The Big Sky
The Call Sign Conundrum
To be an effective and efficient air traffic controller, you've got to know the language of ATC thoroughly. One of the first tasks issued to a fledgling controller is to memorize a list of call signs and company three letter identifiers so communication between pilots and controllers is understood on the first attempt. When an unfamiliar airline identification code or call sign is encountered, it can cause confusion and loss of valuable time until both parties understand what they'll answer to over a frequency. Call sign confusion can lead to missed calls or readback errors, both detrimental to the safety of the ATC system. While training, before you could control air traffic on your own, you had to prove that you knew these codes and call signs of flights that routinely traversed your airspace by heart. Here's a bit of history and some of my observations about call signs that I've heard over the years...
The worldwide assignment of civil call signs is overseen by the International Civil Aviation Organization (ICAO), headquartered in Montreal Canada. A three letter identification code is assigned to an aviation operator, and an associated voice call sign is attached to this code. An example is: American Airlines Inc. is issued the code "AAL", and the radio call sign "AMERICAN". The International Air Transport Association (IATA) uses a different two-letter system for airline identification, but these aren't used in ATC operations. When I began my ATC training in 1979, the system did feature two letter codes for major airlines, and three letter codes that identified air taxi or commuter airlines. This changed somewhere during the 1990s if I remember correctly, as the ICAO ran out of two letter IDs, and every operator was assigned a three letter identifier code. The old Alitalia code was AZ; it changed to "AZA". Similarly, Finnair was assigned "AY", now it's "FIN". The voice call signs didn't change though, which meant less confusion on our part.
Most airlines and other commercial operators use a call sign and a number to identify their flight, such as "DELTA 263"; to a controller it would look like "DAL263" on a radar screen or flight plan readout, using Delta's three letter code "DAL". Sometimes there are letters added too, such as "LUFTHANSA 423 ECHO"; it'd look like "DLH432E" on a radar screen (DLH is the three letter ICAO code for Lufthansa , or more specifically "Deutsche Lufthansa, A.G.". Some charter flights using British Airways Concorde jets (long since retired) had just their last three letters of their registrations, such as "SPEEDBIRD CONCORDE OSCAR ALPHA FOXTROT", which looked like "BAWOAF" on a flight plan. When working similar sounding call signs within your sector at the same time, such as "CLIPPER 101" and "AIR INDIA 101", we were directed to state the call sign again at the end of the identifier for emphasis, such as "CLIPPER 101 CLIPPER..."
Assignment of military call signs for routine flights is handled by the ICAO. Localized tactical flights are assigned by a military headquarters function in conjunction with an FAA staff office. The call sign "REACH" is an example of the former; a blanket voice call sign for all USAF Air Mobility Command (AMC) transports, using a three-letter code of "RCH". It was derived from the description of "Global Reach" - the AMC's main mission. Most often in the U.S., a number will follow the call sign, thus, a C-17 transport flight could look like "RCH2054" to a controller. Going back to the early days of ATC computers, there is a maximum of seven characters that can be used to identify a flight in a flight plan, so there were and are times one would get creative while truncating a word in a long call sign that had to be entered into our computer. I controlled the "BLACK BUCK" British Vulcan bomber flight from Brazil back to Great Britain after it had a mechanical issue during the FalklandsWar, we had to reduce the name on the flight plan to "BLKBUCK".
Some of the more colorful voice call signs for airlines make a lot of sense with a bit of background information added. "WILD ONION" was the call sign of Chicago Air Inc., when it was still in business. The airline flew out of Chicago's Midway airport... and "Chicago" is a name derived from an Indian word for "wild onion". ValuJet's voice call sign was "CRITTER"; a pilot told me that the call sign arose from the nickname of the stylized airplane mascot painted on the airline's jets. Republic Airlines Inc. is based in Indianapolis IN, and uses the call sign "BRICKYARD"... after the famous Indianapolis Motor Speedway nickname. The famous "SPEEDBIRD" call sign used by British Airways has an interesting history that begins before World War II. It is the name of the stylized logo that was first introduced in the 1930s on prop-driven aircraft... the call sign has nothing to do with the first use of jet transports (Comet jetliner) or the Concorde SST (although the special call sign "SPEEDBIRD CONCORDE" was used to alert ATC about the difference in performance compared to other mainline jets).
Military call signs can sometimes take on the flavor of the base that the aircraft call home. A pair of squadrons that used to fly out of Loring AFB, ME were called "MOOSE" and "TATER", after two well known symbols of Maine. Similarly, "MAPLE" is a call sign attached to the Air National Guard F-16 unit in Burlington Vermont and "CAPE" was a call sign issued to another ANG unit based at Otis ANGB on Cape Cod Massachusetts. A Canadian F/A-18 squadron uses the call signs "LARK" and "ALOUETTE" interchangeably, as "lark" in English translates into "alouette" in French. The squadron is a French-speaking unit based at Bagotville, Quebec .
Memorizing every call sign in North America was impractical and nearly impossible, but the more call signs you committed to memory, the faster you could communicate with pilots when working at a sector. If you ever have a spare hour or two and are interested in just how many and diverse the world's call signs are, the FAA's (Joint Order) JO 7340.2 Contractions manual has an entire list. You can look up and compare any of the three main categories; voice call sign, company name, or three letter identification code. Repetition of working the same flights by the same companies helped me remember their call signs, but every once in a while an unrecognizable identification would show up and stand out. Usually we'd have a bit of lead time for someone to look up the call sign in the JO 7340.2 manual, so there'd be no surprises and we could communicate clearly between each other on the first try.
By Ken Kula