Precision approach terrain charts
The International Civil Aviation Organisation (ICAO) and The Civil Aviation Safety Authority (CASA) require airport operators to produce Precision Approach Terrain Charts (PATC) for runways available for Category II/III operation.
Perth Airport has prepared a PATC chart for Runway 21 (Category III). Perth Airport also provides a PATC chart for Runway 03 (Category I) given it is the corresponding runway.
The topography of the approach terrain can be important in all-weather operations because it can affect radio altimeter operation.
Radio altimeters (RA) are useful for any operation and are typically required for autoland, HUD guidance to landing, and authorization for Category II and Category III operations. The ground below the last part of the final approach should be regular and preferably level. This is important to ensure correct RA operation for pilot use as well as for terrain awareness and warning system and automatic landing system operation.
At runways with significant irregular approach terrain, it may be necessary for an operator to conduct aeroplane model-specific assessments of the effect of the irregular terrain on approach and landing operations. Isolated buildings or projections that do not materially disturb radio altimeter indications are usually acceptable.