GEN 3.4  Communication Services


1.1   Civil

Skeyes, ANA and Eurocontrol are the responsible authorities for the provision of telecommunication and navigation facility services within the areas indicated under § 2 below.

The services are provided in accordance with the provisions contained in the following ICAO documents:

  • ICAO Annex 10. Aeronautical Telecommunications
  • ICAO Doc 7030. Regional Supplementary Procedures
  • ICAO Doc 7910. Location Indicators
  • ICAO Doc 8400. ICAO Abbreviations and Codes (PANS-ABC)
  • ICAO Doc 8585. Designators for Aircraft Operating Agencies, Aeronautical Authorities and Services
1.1.1   Skeyes

Tervuursesteenweg, 303
1820 Steenokkerzeel

TEL: +32 (0) 2 206 22 03

FAX: +32 (0) 2 206 22 00



1.1.2   ANA

Administration de la Navigation Aérienne
Service CNS
BP 273
L-2012 Luxembourg

TEL: +352 47 98 25 00 1

FAX: +352 46 98 25 09 0



1.1.3   Eurocontrol

Maastricht UAC
Horsterweg 11
6199 AC Maastricht Airport

TEL: +31 (0) 43 366 12 34

FAX: +31 (0) 43 366 13 00




1.2   Military

Within Belgian Defence, Comopsair is the responsible authority for the provision of military telecommunication and navigation facility services within the area indicated under § 2.2 below.


Air Component - COMOPSAIR
Air Operations Support (A 3.2)
Kwartier Koningin Elisabeth
Bldg 1
Eversestraat / Rue d’Evere 1
1140 Brussels

TEL: +32 (0) 2 701 17 04



2.1   Civil
2.1.1   Skeyes

Skeyes is responsible for the provision of radio navigation and surveillance services within the territory of Belgium.

Skeyes is responsible for the provision of voice and data communications services within the area of responsibility of its air traffic services (see GEN 3.3, § 2.1.2).

Note: Data link services are provided in cooperation with SITA, ARINC and Sat AIRCOM.

2.1.2   ANA

ANA is responsible for the provision of radio navigation and surveillance services within the territory of Luxembourg.

ANA is responsible for the provision of voice and data communication services within the area of responsibility of its air traffic services (see GEN 3.3, § 2.1.2).

2.1.3   Eurocontrol

Eurocontrol Maastricht UAC is responsible for the provision of voice and data communication services within the Brussels UIR above FL 245.

2.2   Military

Military communication services are provided for the Brussels FIR/UIR.

COMOPSAIR is responsible for the provision of military communications services within the area of responsibility of its air traffic services (see GEN 3.3, § 2.2).


3.1   Radio Navigation Services

The following types of radio aids for navigation are available:

  • Non-directional radio beacon (NDB)
  • VHF omnidirectional radio range (VOR) - Doppler VOR (DVOR)
  • VHF direction-finding station (VDF)
  • Instrument landing system (ILS)
  • Distance measuring equipment (DME)
  • UHF tactical air navigation aid (TACAN)
  • Terminal area surveillance radar (TAR)
  • Secondary surveillance radar (SSR)
  • Surface movement radar (SMR)
  • En-route surveillance radar (RSR)
  • Global navigation satellite core constellations (GPS)
  • Satellite based augmentation systems (EGNOS)

According to the judgement of the direction-finding station, bearings are classified as follows:

Class AAccurate within ± 2 DEG
Class BAccurate within ± 5 DEG
Class CAccurate within ± 10 DEG

Direction-finding stations have 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.

3.1.1   Miscellaneous

Due to Clacton VOR/DME (CLN) operating on FREQ 114.550 MHZ / CH 92Y, aircraft equipped with receivers with channel spacing of 100 KHZ and flying in lower airspace may be subject to erroneous indications at the limit of the designated operational coverage of BUB (FREQ 114.600 MHZ) and KOK (FREQ 114.500 MHZ).

Consequently, it is recommended that these aircraft use only a coverage of 50 NM for BUB and 40 NM for KOK in the north sector of both stations between 270 and 090 degrees.

3.2   Voice and Fixed Services
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 it is flying. Aircraft should maintain continuous watch on the appropriate frequencies of the control station and should not abandon watch, except in an emergency, without informing the control station.

