GEN 3.4 COMMUNICATION SERVICES

1 Responsible Service

The responsible service for the provision of telecommunication and navigation facility services in Estonia is divided between Estonian Air Navigation Service and Estonian airports.
1.1 CNS-ATM Department
Post:Estonian ANS
CNS-ATM Department
Kanali põik 3
Rae küla, Rae vald
Harjumaa 10112, ESTONIA
Tel:+372 625 8222
Fax:+372 625 8200
E-mail:eans@eans.ee
AFS:EETNYTYX
URL:www.eans.ee

Hours of operation: MON-FRI 0800 to 1630 LMT.
1.2 Airports

Contact details of AD operators at Estonian airports are given in AIP part AD 2.

The service is provided in accordance with the provisions contained in the following ICAO documents:

Annex 10 –Aeronautical Telecommunications
Doc 8400 –Procedures for Air Navigation Services – ICAO Abbreviations and Codes (PANS-ABC)
Doc 8585 –Designators for Aircraft Operating Agencies, Aeronautical Authorities and Services
Doc 7030 –Regional Supplementary Procedures
Doc 7910 –Location Indicators
Doc 9426 –Air Traffic Services Planning Manual

2 Area of Responsibility

Communication services are provided for the entire Tallinn FIR.

An arrangement for such services on a continuous basis should be made with the Head of the CNS-ATM Department of the Estonian ANS.

Estonian CAA is responsible for the application of the regulations concerning the design, type and installations of aircraft radio stations.

Responsibility for the day-to-day operation of these services lies upon Station Communication Officers located at each international aerodrome.

Enquiries, suggestions or complaints regarding any telecommunication service should be referred to the relevant Station Communication Officer or to the Head of the CNS-ATM Department of Estonian ANS, as appropriate.

3 Types of Service

3.1 Radio Navigation Services
The following types of radio navigation aids are available:
  • LF/MF non-directional beacon (NDB)
  • VHF direction-finding station (VDF)
  • Instrument landing system (ILS)
  • VHF omnidirectional radio range (VOR)
  • Terminal approach radar (TAR/SSR)
  • En-route surveillance radar (RSR/SSR)
  • Locator (L)
  • Distance-measuring equipment (DME)

The coordinates listed refer to the transmitting antennas with the exception of direction finding stations, for which the coordinates of the receiving antennas are given.

According to the estimation of the direction-finding station, bearings are classified as follows:
  • Class A - accuracy within ±2 degrees
  • Class B - accuracy within ±5 degrees
  • Class C - accuracy within ±10 degrees
Direction-finding stations have the authority to refuse to give bearings or headings to steer when conditions are unsatisfactory or when bearings do not fall within the calibrated limits of the station, stating the reason at the time of refusal.
3.2 Voice and/or Data Link Service
3.2.1 Voice Service

The aeronautical stations maintain a continuous watch on their stated frequencies during the published hours of service unless otherwise notified.

An aircraft should normally communicate with the air-ground control radio station that exercises control in the area in which the aircraft is flying. Aircraft should maintain a continuous watch on the appropriate frequency of the control station and should not abandon watch, except in an emergency, without informing the control radio station.
3.2.2 Data Link Service

The messages to be transmitted over the Aeronautical Fixed Service (AFS) are accepted only if they:

  1. satisfy the requirements of ICAO Annex 10, Vol. II, Chapter 3, para. 3.3;
  2. are prepared or received in format specified in ICAO Annex 10, Vol. II, Chapter 4, para. 4.4.15.
3.3 Broadcasting Service

According to ICAO Annex 11, Chapter 4, para. 4.3.7 ATIS broadcast consists of following elements:

  1. broadcast identification information;
  2. operational information.
Information about ATIS is given in the GEN 3.5 para. 9, AD 2 EEEI AD 2.18,AD 2 EETN AD 2.18 and AD 2 EETU AD 2.18.
3.4 Languages Used
Estonian, English.
3.5 Where Detailed Information Can Be Obtained

Details of the various facilities available for the en-route traffic can be found in Part 2, ENR 4.

Details of the facilities available at the individual aerodromes can be found in the relevant sections of Part 3 (AD).

