Falcon 900b Hydraulics

Question 1

What is normal engine driven hydraulic pump pressure?

Answer 1

About 3000 psi (2987 psi according to the book)

Question 2

Which system does the standby pump pressurize?

Answer 2

No. 2 system.

Question 3

Can the standby pump be used on the ground?

Answer 3

Yes, It can be used to pressurize either system no. 1 or no. 2. There is a selector in the rear compartment which can be moved to direct the flow of fluid to either system.

Question 4

How many hydraulic systems are in the airplane?

Answer 4

Two. System one is on the left side and system two is on the right side of the rear compartment

Question 5

What is BIG FAN?

Answer 5

This refers to the major components which would be lost if the hydraulic system failed.
BIG - right left side components
B - brakes
I - Inboard and outboard slats
G - Gear and doors

FAN - left side components
F - Flaps
A - Airbrakes
N - Nosewheel steering

Question 6

How is are the hydraulic reservoirs pressurized?

Answer 6

A small piston moves a big piston. The small piston is moved by hydraulic pressure.

Question 7

How many accumulators are in the hydraulic system?

Answer 7

1. LH System Accumulator - 1500 psi
2. RH System Accumulator 1500 psi
3. Pressure holding accumulator - 1700 psi
4. Thrust reverser accumulator - 1500 psi
5. Parking brake accumulators - 1000 psi
6. Airbrake accumulator - 1000 psi

Question 8

The pump is driven by the accessory section of the engine. What protection is built in if the pump seizes.

Answer 8

The pump has a shear shaft.

Question 9

Each hydraulic system has a filter with it. What is the indication that the filter is clogged?

Answer 9

A clogging detector button on the top of the filter will pop up.

Question 10

What triggers the PUMP light on the warning panel?

Answer 10

If the pressure of any of the three engine driven pumps falls below 1500 psi

Question 11

What triggers the standby pump pressure light?

Answer 11

1. Any time the pump runs longer than 60 seconds.

2. The pump selector in the rear compartment in NOT in the INFLIGHT position

Question 12

Which pumps drive which systems?

Answer 12

#1 system - Nos. 1 and 3 engine driven pumps
#2 system -   No. 2 engine pump and the standby pump

Question 13

On what system are the parking brake accumulators?

Answer 13

System #2

Question 14

What two conditions will turn the standby pump on?

Answer 14

1. If the pump switch is in the ON position - anytime the pressure drops below 1500psi in the No. 2 system.
2. If the pump switch is in the AUTO position - whenever the No. 2 hydraulic pressure drops below 1500psi AND the airbrakes are used.

Question 15

There are 2 emergency systems on the #2 hydraulic system. What are they?

Answer 15

1. Emergency brakes

2. Emergency slats (outboards only). (29-3)

Question 16

How are the hydraulic systems pressurized?

Answer 16

A small piston is drives a large piston in the reservoirs. The small piston is driven by hydraulic pressure.

Question 17

What happens to pressure in the hydraulic reservoirs when the engines are shut down?

Answer 17

Pressure is retained in the reservoirs by accumulators.

Question 18

Why is it important to shut down the standby pump prior to engine shut down?

Answer 18

To prevent standby pump motor operation with the battery only. It draws a lot of power. (29-18)

Question 19

What would happen if the #1 engine driven pump failed?

Answer 19

Nothing. If there are no leaks in the #1 hydraulic system the #3 pump would just take over the task of system pressurization. (29-12)