On frequencies published as “guarded”, a permanent listening watch is maintained during the responsible unit’s operational hours. On frequencies published as “stand-by”, no permanent listening watch is maintained.

3.2.2   Fixed Service

The messages to be transmitted over the AFS are accepted only if:

  • they satisfy the requirements of ICAO Annex 10, volume 2, chapter 3
  • they are prepared in the form specified in ICAO Annex 10
  • the text of an individual message does not exceed 200 groups
3.3   Broadcasting Service

Sub-area meteorological broadcasts (VOLMET) are available H24 for use by aircraft in flight. Full details are given in GEN 3.5, § 1.7.

At EBAW, EBBR, EBCI, EBLG, EBOS and ELLX, ATIS broadcasts are available to pass routine arrival and departure information. Full details are given in the relevant AD 2.18 and AD 2.23 sections.

Note: In Belgium, voice toggling (male/female) is used in order to attract attention on the start of a new message.

3.4   Data Link Service
3.4.1   Controller-Pilot Data Link Communication (CPDLC)   General

The CPDLC application provides a means of communication between the air traffic controller and the pilot, using a predefined data link message set. This application includes a set of clearance/information/request message elements which correspond to the phraseologies used in the radiotelephony environment.

CPDLC services are available for all certified aircraft operating within the upper airspace (above FL 245) of the Brussels UIR in the area under the responsibility of Maastricht UAC.

The following CPDLC services are provided in Maastricht UAC area of responsibility:

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

The use of CPDLC is reserved for strategic clearances in this airspace and is conducted at the discretion of ATC.

In Brussels UIR (Maastricht UAC), it is mandatory for all flight crews of CPDLC-equipped (FANS) and Eurocontrol whitelisted ATN aircraft to log on to EDYY for safety and capacity reasons.

If the pilot or ATC is of 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.

To increase acceptance and use of CPDLC, it is very important to confirm and execute all CPDLC Up Links promptly.   Registration and inclusion of air carriers on the white list

Air carriers wishing to conduct CPDLC in Brussels UIR shall register with the EUROCONTROL NM Data link Performance Monitoring at least four weeks prior to the AIRAC date before their first planned flight using data link.

No inquiries shall be made on the frequency. Contact for operational questions:


Volker Stuhlsatz
Eurocontrol MAS-UAC
NL-6191 AC Maastricht-Airport

TEL: +31 (0) 43 366 1510

Email:   Flight Plan

Pilots shall file their aircraft 24-bit address code in the flight plan item 18 “CODE/” (6 hexadecimal characters). To use future air navigation system (FANS) 1/A it is mandated to file the registration mark of the aircraft in item 18 “REG/” (tail number).   CPDLC Use

In the area of responsibility of Maastricht UAC, voice communication and radiotelephony instructions have priority over CPDLC instructions at all times. A clearance requested via CPDLC should subsequently be issued via CPDLC. A clearance requested via radiotelephony should also be issued via radiotelephony.

Only if the controller is asking explicitly for a voice read back, the following phrase should be used by the pilot: e.g. “Call sign -Confirming CPDLC climb FL 370”.

No CPDLC clearances shall be executed until the WILCO message has been sent.

If uncertainty arises regarding a data link message, voice communication shall be used. CPDLC exchanges with Maastricht UAC shall only be conducted when the aircraft is actually under control and responsibility of Maastricht UAC.   DLIC log-on

The data link address for Maastricht UAC is EDYY.

All data link-equipped aircraft included on the Eurocontrol NM Data link Performance Monitoring ATN white list which enter Maastricht UAC airspace are required to log on to EDYY as a secondary means of communication.

This improves safety in air traffic during VHF frequency interference and failures, adverse weather and traffic congestion. It also mitigates the consequences of a LOST COM.

Data link capability is displayed on the screens at Maastricht and the controllers will request appropriately equipped aircraft to LOG ON.

Flight crews can expect to receive uplinks especially during periods of high traffic volume, and are requested to always confirm them as soon as possible with WILCO.   CPDLC Services   ATC Clearances and Instructions (ACL)

Pilots may receive the uplink messages described via data link. Pilots may request changes to flight levels (ascent or descent) via data link or clearance direct to a point on their route.   ATC Communications Management (ACM)

The pilot response to an ATC instruction to change the communication channel shall be WILCO. If the pilot is unable to comply with this data link instruction, he shall revert to voice communication to inform ATC.

