Annex 10 - Aeronautical Telecommunications
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Annex 10 |
Developed by
ICAO, the International Standards and Recommended Practices (SARPS) contained
in the eighteen Technical Annexes to the Convention
on International Civil Aviation (also called Chicago Convention) are
applied universally and produce a high degree of technical uniformity which has
enabled international civil aviation to develop in a safe, orderly and
efficient manner. Among those Annexes, Annex 10 Aeronautical Telecommunications covers three of the most complex
and essential elements of international civil aviation. i.e.
aeronautical communications, navigation and surveillance. Annex 10 is divided
into five volumes:
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Volume I: Radio Navigation Aids.
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Volume II: Communication Procedures.
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Volume III: Digital Data Communication Systems and Voice Communications Systems.
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Volume IV: Surveillance Radar and Collision Avoidance Systems
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Volume V: Aeronautical Radio Frequency Spectrum Utilization.
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International Radiotelephony Spelling Alphabet |
It is
interesting to note that the first internationally recognized phonetic alphabet was adopted by the
International Telecommunications Union (ITU)
Radio Conference in 1927 and was for use by the maritime mobile service;
such alphabet assigns code words to each letter of the alphabet (i.e. Alfa
for A, Bravo for B, etc.), so that critical combinations of letters (and
numbers) can be pronounced and understood by those who
transmit and receive voice messages by radio or telephone regardless of their
native language, especially when the safety of navigation or persons is
essential. The experience gained with that alphabet resulted in several changes
being made by the 1932 Radio Conference of ITU. The resulting alphabet was
adopted by the International Commission
for Air Navigation (ICAN), the predecessor of ICAO, and was used in civil
aviation until World War II.
During WWII,
the military requirements of joint operations let to the development of a
common spelling alphabet for the use of the combined allied services; it became
known as the Able Baker alphabet after the words for the letters A and
B. After World War II, with many aircraft and ground personnel drawn from the
allied armed forces, the "Able/Baker" alphabet continued to be used
in civil aviation. The Second Session of the ICAO Communications Division
naturally adopted in 1946 that alphabet. However, it was recognized that many speech
sounds of this alphabet were associated only with the English language; in
fact, an alternative alphabet "Ana/Brazil" was approved by ICAO and
introduced for the South American and Caribbean regions.
The
coexistence of two spelling alphabets led IATA at its First Technical
Conference in Nice in 1947 to submit for consideration by ICAO a first draft of
a proposed single universal alphabet. During 1948 and 1949, Professor Jean-Paul
Vinay of the University of
Montreal, Canada, worked on the problem in collaboration with the ICAO language
section. After those studies, consultations with communications experts and comments
from all of ICAO’s member governments, a new ICAO alphabet was adopted and incorporated
in the Aeronautical Telecommunications Annex 10 for implementation on 1
November 1951 in civil aviation, with one year transition to this new alphabet.
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Immediately,
problems were found with the newly adopted alphabet. Some users felt that they
were so severe that they reverted to the old "Able Baker" alphabet. Because
of the complaints, ICAO decided in 1952 to re-examine the question and its
member governments (through airlines, pilots, air traffic controllers, etc.) were
invited to collaborate in further studies and actual tests which could be as
objective as possible; testing was conducted among speakers from 31 countries,
principally by the governments of Canada, the United Kingdom and the United
States. The conclusions confirmed strikingly the basic soundness of the
original work. After much study, only the five words, i.e. Charlie, Mike,
November, Uniform and X-Ray, representing the letters C, M, N, U, and X were
replaced in the original alphabet. The final version given in the table shown
here on the left-side (and printed in Annex 10, volume II) was implemented by
ICAO on 1 March 1956, and thus was adopted by many other international and
national organizations, including the North
Atlantic Treaty Organization (NATO), ITU, the International Maritime
Organization (IMO), etc. The phonetic alphabet became to be formally known as
the International Radiotelephony Spelling Alphabet or the NATO
Phonetic Alphabet.
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Canada – 1 June 1955 – First Day
Cover 10th
Anniversary of the interim Agreement and first PICAO Meeting Picture representative of a Communications Service, showing a
Monitor Control Unit which provides facilities for an instructor to monitor
any selected or all operating circuits in the complete trainer; a tape
recorder either records any one selected circuit or may inject any
prefabricated instructional material into any selected or all circuits in the
system. The Monitor Control Unit was part of a Synthetic Air Traffic
Communications Trainer, displayed at ICAO headquarters during the Personnel
Licensing Division (held from 22 January to 14 February 1952) and designed by
the US Civil Aeronautics Administration and ICAO, could be shipped to any
section of the world where ICAO training assistance teams (within the
framework of the UN Expanded Programme for Technical Assistance) would train
local personnel in the operation of modern aerodrome equipment. |
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First Day Cover - Special Middle
East Communications Meeting Rhodes, Greece - 11 to 31 May 1954 This Meeting was called to consider among other items for the
region: 1) proposals to amend the interim and final aeronautical fixed
telecommunications network (AFTN) plans in the light of changing operational
requirements; 2) proposals to amend the operational requirements for radio
navigation aids in the light of recent developments in air operations; 3)
review of progress of implementation of the regional plan for very high
frequency communications in the aeronautical mobile service. |
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ICAO Phonograph recording (with the
4-page accompanying pamphlet) illustrating the correct way of pronouncing the
words of the new Radiotelephony
Spelling Alphabet, distributed to all countries in November 1955 when
the alphabet was introduced. |
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