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Old June 20th 06, 01:03 PM posted to rec.aviation.ifr,rec.aviation.piloting,rec.aviation.student
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Default NTSB report - ILS and ATC. How does it all come together?

M wrote:
I don't understand your calculation. At 2.5 miles from the touch-down
zone (assuming that's what it is), the GS should be about 750 feet
above the touch-down zone elevation. The pilot was way below the
glideslope.

(Simple and quick approximate calcuation method: 2.5mi = 15000 feet.
The 3 degree ILS is approximately 1:20 approach ratio. So 15000 / 20 =
750 ft).



Using trigonometry, I get ~ 785ft 2.5 miles out from the touch down
zone, so your method is pretty accurate. Here's my calculation:

Assuming:
Distance = 15,000 ft
Slope: 3 degrees

Height = Distance * sin(Slope) = 785.04 ft.

Mike



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Mike