Utility Hydraulic System Flashcards
5 groups/solenoid valves for isolation
- No 1 Engine Start
- No 2 Engine Start
- Ramp and Cargo Door (tongue)
- PTUs, Center Hook, Winch
- Power Steering, swivel locks, brakes centering
cams
9 Subsystems
- Power Transfer Units
- APU Start System
- Engine Start System
- Cargo Ramp
- Power Steering
- Swivel Locks
- Wheel Brakes
- Center Cargo Hook
- Cargo Winch/Rescue Hoist
Hydraulic Service Module
2 side of cabin in the ramp area used for adding fluid to all 3 hydraulic systems.
Do not let fluid level go below sight glass or air can be pumped through systems.
Utility Reservoir/Cooler
Assembly
- Located on the #2 side in
the aft pylon, stores and
cools fluids for system
operation - Cooler fan operates while
the fluid temperature is
between 63-54 degrees C. - If either the #1 AC or #1
DC system fails with no
bus-tie, the hydraulic oil
cooler fan will not function.
Utility Reservoir Pressurization
Accumulator
- Located in the aft pylon
hydraulics compartment
adjacent to the
reservoir/cooler. - Maintains pressure on the
reservoir/cooler. - 2500-3000 psi on preflight
Utility System
Hand Pump
Located on #2 side of ramp area. Used to pressurize APU start accumulator and in emergencies used to operate utility subsystems (if emergency utility pressure valve is open instead of normal).
Electric Pump for the Utility
System Hydraulic Accumulator
(EPUSHA)
Located on the #2 side of the ramp area aft the hand pump. Used to pressurize APU start accumulator to a minimum of 2500 psi, maximum of 3500 psi. Do not exceed 5 EPUSHA operations to prevent depletion of battery.
APU Start Accumulator
The Bomb. Stores fluid under pressure for: APU starting and Emergency operation of subsystems when no other pressure is available.
APU Motor/Pump
- Located on the forward end
of the APU. - Provides 3350 psi to start
the main engines and
complete ground checks - Can only be used in flight
during emergencies if the
transmission driven pump
fails
APU Start Module
- Located on #2 side of the
aft ramp compartment - Controls the APU
motor/pump and APU start
accumulator pressure during
the APU start sequence. - Pressure should indicate
approx 3000psi.
Utility Hydraulic Aft Transmission driven pump
- Located on the No 2 side of
the aft transmission. - Provides pressure to the
system when the rotors are
turning. - Provides 3000 psi,
hydraulic fluid cools and
lubricates pump
Flight hydraulic Power Transfer Unit
No 1 in fwd pylon, No 2 in aft pylon. Provides pressure to operate flight controls during ground operations and emergencies (the motor side of the PTU operated by utility hydraulic system)
Auxiliary Ground Power Unit
(AGPU)
Provides 3000 psi if connected at service panel on No 2 side of A/C
Utility Hydraulic
Pressure Control
Module
- Located overhead in the aft cargo compartment on the No 1 side
- Receives pressure input from APU start accumulator, APU motor/pump, Util Hyd system pump, and AGPU
- Controls fluid flow via solenoid valves connected to switches in cockpit. 1 visual
contamination indicator
Utility Hydraulic Return control module
- Located overhead on the No 2 side of the aft ramp compartment.
- Provides central collection point for all fluid returning to the reservoir/cooler.
- Filters the fluid, 3 visual contamination indicators.
Maintenance
Panel
Has indications for the following:
- Utility hydraulic pressure
- Utility hydraulic fluid
temperature - Utility hydraulic reservoirs
level indicator - Utility hydraulic filter
change indication lights - Pump fault indication lights
