SSR Transponder codes
Before entering BUCUREŞTI FIR from an adjacent region where the operation of the transponder has not been required pilots of IFR flights shall operate the transponder on Mode A code 2000 and Mode C pressure-altitude reporting mode and maintain that code setting unless otherwise instructed by the ATC.
Unless otherwise instructed, pilots of VFR flights shall operate the transponder in Modes A and C code A7000 in order to ensure uncontrolled flights detection in BUCUREŞTI FIR. Using a transponder does not exonerate the pilots of their obligation as regards visual surveillance and prevention of collisions as described in the air rules. Pilots shall exercise extreme caution when selecting Mode A code 7000, due to its similarity with the Special Purposes Mode A codes. The pilot of a VFR flight flying in uncontrolled airspace, in case the aircraft is equipped with a
transponder without altitude reporting capability, shall not use the transponder, unless a mode A code has been assigned by the ATC Unit.
SSR Code assignment:
6701 – 6777 local VFR flights
5401 – 5477 international IFR flights
4001 – 4077 local IFR flights