Hydraulic System Flashcards
(40 cards)
What are the three hydraulic systems?
Utility
Booster
Auxiliary
What does the utility hydraulic system normally supply:
wing flaps, main landing gear, nose landing gear, normal brakes, nose wheel steering, aerial refueling reels, and half of the aileron, rudder and elevator control boost system
What does the booster hydraulic system supply:
Half of the flight control boost system not powered by the utility hydraulic
What does the auxiliary hydraulic system supply:
The auxiliary hydraulic system supplies hydraulic power for cargo door and ramp operation, emergency brake operation, and emergency nose landing gear extension.
The auxiliary hydraulic system also supplies hydraulic power to the utility hyd sys on the ground by connecting the two systems through the ground test valve.
In the case of utility hyd failure in flight, the aux system can be used to operate the inflight refueling system through the utility-auxiliary interconnect valve located in the cargo compartment, on the aft face of the left wheel well bulkhead at fuselage station 617
What are the components of the utility and booster hydraulic systems:
Hydraulic reservoir Suction boost pump Engine-driven hydraulic pump Shutoff valves Check valve Pressure relief valve Filters Accumulator
How much fluid does the utility hydraulic system reservoir hold and where is it located
5.5 gallons of fluid and is located in the cargo compartment, forward of the left main landing gear wheelwell
The booster hydraulic system reservoir holds how much fluid and where is it located
3.1 gallons of fluid and is located in the cargo compartment, forward of the right main landing gear wheelwell
The hydraulic reservoirs are non-___________, ______-fed, hydraulic fluid containers
Pressurized
Gravity
Suction boost pumps provide fluid to which systems, provide _ to __ us gallons per minute at pressures __ to __ psi
Utility and booster
0 to 20 gallons
70 to 90 psi
The engine driven hydraulic pumps increase pressure to
3000 psi
No 1 and 2 engine driven hydraulic pumps supply which system
Utility
No 3 and 4 engine driven hydraulic pumps supply which system
Booster system
Where are the engine driven hydraulic pumps mounted on the engine ?
They are installed on the gearbox mounted accessory drive of each engine
Describe the engine driven hydraulic pumps
They are nine-piston, variable-volume type pumps. An internal control mechanism varies output volume with system demand. The flow capacity of each engine depends on engine RPM
What is the purpose of the suction line and pressure line shutoff valves
These valves work in unison to isolate the engine driven hydraulic pumps in case of a component failure or an engine shutdown
What is the purpose of check valves.
Check valves prevent a reverse flow of hydraulic fluid
How many check valves are there on the utility and booster systems?
Utility and booster systems each have six check valves mounted in various locations. The two pump case drain check valves for the two engines used with the utility or booster hydraulic system are mounted to the respective engines. The two isolation check valves are mounted in each dry bay behind the respective engines.
In the booster hydraulic system two check valves are in the reservoir area; the bypass check valve and the priming check valve.
In the utility hydraulic system the bypass check valve is in the reservoir area, however the priming check valve is mounted on the left wing aft beam forward of the life raft liner.
What do the pressure relief valves do?
Pressure relief valves open to protect the utility and booster hydraulic systems from excessive pressure if an engine driven hydraulic pump fails to regulate pressure
There are two pressure relief valves. One is in the utility and one in the booster system
The relief valve opens at 3,450 psi and reseats at 3,100 psi. They bypass 23 gallons per minute when fully open
How many hydraulic filters are there?
There are four in each system: one system return filter, one engine pump case drain filter, and two high pressure engine filters
What does the system return filter do
It removes contaminants from fluids returning to the reservoir
What does the engine pump case drain filter do
They remove contaminants from the hydraulic fluid returning from the engine driven hydraulic pumps to the reservoirs
What do the high pressure engine filters do
They remove contaminants from the hydraulic fluid pressurized by the engine driven hydraulic pumps
What is the purpose of the accumulators
They dampen pressure surges in the pressure lines
What is the purpose of the ground test valve
The ground test valve allows the auxiliary hydraulic system to be tied to the utility hydraulic system. The auxiliary hydraulic system pressure then operates the utility hydraulic system components.
