2.1 Emergency procedures
2.1.1 Except when encountering a state of emergency, pilots shall operate transponder and select modes and codes in accordance with ATC instructions. In particular, when entering Tbilisi FIR pilots who having already received specific instructions from ATC to set transponder, shall maintain that setting until otherwise instructed.
2.1.2 Pilots of aircraft about to enter Tbilisi FIR who have not received specific instructions from ATC concerning the setting of the transponder shall operate the transponder on mode A+C code 20 (or 2000) before the entry and maintain that code setting until otherwise instructed.
2.1.3 If the pilot of the aircraft encountering a state of emergency has previously been directed by ATC to operate the transponder on a specific code, this code setting shall be maintained until otherwise advised. In all other circumstances, the transponder shall be set to mode A+C code 77 (or 7700).
2.1.4 Despite the procedure set out in paragraph 2.1.1 above, a pilot may select mode A+C code 77 (or 7700) whenever the nature of the emergency is such that this appears to him to be the most suitable course of action.
Note: Continuous monitoring of responses on mode A+C code 77 is provided.
2.2 Radio communication failure and unlawful interference procedures
2.2.1 Radio communication failure procedure
Radio communication failure procedures are prescribed in ICAO Annex 2 paragraph 3.6.5 and Doc 7030/4-EUR, Part 1 (see AIP ENR-1.8.3).
2.2.2 Unlawful interference procedure
Pilots of aircraft in flight subjected to unlawful interference shall endeavor to set the transponder to mode A Code 7500 to give indication of the situation, unless circumstances warrant the use of A+C code 77 (or 7700).
Note: Mode A Code 7500 is permanently monitored in the Tbilisi FIR.
2.3 System of SSR Code assignment
2.3.1 The following
SSR mode A/3 codes are assigned to international flights:
6740 - 6777 2.3.2 The following
SSR mode A/3 codes are assigned to local flights:
7040 - 7057 2.3.3 The following
SSR mode A/3 codes are assigned to search and rescue flights:
7711 - 7717, 7721 - 7723 2.3.4 The following
SSR mode A/3 codes are assigned to VFR flights: 0060 - 0077
2.4 Graphic portrayal of radar coverage area
The charts portray SSR coverage area at the following flight levels: FL90, FL195, FL290, and FL410.