When an aircraft is transferred by data link to an adjacent sector/ATS Unit, the pilot shall acknowledge the instruction by WILCO, and shall contact the next sector/ATS Unit by voice communication on the instructed channel.   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. For FANS 1/A+ aircraft a ROGER response will be expected in response to this instruction.

If the 'Check Stuck Microphone' instruction relates to the RTF channel currently being used, the pilot shall check that the 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.   Message Restrictions

Pilots shall not use free-format free-text messages when communicating with Maastricht UAC via CPDLC. Use of such a free-text message will result in an error response.   CPDLC Failure

In case of a CPDLC failure, CPDLC clearances that have not yet been confirmed shall be repeated over radiotelephony and/or confirmed. If either the pilot 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.   CPDLC Messages

The controller or pilot shall construct CPDLC messages using the defined message set. The following uplink clearances and instructions may be expected when using CPDLC with Maastricht UAC:

  • ATC Uplink Clearances and Instructions, supported for ATN and FANS 1/A aircraft
    • Vertical clearances:
      • MAINTAIN [level]
      • CLIMB TO [level]
      • DESCEND TO [level]
      • CLIMB TO REACH [level] BY [position]
      • DESCEND TO REACH [level] BY [position]
      • CLIMB TO [level], to cross [position] AT or ABOVE
      • DESCEND TO [level], to cross [position] AT or BELOW
    • Contact/monitor/surveillance requests:
      • CONTACT/MONITOR [unit name] [frequency]
      • SQUAWK [code]
    • Lateral offsets:
    • Route modifications:
      • PROCEED DIRECT TO [position]
      • CLEARED [route clearance]
      • CLEARED TO [position] VIA [route clearance]
    • Speed changes:
      • MAINTAIN [speed]
      • MAINTAIN [speed] OR GREATER
      • MAINTAIN [speed] OR LESS
    • Air traffic advisories:
      • CHECK STUCK MICROPHONE [frequency]
      • WHEN CAN YOU ACCEPT [level]
  • ATC Uplink Clearances and Instructions, only for ATN aircraft
    • Route modifications:
      • TURN [direction] HEADING [degrees]
      • FLY HEADING [degrees]

Pilots shall respond to all uplink clearances and instructions with the appropriate data link operational response, before manoeuvre execution.

  • Pilot Downlink Request

    The following downlink requests may be sent by pilots using CPDLC with Maastricht UAC:

    • Vertical request:
      • REQUEST [level]
      • REQUEST CLIMB TO [level]
      • REQUEST DESCENT TO [level]
    • Route modifications request:
      • REQUEST DIRECT TO [position]
    • Speed requests:
      • REQUEST [speed]

When using CPDLC, the maximum dialogue time is 120 SEC. CPDLC shall only be used for non time critical requests, i.e. requests that do not require the immediate reaction of the controller. Nevertheless, as in radiotelephony, it is of paramount importance that the CPDLC messages shall be answered with the least possible delay. If the downlink request is cut off because the time limit was exceeded, the pilot should also repeat the request via radiotelephony.   Additional FANS 1/A Procedures

FANS 1/A is subject to potentially high network latency and changing round trip delay. FANS 1/A crews have to pay attention to the Up Link time stamps to ensure they avoid in the busy airspace of Maastricht UAC the execution of old and void clearances which have been delayed in the network.

Due to low end-to-end integrity, no flight profile change messages will be sent, e.g. FLY HEADING, and TURN Up Links.

To protect FANS 1/A aircraft against message misdirection, Maastricht will prepend the Flight-ID to all uplink CPDLC messages. Pilots should check the Flight-ID to ensure that the correct message was received before executing the uplink message.

Flight crews shall cross-check that the CPDLC address of any Up Link corresponds to the name of the ATC unit with which the flight is conducting voice communications.

Mitigation for any late arrival of FANS 1/A messages is referred to as “commanded termination”.

The crew will be required to disconnect from the data link service, and not allowed to re-LOG-ON to the current data authority.

Due to the risk of undetected Up Linked CPDLC message duplication, FANS 1/A crews shall be especially vigilant if they receive the same Up Link twice and confirm with ATC in case of doubt, e.g. with a voice communication.   FANS 1/A Uplink: Message Latency Monitor

To protect FANS 1/A aircraft against execution of message that haven been delayed, Maastricht UAC will uplink UM169 SET MAX UPLINK DELAY VALIUE TO 300 SECONDS to all FANS 1/A aircraft. FANS 1/A crews shall set the latency time monitor to 300 seconds appropriately.

