I want to learn what is the distance unit on a navigation display.


I pointed the distance marks with red circles on the navigation display. What are these 10, 15 etc. values' unit? Are they representing mile, nautical mile or kilometer?

And can it be adjusted in a different measurement unit (mile, kilometer or nautical mile) or is it a standard unit for aviation and navigation displays?

  • 1
    $\begingroup$ Can you add the image source please? $\endgroup$
    – user14897
    Commented Jan 19, 2018 at 13:51
  • 5
    $\begingroup$ At top right of the image it indicates that the SBG waypoint is 7.5NM away, and that waypoint is shown exactly (?) between the 5 and 10 range rings on the main part of the display. So by inspection, it's in nautical miles. You can read about standard units in aviation in this question. $\endgroup$
    – Pondlife
    Commented Jan 19, 2018 at 14:09

1 Answer 1


They are nautical miles, which is the standard for essentially all discussions of distance in aviation. (Visibility being an exception; it can be reported in essentially every unit except nautical miles.) The software certainly could switch the display to another scale such as kilometers, although I’m not familiar with any systems that provide that option.

  • $\begingroup$ In addition the mode (here "arc") and the range (here "20" NM) can be selected using the EFIS control panel. $\endgroup$
    – mins
    Commented Jan 19, 2018 at 16:29

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