The Aviation Phonetic Alphabet: Every Letter and Number, and How Pilots Use It on the Radio

The aviation phonetic alphabet is the ICAO spelling alphabet: Alfa, Bravo, Charlie through Zulu, one word per letter, plus spoken numbers such as "tree" for 3, "fife" for 5 and "niner" for 9. The FAA publishes it in AIM 4-2-7, and it is on the Part 107 knowledge test.

Most pages on this topic stop at the 26 words. That is the easy part, and most people half know it from films already. The part that costs points, and makes a radio call sound wrong to every pilot listening, is what comes next: how numbers are spoken, how an N-number is shortened, and why "10,000" is not said the way you would say it at a checkout.

What is the aviation phonetic alphabet?

It is a set of code words that stand in for letters when you speak over a radio. "B," "D," "E," "P," "T" and "V" all sound alike through a noisy, compressed aviation radio. "Bravo," "Delta," "Echo," "Papa," "Tango" and "Victor" do not.

The AIM describes it as the International Civil Aviation Organization (ICAO) phonetic alphabet. It says FAA personnel use it when conditions mean the information cannot be readily received otherwise, and that pilots should use it when identifying their aircraft during initial contact with ATC. It adds that you should use the phonetic words for single letters and to spell groups of letters or difficult words when reception is poor.

The full phonetic alphabet, with FAA pronunciations

This is the table from AIM TBL 4-2-7. The pronunciation column is the FAA's own, capitals marking the syllables. Note the spellings: the FAA writes Alfa and Juliett, not "Alpha" and "Juliet," so that speakers of other languages pronounce them correctly.

Two pronunciations catch English speakers. Papa is "PAH-PAH," not "POP-uh," and Quebec is "KEH-BECK," with no "kwuh."

How do pilots say numbers on the radio?

The same table gives spoken forms for the digits. Four of them differ from everyday speech, and they differ for the same reason the letters exist: clarity through static.

In practice, you will hear plenty of US pilots say "three" and "five" normally. "Niner" is the one almost everybody uses, and it is the one to adopt first.

How are altitudes, frequencies and other figures spoken?

This is AIM 4-2-8, and it is the part most competitor pages leave out. The rules are specific:

• Round hundreds and thousands up to 9,900 are spoken as words. 500 is "five hundred." 4,500 is "four thousand five hundred."
• Above 9,900, the digits before "thousand" are separated. 10,000 is "one zero thousand." 13,500 is "one three thousand five hundred."
• All other numbers are spoken digit by digit. 10 is "one zero."
• A decimal point in a frequency is "point." 122.1 is "one two two point one." ICAO uses "decimal," and the FAA accepts it.

The paragraphs after it cover the rest of the phraseology. Headings and wind directions are always three digits and assumed magnetic: a wind from 220 is "wind two two zero," and "true" is added only when it applies (AIM 4-2-10). Speeds are separate digits plus "knots" (AIM 4-2-11). Times are in UTC, where "Zulu" may be used, so 0920 UTC is "zero niner two zero" (AIM 4-2-12). The Zulu time article covers the conversion.

How is an aircraft call sign spoken?

This is the single most common use of the alphabet, and it is covered in AIM 4-2-4. A US civil registration such as N6132F can be spoken two ways:

• "November Six One Three Two Foxtrot," with the N spoken as November.
• "Cessna Six One Three Two Foxtrot," with the type or manufacturer's name. When the name is stated, the AIM says, the "N" is dropped.

After communications are established, ATC may shorten the call sign to the prefix plus the last three characters, "Cessna Three Two Foxtrot," and the pilot may then use the shortened form. The pilot does not start it. The AIM is blunt about why: pilots with similar call signs have acted on clearances meant for someone else.

Two other call sign conventions show up on the test. Air taxi and other commercial operators without an FAA-authorized call sign prefix their identification with "Tango." Airlines use their authorized name plus the flight number in group form, for example "United Twenty-Five Heavy."

Where else does the alphabet appear in aviation?

Once you know it, you see it everywhere in the products a remote pilot reads:

• ATIS letters. Each recorded broadcast is identified by a phonetic letter that advances with every update, so "information Kilo" tells a controller which version you heard. See ATIS vs AWOS vs ASOS.
• AIRMETs. Sierra, Tango and Zulu cover IFR and mountain obscuration, turbulence and surface winds, and icing. SIGMETs use November through Yankee, skipping Sierra and Tango. The AIRMET vs SIGMET article has the detail.
• Taxiways. Taxiway Alfa, Bravo and so on are spoken with the alphabet.
• Airways. V12 is spoken "Victor Twelve."

