FLIGHT ALLIANCE201706 | Page 10

I International call signs In most countries, the aircraft call sign or "tail number"/"tail letters" (also known as registration marks) are linked to the international radio call sign allocation table and follow a convention that aircraft radio stations (and, by extension, the aircraft itself) receive call signs consisting of five letters. For example, all British civil aircraft have a five-letter call sign beginning with the letter G. Canadian aircraft have a call sign beginning with C–F or C–G, such as C–FABC. Wing In Ground-effect vehicles (hovercraft) in Canada are eligible to receive C– Hxxx call signs, and ultralight aircraft receive C-Ixxx call signs. In days gone by, even American aircraft used five letter call signs, such as KH–ABC, but they were replaced prior to World War II by the current American system of civilian aircraft call signs. The dash ("-") in the registration is only included on the fuselage of the airplane for readability. In air traffic management systems (ATC radar screen, flow management systems, etc.) and on flight plan forms, the dash is not used (e.g. PHVHA, FABCD, CFABC). After an aircraft has made contact with an air traffic control facility, the call sign may be abbreviated. Sometimes the aircraft make or model is used in front of the full or abbreviated call sign, for instance, the American aircraft mentioned above might then use Cessna Eight- Charlie-Papa. Alternatively, the initial letter of the call sign can be concatenated with the final two or three characters, for instance a British aircraft registered G–BFRM may identify as Golf–Romeo–Mike while the American aircraft might use November–Eight-Charlie-Papa. The use of abbreviated call signs has its dangers, in the case when aircraft with similar call signs are in the same vicinity. Therefore, abbreviated signs are used only so long as it is unambiguous. A - Z of Flight June 2017 www.alliance-airways.net 1 ! 0