PS Magazine - TB 43-PS-622
PS, The Preventative Maintenance Monthly
ISSUE 622
SEPTEMBER 2004
PS 622
SEP 04
10
M977-Series
HEMTTs…
When lifting
ammunition with
the crane on your
M9
77
-series
HEMTT, the
last
thing you want to
see is a sling
failure.
in fact, you
don’t even
want to be in
the same zip
code if that
ammo comes
crashing
down.
hold it!
I see
some
rust
around the
hooks!
Double basket chain sling
holds up to 6,000 pounds
Wire Rope Damage
Kinking
Crushing
Caging
Popped core
Step one
in preventing sling failure
is to keep the sling properly marked.
At a minimum, the sling should show
the ID number (vehicle number and
sling NSN), load rating, and the next
required inspection date.
Unmarked slings are more likely to
be abused. Without those guidelines,
the slings may be overloaded or used
for the wrong purpose. That’s
very
dangerous for you and others.
There are two slings authorized for
use with the HEMTT. The double bas-
ket chain sling, NSN 3940-01-209-
6008, has a rated load of 6,000 pounds
(3,500 pounds per chain). The six-
legged projectile sling, NSN 3940-01-
241-7400, has a rated load of 5,400
pounds (1,350 pounds per leg).
Step two
is to functionally load-
test the slings annually at 100% of
their rated capacity. TB 43-0142,
Safety inspection and Testing of
Lifting Devices,
tells you how.
Step three
requires inspecting the slings
annually. Here’s how:
Double Basket Chain Sling
With the sling on the ground, eyeball
the chains link-by-link. Watch for any
link that does not hinge freely with its
adjoining link and for obvious signs of
stretching. Also look for bent or twisted
links, defective welds, nicks, gouges, and
any wear that exceeds 3/64 inch from the
chain’s original 1/4-in thickness.
If you spot any of these problems, the
sling is unsafe and should be replaced.
Six-legged Projectile Sling
Replace the sling’s wire rope when
you find broken wiring (six or more ran-
domly distributed broken wires or three
broken wires in one strand).
Next, check the diameter of the wire
rope. If it’s reduced by more than 1/32
inch from the rope’s original 3/8 inch
diameter, replace it.
Pay special attention to the wire rope
near the hooks. Internal corrosion is a
problem there. Replace ropes with wire
strands that show signs of pitting.
Wire ropes that show severe kinking,
crushing, caging, or a popped core should
also be replaced.
622.10-11(C)
7/30/04
4:22 PM
Page 1
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