PS Magazine - TB 43-PS-618
PS, The Preventative Maintenance Monthly
ISSUE 618
MAY 2004
The problem is that some
cans stored in your hangar cab-
inet look similar, depending on
which brand you use. If you
have the petroleum based fluid
in your bird and you mistaken-
ly mix in the synthetic fluid,
that could cause hydraulic sys-
tem problems.
When synthetic hydraulic
fluids contaminate petroleum
based fluids and are exposed to
certain operating temperatures,
carbon deposits form. Additive
dropout results when synthetic
and petroleum lubricants have
been mixed.
Then you have to drain the
entire hydraulic system and
add the right fluid, depending
on the outside temperatures.
When you finish servicing
the hydraulic pumps, make
sure the selector valve handle
is in the capped OFF position.
Otherwise, when the pilot
starts the bird, the hydraulic
system will drain the pump and
overflow the reservoirs.
PS 618
MAY 04
36
UH-60A/L/Q…
M
echanics, good judgment comes from experience. Unfortunately, experience usu-
ally comes from bad judgment.
When it’s time to service
your bird’s hydraulic pump
modules with fluid, like it
says in Para 1-3-8 of TM 1-
1520-237-23-1,
use good
judgment. Make sure you
know what type of fluid is in
your bird’s system
before
adding any fluid.
Always use the correct
fluid listed in Appendix D, on
Page D-14 of TM 1-1520-
237-23-9.
For example, if the temperature is below -29°F, always add the petroleum-based
fluid to the reservoir and eyeball the reservoir window. When operating at tempera-
tures above -29°F, always add the synthetic fluid.
Check type of hydraulic fluid before servicing
Mechanics,
got this
type? No
problem…
cans are
clearly
marked
Mechanics,
got this
type?
Make sure
you grab
the
right
one
before
servicing
Petroleum
based
Synthetic
based
Valve in capped OFF position when done?
time to service
the hydraulic
pump modules.
hold on!
are you sure
that’s
the
fluid already
in the system?
this black
hawk isn’t big
enough for
both of us!
Grab the
Right
Type of Hydraulic Fluid
618. 36-37 (C)
3/29/04
10:52 AM
Page 1
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