There are variations between aircraft types in implementation of the message latency monitor function:

  • Automatic rejection of a delayed uplink message by sending the error message ERROR INVALID DATA. UPLINK DELAYED IN NETWORK AND REJECTED RESEND OR CONTACT BY VOICE to ATC and not showing the UL to the crew, or;
  • Displaying delayed messages to the crew with an indication that the message has been delayed. It is then up to the pilot to act appropriate.

When the pilot receives the uplink CPDLC message SET MAX UPLINK DELAY VALUE TO 300 SECONDS he/she shall:

  • Send a positive response to ATC as prompted by the avionics (ACCEPT [ROGER]) regardless of whether the aircraft supports the latency monitor;
  • If equipped with a correctly functioning message latency monitor, enter the specified uplink delay into the avionics. Some avionics will automatically set the delay value in accordance with the uplink message and do not allow for a manual input.

When a crew receives a CPDLC uplink message with an indication that the message has been delayed the crew shall:

  • Revert to voice communications to notify the ATS unit of the delayed message received and to request clarification of the intent of the CPDLC message, and;
  • Respond appropriately to close the message as per instructions of the controller;
  • The pilot must not act on the delayed uplink message until clarification has been received from the controller.
    In case of an uplink message time-out, ATC will acknowledge receipt of the uplink message via voice communication. In case the uplink message was not received, the pilot will be instructed to terminate CPDLC (DM101: REQUEST END OF SERVICE) until the next ATC unit to avoid potential late uplink messages.
3.4.2   D-VOLMET and D-ATIS

Digital VOLMET (D-VOLMET) and digital ATIS (D-ATIS) are available H24 via data link. The information provided is identical with the information provided through broadcasting (see § 3.3 above).

The system operates in accordance with specifications AEEC 622 and 623. Aircraft can interface with the service through the SITA and ARINC service providers’ networks where available to aircraft.

Uplink messages will be formatted according to the line width indicated by the value of the avionics indicator contained in the down-linked request. Formatting of the up-linked information takes into account pre-defined rules intended to enhance the readability of the messages.

Note 1: A single VOLMET message is provided for en-route (E) requests associated with EBAW, EBBR, EBCI, EBLG or EBOS.

Note 2: For EBBR a separate ATIS message is provided for arrival (A) or departure (D) requests; for EBAW, EBCI, EBLG and EBOS, a combined ATIS message is provided for arrival (A) or departure (D) requests. A continuous update sequence is generated for a contract (C) request and ended by a terminate (T) request, or else automatically timed out after 1 hour.

D-VOLMET and D-ATIS information is also made available (for non-operational use only) in the following ways:

Free dial-in voice service:

TEL: +32 (0) 2 206 25 25

Internet text service (registration required):

Note: Message content should not differ from the airborne content (voice and text), but a small synchronisation lag may be noticed.

3.5   Languages Used
3.5.1   Civil

In the Brussels FIR/UIR English shall be used to contact ATS units providing ATC, FIS and AFIS. For the preferential language to be used on non-controlled aerodromes and heliports, see AD 2 and AD 3.

3.5.2   Military

In the Brussels FIR/UIR, for communication with military ATS, only English shall be used for the normal communication and flight safety messages.

3.6   Frequencies for gliding
122.385 (8.33 KHZ CH)A/ABelgium GND / FL 100
126.810 (8.33 KHZ CH)
135.235 (8.33 KHZ CH)

Users have to apply the most strictly as possible the limitations in levels and distances as mentioned above, to avoid interference of the other stations using the same channel to enable aircraft to exchange necessary operational information and to facilitate the resolution of operational problems.

Unless specifically approved by the Belgian CAA, these frequencies are not to be used for special events. Frequencies for special events shall continue to be requested through existing channels.




5.1.1   Belgium   Civil

Operations (VFR)EBBUZFZX
Operations (IFR)EBBUZQZX
Operations (FMP)EBBRFMPC
Basic InformationEBKTZTZX
ManagementEBSPYDYX   Military

Test Flying OfficeEBCIYXYX
5.1.2   Luxembourg
5.1.3   Eurocontrol
Network ManagerEUCHEUCX