a. “... (call sign), radar contact ...”
b. “... (call sign), identified ...”
The minimum horizontal radar separations are:
Levels assigned by the radar controller to pilots will provide a minimum terrain clearance according to the phase of flight.
General
When an aircraft carries a serviceable SSR transponder, the pilot shall operate the transponder at all times during flight, regardless of whether the aircraft is within or outside airspace where SSR is used for ATS purposes.
Pilots shall not operate the IDENT feature unless requested by ATS.
Except for flight in airspace for mandatory operation of transponder, aircraft without sufficient electrical power supply are exempted from the requirement to operate the transponder at all times.
When entering the Riga FIR, pilots who have already received specific instructions from ATS unit concerning the setting of the transponder, shall maintain that setting until otherwise instructed.
Except specific contingency situation, pilots shall:
1. Emergency procedures
Except when encountering a state of emergency, pilots shall operate transponders and select modes and codes in accordance with ATC instructions. In particular, when entering the Riga FIR, pilots who have already received specific instructions from ATC concerning the setting of the transponder, shall maintain that setting until otherwise instructed.
The pilot of an aircraft equipped with SSR shall select Mode A 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 Mode A Code 7700 whenever there is a specific reason to believe that this would be the best course of action.
Pilots of aircraft about to enter the Riga FIR who have not received specific instructions from ATC concerning the setting of the transponder shall operate the transponder on mode A/3+C code 20 (or 2000) before entry and maintain that code setting until otherwise instructed.
If the pilot of an 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/3+C code 77 (or 7700).
Notwithstanding the procedure in paragraph 2.1.1 above, a pilot may select mode A/3+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/3+C code 77 is provided.Mode A Code 7700 is permanently monitored in the Riga FIR.
2. Air-ground communication failure and unlawful interference procedures
2.1 Radio communication failure procedure
In the event of an aircraft radio receiver failure, a pilot shall select mode A/3+C code 76 (or 7600) and follow established procedures; subsequent control of the aircraft will be based on those procedures.
In the event of a radio communication failure, Mode A code 7600 shall be selected. Applicable radio communication failure procedures are to be followed.
Note: Mode A Code 7600 is permanently monitored in the Riga FIR.
2.2 Unlawful interference procedure
Pilots of aircraft in flight subject to unlawful interference shall endeavor to set the transponder to Mode A Code 7500 to provide an indication of the situation, unless circumstances warrant the use of A/B Code 77 (or 7700).
The pilot of an aircraft which is subjected to unlawful interference shall attempt to select Mode A Code 7500 to provide an indication of a state of unlawful interference. If circumstances so warrant, Mode A Code 7700 should be used instead.
Note: Mode A Code 7500 is permanently monitored in the Riga FIR.
3. System of SSR code assignment
The functional codes 4300-4377 (international flights), 0060-0077 and 3360-3377 (domestic flights) are assigned by Riga ATC for departing, arriving and overflying traffic.
SSR codes used for IFR flights in Riga FIR are assigned and managed by European Centralised SSR Code Assignment and Management System (CCAMS).
SSR codes used for VFR flights in Riga FIR are assigned and managed by ATS unit according to the SSR Code Allocation List.
4. Voice and CPDLC position reporting requirements
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5. Graphic portrayal of area of SSR coverage (see Figure 2)
* Initial publishing and distribution of NOTAMs, regarding the operational status of the Martna Mode A/C MSSR, will remain on own responsibility of “Lennuliiklusteeninduse Aktsiaselts” (Estonian Air Navigation Service Provider).
** Initial publishing and distribution of NOTAMs, regarding the operational status of the Palanga Mode S MSSR and Vilnius Mode S MSSR, will remain on own responsibility of SE “Oro Navigacija” (Lithuanian Air Navigation Service Provider).
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