In cases where the facility is serving both the en-route traffic and the aerodromes, details are given in the relevant sections of Part 2 (ENR) and Part 3 (AD).

4 Requirements and Conditions

The requirements and the general conditions, under which the communication services are available for international use, as well as the requirements for the carriage of radio equipment, are contained in the Aviation Act of Estonia.

The main provisions are briefly summarised below:

5 Controller-Pilot Data Link Communications (CPDLC)

5.1 General

CPDLC services are available for aircraft operating within the airspace of Tallinn FIR between FL195 and FL660.

The following CPDLC services are provided in this airspace:

  • DLIC (data link initiation capability);
  • ACL (ATC clearances and instructions);
  • ACM (ATC communications management);
  • AMC (ATC microphone check).

Use of CPDLC in Tallinn FIR is not mandatory and is conducted at the discretion of ATC. Voice shall remain the primary means of communication in time-critical situations.

CPDLC messages shall be answered with the least possible delay. If required, e.g. due to the downlink request message having exceeded its time limit, the pilot shall repeat the request via radiotelephony.

Voice read-back is not required for any CPDLC clearance or instruction.

5.2 Flight Plan

Pilots intending to conduct CPDLC communications within Tallinn FIR shall insert the following in the respective items of their filed flight plan:

  • Item 10a - J1 for CPDLC ATN VDL Mode 2 capable aircraft;
  • Item 18 - the indicator CODE/ followed by the aircraft 24-bit address expressed in an alphanumerical code of six hexadecimal characters.
5.3 CPDLC Use

CPDLC clearance shall not be executed until the flight crew has sent a WILCO message in response to CPDLC clearance or instruction received. If uncertainty arises regarding a CPDLC clearance or instruction, voice communication shall always be used for clarification. CPDLC exchanges within Tallinn FIR may only be conducted when the aircraft is under the control and responsibility of Tallinn ACC.

5.4 Restrictions on the Use of CPDLC

CPDLC services are not available for aircraft operating within the Feeder sector or Tallinn TMA (see ENR 2.1). Pilots are requested to refrain from transmitting Downlink Messages when operating in the Feeder sector or the TMA even if the CPDLC connection has not been terminated.

5.5 CPDLC Services
5.5.1 DLIC Log-on

The CPDLC designator for Tallinn FIR is EETT. Log-on shall be initiated by the flight crew 20 minutes prior to entry into Tallinn FIR. For aircraft departing from an aerodrome located within Tallinn FIR the log-on can be initiated on the ground. Aircraft departing from an aerodrome in close proximity to Tallinn FIR can log-on when still on the ground, if Tallinn ACC is the first CPDLC-capable unit. Log-on shall be initiated by the flight crew using their ICAO call sign as filed in the flight plan.

Following the completion of the log-on procedure, at the convenience of ATC, a Start-CPDLC may be performed to enable the sending and/or receiving of CPDLC messages for a particular flight in the designated CPDLC airspace.

Irrespective of the number of sectors crossed during flight, only one log-on per flight is required within Tallinn FIR.

5.5.2 ATC Communications Management (ACM)

When an aircraft is transferred by data link to an adjacent sector/ATC unit, the pilot shall acknowledge the instruction using data link by WILCO, and shall then contact the next sector/ATC unit by voice communication on the instructed channel. If the pilot is unable to comply with this CPDLC instruction, they shall revert to voice communication to inform ATC.

ACM Messages
ATC Message Element
Flight Crew Response
CONTACT [unit name] [frequency]
WILCO

An aircraft operating within Tallinn FIR that cannot be reached by the ATC on the appropriate voice channel may be issued the following pre-formatted Free Text CPDLC message:

CONTACT TALLINN ACC ON VOICE CHANNEL

No CPDLC response form the aircraft is expected and the flight crew shall contact Tallinn ACC through the appropriate voice channel.

5.5.3 ATC Clearances and Instructions (ACL)

Aircraft that has logged on and generated "DM99 CURRENT DATA AUTHORITY" message and for which the ATC has completed the CPDLC Start procedure may receive ATC clearances and instructions via CPDLC uplink messages. Flight crew may request changes to flight levels (climb or descent) or clearance direct to a point on their route via CPDLC downlink messages.

