Flight Controls

Question 1

5 sections of flight controls

Answer 1

1. Cockpit controls
2. Lower controls
3. FWD upper controls
4. AFT upper controls
5. Control cables

Question 2

Common quote for flight control rigging:

Answer 2

“Through a series of control rods and bellcranks”

Question 3

What are Viscous Dampers?

Where are they located?

Answer 3

Dampen pilot controlled control inputs from vibrations

Roll channel
Yaw (RH pilots pedal box)

Question 4

With a DC electrical failure, what will happen to the mag brake?

Answer 4

The mag brake is electrically de-energized, so it will remain engaged in a DC electrical failure

Question 5

What are Mag Brakes?

Centering springs?

Answer 5

A rod surrounded by magnets that are electrically de-energized and allows the pilot to establish a neutral, or center position of the controls.

When the cyclic is displaced centering springs are depressed and provide artificial feel to the pilot.

Question 6

What is attached to the RH pilots cyclic controls in the pedal box?

Answer 6

Longitudinal stick indicator

Question 7

What connects the lower control rods from the pedal box to the lower boost actuators?

Answer 7

Lower idler bellcrank

Question 8

What is a mixing unit?

Answer 8

Takes 4 inputs (yaw, pitch, roll, collective) and combines it into 2 outputs:

Collective pitch & Lateral roll

Question 9

What is the purpose of the upper boost actuators?

Answer 9

To hydraulically boost control inputs into FWD and AFT upper controls

Question 10

Directional pedal adjustment?

Answer 10

Mag brake that is electrically de-energized. Does not contain centering springs like the cyclic

Question 10

What is a collective Downrate limiter?

How does it work?

Answer 10

Prevents sudden application of full downward collective

Contains viscous damper. Check valve inside of damper allows non restricted upward movement.

Question 11

When will the collective downrate limiter shear?

Answer 11

If in a malfunction or emergency, a downward force of 75lbs

Question 12

At what rates does the collective downrate limiter work?

Answer 12

Non restricted downward at 4 degrees per second.

Lowered at greater rates, the first 4 degrees is unrestricted, where as the rest is restricted to 4 degrees per second

Question 13

What axis contain balance springs?

Answer 13

Collective
Yaw
Pitch

Question 14

What is the purpose of balancing springs?

Answer 14

Compensate for unbalanced control forces

Question 15

What do Lower stick dual boost actuators do?

Answer 15

Provide hydraulic boost to flight controls.

Eliminate dynamic feedback from rotor systems and SAS extensible links

Question 16

What does the FWD upper controls do?

Answer 16

Provide second level of hydraulic boost to flight controls

Final stage of control mixing

Question 17

What happens when the lateral upper boost actuator moves its control rod?

Answer 17

Tilts swatshplate resulting in roll

Question 18

What happens when the pitch UBA moves its control rod?

Answer 18

It raises or Lowers the swashplate resulting in an increase or decrease in blade pitch

Question 19

What are walking beam assemblies?

Answer 19

Assemblies they take control rod input and translate it to cable movement and then back into control ride movement

Question 20

What replaces the longitudinal link on the aft swashplate?

Answer 20

Longitudinal speed trim actuator

Question 21

What is the purpose of longitudinal speed trim?

Answer 21

Prevent bending stresses on the Vert shaft

Allow for level cruise flight