Sydney single runway operation on 5 October 2023
Sydney (SYD) airport has well publicised operational constraints including a nighttime curfew and a cap of 80 aircraft movements (arrivals and departures per hour). It operates three runways, the parallel 16/34 runways, and the “cross-wind” runway 7/25. These runways are used in several different combinations resulting in several different operational “modes”. Particular modes are preferred during certain times of the day due to noise mitigation procedures, for example, “mode 1” using 34L for arrivals and 16R for departures is the preferred mode during the curfew (during which a limited number of operations are allowed). When weather conditions necessitate the use of some modes, a reduction in aircraft movements is required. This includes when intersecting runways or a single runway are in operation.
Yesterday (5 October 2023), strong and gusty westerly winds required the use of runway 25 for both arrivals and departures at times (mode 13), although other modes were also used throughout the day. This necessitates a reduction in the number of aircraft movements. Planning starts well in advance when Air Services Australia release the Air Traffic Flow Management Daily Plan (ATFM). Version 1 is released the evening before and establishes an hourly “flow rate”, or the number of arrivals that SYD can accept each hour, based on the expected runway mode in operation during each hourly block. The flow rate balances arrivals and departures, with the total number being roughly equal throughout the day, although the balance between arrivals and departures may differ during each hour. At approximately 6am, an updated version 2 is released that takes into account updated weather and consequently potential adjustments to the runway modes in each hourly block. Importantly, it also updates planning with expected arrival times for the now significant number of long-haul flights that are now in the air and had not yet taken off at the time of version 1. For example, yesterday’s first scheduled arrival was QF 2 from LHR via SIN at 6:10am. It departed SIN at 2:55am AEDT, well after the finalisation of version 1, with it’s expected arrival time being 10 minutes earlier than scheduled. BA 15, also from LHR via SIN was also scheduled to arrive at 6:10am, but has departed SIN late, and is now expected at approximately 7:10am. Thus, version 2 refines the availability of and the demand for arrivals slots as expected arrival times get updated (compared to scheduled arrival times). The ATFM is not cast in stone, and the flow rate may be increased or decreased at any given time based on the actual conditions.
