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 good pilots, we're all in this
Any sudden shift in wind speed or direction is going to have
adverse effects on an airplane. If it happens close to the ground,
you may not have room to recover.
You’d think wind doesn’t affect an aircraft once it
is flying, except for drift and groundspeed. This is true with
steady winds or winds that change gradually. It isn’t true,
however, if the wind changes faster than the aircraft mass can be
accelerated or decelerated.
- If a strong tailwind component shears suddenly to a headwind,
airspeed increases, lift is enhanced, and the airplane will
end up high and fast -- shearing toward a headwind is a
performance increasing event, not bad on
takeoff but potentially dangerous if the shear happens just as
you’re crossing the tree line when landing on a short runway
(when the headwind shear will make you land long).
- A headwind quickly shearing to a tailwind, conversely, is a
performance decreasing event.
You’ll find yourself low and at too low an airspeed... not
good either landing or taking off.
Thunderstorms and strong frontal passages can cause hazardous
wind shear. Wind shear can be found on all sides of a thunderstorm
cell. The wind shift line or gust front associated with
thunderstorms can precede the actual storm by up to 15 nautical
miles. If a thunderstorm is near an airport, low-level wind shear
hazards may exist in the pattern. At some large airports a
low-level wind shear alert system (LLWAS) has been installed.
A cold front wind shear occurs just after the
front passes and for a short period thereafter. If the front is
moving 30 knots or more, the frontal surface will usually be 5,000
feet above the airport about 3 hours after the frontal passage.
With a warm front, the most critical period is
before the front passes the airport. Warm front windshear may exist
below 5,000 feet for approximately six hours before frontal
passage, but ends after the front passes the airport. Data compiled
on wind shear indicate that the amount of shear in warm fronts is
much greater than that found in cold fronts.
Aircraft speed, aerodynamic characteristics, power/weight ratio,
powerplant response time, and pilot reactions are factors that have
a bearing on wind shear effects. Wind shear can cause problems for
any aircraft and any pilot.
Aero-tip of the day: Be alert to the
possibility of low-level wind shear at any time near fronts or
thunderstorms. Delay takeoff, or divert for landing, if faced with