Does aviation use the NATO phonetic alphabet?

Yes, and the two are the same list. Civil aviation calls it the ICAO alphabet and the military calls it the NATO alphabet. It replaced the older "Able, Baker, Charlie" alphabet used by US forces in the Second World War and in early civil aviation, which relied on sounds unique to English. ICAO implemented the final version of today's list on 1 March 1956, after testing among speakers from many nations. Words that were confused with one another, or unintelligible in poor reception, were replaced.

Why is this on the Part 107 exam?

The Remote Pilot Airman Certification Standards list Radio Communications Procedures as Task A under Operations. Its knowledge elements explicitly include aircraft call signs and registration numbers (UA.V.A.K6), the phonetic alphabet (UA.V.A.K7), and phraseology for altitudes, directions, speed and time (UA.V.A.K8). Operations carries 25% of the current test blueprint, so these are not throwaway questions.

The questions usually give you a transcript, not a table. Expect a CTAF call such as "Weston traffic, Cessna Two Three Four Five November, left downwind runway two eight" and a question about where that aircraft is or which runway it is using. Or a written altitude and four ways to say it. The alphabet itself is rarely the trap. Reading the whole call is.

What this means when you are actually working

Part 107 does not require you to carry a radio, and the usual guidance near a non-towered field is to monitor the CTAF rather than transmit. That makes the phonetic alphabet a listening skill first. You are decoding other pilots' calls in real time to find out who is in the pattern, where they are and what they will do next. See CTAF vs UNICOM for which frequency to monitor.

It matters off the radio too. When you call a facility, spell an N-number to an insurer, or read a LAANC or waiver reference number over the phone, the alphabet removes the "was that B or D?" round trip. The same goes for a crew calling out a battery ID across a windy site. It costs nothing to use and saves the misunderstanding that usually happens at the worst moment.

Frequently asked questions

Why do pilots say "Papa"?

Papa is the ICAO phonetic word for the letter P. Spoken alone, P sounds almost identical to B, D, E, T and V over a radio, so a whole word is used instead. The FAA pronunciation is PAH-PAH, stressed on the second syllable. You hear it in call signs, taxiway names and ATIS letters.

Why do pilots say "Foxtrot"?

Foxtrot is the ICAO phonetic word for F, which is easily confused with S over a radio. The FAA pronunciation is FOKS-TROT. You will hear it most often as the last letter of an N-number, as in "Cessna Six One Three Two Foxtrot," and in taxiway names at larger airports.

Does aviation use the NATO phonetic alphabet?

Yes. The ICAO alphabet used in civil aviation and the NATO alphabet used by the military are the same 26 words, Alfa through Zulu. ICAO implemented the final version on 1 March 1956, replacing the older Able, Baker alphabet. The FAA publishes it, with pronunciations, in AIM 4-2-7.

Why do pilots say "niner" instead of nine?

Niner keeps 9 from being confused with 5 over a noisy radio, because the extra syllable makes it distinct. The FAA's pronunciation table in AIM 4-2-7 lists 9 as NIN-ER. Other digits change too: 3 is TREE, 4 is FOW-ER and 5 is FIFE, although US pilots use niner most consistently.

How do you say 10,000 feet on the radio?

"One zero thousand." Under AIM 4-2-8, numbers above 9,900 are spoken by separating the digits before the word "thousand." So 13,500 is "one three thousand five hundred." Round figures up to 9,900 are spoken as words, which is why 4,500 is simply "four thousand five hundred."

Do drone pilots need to use the phonetic alphabet?

Part 107 does not require a radio, so you are rarely transmitting. But the phonetic alphabet, call signs and phraseology are all listed knowledge elements in the Remote Pilot ACS, so you need them for the test. On the job they let you decode CTAF traffic and read identifiers over the phone without errors.

Want to see how radio phraseology questions look on the real test? Take the free Part 107 practice test.

Sources

• AIM Chapter 4, Section 2: Radio Communications Phraseology and Techniques (4-2-4 call signs, 4-2-7 phonetic alphabet, 4-2-8 figures, 4-2-9 through 4-2-12)
• AIM Chapter 4, Section 1: Traffic Advisory Practices at Airports Without Operating Control Towers
• FAA Remote Pilot Small Unmanned Aircraft Systems Airman Certification Standards (Task V.A, Radio Communications Procedures)
• FAA Remote Pilot Small Unmanned Aircraft Systems Study Guide (FAA-G-8082-22)
• 14 CFR 107.43: Operation in the vicinity of airports
• NATO: The NATO phonetic alphabet (history)