The carriage and operation of Mode S transponders is mandatory in the Brussels FIR/UIR for all aircraft operating:
During missions, police aircraft are exempted for replying to Mode S interrogations, provided they activate the A/C modes of the on-board transponder and advise the ATC unit concerned.
The carriage and operation of a serviceable transponder - capable of replying to Mode A and C interrogations - is mandatory in the Brussels FIR/UIR for all aircraft operating in military controlled airspace.
In Belgium an exemption to these rules may be granted for a single (ferry-) flight to a maintenance facility, provided that the request is made before the flight, to the ATC unit of the airspace concerned.
Note: Pilots are reminded about the importance of having a well-functioning transponder to be switched on in the Brussels FIR/UIR; ATC is allowed when possible to refuse aircraft without a well-functioning one.
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 designated by the competent authority for mandatory operation of transponder, aircraft without sufficient electrical power supply are exempted from the requirement to operate the transponder at all times.
Note 1: Pilots of aircraft engaged in formation join-ups are expected to continue operating the transponder until established in formation. Once established in formation, all except the lead aircraft should be instructed to ‘squawk standby’.
Note 2: Pilots of non-powered aircraft are also encouraged to operate the transponder during flight outside airspace where carriage and operation of SSR transponder is mandatory.
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 Brussels FIR, pilots who have already received specific instructions from ATC concerning the setting of the transponder shall maintain that setting until otherwise instructed.
To indicate that it is in a specific contingency situation, the pilot of an aircraft equipped with SSR shall:
Note 1: If a pilot has selected Mode A Code 7500 and has been requested to confirm this code by ATC, the pilot should, according to circumstances, either confirm this or not reply at all. If the pilot does not reply, ATC will take this as confirmation that the use of Code 7500 is not an inadvertent false code selection.
Except in the cases described above, the pilot shall:
Note 2: When requested by ATC to confirm the code selected, the pilot should verify the Mode A code setting on the transponder; reselect the assigned code if necessary; and confirm to ATC the setting displayed on the controls of the transponder.
Pilots operating in Belgian class G airspace who are not receiving FIS, but are monitoring the COM channel of Brussels FIC, should select Code 5101 if the aircraft is equipped with a Mode S transponder.
When the aircraft carries serviceable Mode C equipment, the pilot shall continuously operate this mode unless otherwise dictated by ATC.
Aircraft equipped with Mode S having an aircraft identification feature shall transmit the aircraft identification as specified in Item 7 of the ICAO flight plan or, when no flight plan has been filed, the aircraft registration.
In order to be interpreted properly, there must be no spaces between the designator letters and flight number, nor any additional/superfluous zeros preceding the flight number. In case the aircraft identification can be entered manually, entry should be part of the start-up procedures.
Correct setting of aircraft identification is essential for identification and correlation (of radar track with flight plan data). An incorrect setting of the aircraft identification will be reported to the Belgian Civil Aviation Authority.
Note 1: For Mode S transponder ground operation at EBBR, see EBBR AD 2.20, § 1.4.
Note 2: For Mode S transponder ground operation at ELLX, see ELLX AD 2.20, § 1.1.
In case of a transponder failure after departure, ATC units will attempt to provide for continuation of the flight to the destination aerodrome in accordance with the flight plan. Pilots may, however, be expected to comply with specific restrictions.
Note: When an aircraft experiencing transponder failure after departure is operating or expected to operate in an area where the carriage of a functioning transponder with specified capabilities is mandatory, the ATC units concerned will endeavour to provide for continuation of the flight to the aerodrome of first intended landing in accordance with the flight plan. However, in certain traffic situations, either in terminal areas or en- route, continuation of the flight may not be possible, particularly when failure is detected shortly after take- off. The aircraft may then be required to return to the departure aerodrome or to land at the nearest suitable aerodrome acceptable to the operator concerned and to ATC.
In the case of a transponder which has failed and cannot be restored before departure, pilots shall:
Note: In case of a transponder failure which is detected before departure from an aerodrome where it is not practicable to effect a repair, the aircraft concerned should be permitted to proceed, as directly as possible, to the nearest suitable aerodrome where repair can be made. When granting clearance to such aircraft, ATC will take into consideration the existing or anticipated traffic situation and may have to modify the time of departure, flight level or route of the intended flight. Subsequent adjustments may become necessary during the course of the flight.
Codes will be assigned in accordance with the SSR code allocation list for the ICAO EUR Region, which is based on the Originating Region Code Assignment Method (ORCAM).
Codes protected for international transit, transit codes, which are assigned to overflying or inbound flights, will be retained by ATC.
Code 1000 will be assigned or retained to indicate an eligible (flagged by the IFPS) IFR flight, where the downlinked aircraft identification is validated as matching the aircraft identification entered in the flight plan.
