Was that an “m” or an “n?” Even today most of us have experienced the frustration of trying to communicate the spelling of our name, a street name, or other information over the phone only to have the other party not understand it. Now imagine living back in the early days of telephone when the connection was not remotely as good and the audio nowhere near as crisp as it is today.
Operators quickly came up with standardized telephone spelling alphabets that could be used by both parties to clarify ambiguous letters. Each letter of the alphabet was paired with a designated, easily understandable word starting with the corresponding letter. By using a word to represent a letter, the listener would be more apt to correctly understand the message even with garbled transmissions. This idea naturally carried over into radio communications as well.
Prior to the 1950s, military and civilian personnel in countries around the world each used their own version of a phonetic alphabet. While this worked well internally, there was still a need for a standardized international radio telephony alphabet. The International Civil Aviation Organization (ICAO), took on the project of developing such an alphabet for the civilian aviation sector.
Starting in the late 1940s, the ICAO team collected information on as many phonetic alphabet systems as they could find. After reviewing over 200 systems and consulting linguistics professors, the team created a set of criteria that the words included in their “word-spelling alphabet” must meet. The ICAO defined a word-spelling alphabet as “a conventional code of highly intelligible and non-confusable words for use in identifying letters of the alphabet.”
To be considered, words must meet the following criteria:
- Be a “live word” in the English, French, and Spanish languages
- Be easily pronounced and recognized by airmen of all languages
- Have good radio transmission and readability characteristics
- Have a similar spelling in at least English, French, and Spanish, and the initial letter must be the letter the word identifies
- Be free from any association with objectionable meanings
After going through several permutations and revisions in the early 1950s, the ICAO alphabet that was released in 1956 is still in use today. The ICAO phonetic alphabet is also known as the International Radiotelephony Spelling Alphabet or the NATO phonetic alphabet. It is used not only in the civil aviation community but also by the militaries of NATO countries. Public safety organizations use a phonetic alphabet as well, but in the United States, those agencies use the Association of Public-Safety Communications Officials-International (APCO) rather than ICAO alphabet.
ICAO Aviation Alphabet
The ICAO alphabet consists of twenty-six letter and word pairings. Below is the current ICAO alphabet along with the phonetic pronunciations and emphasis placements for each word.
LETTER |
WORD |
PRONUNCIATION |
A |
Alfa |
Al fah |
B |
Bravo |
Brah voh |
C |
Charlie |
Char lee |
D |
Delta |
Dell tah |
E |
Echo |
Eck oh |
F |
Foxtrot |
Foks trot |
G |
Golf |
Golf |
H |
Hotel |
Ho tell |
I |
India |
In dee ah |
J |
Juliett |
Jew lee ett |
K |
Kilo |
Key loh |
L |
Lima |
Lee mah |
M |
Mike |
Mike |
N |
November |
No vem ber |
O |
Oscar |
Oss cah |
P |
Papa |
Pah Pah |
Q |
Quebec |
Keh beck |
R |
Romeo |
Row me oh |
S |
Sierra |
See air rah |
T |
Tango |
Tang go |
U |
Uniform |
You nee form |
V |
Victor |
Vik tah |
W |
Whiskey |
Wiss key |
X |
X-ray |
Ecks ray |
Y |
Yankee |
Yang key |
Z |
Zulu |
Zoo loo |
ICAO Aviation Numerals
In addition to the phonetic alphabet, pilots should also be familiar with the ICAO aviation numerals. Some use standard pronunciation and others are modified slightly for ease of comprehension on the air.
Number |
ICAO Spelling |
Pronunciation |
0 |
Zero |
Ze ro |
1 |
Wun |
Wun |
2 |
Too |
Too |
3 |
Tree |
Tree |
4 |
Fower |
Fow er |
5 |
Fife |
Fife |
6 |
Six |
Six |
7 |
Seven |
Sev en |
8 |
Eight |
Ait |
9 |
Niner |
Nin er |
For additional learning, check out the Dictionary of Aeronautical Terms.