
• moves flight control

Question 4

Explain anti-balance tab

Answer 4

• tab moves same direction
• extra force needed for flight control position

Question 5

Explain spring tab

Answer 5

• moves opposite direction
• helps control surface move when a certain force has been met

Question 6

Explain lateral trim

Answer 6

• controlled by switch on centre console
• electrically controlled

Question 7

Explain directional (yaw) trim?

Answer 7

• controlled by rotary knob on centre console
• electrically controlled

Question 8

Why are the flaps lowered

Answer 8

• increase camber of wings
• provide greater lift and control at slow speeds

Question 9

Why are composites becoming more common now

Answer 9

Due to weight saving

Question 10

Explain Krueger flaps

Answer 10

• extendable lift enhancing device
• increases wing camber
• produces nose up pitching moment

Question 11

When flaps are extended what is the nose pitch

Answer 11

• nose pitched down

Question 12

Explain how roll spoilers work

Answer 12

Spoilers on one wing moves up and spoilers on the other wing stay down

Question 13

Why is there a max deflection angle when deploying spoilers in flight

Answer 13

Prevent structural damage

Question 14

Function of speed brakes

Answer 14

• increase drag (reduce aircraft speed)

Question 15

Explain ground spoilers

Answer 15

• If ARMED they should automatically deploy
• dumps the lift

Question 16

When properly maintained, how accurate is a tensiometer

Answer 16

98%

Question 17

Explain tension regulators

Answer 17

• used due to expansion and contraction (temp change)
• e.g. if cable tightens, spring in regulator is compressed

Question 18

Explain push-pull rods

Answer 18

Transmit forces in either direction

Question 19

Disadvantage of push-pull rods than cables

Answer 19

Weight

Question 20

Explain bell cranks

Answer 20

Change the direction of movement

Question 21

Explain torque tubes

Answer 21

-angular or twisting motion is needed
- transmit torsional force

Question 22

What are torque tubes often used to actuate

Answer 22

Ailerons, flaps and slats

Question 23

Explain screw jacks

Answer 23

• used where moving surfaces that experience extreme aerodynamic loads
• convert rotary motion to linear

Question 24

Explain damping mode

Answer 24

• servo unit is depressurised
• used as gust damper when aircraft on ground

Question 25

Pneumatic systems on aircraft are primarily used as
- Back- up
- primary system
- secondary system

Answer 25

Back-up system

Question 26

Explain fly-by-wire

Answer 26

Movement of flight controls are converted to electronic signals

Question 27

Explain yaw damper

Answer 27

-swept back aircraft generate ‘Dutch roll’ motion
- yaw damper counters the rolling tendency

Question 28

Explain rudder limiter

Answer 28

• Limiting control surface deflection during high speed operation
• reduce strain

Question 29

Explain gust lock systems

Answer 29

• A lock for mechanical flight controls