Areas and Area PT2 easements related to easements PT1 (Radio Reception Centres) in the Somme

The attitude of an easement is the spatial field (i.e., the geographical area) within which the easement applies. This spatial field may be defined either in 2D or in 3D in particular in the particular cases of clearance easements at airports, easements for the protection of radio transmission centres.The attitude shall include primary clearance zones, secondary clearance zones, special clearance zones and clearance areas.The maximum distance separating the limit of a radio station and the perimeter of the easement areas may not exceed:- 2 000 metres in the case of a secondary clearance zone;- 400 metres in the case of a primary clearance zone surrounding an aeronautical safety facility or a radio-gonometric centre;- 200 metres in the case of a radio area not exceeding a maximum area of clearance. In practice, the beam shall be assimilated to a band and the attitude shall not exceed 50 m on either side of the axis.The maximum width of a clearance area protecting a radio tracking or navigation station may not exceed the width of the angular area explored by the station, increased, where appropriate, by a safety margin of not more than one degree beyond the two limits of that area.