PTM Ch. 13 Hydraulic Power System Flashcards
Hydraulics control what?
Actuation of landing gear, flaps, and NWS
A separate hydraulic system is provided for what?
Brakes
The auxiliary system, pressurized by a hand pump, supplies pressure only for emergency what?
Extension of the landing gear
What is the normal pressure in the hydraulic system?
2000 psi
What pressurized the main hydraulic system?
Two variable-volume pumps
Can the system run on one pump?
Yes but at a reduced rate
What kind of hydraulic fluid do we use?
Brayco MIL-H-83282
Where do the hydraulic pumps take the fluid?
From the reservoir through shutoff valves.
The HYDR PRESS (L/R) annunciators come on when?
To warn that the hydraulic pump output is low or pump failure.
What happens if pressure surges in the system?
Dampened by an accumulator
The hydraulic reservoir is pressurized by what?
31 psi regulated bleed air
The engine-driven pumps draw fluid from where?
Above the standpipes in reservoir
The fluid below the standpipes is reserved for what?
Hand pump operation during emergency extension of the landing gear
Can the gear be retracted with the aux system?
No
When would you use the HYDR SHUT OFF switches?
Only in the event of fire, engine shutdown in flight, or when mx is to be performed
What is the 31 psi in the hydraulic reservoir used for?
Keep pressure on hydraulic fluid when in high demand. (Flap and gear extension)
It also prevents foaming of the fluid
When does the L/R HYD position disagreement light illuminate?
When the hydraulic SOV is in motion
What if the L/R HYD light doesn’t extinguish?
The valve hasn’t fully opened or closed
How much fluid is needed in the hydraulic glass fluid-level?
Fluid needs to be in the upper indicator. If there isn’t MX is required.
How to use the emergency extension?
- Follow checklist
- Airspeed 175 (173 DOWTY)
- Gear handle- down
- Emergency release handle- rotate 90 degrees CCW
- Hand pump valve handle- pull pin and pump
Pump handle is used for emergency gear extension to what pressure is achieved?
500-800 psi
The purpose of the accumulator in the hydraulic system is for what?
Dampen pressure surges
