16_HYDRAULIC SYSTEM Flashcards
How many hydraulic systems are on the plane?
3
A, B and standby
What system powers all the flight controls?
Either A OR B can power all - with NO decreased in controllability.
Where are the hydraulic reservoirs located?
Each system has a reservoir in the MAIN wheel well.
How are thehyd reservoirs pressurized?
they are pressurized by bleed air.
What are the Hyd Sys A components?
Acronym: A REAL GIANT P
A - Autopilot A
R - Rudder
E- Elevator (and elevator feel)
A - Ailerons
L - landing Gear
G - Ground spoilers
I - flIght spoilers (1/2)
A - Alt Brakes
N - NWS
T - #1 thrust reverser
P - PTU
What are the Hyd Sys B components?
2 Thrust reverser
Controls:
Aileron
Rudder and Yaw Damper
Elevator (and elevator feel)
Wing:
leading edge flaps and slats
auto slats
1/2 flight spoilers (2 on each wing)
trailing edge flaps
Under:
Normal Brakes
Landing Gear Transfer Unit
Alternate NWS
Misc:
Autopilot B
1/2 flight spoilers
How many pumps does each Hyd system have? What are they and how are they powered?
each system has 2 pumps
1 engine driven - 1 AC electric driven
Which pump (eng or elect) pumps more? Approx how much more?
The engine driven pump supplies approx 4x the fluid vol.
ENG 1 (or 2) pump on/off switch controls what?
it controls the engine driven pump - OUTPUT pressure. In the OFF position the pump continues as long as engine is going.
What effect does pulling the Eng Fire Switch have on the hydraulic system?
it shuts off the fluid flow to the eng driven pump and deactivates the related LOW PRESSURE light.
What does the Elec 2 (system A) or Elec 1 (system B) pump on/off switch do?
It controls the related ELECTRIC motor driven pump.
What happens if an overheat is detected in either hyd system? (electrical hyd pumps)
the related OVERHEAT light illuminates
power is removed from the pump
and the LOW PRESSURE light illuminates.
What could cause an intermittant illumination of the LOW PRESSURE light (hyd) and what else comes on?
it could be caused by a loss of an engine driven hyd pump with a high demand on the system.
It could also illuminate the FLIGHT CONTROL LOW PRESS light, MC light, FLT CONT and HYD annunciator lights.
How is the hydraulic fluid cooled? Location?
hyd fluid used for cooling and lubricating the pumps passes through a heat exchanger (before going to reservoir)
Heat Exchanger System A: in Main Fuel Tank #1
System B: in Main Fuel Tank #2
Is there any limitation for use of the electric motor driven hyd pumps? If so what is it?
Minimum fuel for GROUND operation of the elect motor driven pump is 1,675# in the related MAIN tank.
What does a LOW PRESSURE light mean? (hyd system)
Pump output pressure is low (either motor or elect driven pumps)
If there is a leak in the ENGINE DRIVEN pump or its lines - how low will it get and why?
there is a standpipe in the reservoir that prevents total fluid loss. In this situation it will drain to approx 20%.
With a leak in the eng driven hyd pump or lines - does Hyd A maintain hyd pressure? If so, how?
Yes
its maintained by the electric motor driven pump
If a leak develops in the electric motor driven pump, its lines or common components with the Eng Pump will pressure still be available? What will the reservoir level read (in %)?
in this situation, the reservoir will steadily decrease to 0% and ALL PRESSURE IS LOST.
What happens if there is a leak in hyd B pump, line or compenent?
the qty will decrease until it indicates approx 0% and system B pressure is LOST.
Does Sys B hyd reservoir have a standpipe? If so, what for and at what level?
it has 1 standpipe that supplies fluid to both eng and elect hyd pumps. With the fluid at the TOP of the standpipe, the indicator will read 0% BUT it will be enough to use for the PTU.
Does a leak in sys B hyd affect the standby hyd system?
No
What is the purpose of the PTU?
to supply the additional volume of hyd fluid needed to operate the AUTOSLATS and LE FLAPS and SLATS at the NORMAL RATE when the sys B ENG DRIVEN pump volume is lost.
What does the PTU control?
Autoslats
LE Flaps and Slats
at a normal rate
