Kyle Boatright wrote:
I'm always puzzled by the impact obstacles (trees, buildings, etc) have on a
crosswind.

On the day ten years ago when I earned my tailwheel endorsement, there was a
15 knot direct crosswind above the treeline. But, the field was buried in a
small gap between 75' trees and the crosswind effectively disappeared once
the airplane descended below the trees. Even better, there was no
turbulence. I'm still surprised at how easy it was to land in those
conditions.

As opposed to yesterday, when I was landing at a nearby field in a 10 knot,
60 degree crosswind. There was a row of 50' trees a hundred and fifty feet
upwind of the runway, and those trees (presumably) created a nasty burble at
groundlevel.

Because of my widely varied experience with obstacles interacting with
crosswinds, I struggle to pick the *best* runway or landing spot. Is it
better to bet on an obstacle reducing the crosswind, or is that obstacle
likely to cause a burble that will result in a rotten (or exciting) landing?
I'm still trying to crack the code on this one...

Thoughts?

KB




Hi KB;

The way I've always handled this and taught others to handle it is NEVER
to fly ANY approach based entirely on expected wind conditions. I know
this sounds over simplistic on the face of it, but you'd be surprised
how many pilots get a handle on wind somewhere between the base turn and
final and get mentally nailed into that wind mindset. The result can
easily be over concentration on an expected wind direction down through
the approach. Then a sudden gust or wind change catches you napping. The
result of that is a second or two DELAY in reaction time to the change.
Usually it comes out ok, but if a pilot gets caught at exactly the wrong
instant (usually down low just before the flare or entering the flare)
that two second delay can suddenly become a potentially serious affair.

What I like to instill in the pilots I train (in my case have trained
:-) is what I call a non committal mindset for wind on the approach.
Loosely explained, this simply amounts to a pilot developing a habit
pattern that digests wind data as received, and begins the approach with
that data in mind, but instead of thinking of wind direction, I like
pilots to think wind CONTROL.
By thinking aircraft control as opposed to expected wind, what happens
is that you are mentally and physically a bit more "loose" on the
approach because you're not expecting a specific wind correction; you
are correcting for what's HAPPENING NOW all through the approach.
Basically it's nothing more than a slight change in the way a pilot
THINKS and FLIES the approach. You're cutting into that 2 second
reaction time because now you're flying the approach as though the winds
were unexpected instead of expected. You have nothing to lose and
everything to gain by using this mindset. If the winds are as expected,
you're automatically correcting for them. But if you get nailed, you're
loose and expecting that as well!!
DH

--
Dudley Henriques