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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