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Old August 19th 03, 06:51 PM
Marty Ross
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Default How much turbulence is too much?

In reviewing the Warrior II's performance numbers in preparation for my
recent trip across California, I realized that Va would be much lower than I
had always considered it (given that it's just me inside, with gas burning
off towards reserve only). The Va that's written on my lapboard is 111
KIAS, however that's figured at gross weight (2325 lbs). It goes down all
the way to 88 KIAS (at 1531 lbs.), so I was surprised to see how slow I need
to go, according to normal procedures, when it gets turbulent in the Warrior
(e.g., I should slow down to mid-90's)!

-----------
(from the Warrior's POH, sec. 4.37: "Turbulent Air Operation"):
"In keeping with good operating practice used in all aircraft, it is
recommended that when turbulent air is encountered or expected, the airspeed
be reduced to maneuvering speed to reduce the structural loads caused by
gusts and to allow for inadvertent speed build-ups which may occur as a
result of the turbulence or of distractions caused by the conditions."
-----------

I specifically note this POH's references to "good operating practice used
in all aircraft" and "the structural loads caused by gusts" as they relate
to another question (of turbulence causing increased airframe stress) on
this thread.


"David Megginson" wrote in message
...
Ray Andraka writes:

How does one know if the turbulence is great enough that you should
slow down to Va to keep from structurally damaging the airplane?


If you have to ask, slow down.

Seriously, if I'm just bumping a bit (light chop), I don't worry. If
I'm actually getting uncommanded altitude or orientation changes
(i.e. a sudden 10-degree bank, or a sudden 200 foot altitude change),
I slow down to Va.

I also use some common sense. If I'm flying at 2500 ft AGL under a
clear sky in the afternoon (in the flatlands), I know it's just
thermals and a bit of mechanical turbulence: no big deal. If I'm
flying under cumuloform clouds and they're starting to build (and
there's reported ACC, TCU or CB), I assume that the turbulence could
get bad without warning, so I slow down as soon as I start bouncing
around.


All the best,


David

--
David Megginson, , http://www.megginson.com/