NATO phonetic alphabet

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The NATO phonetic alphabet is a common name for the radiotelephony spelling alphabet of the International Civil Aviation Organization (ICAO), which assigned words to the letters of the English alphabet so that critical combinations of letters could be pronounced and understood by aircrew and air traffic controllers regardless of their native language. The International Telecommunication Union (ITU), Federal Aviation Administration (FAA), and American National Standards Institute (ANSI) have similar versions.

Alphabet and pronunciation

Unless otherwise specified, the spelling and pronunciation given is that officially prescribed by the ICAO and adopted by the FAA and the ITU. The ICAO indicates unstressed numeric syllables in lower case (stressed in UPPER CASE), unlike its own alphabet, where stressed syllables are UNDERLINED UPPER CASE (unstressed in UPPER CASE). In the interests of uniformity, the FAA style of stressed syllables in BOLD will be used here (underlines might be confused with links). The ICAO states that the pronunciation of the words in the alphabet as well as numbers may vary according to the language habits of the speakers. In order to eliminate wide variations in pronunciation, posters illustrating the pronunciation desired are available from the ICAO.

Wherever the agencies (ICAO, ITU, FAA, ANSI) differ, each agency's preferred pronunciations or spellings are also given in the table. The ICAO and ITU, but not the FAA, give an alternate pronunciation for a couple of letter-words. The FAA gives different spellings for their pronunciations depending on the publication consulted. These are from the FAA Flight Services manual (§ 14.1.5) and the ATC manual (§ 2-4-16). ANSI gives English spellings, but does not give pronunciations or numbers. The ITU numbers are quite different from all other versions (and no stress is given).

History and use

Despite its common name, the alphabet doesn't seem to appear in any official North Atlantic Treaty Organization publication. It may have received the name NATO phonetic alphabet because it has been adopted by the military of each of NATO's major countries, and is thus used by them when engaged in NATO exercises.

All of the words are recognizable by native English speakers because English must be used upon request for communication between an aircraft and a control tower whenever two nations are involved, regardless of their native languages. But it is only required internationally, not domestically, thus if both parties to a radio conversation are from the same country, then another phonetic alphabet of that nation's choice may be used.

The first internationally recognized alphabet was adopted by the ITU in 1927. The experience gained with that alphabet resulted in several changes being made in 1932 by the ITU. The resulting alphabet was adopted by the International Commission for Air Navigation, the predecessor of the ICAO, and was used in civil aviation until World War II. It continued to be used by the international maritime service, probably until 1959:

Amsterdam Baltimore Casablanca Denmark Edison Florida Gallipoli Havana Italia Jerusalem Kilogramme Liverpool Madagascar New_York Oslo Paris Quebec Roma Santiago Tripoli Upsala Valencia Washington Xanthippe Yokohama Zurich

During World War II, the requirements of joint Allied operations led to the development of the Joint Army/Navy Phonetic Alphabet ("able baker"), although several RAF phonetic alphabets were also used. After the war, with many aircraft and ground personnel drawn from the allied armed forces, "able baker" continued to be used in civil aviation. But many sounds were unique to English, so an alternative "Ana Brazil" alphabet was used in Latin America. But the International Air Transport Association (IATA), recognizing the need for a single universal alphabet, presented a draft alphabet to the ICAO in 1947 which had sounds common to English, French, and Spanish. After further study and modification by each approving body, the revised alphabet was implemented November 1, 1951:

Alfa Bravo Coca Delta Echo Foxtrot Golf Hotel India Juliett Kilo Lima Metro Nectar Oscar Papa Quebec Romeo Sierra Tango Union Victor Whisky Extra Yankee Zulu

Immediately, problems were found with this list—some users felt they were so severe that they reverted to the old "able baker" alphabet. To identify the deficiencies of the new alphabet, testing was conducted among speakers from 31 nations, principally by the governments of the United Kingdom and the United States. Confusion among words like Delta, Nectar, Victor, and Extra, or omission of other words under poor receiving conditions were the main problems. After much study, only five words representing the letters C, M, N, U, and X were replaced. The final version given in the table above was implemented on March 1, 1956, and was undoubtedly adopted shortly thereafter by the ITU, because it appears in the 1959 Radio Regulations as an established phonetic alphabet. Because the ITU governs all international radio communications, it was also adopted by all radio operators, whether military, civilian, or amateur (ARRL).

In the official international version of the alphabet, the non-English spellings Alfa and Juliett are found. Alfa is spelled with an f for the benefit of native Spanish speakers because they will pronounce ph as if it were a p with a silent h—the English word alpha is alfa in Spanish. Juliett is spelled with a tt for the benefit of native French speakers because they will treat a single t as silent—the English word Juliet is Juliette in French, but the ICAO did not adopt the final e because it might be misunderstood by native Spanish speakers as indicative of a final syllable tuh. In English versions of the alphabet, one or both may revert to their standard English spelling.

