9 / 20

Flying at 18 000 feet over the ocean, you receive distress messages on the VHF distress frequency from an aircraft as it prepares to ditch. The final transmission you receive fades as the pilot transmits the aircraft’s altitude to be 2000 feet. Assuming no attenuation factors, at what range from you would you expect the distress aircraft to be?

  • A
    220 NM
  • B
    179 NM
  • C
    189 NM
  • D
    119 NM

This question basically asks for maximum VHF range between these two aircraft.
The range of the VDF depends on the following:

  • The formulae used to calculate the range of these radio waves is called the line of sight formulae and is as follows:

Maximum theoretical range (in nm) = 1.23 x √H1 + 1.23 x √H2
√18 000 + √2 000 = 178.7
178.7 x 1.23 = 219.8 which approximates 220.

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.

  • Ireland
    2
  • Italy
    2
  • Germany
    1
  • Lithuania
    1
  • Poland
    1
Keyboard Shortcut Use Keyboard Shortcuts