4.Procedures for SSR transponder setting
4.1Procedures for pilots
An aircraft equipped with the SSR transponder shall operate the transponder during the flight. The SSR transponder shall reply to mode A and C interrogations.
Pilots of uncontrolled VFR flights equipped with SSR transponder Mode A and C shall set Code 7000 unless ATS unit has assigned other code.
SSR code assigned by ATS unit shall be maintained by the aircraft until termination of the flight or until the instruction of ATS unit is given to change the code or to switch off the transponder.
Pilots of aircraft equipped with Mode S having an aircraft identification feature shall set the aircraft identification in the transponder.
If FPL has been submitted, transponder setting shall exactly correspond to the aircraft identification specified in item 7 of the FPL.
If FPL has not been submitted, the setting shall correspond to the aircraft registration marking (e.g. OKABC or OKUUA14).
4.1.1Codes for special purposes
In case emergency set Code 7700
In case of radiocommunication failure set Code 7600
Note: Radio communication failure (RCF) is considered a state when during the VFR flight within controlled airspace of class C or D, the pilot despite all attempts failed to establish a communication with ATC unit.
In case of unlawful interference set Code 7500
4.2Equipment of aircraft conducting VFR flights by SSR transponder
4.2.1Equipment of Aircraft by SSR Mode S Transponder with Enhanced Surveillance functionality (ELS)
The carriage and operation of Mode S with ELS functionality is mandatory for VFR flights:
- within FIR Praha above FL 95 and
- within TMA Praha and CTR Ruzyně.
4.2.2Equipment of Aircraft by SSR Transponder with a Mode A and C
VFR flights operating outside the Mode S designated airspace, as described above shall be equipped with SSR transponder capable to reply to Mode A interrogations with Mode C pressure-altitude reporting as follows:
- all powered aircraft and balloons operating VFR flights at or above FL 60, or altitude at or above 5000 ft (1500 m) AMSL, if transition level is FL 70,
- all aircraft operating VFR en-route flight at night.
4.2.3Exemptions from the equipage requirement
Potential granting of an exemption from the requirement to carry SSR Mode S transponder is described in AIP CR, subsection GEN 1.5
An exemption from mandatory carriage of SSR Mode A/C transponder can be approved by respective ATC unit with regards to traffic situation on crew’s request prior to entering its area of responsibility.