Hydraulic Systems

Question 1

What is powered by the #1 Hydraulic system?

Answer 1

FAIREP

• Flaps
• Anti-skid Brakes
• Inboard Roll Spoilers
• Rudder (lower PCU)
• LH/RH Elevators (outboard PCU’s)
• Power Transfer Unit (PTU)

Question 2

What is powered by the #2 Hydraulic system?

Answer 2

PROGEN

• Park/Emerg Brake
• Rudder (upper PCU)
• Outboard Roll Spoilers
• Gear (Landing Gear)
• Elevators LH/RH (centre PCU’s)
• Nose Wheel Steering

Question 3

What does the #3 Hydraulic system serve as a backup to?

Answer 3

• LH/RH Elevators

Question 4

How is the #1 Hydraulic system powered?

Answer 4

• Engine Driven Pump

- backed up by a standby Hydraulic pump

Question 5

How is the # 2 Hydraulic system powered?

Answer 5

• Engine Driven pump

- Backed up by a power transfer unit (PTU)

Question 6

How many Hydraulic Systems are on the Q400?

What are they?

Answer 6

• 4
• # 1 and #2 (main systems)
• # 3 backs up the elevators
• Alternate landing gear extension Hydraulic system

Question 7

What are the minimum quantities you must have for dispatch in the #1, #2, and # 3 Hydraulic systems?

Answer 7

• 40% min in all 3

Question 8

The #1 Hydraulic system reservoir (8 US quarts) is located where?

Answer 8

The #1 Nacelle

Question 9

The #2 Hydraulic reservoir is located where?

Answer 9

The #2 Nacelle

Question 10

What happens if the the Hydraulic fluid in each reservoir is above temperature limits?

Answer 10

The related #1/#2 HYD FLUID HOT light comes on.

Question 11

The #1 and #2 Hydraulic system each have an isolation valve which is normally open. What happens if the system fluid quantity is low?

Answer 11

2 system:

The isolation valve closes, and the related #1 or #2 HYD ISO VALVE caution light comes on.

Hydraulic power is only available for:
#1 system: 
- flaps
- PTU
- Rudder
- Elevators

• Rudder
• Elevators

Question 12

The Firewall Shut-off Valve will close if:

Green light = open, white light = closed

Answer 12

• Engine 1 or 2 PULL FUEL/ HYD OFF handle is pulled
• # 1 or #2 Hydraulic reservoir fluid quantity is low
• Hydraulic fluid overheats

Question 13

The standby Hydraulic Pump is backup for which system?

Answer 13

1 Hydraulic system

Question 14

Standby Hydraulic is an AC motor powered by?

Answer 14

The right 115v AC Bus

Question 15

When does the Standby Hydraulic Pump operate automatically?

Answer 15

• # 1 engine fails in flight, or
• # 1 reservoir is not empty, and
• Park brake is off, and
• Flaps are set to more than 0 degrees, and
• AC power is available

Note: the standby hydraulic pump flow rate is less than the EDP, thus services will operate at a slower rate.

Note: When the standby hydraulic pump operates automatically, the green ON legend does not come on.

Question 16

A priority valve is included in the #1 Hydraulic system and is normally open. If the Hydraulic pressure in #1 system decreases below 2100 psi….

Answer 16

The priority valve closes. This shuts off Hydraulic power to the flaps and PTU. Hydraulic power is maintained to the elevators, rudder, inboard spoilers and brakes.

Question 17

The PTU is a backup source to which system?

How does it operate?

Answer 17

2 Hydraulic system

The PTU uses Hydraulic pressure from the #1 system to power the Hydraulic motor. The motor then operated the Hydraulic Pump to pressurize the #2 system.

Hydraulic fluid is not shared or transferred between #1 and #2 Hydraulic systems during PTU operation. Hydraulic pressure must be available in the #1 and #2 system for PTU operation.

Question 18

The PTU may be operated manually or automatically. It automatically operates if:

Answer 18

• # 2 reservoir is not empty, and
• park brake is off, and
• Flaps are set to more than 0, and
• # 1 EDP pressure is more than 2,400 psi

Question 19

What does the #3 hydraulic system power?

Answer 19

• It is an independent system which powers the left and right inboard elevator PCU’s.
• The system operates automatically if the #1 and/or #2 hydraulic systems lose pressure or if both engines fail.

Question 20

Where is the alternate landing gear hydraulic reservoir located?

Answer 20

• Lower right nose compartment

Question 21

What is the minimum hydraulic quantity for dispatch?

Answer 21

• 40% in all 3 systems

Question 22

Where is the standby pump pressure indication?

Answer 22

• MFD 2, scale indicates from 0-4000 in 1000 psi increments.

Question 23

Where are the PTU pressure indications displayed?

Answer 23

• There is no pressure monitoring when the PTU is selected on manually. Thus, the green ON advisory light, on the PTU CNTRL switchlight, must be monitored when the PTU has been selected on.

Question 24

When does the #1 hydraulic system priority valve close?

A priority valve is included in the #1hyd system and is normally open

Answer 24

• If the hydraulic pressure in the #1system decreases below 2100 psi
• This shuts off hydraulic power to the flaps and PTU. Hydraulic pressure is maintained to the elevators, rudder, inboard spoilers and brakes.

Question 25

Which services will still operate when the #1 isolation valve closes?

Answer 25

- Flaps - PTU - Elevator - Rudder In other words, the following will be unavailable: - inboard roll spoilers - Normal brakes (anti-skid)

Question 26

Which services will still operate when the #2 isolation valve closes?

Answer 26

- Elevator - Rudder In other words the following services become unavailable: - outboard spoilers - nose wheel steering - emergency/ park brakes - Landing gear

Question 27

When do isolation valves close?

Answer 27

- If the system fluid quantity is low, the isolation valve closes, and the related #1 or #2 HYD ISO VLV caution light comes on. Hydraulic power is available only for: #1 system: Flaps, PTU, Rudder, Elevators #2 system: Rudder, Elevators

Question 28

What is the #4 hydraulic system for?

Answer 28

- Alternate Landing Gear extension system

Question 29

When is the #3 hydraulic system used?

Answer 29

- An independent system that powers the left and right inboard Elevator PCU’s. - It operates automatically if the #1 and/or #2 hydraulic systems lose pressure or if both engines fail. - It can also be engaged manually by pushing the HYD #3 ISOL VLV switchlight.

Question 30

How is the #3 hydraulic system powered?

Answer 30

- A DC motor pump operates automatically to keep the accumulator pressurized between 2600 to 3250 psi. - Electrical power is supplied to the DCMP by the standby battery. - When the DCMP isn’t operating, the accumulator holds a reserve of pressure. - The DCMP operates intermittently and is controlled by two pressure switches installed on the accumulator isolation valve. One switch signals the DCMP to operate if system pressure drops to 2600 psi and commands the DCMP to stop when the system reaches 3250 psi.

Question 31

When does the #3 HYD PUMP caution light illuminate?

Answer 31

- A switch causes the #3 HYD PUMP caution light to come on when the system pressure falls to 900 psi, or the DCMP has been operating for more than 60 seconds on the ground.

Question 32

Hydraulic System Abbreviations to remember which system powers what?

Answer 32

FAIREP: - Flaps - Anti-skid brakes - Inboard Spoilers - Rudder - Elevator - PTU PROGEN: - Parking (emerg) brake - Rudder - Outboard roll spoilers - Gear - Elevator - Nose-Wheel steering