AOPA Pilot Magazine - October 2013 - 22

LICENSE TO LEARN

Having a clue, or two

BY ROD MACHADO

Look to the runway for the answers
IF YOU KNOW what to look for, there’s something deeply
satisfying about watching a runway’s geometry grow
proportionally in your windscreen. I’m speaking of the
picture you see on a stabilized approach whose trajectory takes you to a nice safe spot located somewhere in
the center of the first third of the runway. The runway’s
expanding trapezoidal shape provides the assurance
that your glidepath is steady and true, but only if that
shape doesn’t change over time. So let’s see how your
approach shapes up.
On a stabilized approach, your airplane’s attitude,
airspeed, and descent rate are constant. The optical for
your flying skill reveals itself in your windscreen as a
distant spot on the runway that appears not to move.
We call this the stationary spot for obvious reasons. It’s
where the airplane’s trajectory intersects the landing
surface. Hopefully, this intersection occurs somewhere
on the runway.

The runway’s trapezoidal shape as it appears in
your windscreen should remain exactly the same
all the way down, despite growing in size.

ROD MACHADO

will be a featured
speaker at AOPA
Aviation Summit
October 10 through
12 in Fort Worth,
Texas.

22 | AOPA PILOT October 2013

While heading toward this stationary spot on a normal glidepath (i.e., not too steep, not too shallow), the
ends of the runway should appear to be separated by
a reasonable distance (they shouldn’t appear to be too
close together or too far apart). The runway’s trapezoidal shape as it appears in your windscreen should
remain exactly the same all the way down, despite growing in size. On the other hand, if you’re on final approach
and the runway’s trapezoidal shape changes because its
ends are moving farther apart or closer together, then
your glidepath is also changing. You can’t kid Euclid.
Most likely your stationary spot has gone rogue and is no
longer located in the first third of the runway (if it’s even
still located on the runway). This is how your eyeballs
provide you with something known as a “clue” about
your airplane’s trajectory. So look for your clue on final,
because if you land somewhere other than on the runway, pilots will claim that you didn’t have one.
The behavior of pilots who fail to pick up their clue
on final typically falls into one of two categories.
Pilots who fail to descend quickly enough on final
approach fall into the where’d it go? category. As they

turn final, the runway trapezoid appears long and thin
because its ends are separated by a large distance that
gets larger over time. In many instances the runway
threshold disappears under the cowling, prompting
the pilot to ask, “Where’d it go?”
Some pilots attempt to salvage this approach by
turning their elevator into a threshold divining rod—
one that’s specifically tuned to locate the beginning of
any runway. They move the elevator forward as if dowsing for the threshold far below, and commence flying
a steep and fast approach. Given the large amount of
energy that would have to be dissipated prior to landing, these approaches are difficult to salvage. They do,
however, produce a lot to salvage unless the pilot wises
up and goes around.
On the other hand, pilots who descend too quickly
on final approach fall into the what happened to it? category. As they turn final approach, the runway trapezoid
appears short and squatty because its ends are separated
by a short distance that becomes even shorter over time.
The normal-looking runway trapezoid they expect to
see on final now looks like a helipad, appearing nearly
as tall as it is wide, thus prompting them to point and
ask, “What happened to it?”
Most likely, the stationary spot that was once located
on the runway went mobile and has now relocated itself
to a place short of the runway threshold. A pilot can salvage this approach by activating the airplane’s salvage
lever—otherwise known as the throttle. The elevator
should not be your only line of defense after mumbling
the words, “Is that it?” So throttle up and simultaneously readjust your flight path with the elevator. This
is how you achieve a normal glidepath to the runway
and salvage the approach.
Those of us who aren’t named Euclid can get an
extra clue or two about our glidepath by observing the
runway’s geometric shape on approach. Perhaps an
older military pilot who flew before VASIs were common expressed this idea best in a recent blog post:
“One of the key things I used to impress on my
students was the need to monitor two things continuously during a landing, runway aspect and speed. This
ensured that they only concentrated on the absolute
minimum number of things that mattered during the
approach and landing.”
AOPA
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www.rodmachado.com

http://www.rodmachado.com

AOPA Pilot Magazine - October 2013

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