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Module 13. Aircraft aerodynamics, structures and systems

Aircraft is 9000 ft. When is it out of VHF range

  • 100 nm
  • 120 nm
  • 140 nm

Explanation

VHF is line-of-sight, so range is limited by aircraft height. Using the approximation range (nm) is about 1.23 times the square root of height in feet, the square root of 9000 is roughly 95, giving about 117 nm, so the aircraft passes out of range at around 120 nm.

hkcasper asking:

pls correct me if i m wrong , square foot of 9000 x 1.23 , answer should be 120 nm instead of 140nm?

Community Comments (2)

D
dimky Posts: 514 05.02.2013 / 17:39
Hello.

You absolutely right. Formula for calculating range is 1.25 * sqrt(Altitude).
Thank you for correction.
J
Jordi Posts: 198 28.11.2022 / 18:45
the question should be ; When an aircraft is at a height of 9500ft and the QNH is 500 ft what is the distance that VHF Com cover?

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