Hydraulic System Flashcards
How many systems can a Power Transfer Unit (PTU) pressurize
at the same time?
Only one, either the Blue or Yellow system
What is the hydraulic hand pump in the right main gear area
used for?
It opens cargo doors when electric power is not available
While using the RAT to pressurize the Yellow hydraulic system,
why won’t Yellow system pressure be available for braking
during landing?
Yellow system pressure cannot be guaranteed below 140 KIAS
Why does the yellow system Hydraulic Fire Valve close when a
low quantity condition is sensed?
This saves fluid for RAT operation
What is the purpose of the hydraulic priority valves?
To give priority to primary flight controls and brakes when
hydraulic system pressure is low
On the ground, when may the indications for hydraulic
quantity be outside the upper green arc?
OAT above 20° C – indicator may indicate quantity as high as
the upper right mark
What system does the Ram Air Turbine (RAT) power?
Yellow system
What does the Parking Brake ACCU PRESS switch do?
It momentarily activates Yellow hydraulic system electric
pump
How does a Power Transfer Unit (PTU) work?
It uses the Green hydraulic system to pressurize either the
Blue or Yellow hydraulic system
If the engine driven hydraulic pump for the Yellow system
fails, what is available to recover the Yellow system?
Green to yellow PTU and the yellow RAT
Which component is not used inflight to recover a failed
hydraulic system?
Hand pump
What is transferred using a PTU?
Hydraulic power only
If the Yellow and both Green hydraulic pumps fail, extending
the RAT will recover what system?
Recover only the Yellow system
How do you know the Power Transfer Unit (PTU) is working?
You can confirm PTU operation on the hydraulic systems page
The parking brake could be affected by a total loss of fluid
from which hydraulic system?
Yellow
