SERA.13005 SSR transponder Mode A code setting

(a)To indicate that it is in a specific contingency situation, the pilot of an aircraft equipped with SSR shall:

(1)select Code 7700 to indicate a state of emergency unless ATC has previously directed the pilot to operate the transponder on a specified code. In the latter case, a pilot may nevertheless select Code 7700 whenever there is a specific reason to believe that this would be the best course of action;

(2)select Code 7600 to indicate a state of radio-communication failure;

(3)attempt to select Code 7500 to indicate a state of unlawful interference. If circumstances so warrant, Code 7700 should be used instead.

(b)Except in the cases described in (a) above, the pilot shall:

(1)select codes as instructed by the ATS unit; or

(2)in the absence of ATS instructions related to code setting, select code 2000 or another code as prescribed by the competent authority; or

(3)when not receiving air traffic services, select code 7000 in order to improve the detection of suitably equipped aircraft unless otherwise prescribed by the competent authority.

(c)When it is observed that the code shown on the situation display is different from what has been assigned to the aircraft:

(1)the pilot shall be requested to confirm the code selected and, if the situation warrants, to reselect the correct code; and

(2)if the discrepancy between assigned and displayed codes still persists, the pilot may be requested to stop the operation of the aircraft's transponder. The next control position and any other affected unit using SSR and/or multilateration (MLAT) in the provision of ATS shall be informed accordingly.