Hydraulic System

Question 1

How many separate hydraulic systems are there on the CRJ 900

Answer 1

Three

Question 2

Hydraulic systems 1, 2, and 3 normal pressure is

Answer 2

3000 psi

Question 3

Low pressure (Caution) occurs at what pressure

Answer 3

< 1800 psi

Question 4

High hydraulic pressure occurs at what pressure

Answer 4

3200 psi

Question 5

What is the normal system quantity hydraulics

Answer 5

45% to 85%

Question 6

Hydraulic System High temperature condition occurs at what temp

Answer 6

≥ 96°C

Question 7

The HYD HI TEMP caution indicates that hydraulic fluid is hot in what part of system?

Answer 7

The reservoir

Question 8

How many hydraulics pumps are there

Answer 8

Six,
3 full-time (“A” pumps),
3 part-time (“B” pumps)

Question 9

When will the “B” pumps operate

Answer 9

Switch ON or with switches in AUTO at least one generator online and flaps > 0
The respective bus is powered and flaps not 0°
Note: Hydraulic pumps 1B and 2B are powered by busses associated with their respective cross side engine driven generators.

Question 10

When will hydraulic pump 3B operate

Answer 10

Switch ON or with switches in AUTO at least one generator online and flaps > 0
The respective bus is powered and flaps not 0°
or ADG deployed

Question 11

What type of hydraulic fluid is used

Answer 11

Skydrol

Question 12

What color is the hydraulic fluid

Answer 12

Purple

Question 13

When will pressure relief occur

Answer 13

≥ 3750 psi

Question 14

Which hydraulic pumps are A pumps?

Answer 14

System 1 engine driven hydraulic pump
System 2 engine driven hyraulic pump
System 3 AC motor pump A

Question 15

Which hydraulic pumps are B pumps?

Answer 15

System 1 AC motor pump
System 2 AC motor pump
System 3 AC motor pump B

Question 16

With the B pump switched in AUTO, will the B pumps automatically turn on to back up a failed A pump?

Answer 16

No

Note: The operation of the B pumps in AUTO is triggered by flap position, not system pressure.