CAP 413, Manual

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CAP 413 Radiotelephony Manual
Chapter 2 Page 10
1.9 Military Aircraft Callsigns
1.9.1 Aircraft Callsigns
Military aircraft use callsigns derived from 2 systems. Front line aircraft, in the main,
use operational callsigns consisting of a 3 character prefix of numbers and letters
(trigraph) suffixed by a 2 number (dinome) mission identifier. Callsigns for Flying
Training Units (FTUs) and Search and Rescue (SAR) aircraft use fixed ICAO allocated
3 letter designators with figure suffixes as pilot number callsigns. The term FTU
embraces all flying training units (including University Air Squadrons (UASs) and
Gliding Schools (GSs)), Maintenance Units and Air Experience Flights (AEFs), plus the
Operational Conversion Units (OCUs) of HQ AIR who will nominate which OCUs are
not included in the scope of this sub section. The salient features of the 2 systems
are outlined in the following paragraphs.
1.9.2 Mission Number Callsigns
Mission number callsigns are based on a 3 character group of which the last character
is a letter and the first 2 characters are either letter/number or number/letter. They are
valid for a 24 hour period but the system has insufficient capacity to provide entirely
different callsigns for each individual aircraft sortie. Callsigns are configured using a 3
element base callsign root with a 2 number suffix allocated at random by the tasking
agency. If several aircraft in formation make up a single mission, the mission is
allocated a single callsign and each aircraft is given a further identifying letter suffix.
For example T4G (root plus mission), T4G22A, B, C and D (root, mission and 4 aircraft
formation).
1.9.3 Pilot Number Callsigns
The Pilot Number Callsign system is based on a 2 or 3-figure pilot number suffix to a
3-letter callsign root, e.g. VYJ 44 or CWP 186:
• Callsign Root. Each major FTU is allocated one CAA approved fixed 3 letter callsign
root. Four individual trigraphs are allocated to the UASs, one to all AEFs and one to
all GSs.
• Pilot Numbers. Pilot Numbers are allocated as follows:
• Where possible a Pilot Number is allocated to each pilot when posted to an FTU,
and normally is to be retained for the duration of the appointment or course of
instruction.
• For UASs, AEFs and GSs, the respective HQs will allocate blocks of Pilot
Numbers to each element to simplify identification of pilots from different
elements using the same callsign root.
1.9.4 Formation Callsigns
When aircraft are operating as a formation, the use of formation callsigns may be
desirable to facilitate communications both within the formation and by the leader
with ground stations. Formation callsigns should be as detailed in 1.9.2 above, or as
authorised by single Service regulations.
1.9.5 Word Callsigns
If 2 or more aircraft are flying as a formation, the formation may be allocated an
approved word callsign, in addition to the normal mission/pilot numbers allocated to
each aircraft. The mission/pilot numbers will only be used in the event of a split. For
the duration of the formation flight, the aircraft should be identified by adding the
words 'one', '2', etc. to the formation callsign, e.g. Bear one, Bear 2, etc. Where
formations operate using the callsign of the lead aircraft, controllers are to add the
word 'flight' or 'formation' to the callsign, when transmitting instructions relevant to
the whole formation e.g. 'EAGLE 51 FLIGHT'. Where a transmission is relevant to
only one element of the formation, this should be clarified e.g. 'EAGLE 51 ONLY',
climb etc.'.
31 March 2011