The reflection of electromagnetic waves is a very complex matter and depends on the type and the frequency of the installation, the shape of the object, the dimensions, the used materials, the position and orientation with regard to the antenna… Therefore, it is impossible to draw up simple rules for putting up (temporary) constructions.
That is why, in ICAO EUR DOC 015, a combination of surfaces is presented for each type of system. Based on this document, the “Servitudes” (obstacles clearance constraints) of Belgocontrol have been drawn up. Objects that exceed these surfaces must each be separately examined by the relevant technical services of Belgocontrol. Only the Urbanism Service of Belgocontrol can establish whether an object exceeds the servitude surfaces or not. It is the same service that is responsible for selecting the files that are to be treated by the technical services.
Besides these “servitudes”, which are directly linked to the correct functioning of the installations, there is a second type of surfaces, as imposed by ICAO DOC.8168 (“PansOps-surfaces”), which protect the routes from and to the airports.
Each route is protected by specific surfaces that guarantee a safety margin between the aircraft on that route on the one hand and each obstacle on the ground on the other hand.
New constructions or the raise of existing constructions (e.g. placing antennae on top of a building) that exceed these surfaces constitute an obstacle with a direct impact on air traffic safety. The Urbanism Service will then issue a height restriction, or when worst comes to worst, a negative recommendation for the obstacle concerned so that safety will remain assured.
In order to secure the ‘Servitudes and the PansOps-surfaces, the following rules have been introduced:
- Objects and works for which a building permit needs to be obtained and that are situated within the zone where restrictions are of application, are transmitted by the town and country planning department (communal administration) –through the DGLV/DGTA– to the Urbanism Service of Belgocontrol for advice. A preliminary recommendation can also be obtained directly from the Belgocontrol Urbanism Service.
- For temporary installations for which no permit is needed (such as cranes, scaffolding,…) but that are situated within the zone and stand taller than 6m, a request must be introduced at the Belgocontrol Urbanism service at least 2 months before their establishment.
- High vegetation can after a while also form a risk for aviation and must be cut or cleared.
In a few specific cases, additional rules are applicable :
- For transmitting equipment at a distance of less than 1 km from the airport domain or from Belgocontrol equipment, an application must be filed with the Belgocontrol Urbanism Service.
- Exceptional constructions (such as power lines, wind turbines and constructions standing taller than 60m above ground level) must always be examined by the Belgocontrol Urbanism Service. The owner must again contact Belgocontrol 30 days before the start of the works, in order to enable the publication of the new “obstacle” if necessary.
A third set of restrictive surfaces is enforced by ICAO in ANNEX14. These surfaces that are situated all around the airport, do not fall under the competence of Belgocontrol and are under supervision of the airport operator concerned. You can obtain more information on this subject via the DGLV/DGTA.
