Ch. 2 - Flight Control System

Question 1

What are the 3 sections of the flight control system?

Answer 1

1 Mechanical control system
2 flight control servo system
3 automatic flight control system

Question 2

Describe mechanical flight control system.

From control to mixing unit.

Answer 2

The flight controls are routed aft and outboard of each pilot seat, vertically up each side of the aircraft in our combined at the overhead torque shafts in the Hyd bay.

From the torque shafts the inputs from the trim servos and flight controls go to the pilot assist servos in the mixing unit.

Then fore, aft and lateral are transferred to the swashplate assembly via the primary servos and the bridge assembly.

The yaw inputs go to the tail rotor quadrant through the tail rotor cables.

Question 3

If both tail rotor cables are severed what will happen?

Answer 3

Two centering springs will counter the tail rotor servo pilot valve and position the tail rotor to neutral setting.

Question 4

The tail rotor cables provide mechanical input to the ________ which will ________________.

Answer 4

Tail rotor servo

Change the pitch change shaft, which move the pitch change beam, which moves the pitch change links and changes the pitch angle of the tail rotor.

Question 5

The 2nd stage of the tail rotor servo is powered by what?

Answer 5

The backup pump

Question 6

To secure the pitch and roll trim actuators you must________

Answer 6

Push the TRIM button on the AFCS control panel

Question 7

The Boost servos do what?

Answer 7

Reduce cockpit control forces

And SAS system feedback

Question 8

Control mixing:

Collective to yaw

Answer 8

Caused by main rotor torque

The nose yaws right when collective is increased

So tail rotor thrust is increased

Question 9

Control mixing:

Collective to lateral

Answer 9

The helicopter drifts right when collective is increased

It’s caused by lateral lead from the tail rotor

So the rotor disc is tilted left

Question 10

Control mixing:

Collective to longitudinal

Answer 10

Is caused by rotor down wash on the stab

The nose pitches up and the helicopter drifts aft when the collective is increased

So the rotor disc is tilted forward

Question 11

Control mixing:

Yaw to Longitudinal

Answer 11

Is caused to the tail rotor lift vector

The nose pitches down and the helicopter drifts forward when left pedal is applied

So the rotor disc is tilted aft

Question 12

Control mixing:

Collective/airspeed to yaw

Answer 12

The tail rotor pylon loads the side of the aircraft as speed increases

It forces the nose to yaw left as airspeed increases

So trim input is removed as the side load increases with airspeed

Question 13

What does the pilot-assist servo assembly contain?

Answer 13

Boost servos
SAS actuators
Hydraulic (pitch and roll) trim actuators

Question 14

Hydraulic power is required to move ___.

Answer 14

The primary servos

Question 15

Are the Pitch and Roll trim actuators electrical or hydraulic?

What is the rest of the pilot-assist servos?

Answer 15

Hydraulic

Electrical