Flight Control

How are changes in direction of a control cable accomplished?

• Pulleys

• Bell cranks

• Fairleads

• Turnbuckles

Answer explanation

Changes in direction of a control cable are primarily accomplished using pulleys, which redirect the cable's path efficiently. Other options like bell cranks and fairleads serve different functions, making pulleys the correct choice.

What is the smallest size cable that may be used in aircraft primary control systems?

• 1/4 inch

• 5/16 inch

• 1/8 inch

• 3/32 inch

Answer explanation

The smallest size cable that may be used in aircraft primary control systems is 1/8 inch. This size ensures adequate strength and safety for critical control functions in aviation.

The cable-operated control system of an all-metal aircraft, not incorporating a temperature compensating device, has been rigged to the correct tension in a heated hangar. If the aircraft is operated in very cold weather, the cable tension will

• decrease when the aircraft structure and cables become cold

• increase when the aircraft structure and cables become cold

• be unaffected if stainless steel cable is installed

• remain constant

Answer explanation

As the temperature drops, the metal components of the aircraft contract, leading to a decrease in cable tension. Therefore, the correct answer is that the cable tension will decrease when the aircraft structure and cables become cold.

When inspecting a control cable turnbuckle for proper installation, determine that

• no more than four threads are exposed on either side of the turnbuckle barrel

• the terminal end threads are visible through the safety hole in the barrel

• the safety wire ends are wrapped a minimum of four turns around the terminal end shanks

• the turnbuckle is painted red

Answer explanation

The correct choice is that the safety wire ends are wrapped a minimum of four turns around the terminal end shanks. This ensures proper securing of the turnbuckle, preventing accidental loosening during operation.

If all instructions issued by the swaging tool manufacturer are followed when swaging a cable terminal, the resultant swaged terminal strength should be

• the full rated strength of the cable

• 80 percent of the full rated strength of the cable

• 70 percent of the full rated strength of the cable

• 50 percent of the cable strength

Answer explanation

Following the manufacturer's instructions ensures that the swaged terminal achieves the full rated strength of the cable, making it reliable and safe for use.

Excessive wear on both of the sides of a control cable pulley groove is evidence of

• pulley misalignment

• cable misalignment

• excessive cable tension

• lack of lubrication

Answer explanation

Excessive wear on both sides of a control cable pulley groove indicates that the pulley is not aligned properly. This misalignment causes uneven wear, confirming that 'pulley misalignment' is the correct answer.

Where does the breakage of control cable wires occur most frequently?

• Breakage usually occurs where cables pass over pulleys and through fairleads

• Breakage sites are unpredictable

• Breakage usually occurs where cables are swaged to terminals

• Breakage occurs at the turnbuckle

Answer explanation

Breakage usually occurs where cables pass over pulleys and through fairleads due to the constant bending and friction at these points, making them the most vulnerable areas for wear and damage.

If the vertical fin of a single-engine, propeller-driven airplane is rigged properly, it will generally be parallel to

• the longitudinal axis but not the vertical axis

• the vertical axis but not the longitudinal axis

• both the longitudinal and vertical axes

• neither axis

Answer explanation

The vertical fin is designed to provide stability and control in the yaw axis, aligning with the vertical axis of the aircraft. It is not typically aligned with the longitudinal axis, which runs from nose to tail.

Washing-in the left wing of a monoplane, for purposes of rigging corrections after flight test, will have what effect on the lift and drag of that wing?

• Both drag and lift will decrease

• Both drag and lift will increase

• The drag will decrease due to the effect of the lift increase

• Lift increases but drag decreases

Answer explanation

Washing-in the left wing increases the angle of attack, leading to higher lift. However, increased lift also results in increased induced drag. Therefore, both drag and lift will increase.

Ideally, rigging and alignment checks should not be undertaken in the open. However, if this cannot be avoided, the aircraft should be positioned with the

• tail into the wind

• left wing into the wind

• nose into the wind

• right wing into the wind

Answer explanation

Positioning the aircraft with the nose into the wind minimizes the risk of wind-induced movement during rigging and alignment checks, ensuring safety and accuracy.