Lesson 7: Switches, Seals, and Components

Question 1

What the 4 types of Hydraulic switches?

Answer 1

Pressure
thermal
position
limit

Question 2

What is the purpose of a pressure switch?

Answer 2

close circuit for caution light

enable/disable backup pump operation

Question 3

What are the types of pressure switches?

Answer 3

Piston
Diaphragm
Differential Pressure

Question 4

How does a piston type switch work?

Answer 4

hydraulic pressure forces a piston against a spring to open micro switch

Question 5

How does a diaphragm switch work?

Answer 5

similar to piston type but uses a diaphragm

Question 6

This type of switch uses a integral diaphragm to compare 2 different sources which will result in a CLOSED micro switch

Answer 6

Differential pressure switch

Question 7

What does a pressure transmitter do?

Answer 7

indicates pressure to the flight deck

Question 8

What is the purpose of a thermal switch?

Answer 8

enable/disable pump operation
caution light when temp exceeded
temp indication

Question 9

Purpose of a position switch

Answer 9

provides position on an actuator or flight control

Question 10

What are the types of POSITION switches?

Answer 10

Micro switch
rotary
potentiometer
lvdt/rvdt
proximity sensor

Question 11

All flight control indications originate from what?

Answer 11

Position switches

Question 12

Purpose of limit switches?

Answer 12

stops an actuator at the LIMIT of its movement

Question 13

Autopilot
horizontal stab
flap/slat
use what switch?

Answer 13

LIMIT

Question 14

This component smooths out pulsations in the flow

Answer 14

Damper

Question 15

What are the 2 types of dampers?

Answer 15

piston and vane

Question 16

Piston dampers are used on what

Answer 16

flight controls

Question 17

This component is commonly used to cool hydraulic fluid and case drain fluid

Answer 17

heat excahnger

Question 18

Purpose of hydraulic seals?

Answer 18

minimize leakage and loss of pressure
reduce wear
prevent contamination

Question 19

2 types of seals?

Answer 19

Packing and gasket

Question 20

This type of seal is used for when a lot of movement exists

Answer 20

packing

Question 21

this type of seal is used when no movement exists

Answer 21

gasket

Question 22

what side of the shape is on the high pressure side?

Answer 22

inside of shape

Question 23

What is the most common seal used on the aircraft?

Answer 23

O Rings

Question 24

What does the colour code of the o ring identify?

Answer 24

fluid type

Question 25

When do we use Back up rings?

Answer 25

when system pressure is greater than 1500 psi

Question 26

2 types of back up rings?

Answer 26

Leather and teflon

Question 27

MOst effective way to know youre using the right o ring?

Answer 27

Part Number

Question 28

you mus always lubricate the o ring with?

Answer 28

the fluid being used

Question 29

What are the types of hydraulic back up supply sources?

Answer 29

EMP
Hydraulic Motor (PTU/PDU)
ATM
RAT
Accumulator/air bottle

Question 30

Purpose of Electric Motor Pump?

Answer 30

electricity to drive hydraulic pump
ac/dc
primary pump on small airc
backup for large

Question 31

Purpose of Hydraulic motor?

Answer 31

hydraulic system pressure used to operate hydraulic motor = turn drive shaft

Question 32

This component one system is used to pressurize another system, without a transfer of fluid,

Answer 32

PTU

Question 33

What are PDUs used for?

Answer 33

flap/slat
horizontal stab
drive train

Question 34

Purpose of air turbine motor?`

Answer 34

drive hydraulic pump using pneumatic system

Question 35

This backup is your last hope

Answer 35

the RAT

Question 36

this backup is used for brakes

Answer 36

accumulator/ air bottle