PS Magazine - TB 43-PS-617
PS, The Preventative Maintenance Monthly
ISSUE 617
APRIL 2004
M
echanics, when MWO 1-1520-237-50-76 installed the AN/ARC-220 high fre-
quency radio antenna, it told you that the mast compression sleeves and coupling
nuts needed only a snug tightening with an adjustable wrench, NSN 5120-00-264-
3796, or equivalent.
Well, snug won’t cut the mus-
tard because that’s not tight
enough. Right now, do a torque
check of the compression coupling
nuts to make sure they’re 27-30
lb-ft. Then check that the lead-in
and shorting mast compression
sleeves are 18 lb-ft. When the
torquing is complete, inspect the
sealing compound, NSN 8030-00-
009-5023, around the edges of the
supports and add more as required.
Aircraft vibration after the
antenna is installed can work the
nuts loose and corrosion can
develop if water gets into the
antenna. This can cause transmit
degradation, tune fail, and burn
damage to the RF cable and the
power amplifier coupler.
UH-60…
‘Course, always make sure you’re not within 3 feet of the high-powered antenna
when the pilot or crew chief is self-testing the radio or transmitting. The farther
away you are from the antenna, the better off you’ll be. Stand too close too long and
the high frequencies can cause heating of the body. Touching the antenna while the
radio is transmitting can burn or electrocute you.
Make a note until the torque changes are updated in TM 11-1520-37-23-3 and
MWO 1-1520-237-50-76.
M
echanics, defeat is what you’ll feel every time “de feet” step on and break Black Hawk
engine parts while doing rotor head maintenance.
Your bird’s work platform and step areas are a good place for big feet, so keep them
there.
The engine temperature bulb, the engine alternator connector, and the engine starter
speed sensor wiring are the victims when you step on them to get to the rotor head.
For example, stepping on the engine starter speed sensor can damage the internal con-
nections. Then the starter will not sense the engine speed and won’t shut off after the
engine gets up to speed. The pilot has to manually shut off the starter in the throttle
quadrant. And you’ll suffer the wrath of the AVIM electrician for an unnecessary broken
starter switch.
Remember, “de feet” can break connectors and wires, bust lines and make your bird
NMC. Use the authorized step zones.
Torque head in compression sleeves to 18 lb-ft
Torque antenna tube
compression coupling
to 27-30 lb-ft
PS 617
APR 04
39
engine
checks
out… I’m
going
topside.
hey!
watch
where you
put your
feet.
we’ve got
a loose
antenna!
it’s snug.
that’s
s’posed to
be good
enough.
a snug fit
isn’t
good
enough for
this bird!
617. 38-39 (C)
2/28/04
1:17 PM
Page 1
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