Flight Training - June 2020 - 47

ADVANCED PILOT CAREER PILOT

EARTHQUAKES,
VOLCANOES, AND COUPS
D'ÉTAT MIGHT NOT BE
AS MUCH OF AN ISSUE
IF YOU ONLY FLY WITHIN
THE CONTINENTAL UNITED
STATES, BUT THAT'S NO
EXCUSE FOR NEGLECTING
ALTERNATE PLANNING.
your fuel planning leaves you no better
options than landing off-airport, on a
closed runway, or on a taxiway-never
mind penetrating a temporary flight
restriction!-your action pretty well
guarantees a close official examination
of your fitness to continue exercising
pilot-in-command privileges.
If you are flying IFR with a significant chance of a weather diversion,
it's worth calculating how a diversion
could affect your rationale for making
the flight in the first place. There's no
single answer. If the occasion's a family
reunion, you're heading up a day early,
and good weather and rental cars are
available 50 miles away, it makes sense
to go. But if you're planning to land at
Cleveland's Burke Lakefront and walk
up to Progressive Field to meet old
friends at an Indians home game, the
forecast's already at minimums, and
the nearest reliable alternate is Erie,
Pennsylvania, you could be forgiven for
deciding to stay home. Unless you enjoy
unplanned stays in unfamiliar hotels,
even a one-in-four chance of being
unable to complete the flight as planned
may be reason to cancel it or wait for
better weather. Your freedom to fly
includes the freedom to decide not to fly
on days when aviating seems less likely
to work to your advantage. FT
DAVID JACK KENNY is an airline transport
pilot and freelance aviation writer living in
Frederick, Maryland.

WEATHER
RADAR RULES

VITAL TOOL REQUIRES KNOWLEDGE OF ITS SHORTCOMINGS
BY PETER A. BEDELL

HOW IS IT that jet airplanes reliably fly
in nearly all weather conditions? Performance and equipment are two big
reasons. For example, a jet's performance allows it to rapidly climb up
through icing layers, making iced-up
jets a rare occurrence. Even iced-up
jets have reliable ways to shed it in the
form of heated surfaces such as leading
edges, engine inlets, windshields,
and more. Another big advantage
jets have is weather radar to avoid
thunderstorms.
Weather radar has been around for
decades and has been miniaturized
enough to find a home in larger light
general aviation airplanes since the
1970s. It provides a real-time image of
the weather. Nexrad images that can
be datalinked to in-cockpit displays
represent a more recent technology
that, although beneficial, is subject to

a potentially hazardous lag from when
the image was obtained to the time it is
processed and reaches the instrument
panel. While Nexrad datalink is a great
tool, it is not good for getting up close
and personal with thunderstorms.
Radar is the way to go but it, too, has its
limitations.
It's smart to think of weather radar
as a water detector. It only paints
precipitation, and liquid precipitation reflects most effectively. Frozen
precipitation such as snow and ice/
hail may not even show up. Radar uses
a receiver/transmitter. It transmits a
beam of energy that reflects back to a
receiver. This gets translated into an
image on a screen. Radar paints land
but not bodies of water. But didn't I just
say radar was a water detector? Land
reflects energy back to the receiver
whereas bodies of water bounce the
AOPA.ORG/FT

47
http://www.AOPA.ORG/FT
Flight Training - June 2020

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