TM 1-1520-238-T-5
7–2
Change 1
SECTION I.
EQUIPMENT DESCRIPTION AND DATA
7–1.
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES
7–1
a. Characteristics.
(1) The primary hydraulic system provides hydraulic power for the operation of the main rotor and tail rotor
servocylinders.
(2) The utility hydraulic system provides hydraulic power for the operation of the main rotor and tail rotor
servocylinders, auxiliary power unit (APU) start motor, rotor brake, hydraulically operated weapon system
components and provides a source of stored high pressure fluid for emergency operation of the flight control
servocylinders.
(3) The pressurized air system (PAS) cleans, pressurizes, regulates and distributes air to pneumatically
operated systems and components.
b. Capabilities and Features.
(1) The primary hydraulic system provides 3000 psi hydraulic fluid pressure to hydraulically operated
components. Flow rate is 6.0 gallons per minute (gpm) and capacity is three quarts of MIL–H–83282 or
MIL–H–5606. The primary hydraulic system is serviced and bled using ground service equipment (GSE) through
the GSE panel. External primary pressure is supplied, through the GSE panel, to provide ground hydraulic power
operation for flight controls.
(2) The utility hydraulic system provides 3000 psi hydraulic fluid pressure to hydraulically operated
components. Flow rate is 6.0 gpm and capacity is 2.6 gallons of MIL–H–83282 or MIL–H–5606. The system is
serviced and bled using GSE through a UTILITY GSE panel. External primary pressure is supplied, through the
GSE panel, to provide ground hydraulic power operation for the utility system.
(3) The PAS system provides 35 psi heated air to pneumatically operated components and has three
modes of operation: primary, secondary and external. Engines 1 and 2, or the APU provides primary operation to
drive the shaft driven compressor (SDC), secondary operation uses bleed air from engine 1, and external
operation uses external air from the aviation ground power unit (AGPU).
7–2.
LOCATION AND DESCRIPTION OF MAJOR COMPONENTS
7–2
a. Primary Hydraulic System.
The primary hydraulic system (fig. 7–1) consists of the primary hydraulic
pump, primary hydraulic manifold, primary GSE panel, longitudinal servocylinder, lateral servocylinder, collective
servocylinder, and the directional servocylinder.
(1) Primary Hydraulic Pump.
The primary hydraulic pump, located on the left forward drive pad of the
main transmission accessory geartrain housing, pressurizes and transfers fluid for system operation. The primary
hydraulic pump is a constant pressure, variable delivery, piston–type pump driven by the main transmission
accessory geartrain. The external drive shaft mates with the main transmission accessory geartrain and is
designed to shear under excessive loads.
(2) Primary Hydraulic Manifold.
The primary hydraulic manifold, located on the main transmission deck
forward and left of the main transmission, stores, filters and routes hydraulic fluid for system operation.
(3) Deleted.
