When a pilot communicates with air traffic control, static and other interferences often lead to confusion with English language letters. ICAO developed the International Radiotelephony Spelling Alphabet to ease communication via telephone or radio and avoid misunderstandings when parts of a message containing letters and numbers are spelled out. Also referred to as the ICAO Phonetic Alphabet and the NATO Alphabet (with some modifications), this universal spelling alphabet is a set of words used to clarify messages, no matter the spoken language. Members of the military, police, airline pilots and others working in the aviation and travel industry commonly use it.
The ICAO phonetic alphabet has assigned the 26 code words to the 26 letters of the English alphabet in alphabetical order:
Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.
With short and simple words, ICAO’s phonetic alphabet lowers the chance of misunderstandings and increases operational safety for passengers and crew. Because some letters sound similar (M and N or G and J), it can generate confusion between two people communicating with different accents or when the communication lines are poor. The phonetic alphabet helps limit confusion between the cockpit and the tower.
Not only are the letters in the ICAO phonetic alphabet assigned, but so are the numbers. Similar to the letters, the aim is to avoid confusion with other similar numbers. Therefore, a few of them are pronounced differently from their standard English pronunciation.
Those include the number three, pronounced as tree (tri), five as fife and nine as niner. Consider an aircraft tail number such as M345N. Over the radio, this would be said as “Mike, tree, four, fife, November.”
ICAO adopted its phonetic alphabet 70 years ago, on 1 November 1951, as a universal standard for communicating English letters over a phone or radio. Dissatisfaction with the existing internationally recognized phonetic alphabet submitted to ICAO for consideration led to the first draft of a proposed single universal alphabet.
Through 1948 and 1949, Jean-Paul Vinay, professor of linguistics at the Université de Montréal in Canada, collaborated with ICAO’s language sector to develop a new spelling alphabet. The minimum requirements for the words were to have similar spelling in English, French, and Spanish and to be live words in each of these languages.
After those studies and following consultations with communications experts and comments from all ICAO Member States, a new ICAO alphabet was adopted and incorporated in the Aeronautical Telecommunications Annex 10 for implementation in civil aviation. The words that represented the letters C, M, N, U and X were replaced, and the Organization completed its final version on 1 March 1956, which is still in use today worldwide.
Besides the aircraft radio, you might have noticed that often when you call into an office, the receptionist who answers will reconfirm your name and address using a phonetic alphabet.
Phonetic alphabets are used to confirm email addresses and proper nouns such as names of people and places.
Remember some words are difficult to hear, while others are difficult to spell. This is especially more so with different languages and dialects, while some words are too technical or foreign.
Many people use foreign-language words such as “schadenfreude” (German) and “Rendez-Vous” (French) while speaking in English. The quick cross over in language will often throw off a listener that may not be familiar with or even aware of certain foreign language words. Callers may also use scientific terms, technical terms, and the names of medications which usually sound like words most of us struggle to pronounce. All of these need to be reconfirmed via the spelling alphabet to root out human error.
The most important reason here though is by using a phonetic alphabet we aid in avoiding miscommunication and human errors, whether using a radio or a telephone.
So next time you are on the radio, remember now you will know what you are talking about.