The term for moving to a lower altitude is "descending." Why, then, is the term for moving to a higher altitude "climbing" and not "ascending"? The latter goes better with the term "descending."

Does it have anything to do with "ascend" and "descend" sounding similar on the radio?

  • 1
    $\begingroup$ Perhaps a question for the English Language & Usage site, as it is certainly not limited to aviation. We generally speak of climbing mountains & ladders, and of descending them. $\endgroup$
    – jamesqf
    Apr 11, 2018 at 19:32
  • $\begingroup$ @jamesqf Interesting. I don't think that I've ever heard anybody talk about getting down from a mountain or ladder. I may follow your suggestion. $\endgroup$
    – wecsam
    Apr 11, 2018 at 22:38
  • $\begingroup$ While climb is probably a more common word for "going up something" than ascend, I don't think there really is a single-word antonym for it, other than descend. $\endgroup$
    – jamesqf
    Apr 11, 2018 at 22:53

1 Answer 1


One of the most important goals of standard phraseology in radio communications is to ensure that words are distinct enough that a momentary garble doesn't ruin understanding of the transmission. (This is also why a phonetic alphabet is used -- Alpha, Sierra, Foxtrot, etc., rather than just saying the letters A, S, F, ... Imagine if ATC told you on voice something like "taxi to runway 7 via S, hold short F4" and now instead make it "taxi to runway 7 via Sierra, hold short Foxtrot four". Which is less likely to be misinterpreted?)

Another goal, of course, is to have a limited vocabulary of distinct terms that can be used to state things between people who may not be all that familiar with the language.

As you correctly note, "ascend" and "descend" sound very similar. If you for whatever reason miss out on the first syllable, they're outright identical! I'd call it a Bad Thing (tm) to have a single syllable potentially making the difference between just another day at the office, and a mid-air collision.

So when faced with the choice of whether to say "climb" or "ascend", in light of the fact that we're already using the term "descend", it makes sense to use a clearly distinct term for the opposite case to clearly differentiate the two. Hence "climb". The same argument can be applied to the case of both terms being selected together, without either having been selected before the other.

As an aside, "maintain" is also clearly distinct from both, further reducing the risk of confusion. If your altimeter reads 5,000 ft and are asked to "climb to 4,000 feet" or "maintain 6,500 feet" (as opposed to climb and maintain), then you know that someone needs a reality check, and can ask for clarification, even if that request for clarification is only along the lines of "say again assigned altitude and QNH".

  • $\begingroup$ you are absolutely correct it is because they sound simila same goes for affirm and negative or flight level one hundred and flight level one one zero etc.... $\endgroup$ Apr 11, 2018 at 7:06
  • $\begingroup$ See Also: Using Affirm instead of Affirmative $\endgroup$
    – Dan
    Apr 11, 2018 at 10:09
  • $\begingroup$ @Dan Yes. The same basic reasoning would seem to apply. $\endgroup$
    – user
    Apr 11, 2018 at 11:29
  • $\begingroup$ You said that we are already using the term "descend." Is there a particular reason that we chose it and not some other word? $\endgroup$
    – wecsam
    Apr 11, 2018 at 22:39
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    $\begingroup$ @wecsam I said that if you've already chosen to use "descend", it makes sense to not use "ascend". I also said that the same argument can be made if the two are chosen at the same time. Some word is needed, and at one point or another, which synonym to use becomes an arbitrary choice of one over the other. There may be some specific reason why "descend" was chosen to represent a reduction in altitude, but I'm not aware of it; that might be a decent separate question, though. $\endgroup$
    – user
    Apr 12, 2018 at 6:28

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