Hydraulics

Question 1

Hydraulic System pressure

Answer 1

3000 psi

Question 2

Components of Hydraulic System #1

Answer 2

• 1 x reservoir
• 1 x engine-driven pump
• 1 x electric pump
• 1 x accumulator

Question 3

Systems on Hydraulic Sys #1

Answer 3

– Elevator (left hand outboard actuators)
– Rudder (upper actuator)
– Thrust reverser (engine 1)
– Spoilers (left and right panels 2, 3 and 4)
– Outboard brake
– Emergency parking brake

Question 4

Automatic actuation of the hydraulic shutoff valve (SOV)

Answer 4

125ºC

Question 5

Electric Hydraulic Pump system logic

Answer 5

In Flight activates if:

• EDP or engine failure
• Flaps greater than 0º

On the ground with Flaps greater than 0º and:

• thrust set for takeoff thrust
• ground speed greater than 50 knts

*#2 electric pump will also turn on with ENG 1 running and parking brake released

Question 6

Components of Hydraulic Sys #2

Answer 6

1 x reservoir 
1 x EDP
1 x electric driven pump
1 x accumulator
1 x PTU

Question 7

Systems on Hydraulic Sys #2

Answer 7

– Elevator (left and right hand INBOARD actuators)
– Ailerons (right and left INBOARD actuators)
– Thrust reverser (engine 2)
– Spoilers (left and right panels 1 and 5)
– Inboard brake
– Nose wheel steering
– Landing gear (retraction and extension)
- Emergency parking brake

Question 8

Function of PTU (Power Transfer Unit)

Answer 8

• assist in landing gear extension or retracting during ENG 2 or EDP 2 failure
• pump located in HDY Sys #2; motor located in HYD Sys #1
• will not activate on the ground

Question 9

Systems on Hydraulic Sys #3

Answer 9

– Elevator (right hand outboard actuators)
– Rudder (lower actuator);
– Ailerons (left and right outboard actuators)

Question 10

Components of Hydraulic Sys #3

Answer 10

1 x reservoir
2 x electric driven pump
1 x accumulator

Question 11

HYD Sys 3 overheat protection

Answer 11

• Both Electric Hydraulic Pumps (3A and 3B) will automatically be turned OFF at 125ºC
• inhibited during electrical emergency

Question 12

Why does HYD Sys 3 Elec pump A not have an AUTO position

Answer 12

• Electric Hydraulic Pump 3A (ACMP 3A) is the primary power source for Hyd System 3
• powered by AC ESS BUS

Question 13

How many applications of the parking brake are provided by the accumulator

Answer 13

• 6 applications or 24 hours