The alphabet is used to spell out parts of a message or call sign that are critical or otherwise hard to recognize during voice communication. For instance the message "proceed to map grid DH98" could be transmitted as "proceed to map grid Delta-Hotel-Niner-Eight" and a C-130 Hercules plane directly ahead might be described as a "Charlie One Three Zero in your twelve o'clock". Several letter codes and abbreviations using the phonetic alphabet have become well-known, such as Bravo Zulu (letter code BZ) for "well done", Checkpoint Charlie (Checkpoint C) in Berlin, and Zulu for Greenwich Mean Time or Coordinated Universal Time. In SWAT units Tango is used for terrorists, Sierra for a Sniper etc.

Variants

At some United States airports, the use of Delta for the letter D is avoided because it is also the callsign for Delta Air Lines. "Dixie" seems to be the most common substitute.

In British police work the use of India has been replaced by "Indigo".

Many unofficial phonetic alphabets are in use that are not based on a standard, but are based on words the transmitter can easily remember. Often, such ad-hoc phonetic alphabets are based on (mostly) men's names, such as Alan Bobby Charlie David Edward Frederick George Howard Isaac James Kevin Larry Michael Nicholas Oscar Peter Quincy Robert Stephen Trevor Ulysses Vincent William Xavier Yaakov Zebedee or on a mixture of names and other easily recognizable (and locally understandable) proper nouns such as U.S. states, local cities and towns, etc.

Older phonetic alphabets

In addition to the alphabets referred to above, numerous other phonetic alphabets have been used in the past.

• World War I western front trench slang: Ack Beer Charlie Don Edward Freddie Gee Harry Ink Johnnie King London Emma Nuts Oranges Pip Queen Robert Esses Toc Uncle Vic William X-ray Yorker Zebra
  This appears to be the origin of the RAF slang phrases such as ack emma for morning, pip emma for afternoon and ack-ack for anti-aircraft. Ack Emma was also used for 'Air Mechanic' in the Royal Flying Corps (1914-18).

• British Royal Navy during World War I: Apples Butter Charlie Duff Edward Freddy George Harry Ink Johnnie King London Monkey Nuts Orange Pudding Queenie Robert Sugar Tommy Uncle Vinegar Willie Xerxes Yellow Zebra

Phonetic alphabet in popular culture

The NATO phonetic alphabet is referred to repeatedly in Robert Ludlum's novel The Bourne Identity. The phrase Cain is for Charlie and Delta is for Cain is repeated, always italicised, to symbolise the messages relayed to the main character during the Vietnam war.

The nickname "Charlie" used by US servicemen in the Vietnam War is derived from "Victor Charlie", the NATO phoneticism of the initials of Viet Cong, the armed insurgents in the Republic of Vietnam (South Vietnam).

The rock band Wilco's 2002 album, Yankee Hotel Foxtrot, includes recordings of a numbers station speaking these words, believed to be a transmission of an alphanumeric cipher using this phonetic alphabet.

The name of sports car manufacturer Alfa Romeo is sometimes believed to represent the initials AR in this system, although this is not supported by the company's official history.

UTC (aka Greenwich Mean Time) is sometimes referred to as "Zulu" time, after the Z letter designation given to the GMT time zone.

The call sign "Sierra Oscar" is frequently heard in the British TV serial The Bill.

In the Simpsons episode "Separate Vocations", the license plate "EX-CON" was spelled in a parody of the phonetic alphabet as "Eggplant Xerxes Crybaby Overbite Narwhal".

References

• L.J. Rose, "Aviation's ABC: The development of the ICAO spelling alphabet", ICAO Bulletin 11/2 (1956) 12-14
• Aeronautical Telecommunications: Annex 10 to the Convention on International Civil Aviation, Volume II, Chapter 5
• International Telecommunication Union, "Appendix 16: Phonetic Alphabet and Figure Code", Radio Regulations (Geneva, 1959) 430-431

External links

• ICAO Radiotelephony Spelling Alphabet (pp A-6 & A-10) (http://www.icao.int/anb/panels/amcp/wg/C/wgc3/wgc3_wp7.doc) (an official source, but in Microsoft Word format (332KB), not HTML)
• ICAO Phonetics by the FAA (http://www.faa.gov/ATPubs/ATC/Chp2/atc0204.html#2-4-16)
• American National Standard T1.523-2001, Telecom Glossary 2000 (http://www.atis.org/tg2k/_phonetic_alphabet.html) (English version of alphabet)
• ICAO phonetic alphabet by Canada (http://www.tc.gc.ca/CivilAviation/general/CCARCS/TP11957/Appendices/appendixa.htm)
• ITU Phonetic Alphabet and Figure Code (http://life.itu.ch/radioclub/rr/ap14.htm)
• Most comprehensive collection of phonetic alphabets (http://www.bckelk.uklinux.net/menu.html)af:NAVO spelalfabet

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