Hydraulics

Question 1

Where is the AUX system reservoir located?

Answer 1

In the left system reservoir

Question 2

Which hydraulic system(s) can operate the HMG?

Answer 2

Left and PTU

Question 3

Which hydraulic systems are capable of providing hydraulic power to extend and retract the landing gear in flight?

Answer 3

Left and PTU

Question 4

With a duel hydraulic failure and only the AUX system fluid in the left hydraulic reservoir, what can the auxiliary hydraulic pump power?

Answer 4

Flaps and brakes

Question 5

How is hydraulic fluid used during opening of the main entrance door?

Answer 5

Trapped hydraulic pressure in the door system is used to dampen the extension rate

Question 6

How many hydraulic differential pressure indicators are on the aircraft?

Answer 6

Five for the left system, three for the right system, one PTU, one AUX

Question 7

What is the capacity of the hydraulic replenisher tank?

Answer 7

1.5 gallons

Question 8

What is the maximum reservoir quantity of the left hydraulic system?

Answer 8

2.75 gallons

Question 9

What is the maximum reservoir quantity of the right hydraulic system?

Answer 9

0.70 gallons

Question 10

What is the pre-charge pressure of the hydraulic accumulators with both systems unpressurized?

Answer 10

1200 psi @ 70F (21C), with a 25 psi increase or decrease for each 10F

Question 11

What activates the PTU when it is armed?

Answer 11

If the left hydraulic system pressure drops below 1500 psi with at least 1.5 gallons of fluid in the left system and pressure in the right system, the PTU will automatically turn ON

Question 12

What will cause the PTU to shut off automatically?

Answer 12

If the left hydraulic system pressure is restored, loss of fluid in the left or right system, a “R HYDRAULIC RESERVOIR HOT” CAS message (>104C)

Question 13

If the PTU shuts off due to an overheat condition, can it be turned ON?

Answer 13

Yes, it can still be hard-selected ON (override)

Question 14

What does the PTU power?

Answer 14

Flaps, Landing Gear, Brakes, Nose Wheels Steering, Ground Spoiler Servos, and HMG

Question 15

What does the AUX Hydraulic pump power?

Answer 15

• Closes the main cabin door
• Opens and closes the landing gear doors, brakes and flaps
• Parking brake accumulator pressure

Question 16

What is the flow rate of the AUX PUMP?

Answer 16

Approximately 1 GPM at 3,000 PSI (much less than the other systems)

Question 17

What is indicated by a “AUX HYDRAULIC HOT” CAS message?

Answer 17

It indicates that the auxiliary hydraulic pump is greater than 356F

Question 18

Will the AUX PUMP turn off automatically with a “AUX HYDRAULIC HOT” CAS message?

Answer 18

No, it must be manually selected OFF

Question 19

When armed, what causes the aux pump to come ON automatically?

Answer 19

Depressing any brake pedal 10 degrees when the left and PTU system pressure is below 1500 psi

Question 20

What is the purpose of the AUX PUMP / BRAKE SYSTEM check?

Answer 20

To check the automatic latch-on feature of the aux hydraulic pump and to be able to achieve 3000 +/- 300 psi after fully depressing brakes

Question 21

What will cause the PTU to come on automatically from an ARMED state?

Answer 21

Left hydraulic system pressure less than 1,500 psi

Question 22

What components are lost with the failure of the left hydraulic system pump?

Answer 22

The left thrust reverser and Yaw Damp 1

Question 23

What components are lost with a loss of the left hydraulic system fluid, assuming AUX fluid is still available?

Answer 23

Left thrust reverser, HMG, nosewheel steering, automatic ground spoilers, and normal landing gear operation

Question 24

What components are lost with the failure of the right hydraulic system pump, or the right hydraulic system fluid?

Answer 24

Right thrust reverser (along with use of the PTU and yaw damper 2)