0101 - 0117 | departing traffic |
7101 - 7167 | departing traffic |
4401 - 4427 | departing traffic inbound the United Kingdom, the Netherlands, Ireland, Greenland, Iceland, Canada or the United States, and departing traffic re-entering Belgium. |
1000 | eligible (flagged by the IFPS) departing traffic |
4450 - 4457 | codes assigned by Brussels ACC/APP |
5102 - 5173 | codes assigned by Brussels ACC/APP |
6301 - 6313 | codes assigned by Brussels TWR |
6314 - 6327 | codes assigned by Charleroi TWR/APP |
6330 - 6343 | codes assigned by Liège TWR/APP |
6344 - 6361 | codes assigned by Oostende TWR/APP |
6362 - 6367 | codes assigned by Antwerpen TWR |
0041 - 0057 | codes assigned by Brussels INFO |
3501 - 3507 | Departing traffic |
5650 - 5657 | Departing traffic |
7170 - 7177 | Departing traffic |
1000 | Eligible (flagged by the IFPS) departing traffic |
4460 - 4464 | Codes assigned by Luxembourg APP |
4465 - 4467 | Codes assigned by Luxembourg APP/TWR |
4470 - 4477 | Codes assigned by Luxembourg APP/TWR |
ATS units and Air Defence Stations use SSR for identification and automatic tracking of aircraft.
The carriage of a serviceable transponder capable of replying to Mode A and C is compulsory for all aircraft operating in all military controlled airspace. An exemption to this rule may be granted, provided that the request is made before the flight to the authority having jurisdiction over the airspace concerned. Aircraft flying OAT within the Brussels FIR/UIR must have a serviceable SSR transponder.
The carriage of a serviceable Mode S (ELS or EHS) SSR transponder is highly recommended but not yet compulsory for State aircraft flying OAT within the Brussels FIR/UIR including low level VFR flights.
State aircraft flying GAT within the Brussels FIR/UIR shall comply with the regulation for the carriage and operation of SSR mode S airborne equipment published in the AIP and/or related AIC.
State aircraft that do not transmit ADS-B out for technical or operational reasons, will be accommodated in the Brussels FIR/UIR through traditional surveillance methods such as Mode A/C/S.
Flights with a wrong Mode S ACID will be instructed by ATC to correct this. Flight limitations may be imposed until the ACID is correct (e.g. not leaving the CTR or TMA).
Aircraft flying OAT within the Brussels FIR/UIR shall squawk:
Mode 1 | as instructed by the appropriate NATO authority |
Mode 2 | always activated unless instructed otherwise |
Mode 3/A | as instructed by the controlling agency |
Mode C | always activated unless instructed otherwise |
Mode S | Only mandatory for declared Mode S capable Belgian military aircraft. Mode S ACID must exactly match the ACID as entered in item 7 of the FPL (See ENR 1.10, § 2.3.1.1) |
Note: In a formation flight, only one aircraft shall squawk as mentioned above, the other aircraft shall squawk “stand-by”.
Note: Mode 4 is forbidden.
1401 - 1477 | Steenokkerzeel ATCC |
2601 - 2627 | Cross-border to EH/ED |
5401 - 5417 | Koksijde/HELI |
5420 - 5427 | RPAS |
5430 - 5477 | SF260M |
6001 - 6077 | Beauvechain CRC |
6401 - 6477 | Steenokkerzeel ATCC |
4201 - 4207 | Chièvres |
4210 - 4227 | Beauvechain |
4230 - 4247 | Kleine-Brogel |
4250 - 4267 | Florennes |
4270 - 4277 | Koksijde |
A1000 | conspicuity code applicable to civil city pair aircraft, forbidden for OAT fligths. |
A7000 + C | uncontrolled flights, which have not received an instruction concerning the setting of their transponder |
A7500 | unlawful interference |
A7600 | radio communication failure |
A7700 | emergency (unless instructed otherwise by the controlling agency) |
The pilot shall transmit reports at the scheduled times or positions, preceded by “transmitting in the blind due to receiver failure”. These reports should include his intentions and the time of his next intended transmission.
If the pilot is established on a published ATS route, he shall maintain the last assigned speed and level for a period of 7 MIN. After this period, he shall adjust to the level in accordance with the flight plan. If the pilot is established on a published ATS route but he was receiving radar vectors or he was proceeding offset, the pilot shall proceed in the most direct manner possible to rejoin the current flight plan route.
If the pilot has been given level clearances for only a part of the route, he shall fly this level to the point specified in the clearance and then the cruising level of the flight plan. Departing aircraft shall fly the level they are cleared to for 3 MIN and then fly the cruising level of their flight plan.
The pilot may or, if transponder is inoperative, shall fly triangles of 1 MIN legs (TAS higher than 300 KT) or 2 MIN legs (TAS equal or less than 300 KT) clockwise if his receiver still works, anti-clockwise if the radio receiver and transmitter are both out of service. He can expect to be intercepted by a shepherd aircraft.