The COMPASS Jan Issue | Page 12

aircraft is shown for the sake of further discussion below. We can use basic trigonometry to determine the distance from our eyes to an aim point. In the case
If you want to find the distance between where your eyes are pointed on approach and landing versus where your wheels are, you will need some dimensions. Specifically, you need the distance between the aftmost landing gear and the pilot ' s eyes. That may take some detective work or perhaps just a good tape measure. In the case of the G450, the operating manual gives us the distance between wheels: 39’ 1-1 / 4”. The G450 Weight and Balance Manual tells us the nose wheel has a horizontal arm of 48.1” while the pilot is at 41.0”, 7.1” forward of the nose gear. Assuming the pilot’ s eyes are at the point
used for the center of the
of a three degree glide path,
pilot’ s mass, we can deduce:
our G450 pilot’ s eyes will be
263’ behind the aim point,
We’ ll call that an even 40
which means the wheels
feet.
will be 303’ behind the aim
Further research leads us
point. In other words, if
to a Gulfstream Eye Wheel
you are aiming for the five
Height Paper which tells
hundred foot markers and
us the pilot’ s eyes will be
don’ t flare, you wheels will
between 10.4 and 10.8 feet
just barely make the runway.
off the ground, depending on
Add a gust of wind or just
weight and center of gravity.
a little deviation from glide
We’ ll use 10.5 feet.
path, you may not reach the
runway at all. What about
Photo: G450 eye wheel
aircraft with flatter deck
height, from Tom’ s notes.
angles? The Challenger 604,
The Gulfstream Eye Wheel
for example, has 0 ° approach
Height Paper tells us our
deck angle. To isolate only
eyes will be 13.8’ off the
the deck angle factor, we
runway when the wheels
will use G450 dimensions to
touch on landing, which is
explore the impact of deck
what we needed for this
angle on look down angle.
exercise. The process to
find the deck angle of the
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