Flight Controls

Question 1

What is the propose of an aileron balance cable?

Answer 1

It ties the ailerons together in such a way that when one aileron deflects downward, the other one is pulled upward.

Question 2

What is the most common construction configuration of flexible control cables?

Answer 2

7 by 19.

Question 3

What materials are used to manufacture flexible control cables?

Answer 3

carbon steel coated with tin or zinc, or corrosion-resistant steel.

Question 4

What is the definition of a critical fatigue area of a control cable?

Answer 4

Any working length of a cable where the cable runs over, under, or around a pully, sleeve, or through a fairlead; or any section where the cable is flexed, rubbed, or worked in any manner; or any point within 1 foot of a swaged-on fitting.

Question 5

How are the ends of two control cables normally connected together?

Answer 5

With swaged, threaded terminals on the ends of each cable, connected with a turnbuckle.

Question 6

How much is a fairlead allowed to deflect a control cable?

Answer 6

No more than 3°.

Question 7

Why are the control cables of large airplanes normally equipped with automatic tension regulators?

Answer 7

The large amount of aluminum in the aircraft structure contracts so much as its temperature drops in flight that the control cables could become dangerously loose. The automatic tension regulators keep the cable tension constant as the dimensions of the aircraft change.

Question 8

When rigging control cables, there are stops at the control surfaces that limit travel and stops at the control input. Which stops should the system contact first?

Answer 8

The stops at the control surface.

Question 9

How are length adjustments made on a flight control push-pull rod?

Answer 9

One or both ends of the push-pull rod have threaded rod ends.

Question 10

What is the purpose of a torque tube in a flight control system?

Answer 10

To convert a linear motion to an angular or twisting motion.

Question 11

What component in a flight control system is often used to change motion by 90 degrees?

Answer 11

A bellcrank.

Question 12

What is the function of the rudder on an airplane?

Answer 12

The rudder rotates the airplane about its vertical axis.

Question 13

What is an aerodynamically balanced control surface?

Answer 13

A surface with part of its area ahead of the hinge line. When the surface is deflected, the portion ahead of the hinge aids the movement.

Question 14

In what publication could you find correct control surface movement for a particular airplane?

Answer 14

In the TCDS for the airplane.

Question 15

Why is it important than control surfaces be statically balanced?

Answer 15

An out-of-balance control surface can cause severe flutter.

Question 16

Where can you find the specifications for balancing the control surfaces of an airplane?

Answer 16

In the aircraft maintenance manual.

Question 17

What in addition to static unbalance can cause a control surface to flutter?

Answer 17

Worn hinges or improperly adjusted control cable tension.

Question 18

What is the function of the elevators on an airplane?

Answer 18

Elevators rotate the airplane about its lateral axis.

Question 19

What is a stabilator?

Answer 19

A single-piece horizontal tail surface that acts as both the horizontal stabilizer and the elevator. A stabilator pivots about its front spar.

Question 20

What is meant by differential aileron travel?

Answer 20

Aileron movement in which the upward-moving aileron deflects a greater distance than the one moving downward. The up aileron produces parasite drag to counteract the induced drag produced by the down aileron.

Question 21

What is a Frise aileron?

Answer 21

An aileron with its hinge line set back from the leading edge so that when it is deflected upward, part of the leading edge projects below the wing and produces parasite drag to help overcome adverse yaw.

Question 22

What is a ruddervator?

Answer 22

Movable control surfaces on a v-tail airplne that are controlled by both the rudder pedals and the control yoke. When the yoke is moved in or out, the ruddervators move together and act as the elevators. When the rudder pedals are depressed, the ruddervators move differentially and act as a rudder.

Question 23

What is the function of the ailerons on an airplane?

Answer 23

Ailerons rotate the airplane about its longitudinal axis.

Question 24

What is the purpose of a spoiler?

Answer 24

There are spoilers intended for use in flight and others that are used only on the ground. Inflight spoilers are used to aid in roll control. ground spoilers are used after touchdown to decrease lift and increase drag?

Question 25

What is the primary purpose of a trim tab?

Answer 25

to reduce the force needed to move a primary control surface.

Question 26

Why are flaps used on most aircraft?

Answer 26

They allow control at lower airspeeds and reduce the speeds needed for takeoff and landing, shortening runway length requirements.

Question 27

What are the risks associated with misinterpretation of a cable tension chart?

Answer 27

Not understanding a cable tension chart can lead to incorrect tensions. Cable tensions that are set too high can cause damage to the aircraft and premature wear of the system. Tensions set too low can cause insufficient control travel, leading to loss of aircraft control?

Question 28

Why is it important to understand the proper procedures for rigging aircraft flight controls?

Answer 28

Incorrectly rigged flight controls can cause poor aircraft performance, or in the worst case, complete loss of aircraft control.

Question 29

Where are the proper procedures found for lifting and moving aircraft components into place for installation and asembly?

Answer 29

In the aircraft maintenance manual.

Question 30

What risks are associated with the use of incorrect tools and procedures when installing aircraft components and major assemblies?

Answer 30

Incorrect tools and procedures can cause damage to the aircraft or assemblies, leading to their failure.

Question 31

Why are cable tensiometers and other rigging equipment maintained under a calibration schedule?

Answer 31

Proper tensions and accurate dimensions of rigging equipment is critical for airworthiness and aircraft safety.

Question 32

What risks can arise from the multiple scales that are on some cable tensiometers?

Answer 32

The use of the wrong scale or adjustment block used on some tools can lead to incorrect cable tensions.