ACM Messages
ATC Message Element
Flight Crew Response
MAINTAIN [level]
WILCO
 
or
 
UNABLE
 
or
 
UNABLE DUE TO AIRCRAFT PERFORMANCE
 
or
 
UNABLE DUE TO WEATHER
 
or
 
STANDBY
CLIMB TO [level]
DESCEND TO [level]
PROCEED DIRECT TO [position]
FLY HEADING [degrees]
SQUAWK [code]
WILCO
ACM Messages
Flight Crew Message Element
ATC Response
REQUEST [level]
(+DUE TO AIRCRAFT PERFORMANCE)
 
or
 
DUE TO WEATHER)
WILCO
 
or
 
UNABLE
 
or
 
STANDBY
REQUEST CLIMB TO [level]
REQUEST DESCENT TO [level]
PROCEED DIRECT TO [position]

If the ground system receives a message that is not supported, 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. CPDLC implementation in Tallinn FIR only contains the messages listed in section 5.5. All other messages will be replied to with an error message.

5.5.4 Free Text ACL Messages

Use of Free Text ACL messages is not operationally supported. Free Text messages composed by the flight crew will not be responded to by ATC and may result in an error message generated by the ground system.

5.5.5 CPDLC Imposed Silence

In order to contain the sector workload the ATC may require all stations or a specific flight to suspend sending CPDLC requests for a limited period of time. For imposing or revoking CPDLC silence the following phrase, either as a voice or a CPDLC free text message shall be used:

[call sign] STOP SENDING CPDLC REQUESTS

5.5.6 ATC Microphone Check (AMC)

A "CHECK STUCK MICROPHONE" instruction may be sent by ATC in circumstances where an aircraft is inadvertently blocking a voice communication channel. If the "CHECK STUCK MICROPHONE" instruction relates to the RTF channel currently being used, the pilot shall check that their radio equipment is not causing the blockage. If the "CHECK STUCK MICROPHONE" instruction does not relate to the RTF channel being used, no further action by the pilot is required.

ACM Messages
ATC Message Element
Flight Crew Response
CHECK STUCK MICROPHONENIL
5.5.7 Emergency and Distress CPDLC Messages

The following emergency/distress CPDLC messages are supported:

Flight Crew Message Element
ATC Response
PAN PAN PANROGER
MAYDAY MAYDAY MAYDAY
SQUAWKING 7500NIL
5.5.8 Voice Interruption of CPDLC Dialogue

When using voice communication to correct an unanswered CPDLC message, ATC shall initiate voice communication using the phrase:

DISREGARD CPDLC (message type) MESSAGE, BREAK, REPLY WITH UNABLE

and deliver the correct clearance within the same transmission. The pilot shall reply to the CPDLC message with an "UNABLE" message and respond by voice to the clearance received by radio communication.

5.5.9 CPDLC Failure

When alerted that CPDLC has failed, the controller will inform all stations under sector jurisdiction, using the following phrase:

ALL STATIONS, CPDLC FAILURE, [identification of the calling station]

Some failures may result in termination of the existing data link connections with aircraft that are under control of a sector. In this case, it will not be possible for ATC to re-initiate dialogues via CPDLC unless the pilot re-initiates the data link logon process in order to re-establish data link connection. ATC will inform aircraft under their jurisdiction when CPDLC service is restored, using the following phrase:

ALL STATIONS, RESUME NORMAL CPDLC OPERATIONS

In case of a CPDLC failure, CPDLC clearances that have not yet been confirmed shall be repeated over voice communication and/or confirmed. If either the flight crew or ATC consider that CPDLC should not be used in the prevailing circumstances, CPDLC shall be suspended or terminated and the other party shall be informed by voice communication. In case of a scheduled shutdown or an unexpected failure of the CPDLC system, ATC will instruct all aircraft equipped with data link to return to voice communication. In case of an on board failure of CPDLC, the pilot shall return to voice communication and inform ATC.

5.5.10 Log-off

Log-off is automatic on leaving Tallinn FIR or when landing at an airport within Tallinn FIR, no pilot action is required.