Obstacles to air navigation

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The Directorate of Civil Aviation (Direction de l'aviation civile - DAC) is the competent authority for:

  • reviewing applications for obstacles to air navigation; and
  • where applicable, decreeing safety measures meant to safeguard the requirements specific to aviation.

Who is concerned?

Applications for obstacles to air navigation must be submitted by:

  • the owners of the obstacles to air navigation;
  • the designers of the obstacles to air navigation.


The completed application must be filed at least 15 working days before the date on which the obstacle is to be assembled or built.

For wind turbines or objects higher than 614 MAMSL (metres above mean sea level), applications must be filed 3 months in advance.


The processing of the application is free of charge for the applicant.

However, if more detailed studies are required, the costs of these additional studies are borne by the applicant.

How to proceed

Preliminary information

Obstacle limitation surfaces

Obstacle limitation surfaces (OLS) are surfaces that are established to protect the take-off and landing manoeuvres of aircraft arriving at and departing from the aerodrome.

The following aerodromes are located in Luxembourg:

  • ELLX: Luxembourg-Findel international airport;
  • ELUS: Useldange aerodrome;
  • ELNT: Noertrange aerodrome;
  • ELEA: Centre Hospitalier Émile Mayrisch (Émile Mayrisch Hospital) helipad in Esch-sur-Alzette;
  • ELLC: Centre Hospitalier de Luxembourg (Luxembourg Hospital) helipad in Luxembourg-Strassen;
  • ELLZ: helipad at the Sainte Zithe Clinic of Hôpitaux Robert Schumann (Robert Schumann Hospitals) in Luxembourg City;
  • ELLK: helipad at the Hôpital du Kirchberg (Kirchberg Hospital) of Hôpitaux Robert Schumann (Robert Schumann Hospitals) in Luxembourg-Kirchberg;
  • ELET: Centre Hospitalier du Nord helipad in Ettelbruck.

The OLS of the different aerodromes are shown on the map at http://g-o.lu/3/B74o.

All new objects and all height extensions to existing objects in the OLS that exceed the reference point for aerodromes must be analysed by the DAC.

The elevations of the reference points of the different aerodromes are:

  • ELLX: 376 metres above mean sea level (MAMSL);
  • ELUS: 282 MAMSL;
  • ELNT: 464 MAMSL;
  • ELEA: 294 MAMSL;
  • ELLC: 329 MAMSL;
  • ELLZ: 314 MAMSL;
  • ELLZ: 372 MAMSL;
  • ELET 208 MAMSL;

Protection of in-flight aircraft outside an aerodrome's OLS

This applies to objects outside the OLS that, due to their nature, height and location, may present a risk for in-flight aircraft.

There are 2 situations that must be differentiated:

  • in residential areas, objects higher than 100 metres above the ground are considered a risk; or
  • outside congested areas, objects that are higher than 60 metres above the ground are considered a risk.

Note: a residential area is a congested area or an area with a group of at least 10 residences, including the adjacent land located within a 100 metre radius around it.

When objects are deemed to present a risk, a beacon and/or markings may be requested. However, if, within a 600 metre radius of the object, there are other, higher obstacles with beacons or markings, no beacons or markings are necessary if the DAC finds the protection to be satisfactory.

Submitting the application

The applicant must duly complete form DAC-ADM410-1 and send it to the DAC:

The applicant must provide:

  • the geographic coordinates in GPS coordinates: WGS84 DMS degrees, minutes, seconds;
  • before the obstacle is assembled or built:
    • the exact date of assembly;
    • the precise geographic coordinates and dimensions (height and elevation) as built, and measured on-site.

Supporting documents

For objects covering large surfaces – such as buildings, as opposed to essentially vertical objects, such as antennae or wind turbines – the applicant must attach a map with:

  • an overall view;
  • a cutaway view.

Duration of validity

The decision is valid for an open-ended period provided that the key components of the application – location, height, nature of the object – do not change in the course of the project.

Good to know

For the construction and/or assembly of objects, cranes are often required. These cranes are often considerably taller than the object under construction.

As a result, a separate application must be filed for these cranes.

The approval of an object does not automatically mean that the assembly crane is also approved.

Online services and forms

Who to contact

Directorate of Civil Aviation

  • Directorate of Civil Aviation

    4, rue Lou Hemmer L-1748 Senningerberg Luxembourg
    Postbox 283 L-2012 Luxembourg
    Email address:
    Closed ⋅ Opens at 8.30
    8.30 to 12.00, 13.00 to 17.00
    8.30 to 12.00, 13.00 to 17.00
    8.30 to 12.00, 13.00 to 17.00
    8.30 to 12.00, 13.00 to 17.00
    8.30 to 12.00, 13.00 to 17.00

Related procedures and links




Further information

Legal references

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