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|  MIL-H-8891A
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Ground test provisions - Each hydraulic system shall
3.5.4
include a set of self-sealing couplings for attachment of ground test equip-
ment. System ground test provisions shall be so designed that pressurization
of any hydraulic system in the vehicle is not necessary in order to test an-
other hydraulic system. In particular, use of only one hydraulic test stand
shall be necessary to test the system, without use of "Y" connections between
the test stand and the vehicle or use of a second ground test stand connected
to another hydraulic system in the vehicle. (For filtration requirements,
see 3.10.8) A central ground servicing station shall be provided for each
system that includes connections for attachment of ground test equipment for
system checkout and flushing, reservoir bleeding, reservoir fill, and accumu-
lator inert gas charging.
Note:
Single system operation, in multi-system aircraft, and
vigorous cycling of the control surfaces, can cause air
to form in the other non-pressurized, or non-operating,
system(s). Ground support equipment shall be configured
to prevent air formation in the non-pressurized system(s)
that can cause erratic or damaging system operation.
k
Ground test connections - A separate set of self-sealing
3.5.4.1
coupling consisting of bulkhead halves and protective caps shall be provided
.
at a convenient location in the vehicle, easily accessible from the ground,
for attachment of ground test equipment. The ground connections shall be
compatible with those connections supplied on ground test units in use by
the procuring activity. Electric-motor-driven pumps used in emergency or
auxiliary systems shall not be used for ground test purposes unless the
motor is designed for continuous operation.
Note:
No existing connections specified at this time. The
procuring activity shall specify the type of coupling
to be used.
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Reservoir pressurization connection - Reservoirs which
3.5.4.1.1
are normally pressurized by inert gas, a ground charging connection shall
be provided and shall consist of a fitting end in accordance with MS33656-4
or MS33657-4 for attachment to a ground charging unit. A protective cap
with safe automatic venting mechanism add a safety chain shall be provided
to protect the end connection when not in use. The automatic-venting
mechanism must prevent injury to servicing personnel.
Reservoir filling provisions - Servicing connection
*
3,5.4.1.2
and necessary valving to accomplish pressure filling of reservoirs from a
ground source shall be provided. To preclude air introduction, filling
provisions shall be so designed that open fluid containers cannot be used.
Fluid shall be filtered at the fluid source. Fluid level indication shall
be provided. Reference MIL-R-8931 and MIL-H-8890. Filling instructions
shall be provided immediately adjacent to the filling connections, The
ground test connection may be used for this purpose. Where emergency
filling provisions are incorporated the design filling procedure is
subject to prior approval by the procuring activity.
Ground test data - The following data shall be attached
3.5.4.2
in a permanent manner on the aircraft near the ground test connections:
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