曝光台 注意防骗
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the thickest, and therefore safest,
whereas black ice may have running
water underneath and will be quite
thin (for this reason, avoid inflows
or outflows of streams or rivers).
Granular, dirty looking ice is melting.
Large puddles or sheets of water are
also a dead giveaway. However, ice is
never really safe – it doesn’t matter
how many heavy water trucks the
customer may have parked there that
week, helicopters vibrate a lot more
than trucks do or, more particularly,
in a different way, and the hole
punched through for the hosepipe
has already weakened the structure.
Also, however thick they tell you the
ice is, you have no way of knowing
whether it is actually supported by
water underneath (the level may
have dropped), or whether any
running water has eroded the under
surface. Neither do you know
whether any snow on top has
shielded the ice from the cold, or
whether the Sun’s rays have reacted
with bare ice to act as a lens and
create temperatures dangerously
close to a thaw, during which ice
several feet thick can often become
composed of long vertical needles,
known as candle ice (read those old
Hudson Bay survival manuals). Try
and land somewhere else first.
Shut down carefully on an icy
surface, anticipating ground spin
(especially in a Gazelle). After
shutdown, fill any fuel tanks to
prevent condensation, always being
aware of the next payload. Remove
batteries if temperatures are forecast
to be below -10oC. Try to park the
machine facing the sunrise, so the
Sun’s warmth can help with de-icing
the windscreen.
Also see that the battery is fully
charged before departing from base,
and consider taking a spare, together
with an external start cable— if the
ship’s battery runs down completely,
the plates will become sulphated and
won’t actually hold a charge so, even
if you start from an external source,
you won’t be able to start again
without one if you shut down. A
good ploy is to use the external
battery for operating electric fuel
pumps, etc. Check that heaters,
blowers, etc. work and that snow
deflectors are fitted. Also, note
whether tie downs and covers are
serviceable. De-icing fluid cans
should always be carried, as should a
small amount of food. If all this
becomes too much, consider a
support vehicle.
Helicopter External Loads
Note: This part covers the basics for
exam purposes only - for a more
detailed discussion (once you've got
Flight Operations 369
your licence), see The Helicopter Pilot's
Handbook).
In Canada, 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 a multiengined
helicopter that can hover on
one engine, with 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.
Static Electricity
This comes from a number of
sources, mainly engine and
precipitation charging from friction
between the aircraft's surfaces and
airborne particles. There is also a risk
from thunderstorms and airborne
snow particles.
Although the capacitance associated
with this is small, voltages as high as
tens of kilovolts can throw people to
the ground, as well as being
dangerous near potentially explosive
cargoes or fuel tanks, or even shortcircuiting
the hook’s electrics. It's for
this reason that an earthed static
discharge probe is applied to the hook
before any contact takes place and
the procedure kept up as much as
possible. If you can’t get one, make
the guys wear thick rubber gloves.
Setting Up
Before doing anything else, you
should check the following carefully:
Helicopter Condition
Check your HOGE performance
and use the standard lapse rate if you
don’t know what the temperature is
at the dropoff point. Remember
your fuel consumption will be higher
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Canadian Professional Pilot Studies2(104)
