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ERJ-145 > Flight Control System > Flashcards

Flashcards in Flight Control System Deck (29)
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1
Q

Describe the elevator system.

A

Conventional cables and pulleys system with no hydraulic assistance.

2
Q

How is the elevator system arranged?

A

Two seperate and independent cable systems. 1 connects the captain’s column to the left elevator, 2 connects the FO’s column to the left elevator. A torque tube located under the pilots feet is the only connection between the two systems.

3
Q

What is the function of the elevator disconnect?

A

It disconnects elevator system 1 and 2 at the torque tube.

Used if the elevator or cables become jammed. The side that is not jammed controls that sides elevator.

4
Q

How do you know if the elevator disconnect lever has been pulled?

A

The lever is out and a yellow elevator cautions light appears.

5
Q

How many elevator tabs are installed and what is their purpose?

A

An inner spring tab and an outer servo tab on each elevator.

To assist in moving the elevator when under aerodynamic load (not trim tabs).

6
Q

Describe the servo tab.

A

It is the outer of two tabs. Slaved to the elevator and moves proportionally opposite to the elevator to decrease the pilot input force. Operates continuously.

7
Q

Describe the spring tab.

A

It’s the inner of the two elevator tabs. It is rigged to move opposite to the elevator direction to decrease pilot input force. At low speeds it remains neutral. At high speed it functions to assist elevator movement.

8
Q

How is the autopilot and stick pusher incorporated into the system?

A

Attached to the captain’s side system.
If the elevator disconnect is pulled, and the captain’s side is jammed, the autopilot and stick pusher are not available.

9
Q

Describe the pitch trim system.

A

Pitch trim is achieved by an electrically actuated moveable horizontal stabiliser. Pitch trim signals are sent to the Horizontal Stabiliser Control Unit (HSCU) manually or automatically, and the HSCU commands (one of two) electric motors in the Horizontal Stabiliser Actuator (HSA).

10
Q

How does the HSCU control the trimming rate?

A

Based on the airspeed. Trim rate decreases as speed increases.

11
Q

What is the Horizontal Stabiliser Control Unit?

A

It is the brains of the pitch control system.
There are two channels.
The main channel receives input from the yoke and autopilot.
The second channel receives input from the pedestal switches.

12
Q

What is the Horizontal Stabiliser Actuator (HSA)?

A

It moves the stabiliser.
It consists of an electromechanical actuator and two DC motors.
The HSCU main channel drives motor 1 and the backup channel drives motor 2.
Only one motor operates at a time.

13
Q

Describe the pitch trim switches.

A

They are split switches. Both must be moved for the system to activate.

14
Q

What is the priority given to the trim switches?

A

LH switch over rides RH switch.
No set priority is given to the main (LH RH) switches over the pedestal switches, whichever is pressed first is given priority.

15
Q

What happens if both parts of the pitch trim switch are pushed for more than 3 seconds?

A

The trim will only be active for 3 seconds, continual pressing will not keep the trim active. After 3 seconds an aural alert is provided to prompt a release and re engagement if further trim is required.

16
Q

What happens if one half of the trim split switch is pressed?

A

Nothing. However if it is pressed for longer than 7 seconds, the system will recognise the switch has failed stuck in that position and disregard further input from that switch.

17
Q

Why should the pilot keep the aircraft in trim, especially after take-off?

A

To avoid excessive loads on the HSA. Excessive loads on the horizontal stabiliser may stall the HSA, resulting in a temporary loss of pitch trim command.

18
Q

What happens if the HSA is stalled?

A

The pitch trim will not activate. Pressing the trim switches for longer than 16 seconds in this condition will disable inputs from that channel.

19
Q

In what circumstance will the autopilot automatically control pitch trim?

A

When engaged.

When deploying or stowing speed brakes.

20
Q

Describe the roll control system.

A

Roll control is provided by hydraulically actuated ailerons.

There are two systems, connected by a torque tube at the pilots feet.

21
Q

How is aileron system 1 rigged?

A

The LH yoke is connected via cables and pulleys to the LH aileron hydraulic actuator.
This system also contains the autopilot servo.

22
Q

How is aileron system 2 rigged?

A

RH yoke via cables to the RH aileron hydraulic actuator.

This system contains the artificial feel unit (AFU) and the roll trim actuator.

23
Q

What is the purpose of the aileron Artificial Feel Unit (AFU)?

A

Designed to give pilots an aerodynamic load feedback.

24
Q

What is the purpose of the roll trim actuator?

A

It relocates the aileron neutral position.

There is no trim tab.

25
Q

How does each system control the ailerons?

A

The left and right systems are both capable of controlling both ailerons. Left is system 1, right is system 2.

26
Q

What happens to the aileron system if hydraulic fluid is lost?

A

Mechanical reversion mode comes in whereby the cables and connection through the torque link control aileron movement.

27
Q

What happens if aileron or rudder trim is depressed for longer than 3 seconds?

A

The trim will cutout, with no audible tone.

28
Q

What happens is an aileron is jammed?

A

Pull the aileron disconnect.
The unjammed aileron will provide roll.
Aileron disconnect is observed by a light.

29
Q

Describe the rudder system.

A

A dual, in-tandem system. The forward rudder is driven by the control system and the aft rudder is deflected as a function of the forward rudder.