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there, so you may
be used as
transport for firefighters
and their
equipment, as
well as
observation,
where your
passengers will
have some rank
and experience, since they will be
directing ground forces from the air
(this will be especially true for lesserpowered
helicopters). Very often,
you will be moving people in very
short hops over rivers and streams.
One development of this is rappelling,
which is the rapid deployment of fire
crews by rope from a helicopter (and
back in emergency) until the regular
crews arrive. This saves them the
trek to the fire in the first place and
ensures they are not exhausted when
they start. They can survive for up to
48 hours in the bush, and a
Command Spotter will stay in the
helicopter. All this will typically be
46 The Helicopter Pilot’s Handbook
for fires started by lightning, which
are often in remote locations, down
to weather conditions roughly
equivalent to Special VFR.
Rappelling shouldn’t be done when
it’s too windy, or when it’s raining,
as the special rope used will swell up
in the pulleys and stop working (just
for interest, lightning can be up to
50,000° in temperature – when it hits
a tree, the sap boils and the heat can
be held internally for days until fire
actually breaks out).
You will also not necessarily be the
only aircraft about. The combination
of lots of smoke (and poor visibility),
coupled with heat turbulence and
other machines buzzing about could
prove to be extremely dangerous –
many people report it’s just like
being in a war zone (the organised
chaos only makes it more so), but if
you've ever done the British Grand
Prix or joined Biggin Hill circuit you
should be alright. Constant
communications between machines
(on the same frequency) are
essential, especially if you are picking
up from the same swimming pool (in
practice, you will go through the bird
dog if you want to change position).
One pilot reported that the distance
from a pond to the fire was so small
as to only require a fast hover taxi
between them both, which meant
that oil temperatures began to
redline, as there wasn’t enough
airflow to cool things down
(sometimes ash will clog the oil
cooler). You will be tired, as well,
after a couple of days' continuous
flying from dawn to dusk, though
you won’t notice till afterwards, as
adrenalin counts for a lot.
Upslope drops should be avoided as
much as possible, and only be
attempted by experienced crews,
especially on low targets, as you will
need more airspeed than normal to
create a pull-up to clear the area with
the load if necessary, without using
extra power. Aside from trying to do
a 180-degree pedal turn in a high
hover out of ground effect, the
resulting high power setting will
likely fan the flames, as with a hover
drop. It helps if you have a drop off
place to one side, and approach with
some airspeed, so you can climb
with the cyclic, and turn one way or
the other with the least power,
depending on which way round your
blades are going.
With downslope drops, you will not
necessarily see the target until you
clear the ridge, so you will need
targets to line up on beforehand. For
very steep slopes, try reducing speed
before diving off the ridge, so you
don’t end up going too fast. Crossslope
drops are OK, provided you
remember where your rotor disk is.
With North American blade
rotation, keep downhill slopes on
your right, so if the bucket doesn't
open or you run out of power, you
can drop the collective, put the nose
down and be able to use the right
pedal to take the strain off the tail
rotor. Always approach at a 45°,
unless you have a bit of height.
In order not to make embarrassing
mistakes, like dropping water in the
wrong place, you need to be aware
that some fires are deliberately set
(see below), to make use of airflow,
as in “backfiring”, and there may
well be someone around with a
driptorch attached to their machine
to do it with.
After the excitement is over, and the
fire comes under control, typical
Specialised Tasks 47
tasks will be moving men and
materials around, putting out
hotspots, IR scanning, recovering
equipment and generally tidying up.
Aerial Ignition
The waste product from the
　
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本文鏈接地址：The Helicopter Pilot’s Handbook(31)