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Precision Approach Terrain Charts
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The chart provides detailed terrain profile information within a defined portion of the final approach so as to enable aircraft operating agencies to assess the effect of the terrain on decision height determination by use of radio altimeters. The chart is required to portray, in plan and profile, details of the terrain in an area 120m by 900m extending from the runway threshold along the extended centreline of the runway. The upper limit of the profile is defined by the 3° glide slope based on the ILS Reference Datum elevation. Terrain or any feature differing by ± 10ft in height from the centre line profile is shown. The runway threshold and elevation is shown and all heights related to this. Features shown include vegetation, hard, temporary, roads and railways, which have sufficient levels to show their surface elevation (in the case of rivers, high and low tidal variations.) The projected heights of mobile obstacles are shown on the profile, as is the maximum height of vessels which may use waterways.
These charts are now hosted on the NATS AIS website and can be found here: PAT Charts |
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