The service responsible for providing communication and navigation service in the Republic of Lithuania is the state enterprise “Oro navigacija”.
State Enterprise “Oro navigacija”
Head of Technical Department
Balio Karvelio Str. 25
LT-02184 Vilnius, Lithuania
Tel:+370 706 94 775
AFS:EYVCYTYX
The services are provided in accordance with the provisions contained in the following ICAO documents:
Communication and navigation services are provided for the entire Vilnius FIR.
Communication and navigation services for en-route and at international airports in the Vilnius FIR are provided by the SE "Oro navigacija", except at Šiauliai AD. Air Base of the Lithuanian Air Force is responsible for communication and navigation services at Šiauliai AD.
The following types of radio navigation aids are available:
All radio navigation aids are dual installations and equipped with secondary power supply.
The maximum switch-over time to the standby transmitter correspond requirements set in ICAO Annex 10, Volume I; if these requirements cannot be met, the maximum switch-over time will be published as a remark within AD part of the relevant aerodrome, under item AD 2.19.
Radio navigation facilities will not be available for navigation purposes during the maintenance period.
The usable radio navigation aids are indicated in ENR 4 Radio navigation aids/systems and AD part of the relevant aerodrome AD 2.19 item Radio navigation and landing aids.
The change-over point between radio navigation aids of an ATS route is normally mid-way point between these aids or at the point of the change of track, if not otherwise published. Radio navigation aids are regularly flight checked and calibrated.
Unless otherwise notified, the aeronautical stations maintain a continuous watch on their stated frequencies during the published hours of service.
An aircraft should normally communicate with the air ground-control radio station which exercises control in the area being overflown. Crew should maintain continuous monitoring on the appropriate frequency of the control station and should not abandon the monitoring without informing the control radio station, except in an emergency.
Messages to be transmitted over the AFS are accepted only if:
General
Provision of CPDLC in the Vilnius FIR is based on the requirements of the Commission Regulation (EC) No.29/2009. CPDLC is available for all properly equipped flights operating as general air traffic in accordance with the instrument flight rules within the controlled airspace above FL 285.
The following data link services are provided in this airspace:
The use of CPDLC is not mandatory in the Vilnius FIR. CPDLC is conducted at the discretion of ATC and by the initiative of the pilot concerned.
Initial contact with ATS unit is provided by voice communication.
Voice shall remain as the primary mean of communication in time-critical situations
Flight Plan
Pilot intending to conduct CPDLC communications within the Vilnius FIR shall file the flight plan as follows:
CPDLC Use
Within the Vilnius FIR CPDLC exchanges may only be conducted when the aircraft is under control of Vilnius ACC.
In the area of responsibility of Vilnius ACC, voice communication and radiotelephony instructions have priority over CPDLC instructions at all times.
CPDLC clearance shall not be executed by the crew until the pilot has sent a WILCO message in response to the CPDLC clearance or instruction received.
Voice read back is not required for any CPDLC instruction.
In case of any uncertainty about a data link message, voice communication shall always be used.
If the pilot or ATC is in the opinion that CPDLC should no longer be used in the given circumstances, CPDLC shall be discontinued or terminated and the other party shall be informed about this by voice communication.
Data Link Communications Initiation Capability (DLIC) – Log-on
The data link address for Vilnius ACC is EYVC.
Normally log-on should be initiated 10 to 15 minutes prior to entering the Vilnius FIR. Log-on shall be initiated by the pilot. The pilot shall log-on using ICAO callsign as filed in the flight plan.
Irrespective of the number of Vilnius ACC sectors which are entered during the flight, only one log-on per flight is required.
ATC Clearances and Information service (ACL)
The pilot may request changes to flight levels (climb or descent) or clearance direct to a point on the route via the data link. The pilot can send emergency messages via the data link as well.
ATC Communications Management service (ACM)
The pilot response to an ATC instruction to change frequency shall be WILCO. If the crew is unable to comply with this data link instruction, the pilot shall revert to voice communication to inform the ATC. When an aircraft is transferred to an adjacent sector / ATS unit by data link, the pilot shall acknowledge the instruction by WILCO, and then shall contact the next sector / ATS unit by voice communication on the assigned frequency.
ATC Microphone Check service (AMC)
A "Check Stuck Microphone" instruction may be sent by an ATC in case the aircraft is inadvertently blocking a radio frequency. If the "Check Stuck Microphone" instruction relates to the radio telephony frequency currently being used, the pilot shall check that the aircraft radio equipment is not causing the blockage. If the "Check Stuck Microphone" instruction does not relate to the radio telephony frequency being used, no further actions by the pilot are required.
Construction of CPDLC Messages
The text of messages shall be composed in standard predefined message format (e.g. CPDLC message set).
Normally the use of free text messages should be avoided.
Long messages or messages with multiple requests elements (multi-element messages) must not be used.
A list of the standard CPDLC messages available for the exchanges in the Vilnius FIR, along with appropriate responses are presented below.
