[[firstname]]
From ABE (Allentown/Bethlehem/Easton,
Pennsylvania)
to ZRH
(Zurich,
Switzerland),
airports
around the
world are
universally
known by a
unique three-letter
code: the
"International
Air
Transport
Association
(IATA)
Location
Identifier"
in aviation-speak.
It's
obviously
much easier
for pilots,
controllers,
travel
agents,
frequent
flyers,
computers
and baggage
handlers to
say and
write ORD
than the
O'Hare
International
Airport in
Chicago,
Illinois—but
how did this
practice
start, and
why are some
airport
codes easy
to
understand (ABE
and ZRH)
while others
seem to make
absolutely
no sense (ORD)?
When the
Wright
brothers
first took
to the air
in 1903,
there was no
need for
coding
airports
since an
airport was
literally
any
convenient
field with a
strong wind.
However, the
National
Weather
Service did
tabulate
data from
cities
around the
country
using a two-letter
identification
system.
Early
airlines
simply
copied this
system, but
as airline
service
exploded in
the 1930's,
towns
without
weather
station
codes needed
identification.
Some
bureaucrat
had a
brainstorm
and the
three-letter
system was
born, giving
a seemingly
endless
17,576
different
combinations.
To ease the
transition,
existing
airports
placed an X
after the
weather
station code.
The Los
Angeles tag
became LAX,
Portland
became PDX,
Phoenix
became PHX
and so on.
Incidentally
at the
historic
sand dune in
Kitty Hawk
where the
first flight
occurred the
U.S.
National
Parks
Service
maintains a
tiny
airstrip
called FFA—First
Flight
Airport.
Many station
codes are
simply the
first three
letters of
the city
name: ATL is
Atlanta, BOS
is Boston,
MIA is
Miami, SIN
is Singapore,
and SYD is
Sydney,
Australia.
The first
letter(s) of
multiple
cities
served forms
other codes:
DFW for
Dallas Fort
Worth, MSP
for
Minneapolis/St.
Paul, and
GSP for
Greenville/Spartanburg,
South
Carolina.
Sometimes
the city
name lends
itself to
one letter
for each
word, such
as Salt Lake
City (SLC),
Port of
Spain in
Trinidad &
Tobago
(POS), or
even Port au
Prince,
Haiti (PAP).
Most of the
"hard to
decipher"
identifiers
become
obvious if
one knows
the name of
the airport
rather than
the city
served. A
Louisiana
example is
ESF, for
Esler Field
in
Alexandra.
Orly airport
(ORY) and
Charles De
Gaulle
airport (CDG)
serve Paris,
France,
while Tokyo,
Japan has
the Narita
airport (NRT).
When you
know what
the code
represents,
some curious
acronyms
become
obvious: MSY
is the
former
Moisant
Stock Yards
in New
Orleans, CMH
is Columbus
Municipal
Hangar, BWI
is Baltimore
Washington
International,
LGW is
London
Gatwick, and
LHR is
London
Heathrow!
This system
of
identifying
airports
caught on
quickly and
soon
expanded to
include all
radio
navigation
aids used by
pilots. The
VOR on the
field at ORD
sends out
the Morse
code for
ORD.
Recently
some VORs
not located
at the
airport of
the same
name changed
identifiers
to prevent
possible
confusion.
The
clearance
"cross 10
miles south
of
Chattanooga"
was
confusing
when the
airport and
VOR were
five miles
apart. FAA
surprisingly
didn't try
to change
the name of
the city but
changed the
VOR,
resulting in
the
Chattanooga
Airport
(CHA) and
the Choo
Choo VOR (GCO)!
All
localizer
identifiers
are prefaced
with an "I."
Compass
locators are
assigned a
two-letter
identifier,
normally
using the
localizer as
a base. For
example, at
ABC the
localizer
might be
IABC, the
locator
outer marker,
AB, and the
locator
inner marker,
BC. (Note,
outside the
US radio
navigation
aid naming
may be much
less
formal.)
...
continues
More info on
airport
codes in
http://www.mapping.com/airportcodes.html