曝光台 注意防骗
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while still airborne, as well as turning
on your ELT, or SARBE. If time
permits, warn the passengers to don
their lifejackets (without inflating
them, or the liferafts) and tighten
seat belts, remove any headsets, stow
any loose items (dentures, etc.) and
pair off for mutual support, being
ready to operate any emergency
equipment that may be to hand (they
should have been briefed on this
before departure).
One passenger should be the
"dinghy monitor", that is, be
responsible for the liferaft. If it's
dark, turn on the cabin lights and
ensure everyone braces before
impact (the brace position helps to
reduce the flailing of limbs, etc. as
you hit the water, although its
primary purpose is to stop people
sliding underneath the lap strap;
there are different ones for forward
and aft seats).
If only one swell system exists, the
problem is relatively simple—even if
it's a high, fast one. Unfortunately,
most cases involve two or more
systems running in different
directions, giving the sea a confused
appearance. Always land either on
the top, or on the backside of a swell
in a trough (after the passage of a
crest) as near as possible to any
shipping, meaning you neither get
the water suddenly falling away from
you nor get swamped with water,
and help is near.
Although you should normally land
parallel to the primary swell, if the
wind is strong, consider landing
across if it helps minimise
groundspeed (although in most cases
drift caused by crosswind can be
ignored, being only a secondary
consideration to the forces contacted
on touch-down). Thus, with a big
swell, you should accept more
crosswind to avoid landing directly
into it. The simplest way of
estimating the wind is to examine
the wind streaks on the water which
appear as long white streaks up- and
downwind. Whichever way the foam
appears to be sliding backwards is
the wind direction (in other words,
it's the opposite of what you think),
and the relative speed is determined
from the activity of the streaks
themselves. Shadows and whitecaps
are signs of large seas, and if they're
close together, the sea will be short
and rough. Avoid these areas as far
as possible—you only need about
500' or so to play with.
The behaviour of the aircraft on
making contact with the water will
vary according to the state of the sea;
the more confused and heavy the
swell, the greater the deceleration
forces and risks of breaking up
(helicopters with a high C of G, such
as the Puma, will tip over very easily,
and need a sea anchor to keep them
stable – in fact, the chances of any
helicopter turning upside down are
quite high). Landing is less
hazardous in a helicopter because
you can minimise forward speed. In
fact, if you are intentionally ditching,
you should come to a hover above
the water first, then throw out the kit
and the passengers. Having moved
away, settle on the surface. If you
can’t do that, a zero speed landing
Operational Stuff 101
should be aimed for, which means a
steep flare a little higher and sooner
than normal – any fore and aft
movement on landing may cause
rocking. Level off higher, as well.
You need to protect your thumbs
throughout the whole process, as
undoing a seat belt is a lot more
difficult without them. Another tip is
to reduce the length of your neck by
hunching your head into your
shoulders, like a turtle. Be
particularly aware that anything
happening to the blades will be
transmitted through the controls,
and may well be painful, or worse, if
you get the cyclic in your stomach.
At some stage you will be able to do
nothing further with the controls, so
be prepared to take place your limbs
so that they do not flail about.
Keep the knees together, and
prepare to use the hand near the exit
to get out with, and the other to
release the seat belt, but not until the
machine is completely under water
and has preferably stopped moving.
This is to ensure you keep the same
relative position to the chosen exit.
It will also provide extra leverage if
you have to push against anything.
Once on the water, hold the
machine upright and level using all
the cyclic control there is, and use
the rotor brake (if you've got one).
Then let the aircraft sink. Rolling
towards the retreating blade is one
consideration, but this will increase
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本文链接地址：
The Helicopter Pilot’s Handbook(67)
