22.214.171.124.3.1 An aircraft shall not change the type of its radiotelephony call sign during flight, except temporarily on the instruction of an air traffic control unit in the interests of safety.
126.96.36.199.3.1.1 Exept for reasons of safety no transmission shall be directed to an aircraft during take-off, during the last part of the final approach or during the landing roll.
|188.8.131.52.3.3 Subsequent radiotelephony communications
184.108.40.206.3.3.1 Abbreviated radiotelephony call signs, as prescribed in 220.127.116.11.2.2, shall be used only after satisfactory communication has been established and provided that no confusion is likely to arise. An aircraft station shall use its abbreviated call sign only after it has been addressed in this manner by the aeronautical station.18.104.22.168.3.3.2 After contact has been established, continuous two-way communication shall be permitted without further identification or call until termination of the contact.22.214.171.124.3.3.3 In order to avoid any possible confusion, when issuing ATC clearances and reading back such clearances, controllers and pilots shall always add the call sign of the aircraft to which the clearance applies.
|126.96.36.199.3.4 Indication of transmitting frequency
188.8.131.52.3.4.1 PANS.— As the aeronautical station operator generally guards more than one frequency, the call should be followed by an indication of the frequency used, unless other suitable means of identifying the frequency are known to exist.
184.108.40.206.3.4.2 PANS.— When no confusion is likely to arise, only the first two digits of the High Frequency (in kHz) need be used to identify the transmitting channel.
220.127.116.11.3.4.3 PANS.— Wherever VHF communications channels are separated by 25 kHz, only the first 5 digits should be used to identify the transmitting carrier frequency in radiotelephony communications. Not more than two significant digits after the decimal point are used. In the case of these being two zeros, a single zero is considered significant.
Note 2. Caution must be exercised with respect to the indication of transmitting channels in VHF radiotelephony communications when all six digits of the numerical designa- tor are used in airspace where communication channels are separated by 25 kHz, because on aircraft installations with a channel separation capability of 25 kHz or more, it is only possible to select the first five digits of the numerical designa- tor on the radio management panel.
Note 3. The numerical designator corresponds to the channel identification in Annex 10, Volume V, Table 4-1 (bis) see below.
18.104.22.168.3.4.4 PANS.— In airspace where all VHF voice communications channels are separated by 25 kHz or more and the use of six digits as in 22.214.171.124.3.4.3 is not substantiated by the operational requirement determined by the appropriate authorities, the first five digits of the numerical designator should be used, except in the case of both the fifth and sixth digits being zeros, in which case only the first four digits should be used.
Chapter 6. VHF Air-Ground Digital Link (VDL)
Source: ICAO Annex 10.2, 10-5