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shackle that goes inside the eye must
be the right size for the hook,
otherwise it may come out by itself,
or not come out when it’s supposed
to (as a guide, the shackle pin should
be the same thickness as the rope –
DON’T use a bolt instead; it will
bend). Using a swivel will stop the
load from spinning and unravelling
the line. That is, you put the swivel
in the hook, then attach the load to
the swivel (which, by the way, has a
thrust bearing in it). When using a
screw-pin shackle (clevis):
with a rope of whatever description,
don’t have the shackle downwards
(as shown above), because the rope
will slide from side to side and have
a tendency to open the legs (if it rolls
fore and aft, it will also undo the
pin). Rather, place the screw-pin in
the helicopter hook, padding the
empty space either side with washers
or similar, and use it upside down.
Chokers, technically, are lanyards
that hold loads with a slipping noose
which tightens under tension – the
harder the pull, the tighter the grip.
Use chokers at the end of a line
rather than by themselves so that, if
they break, they are kept away from
the blades by the line (this also helps
prevent collective bounce—see
below). Be aware that a choker has
25% less safe working load because
of the bend in the rope at the noose.
The sharper the bend is, the less the
SWL will be.
Long lines (see below) have an
electrically operated hook at the end,
which really makes them an
extended hook, so there will be an
electrical cable for the release
mechanism, which should be
carefully looked after; that is, the line
and cable must be detached properly
by ground crew, otherwise you will
strip the cables, which won’t impress
the engineers. If the insulation
comes off, you may also get a short
circuit. Lines made of Spectron or
Kevlar are strong, but light, so will
trail after you more than a steel line,
hence the maximum external load
speed. These lines also get longer
when new, so, if you can’t prestretch
them, allow a good length of
extra electrical cable.
Use barrel hooks on a sling for
lifting fuel drums, although you
might find varying designs to suit
different helicopters. For example, a
206 might have one for 2 drums
while a 205 might have one for 5.
Whatever you use, use the bungee
cord to keep them together when
there is no tension. Again, don’t
connect the hooks directly to the
aircraft, but to a sling.
Specialised Tasks 25
Minimum Sling Specifications
0-
1500
lb
1500-
3000
lb
3000-
5000
lb
5000-
10000
lb
Lanyards
(steel core)
7/16” ½ ” 5/8” ¾ ”
Lanyards (poly
– 6ft)
5/8” 1-
1/8”
1-
1/4”
1-3/8”
Cables &
Chokers –
single point
7/16” ½ ” 5/8” ¾ ”
Cables &
Chokers –
multi point
3/8” 7/16” ½ ” 5/8”
Shackles,
Clevises
½ ” 5/8” ¾ ” 7/8”
Nets (lb) 1500 4000 5000 10000
Ext hooks 7/16” 5/8”
Use heavier than normal shackles to
accommodate multiple lines.
Loading and unloading areas
Non-involved people should be
absent, and there should be no loose
articles to be blown around by the
downwash and cause damage (it is
possible for slash to snag and
inadvertently operate the manual
release). Approach and departure
lanes should be into wind.
Performance planning
Check your Hover performance Out
of Ground Effect (HOGE), in case
it places a ceiling on your Max All-
Up Weight, although most
helicopters have a higher Gross
Weight anyway for external loads.
Here are charts of suggested
payloads for various types according
to Pressure Altitude:
Preparation of loads
There are 4 basic types of load –
rectangular, cylindrical, heavy
compact and nets, and five ways of
lifting them, starting with nets and
ending up with a four-point sling
(through 1-, 2- and 3-point). Nets
are used for loads consisting of
many small pieces, and are very
useful for killing lift with loads that
can act like a bucket as you fly (like
an Argo). On a 206, one about 10-12
feet square with a 2” square mesh is
　
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本文鏈接地址：The Helicopter Pilot’s Handbook(16)