The reason why pilots say “niner” instead of nine is to avoid miscommunication over an occasionally fuzzy radio transmission. Miscommunication up in the sky among pilots and air traffic control can lead to devastating consequences, so it’s paramount that communication is as clear as possible.
If you think about it, the number “nine” sounds similar to “five”, especially when the radio transmission isn’t crystal clear – as it often isn’t. To a lesser extent, the word nine can easily be confused with the German word for “No”, which is “Nein” and pronounced in exactly the same way.
The importance of the use of numbers in aviation can’t be understated. As numbers are used for altitudes, flight levels, frequencies, velocities, weather-related information, runway directions, and more, it must be immediately clear what numbers are being said and understood.
Pilots pronounce the numbers from 1 to 10 as follows:
0: Zero
1: Wun
2: Two
3: Tree
4: Fower
5: Fife
6: Six
7: Seven
8: Eight
9: Niner
10: One zero
100: Wun hundred
1,000: Wun thousand
10,000 – Wun, zero thousand
As you can see, most numbers are pronounced like you would expect, though a couple of numbers like 1 and 4 are more emphasized for clarity. There are a few numbers that are clearly different, though, and the way 10,000 is said might be particularly confusing to you.
Let’s go through them.
3 is pronounced “tree” to avoid confusion with 2.
5 is pronounced “fife” to make it sound more abrupt and clear and avoid confusion when a pilot says “nine” instead of “niner”
10 is pronounced “one zero” and 10,000 as “wun, zero thousand” because single digit and group form phraseology ensure absolute clarity.
Do All Pilots Say Niner?
The extent to which pilots pronounce numbers as stated above varies. In most circumstances, pilots will say “niner”, though “tree” and “fife” are said less often, even though they are part of the official FAA phonetic pronunciation. It can sometimes be a regional thing too, with some regions using the official FAA phonetic pronunciation more than others.
Generally, pilots will pronounce most numbers like any non-pilot would, except for “niner” unless communications were troublesome. This is largely because the best aviation handheld radios are excellent these days in regard to communication coming through very clearly.
Helen Krasner holds a PPL(A), with 15 years experience flying fixed-wing aircraft; a PPL(H), with 13 years experience flying helicopters; and a CPL(H), Helicopter Instructor Rating, with 12 years working as a helicopter instructor.
Helen is an accomplished aviation writer with 12 years of experience, having authored several books and published numerous articles while also serving as the Editor of the BWPA (British Women Pilots Association) newsletter, with her excellent work having been recognized with her nomination of the “Aviation Journalist of the Year” award.
Helen has won the “Dawn to Dusk” International Flying Competition, along with the best all-female competitors, three times with her copilot.
