Sydney Airport – heavy departures to the United States
On occasion heavy jets bound for destinations in the United States will pass over your suburb after departure.
Heavy jets need to use the westernmost parallel runway because it is longer. After departing towards the north from the westernmost parallel runway, aircraft bound for the USA usually turn and track to the west once they reach 1500 feet. At twelve nautical miles they turn to the north east to track out across the coast. These outbound aircraft need to pass over inbound traffic that is flying south down the coast. For this to occur safely the outbound jets must have reached a specified altitude. However some very large aircraft on non-stop flights are so heavily laden with fuel that their climb performance is affected and they cannot reach the required altitude in time.
When this is the case the aircraft is provided with a “radar departure”, where air traffic control provide a specific heading to ensure the aircraft can pass safely through the inbound traffic. This means these aircraft fly a different route than would normally be expected, including passing over different suburbs. The route will vary for each individual aircraft depending on what other traffic is in the airspace at the time. This creates a spread across suburbs to the north of the airport.
Because there are only a small number of these flights each day, and because the suburbs overflown by each aircraft vary, residents may notice these flights as unusual for their areas.
The image below of actual aircraft tracks shows a month of flights and illustrates the spread across many suburbs.