MD Helicopters MD Explorer - External Hydraulic Pressure Application; Hydraulic System Pressure Application

CSP−900RMM−2 MD Helicopters, Inc.
Rotorcraft Maintenance Manual
Page 204
Revision 20
29-00-00
2. Hydraulic System Pressure Application
A. External Hydraulic Pressure Application
Consumable Materials
(Ref. CSP−SPM)
Item Nomenclature
C112 Hydraulic Fluid
Special Tools
(Ref. CSP−SPM)
Item Nomenclature
T2001 Hydraulic Mule
(1). Open transmission forward left-hand
access door L155 (Ref Section
06-00-00).
Hydraulic Fluid (C112)
Do not mix different specifica
tion hydraulic fluids. Ensure
that only hydraulic fluid (C112) is used to
service the hydraulic systems for all helicop
ter operations in temperatures above -40°F.
(2). Select GSE panel for system which
requires application of external pres
sure. Connect pressure and return lines
from hydraulic mule (T2001) to pres
sure and return ports on GSE panel.
NOTE: The GSE return port must be connected
before applying pressure to prevent fluid
venting overboard due to reservoir overfil
ling.
(3). Remove drain tube from BL port fitting
on manifold/reservoir of selected system
and clamp an approximate 9 foot length
of flex tubing to BL port fitting. Place
other end of flex tube into a bucket.
(4). Open bleed valve until all fluid is
drained from manifold. Close bleed
valve.
Do not exceed 1000 psig dur
ing application of external
hydraulic pressure. Do not set pres
sure below 350 psig.
Use extreme care when adjust
ing hydraulic pressure to avoid
damage to the helicopters hydraulic system.
(5). Preset hydraulic mule pressure before
applying pressure to helicopter system.
(Refer to applicable rigging/test
instructions for proper pressure
setting.)
(6). On helicopters with 900H381502-105
hydraulic manifolds, rapidly increase
pressure from 0 - 250 psi to prevent
fluid venting overboard due to reservoir
overfilling.
(7). Apply hydraulic mule pressure to
helicopter hydraulic system.
Do not make full or abrupt
movements of the main rotor
flight controls with external hydraulic pow
er applied to aircraft. The main rotor flex
beams cannot accommodate full control ex
cursions (combinations of full collective and
full cyclic movements) without centrifugal
force.
(8). Perform applicable system rigging/test.
(9). When rigging/test is complete; on
helicopters with 900H381502-105
Hydraulic Manifolds, rapidly decrease
pressure from 250 -0 psi to prevent
fluid venting overboard due to reservoir
overfilling.
(10). Discontinue pressure application from
hydraulic mule. Shut off hydraulic
mule.
NOTE: Disconnect GSE pressure line prior to
disconnecting the return line, to prevent
fluid venting overboard due to reservoir
overfilling.
(11). Disconnect hydraulic mule pressure
and return lines from GSE panel and
install panel port covers.
(12). Remove flex tubing from manifold BL
port fitting and reconnect drain tube.
(13). Close transmission forward left-hand
access door L155 (Ref Section
06-00-00).
CAUTION
WARNING
CAUTION
CAUTION