HYDRAULIC SYSTEM Flashcards
How many hydraulic systems does the E170 have?
3
Consumers of hydraulic
1) Primary and secondary flight controls
2) Landing Gear
3) Brakes
4) Nose Wheel steering
5) Thrust reversers
Nominal pressure
3000 psig
Main components of hydraulic system
1) 2 engine driven pumps
2) 4 electric hydraulic pumps
3) 1 PTU
4) 3 hydraulic reservoirs
Sources of pressure for system 1/2 — main and backup
Main — Engine driven pumps
Backup — AC electrical pump
Sources of pressure for system 1/2 — main and backup
Main — Engine driven pumps
Backup — AC electrical pump
When is an electric pump used? (Normal and abnormal)
During takeoff and landing
In case of engine / engine-driven pump failure
Where is the PTU installed? The purpose of PTU?
Between system 1 and 2
Purpose — to transfer the power between systems without mixing the fluid (for landing gear only)
Source of system 3 power — main and auxiliary
Main electric pump (main)
Auxiliary electric pump (backup)
PTU operations limitations?
PTU activation is inhibited if:
1) on ground
2) airspeed < 50 kt
Philosophy of redundancy of hydraulic system parts
In case of failure of even two system, no critical control functions will lost
Location of HS1 installation?
Left center fuselage bay
HS1 consumers
1) ELEV OUTBD LH
2) RUD UPPER
3) ENG 1 REVERSER
4) MF SPOILERS 3/4
5) GND SPOILER 2
6) OUTBD BRAKES
7) EMER PARK BRAKE
HS2 consumers
1) ELEV INBD
2) AIL INBD
3) ENG 2 REVERSER
4) MF SPOILER 5
5) GND SPOILER 1
6) BRAKE INBD
7) NOSE WHEEL STEERING
8) EMER/PARK BRAKE
9) LANDING GEAR
Location of HS2 installation?
Right center fuselage bay
Location of HS2 installation?
Right center fuselage bay
Location of HS3 installation?
In the aft fuselage
HS3 consumers
1) ELEV OUTBD RH
2) RUD LOWER
3) AIL OUTBD
ELEC PUMP 1/2 or 3 — AUTO logic
Elec pumps 1/2 turn ON automatically
1) during takeoff and landing
2) in case of MAIN PUMP
Elec pump 3 B turns on automatically
1) 3 A pump failure (INHB during TO/LDG)
PTU activation logic
In case of engine 2 failure during TO or LDG
FLAPS ARE NOT SET TO 0
What provides electric pumps control?
AUTO — SPDU
ON — DIRECT ELECTRICAL CONNECTION FROM CKPT TO ACTUATORS
Conditions of starting ELECTRICAL PUMPS 1/2/3
1/2:
— FLAPS greater than 0 degrees
— TLs set to TO thrust or GS > 50 kts
1:
— EDP is not operational
2:
— EDP 2 is not operational
3B:
— 3A PUMP is not operational
How is the 3A pump power provided in case of engine failure?
1) 3A pump will initially turns off due to a loss of electrical power
2) System Accumulator will provide pressure to flight controls until RAT is deployed and energized
Purpose of pressure accumulator?
1) maintains constant pressure
2) keeps residuals pressure in reservoir to avoid pump cavitations
HYD SYS 3:
1) provides hydraulic to flight controls from the beginning of RAT deployment until 3A PUMP is AC powered
Conditions of AC pump start
In flight:
— EDP/ENG FAIL
— FLAPS > 0
+ 60 s during landing
On ground:
— FLAPS > 0
— TL’s set to T/O thrust or GS > 50 kts
+ 60 s during takeoff
+ AC PUMP 2:
— ENG 1 started & PARK BR released
— Durnig ENG 1 start (N2 > 40%) if PARK BR has been applied within last 6 min
AC PUMP 2 automatically turns OFF after 6 minutes elapsed from PARK BR application
PTU logic (OFF-AUTO-ON)
PTU will automatically turn ON if:
— ENG/EDP 2 fail
— FLAPS > 0
— ENG/EDP 1 NOT FAIL
— Fluid Quantity 2 > 12%
!!! Activation on ground is inhibited
HYD SYS 3: PUMP UNLOADER VALVE & FLOW LIMITER VALVE
In case of electrical emergency avoid overload in the RAM:
1) PUMP UNLOADER — reduces pressure of pump during its start-up
2) FLOW LIMITER — reduces flow to decrease load on RAT
