A good pilot is always learning -- how many times have you heard
this old standard throughout your flying career? There is no truer
statement in all of flying (well, with the possible exception of
"there are no old, bold pilots.") It's part of what makes aviation
so exciting for all of us... just when you think you've seen it
all, along comes a scenario you've never imagined.
Aero-News has called upon the expertise of Thomas P. Turner,
master CFI and all-around-good-guy, to bring our readers -- and us
-- daily tips to improve our skills as aviators, and as
representatives of the flying community. Some of them, you may have
heard before... but for each of us, there will also be something we
might never have considered before, or something that didn't
"stick" the way it should have the first time we memorized it for
the practical test.
It is our unabashed goal that "Aero-Tips" will help our readers
become better, safer pilots -- as well as introducing our
ground-bound readers to the concepts and principles that keep those
strange aluminum-and-composite contraptions in the air... and allow
them to soar magnificently through it.
Look for our daily Aero-Tips segments, coming each day to you
through the Aero-News Network. Suggestions for future Aero-Tips are
always welcome, as are additions or discussion of each day's tips.
Remember... when it comes to being better pilots, we're all in this
Radar is most closely identified with thunderstorms. But radar
images do not tell us where clouds are stormy -- they only show
precipitation. How can we accurately use radar reports, and how do
we use radar returns to avoid thunderstorms?
All "official" aviation radar depictions and
uplinked weather plots are derived from ground-based radars.
Antennae send out strong electric pulses that reflect back when
they encounter resistance; each radar transmitter can also receive,
and therefore detects those signals that have been reflected back.
Radar frequencies can be set for optimal return when hitting rain
Not every bit of the
radar energy reflects back. Some will penetrate the precipitation
until reflected back from a greater range. This allows radar plots
to show precipitation at some depth into the area, instead of
merely drawing a line at the outer edge of rain or snow. But some
energy is absorbed in the process, either "on the way in" to the
precipitation or after reflection "on the way out" en route to the
receiver. Loss of radar signal is called attenuation.
Note: Airborne radar, for those pilots
blessed with such systems, is subject to the same
Consequently radar shows the outer edges of precipitation quite
well, with varying success plotting "returns" inside the outer
edge. In strong precipitation attenuation will leave gaps or "black
holes" on the screen behind plotted returns-not because there's no
activity there, but because all the radar energy was absorbed by
the outer lines of precipitation. Some ground-based radar plots
artificially "fill in" areas between images derived from different
radar stations, using computer models to estimate likely rainfall
rates in attenuated areas.
Radar and thunderstorms
Thunderstorms, nonetheless, usually deliver copious rainfall, so
it's common to look to radar imagery when seeking the location of
thunderstorms. Bear in mind that rain only begins to fall when the
thunderstorm reaches the mature state-long after lightning begins
to flash and dangerous turbulence exists in, around or under the
cloud. Further, heavy rain (as indicated by strong radar returns)
does not always mean a thunderstorm, and may in fact result in a
smooth flight through the in-flight deluge. As a general rule,
- Avoid flying through areas of heavy radar returns.
- Don't assume a thin line of precipitation with no returns
beyond means a safe passage-attenuation may not reveal heavier
returns until you get closer.
- Don't think just because you have the picture in the cockpit
means you know the nuances of flying using radar as a guide-it
takes dedicated instruction (example) to learn how to use radar
Aero-tip of the day: Understand the use, and the limitations, of
weather radar information.