Taxiways

19.49Rapid Exit Taxiways. Rapid exit taxiways, commonly called ‘fast turn-off lanes’, are provided where traffic density is high. They are used to allow aeroplanes to turn off of the duty runway at a speed higher than would be permitted at a right angle turn on to a normal taxiway. They are located along runways and are designed and constructed to cater for turnoff speeds of 93 km/h (50 kt) for code 3 or 4 runways and 65 km/h (35 kt) on code 1 and 2 runways, in wet conditions. Operators will specify the maximum speed for dry runway/taxiway operations. The taxiway is to include a straight section after the turn-off curve to allow an exiting aircraft to come to a full stop clear of the intersecting taxiway. The intersecting angle with the runway should not be greater than 45°, not less than 25°, and preferably 30°.

19.50Minimum Requirements. As previously mentioned, width is the most important factor in taxiway design and construction. The table below specifies the minimum requirements for clearance of the outermost main wheels when the nose wheel is on the centre line of the taxiway. The shoulders of taxiways which are used by turbine aeroplanes are to be prepared to prevent erosion by jet blast, and the ingestion of surface material into the jet engines. Taxiway strips, similar to runway strips, are provided primarily to delineate the area to be cleared of objects which may be obstacles. In the table, wheel base refers to the distance from the front of the nose wheel to the trailing edge of the main gear. Wheel to edge clearance refers to the distance from the outer edge of the main gear tyres to the defined edge of the taxiway.

Aerodromes - Physical Characteristics 19

Characteristics Physical - Aerodromes 19

Figure 19.10: Taxiway curves

19.53 Holding Bays and Runway Holding Positions. Inevitably, at a busy aerodrome, aeroplanes will be required to wait their turn for take-off. It is common to see a stream of traffic waiting along the taxiway for take-off, but at an international airport the queues for take-off can exceed the capability of the taxiway to accommodate all the aircraft waiting. In this situation or where environmental considerations exist, holding bays are provided adjacent to runway entrances which leave the taxiways clear. At some major aerodromes with particularly high traffic levels or intense peaks in traffic density, ‘sin bins’ are established to take aeroplanes out of the stream if something has gone wrong. Regardless of the position of holding bays, the entrance to the runway will be protected by a defined mandatory holding point set back from the edge of the runway to accommodate all the traffic using the runway. A runway holding position must be established on a taxiway if the location or alignment of the taxiway is such that a taxiing aircraft or vehicle can infringe an obstacle limitation surface or interfere with the operation of radio navigation aids (ILS or MLS). The method of indicating a runway holding position is covered later in the notes (under Signs and Markings). A runway holding position, or positions, must be established at the distances in the table on page 384 at an intersection of a taxiway with a runway; and an intersection of a runway with another runway when the former runway is part of a standard taxi-route.

Aerodromes - Physical Characteristics 19

Characteristics Physical - Aerodromes 19

Figure 19.11 Holding points

Runway Holding Point Positions (Distance from Centre Line of Runway)

Figure 19.12 Minimum distances from runway centre lines of holding positions