T
This is in conjunction to rules aimed to avoid confusion that seem to apply in the
United States, which state that "the first and second letters or second and third
letters of an identifier may not be duplicated with less than 200 nautical miles
separation.
Thus, Washington D.C.-area's three airports all have radically different codes:
IAD for Washington-Dulles, DCA for Reagan National (District of Columbia Airport),
and BWI for Baltimore (Baltimore–Washington International, formerly BAL).
Since HOU is used for William P. Hobby Airport, the new Houston-Intercontinental became IAH.
The code BKK was originally assigned to Bangkok-Don Mueang and was later transferred to
Suvarnabhumi Airport, while the former adopted DMK.
Shanghai-Hongqiao retained the code SHA, while the newer Pudong Airport adopted PVG.
The opposite is true for Berlin, the airport Berlin-Tegel uses the code TXL, while its smaller
counterpart Berlin-Schönefeld uses SXF; the new Berlin Brandenburg Airport is going to have the
code BER. Hamburg (HAM) and Hannover (HAJ) are less than 100 NM apart and still use the same
first and middle letter, indicating that this rule might followed only locally.
Since the US Navy reserved "N" codes and the Federal Communications Commission has reserved
rights for "W" and "K", certain U.S. cities which begin with these letters had to adopt "irregular"
airport codes: EWR for Newark, ORF for Norfolk, Virginia, EYW for Key West, Florida, and APC for
Napa, California.[3] This "rule" does not apply outside of the United States: Karachi is KHI, Warsaw
is WAW, Nagoya is NGO. In addition, since "Q" was used for international communications, cities
with "Q" beginning their name also had to find alternate codes, as in the case of Qiqihar (NDG),
Quetta (UET) and Quito (UIO).
IATA codes should not be confused with the FAA identifiers of US airports. Most FAA identifiers
agree with the corresponding IATA codes, but some do not, such as Saipan whose FAA identifier is
GSN and its IATA code SPN, and some coincide with IATA codes of non-US airports.
A - Z of Flight
May 2017
www.alliance-airways.net
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