Konteksts: [..] The procedure to be adopted for ground measurement of off-course clearance will vary from station to station depending upon the layout of the airfield. Typically, pre-surveyed points will be provided at intervals throughout the ±35-degree forward coverage area of the ILS localizer. In the case of localizers operating on the two-frequency principle, additional points may be provided at azimuths where the two patterns have equal signal strength on either side of the centre line. The portable test equipment is positioned at the pre-surveyed points and the off-course clearance signal conditions recorded. The results will be analysed to assess the stability and repeatability of the clearance parameters. For localizers providing clearance beyond the ±35-degree coverage sector, additional readings should be made. The spacing of the points may be greater here than the spacing employed within the coverage sector. [..]