UPLINK MESSAGES
ACM uplink messages
| ATC Message Content | Pilot’s Response |
| CONTACT [unit name] [frequency] | WILCO or UNABLE [+DUE TO WEATHER] or UNABLE [+DUE TO AIRCRAFT PERFORMANCE] or STAND BY |
| ERROR [error information] | NIL System-generated notification of an error. |
| NEXT DATA AUTHORITY [facility] | NIL System-generated notification of the next dataauthority. |
| [free text] | NIL |
| LOGICAL ACKNOWLEDGEMENT | NIL System-generated notification that the receivedmessage is acceptable for display. |
ACL uplink messages
| ATC Message Content | Pilot’s Response |
| UNABLE | NIL |
| STANDBY | |
| MAINTAIN [level] | WILCO or UNABLE [+DUE TO WEATHER] or UNABLE [+DUE TO AIRCRAFT PERFORMANCE] or STAND BY |
| CLIMB TO [level] | |
| DESCEND TO [level] | |
| PROCEED DIRECT TO [position] | |
| ERROR [error information] | NIL System-generated notification of an error. |
| SERVICE UNAVAILABLE | NIL System-generated notification that received message is not supported. |
| [free text] (for additional error information) | NIL System-generated notification. |
| FLY HEADING [degrees] | WILCO or UNABLE [+DUE TO WEATHER] or UNABLE [+DUE TO AIRCRAFT PERFORMANCE] or STAND BY |
| LOGICAL ACKNOWLEDGEMENT | NIL System-generated notification that the received message is acceptable for display. |
| [free text] | WILCO or UNABLE [+DUE TO WEATHER] or UNABLE [+DUE TO AIRCRAFT PERFORMANCE] or STAND BY |
AMC uplink message
| ATC Message Content | Pilot’s Response |
| CHECK STUCK MICROPHONE [frequency] | NIL |
DOWNLINK MESSAGES
ACM downlink messages
| Pilot’s Message Content | ATC Response |
| WILCO | NIL |
| UNABLE | |
| STANDBY | |
| ERROR [error information] | NIL System-generated notification of an error. |
| NOT CURRENT DATA AUTHORITY | NIL System-generated rejection of any CPDLC message sent from a ground facility that is not the current data authority. |
| [free text] | NIL |
| CURRENT DATA AUTHORITY | NIL System-generated notification that the ground facility is now the current data authority. |
| LOGICAL ACKNOWLEDGEMENT | NIL System-generated notification that the received message is acceptable for display. |
| NOT AUTHORIZED NEXT DATA | NIL System-generated notification that the ground system is not designated as the next data authority. |
ACL downlink messages
| Pilot’s Message Content | ATC Response |
| WILCO | NIL |
| UNABLE | |
| STANDBY | |
| REQUEST [level] | Any CPDLC uplink message The ATCO may accept or reject the request or ask to wait. |
| REQUEST DIRECT TO [position] | |
| ERROR [error information] | NIL System-generated notification of an error. |
| DUE TO WEATHER | NIL Indication that the associated message is issued due to specified reason. |
| DUE TO AIRCRAFT PERFORMANCE | |
| [free text] (for additional error information) | NIL |
| LOGICAL ACKNOWLEDGEMENT | NIL System-generated notification that the received message is acceptable for display. |
| REQUEST CLIMB TO [level] | Any CPDLC uplink message The ATCO may accept or reject the request or ask to wait. |
| REQUEST DESCENT TO [level] |
Responding to CPDLC Messages
When a controller or pilot communicates via CPDLC, the response should be via CPDLC. When a controller or pilot communicates via voice, the response should be via voice.
Reverting from CPDLC to Voice
When an immediate response and / or action are required the air-ground communications shall revert to voice.
When it is required to clarify the meaning or the intent of any unexpected, inappropriate or ambiguous CPDLC message, the air-ground communications shall revert to voice.
When it is necessary to ensure the timely execution of an instruction issued by CPDLC, the air-ground communications shall revert to voice.
When a system generates a time-out or an error for a CPDLC message the air-ground communications shall revert to voice.
When corrective actions are required with respect to the unintended messages that have been sent using CPDLC, the air-ground communications shall revert to voice conforming to communication procedures as set out in PANS-ATM.
Message Restrictions and Error Management
If a message received is not supported by a ground system or constitutes an error to the technical rules for CPDLC communication, flight crew will receive an automatic reply indicating the nature of the error and, if applicable, required actions.
Pilot requests via CPDLC should not be send using free text messages.
CPDLC Failure
In case of CPDLC failure, an ATC will instruct all data link equipped aircraft to revert to voice communications.
In case of on-board CPDLC failure, the pilot shall revert to voice communications and inform appropriate ATC unit.
Discontinuation of the Use of CPDLC Pilot Requests
In order to manage the sector workload, a controller may require all stations or a specific flight to avoid sending CPDLC requests for a limited period of time.
Log-off
Log-off is conducted automatically on leaving the VILNIUS FIR. No pilot action is required.
Automatic Terminal Information Service (ATIS) is available for the use of aircraft in flight. Full details are given in section GEN 3.5.
English and Lithuanian.
Details of various en-route facilities can be found in Part 2, section ENR 4.
Details of the aerodrome facilities can be found in Part 3 (AD 2). In cases where the facility is serving both en-route and aerodromes, details are given in the relevant sections of Part 2 (ENR) and Part 3 (AD).
The requirements and general conditions under which the communication and navigation services are available for international use, as well as the requirements for the carriage of radio equipment, are contained in ICAO documents, EC Regulations and other documents.
The list of the main provisions is briefly summarized as follows:
Aircraft operating within the area of responsibility of the ATS shall maintain radio communication in accordance with the ICAO regulations on frequencies as specified in the section ENR 2.1.
When reporting points their geographical names or the call signs of the facility are to be used. For the reporting point not marked by radio aids the 5-letter name codes are transmitted.
If the pilot is not able to establish radio contact on the primary frequency, he should try other frequencies as published for that ATS unit.
Radio communication facilities marked with "VDF" have possibility to measure a magnetic bearing of aircraft (QDR).
Radio station operating on the 121.500 MHz emergency channel may use any call sign assigned to radio stations of the appropriate ATS units.
NIL