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that will indicate the level of an
inversion. You then fly with your
rotors just above the smoke to bring
the warm air down and prevent frost
on crops, so, unlike Chapter 3, this
chapter won't be boring!
Note: Some of this is dangerous!
Don’t try any of it without training!
176 Operational Flying
External Slung Loads
A helicopter can go where cranes are
impractical or more expensive, or
you might not be able to get a load
inside the machine (maybe you
wouldn’t want it there anyway, if it’s
a dead animal or explosives), so you
try and lift it.
In theory, you can lift anything,
provided the payload is available;
I've even been asked to quote for
lowering 800 feet of unrolled
telephone cable down a mine shaft,
because the drum it was rolled on
wouldn’t take the weight. However,
more common tasks are logging,
placing air conditioning or
ventilation equipment on the roofs
of tall buildings, pulling cows out of
bogs, picking up water to put out
forest fires (water bucketing),
dropping solution over forests (top
dressing) or moving seismic
equipment about. In fact, many tasks
done with a helicopter are really
extensions of load slinging, and, in
remote areas, this will be a major
part of your bread and butter – really
specialised stuff will be found as
subheadings below. A typical length
is 25 feet, but can be up to 200, so
don’t forget to include the line as
part of the payload – it will be heavy
(try about a pound a foot).
If you get involved with the airconditioning-
type loads on top of
buildings, you will need a permit
from the local authority, who will
also need a lot of advanced notice.
Check also for any bye-laws, the
local environmental people, police
and fire services (who may charge
you for extra crews).
Logging, officially, is removing felled
and bucked logs from areas where all
trees have been felled. It is very fast,
with lots happening at once, and
there will be a smaller helicopter to
carry the used chokers every 75
minutes or so (chokers are lanyards
with the equivalent of a slip knot
which tightens as the load is taken
up, making it more secure). It is not
an operation based on finesse, as the
machines are continually using full
power cycles and undergo a lot of
twisting, etc. If you’re planning to
buy a helicopter that has been used
on logging, inspect it very carefully!
Selective logging is removing wood
from where trees are standing, and is
considerably more dangerous, at
least to workers on the ground,
because the downwash could
dislodge all sorts of things. Cedar
salvage involves moving loads of cut
cedar blocks, which should all be of
a similar length for best stability.
Logs will be taken from high ground
first so there is less risk of anything
falling on workers below and you
can see what’s going on better. They
Special Use Of Aircraft 177
will be delivered to holding points
on land or in water.
In UK, you will find it useful to
check out the following:
CAP 426 Helicopter External Load Operations
ANO Art 35 Public transport aircraft &
suspended loads
Rule 47 Marshalling signals
ANO Art 55 Picking up and raising of persons &
articles
ANO Art 56 Dropping of articles & animals
In Canada and USA, external loads
come in four classes, A, B, C and D.
A Class A load does not extend
below the landing gear and is usually
bolted to the aircraft, such as a
stretcher, spray kit or fuel tank. A
Class B load can be jettisoned and is
not in contact with land, water or
any other surface. A Class C load is
similar, but remains in contact with
the surface (like when towing) and a
Class D includes a person or is
anything that doesn’t come inside
the other classifications, for which
you need two methods of release
and must use a multi-engined
helicopter that can hover on one
engine in the prevailing conditions,
with appropriate engine isolation.
However, most loads will be Class B.
If you do all this over a built-up area,
an Aerial Work Zone Plan needs to go
to Transport Canada at least 5 days
in advance.
Ex-military pilots will have done all
this as part of their original flying
course, but, in some companies,
"training" is once around the circuit.
If you're "experienced" with some
slinging in the past year you can
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