Managing departures beyond airports

In this second article on airspace capacity management in growing aviation markets, we look at the advanced technique the aviation industry uses to manage departure demand. When there is too little airspace available on busy routes and adding flight paths is not an option, a more coordinated system is needed to manage demand when multiple airports need to use the same enroute waypoints.

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Airspace scarcity

In our previous article, one of the solutions to airspace capacity management issues we discussed was to increase the number of flight paths. In areas of high demand, especially where the level of demand from departing aircraft demand exceeds the capacity of the enroute departure waypoints, additional flight paths can help accommodate more aircraft.

Of course, this option is only suitable where unused airspace is readily available. It becomes problematic in constrained locations where demand is high, and airspace is scarce, such as the Brisbane-Sydney-Melbourne triangle. In a crowded airspace, it makes sense to apply more sophisticated departure management techniques.

Managing multiple capacity demands

Airport CDM implemented on individual airports can use pre-departure sequencing (PDS) and departure managers (DMAN) to manage the surface constraints. But individual solutions are not useful when the constraint is an enroute departure waypoint and the traffic demand comes from other airports.

In Australia, a perfect example is the APAGI waypoint located 100nm south of Brisbane:

APAGI waypoint south of Brisbane


Flights traveling south from the Brisbane, Gold Coast and Sunshine Coast airports pass through the APAGI waypoint. Despite the clear demand issue, ATC currently uses only ad-hoc metering to manage airspace demand on this route.

When similar issues occur in European or US airspace, alternate solutions are made available. Usually, a departure metering system is used to sequence all departing flights intending to pass through the waypoint. This departure metering system is essentially a DMAN that can sequence flights from multiple airports through the next identified constraint point. To manage the airspace capacity demand at the APAGI constraint point, for example, the departure metering system would communicate controlled take-off times to the ATC systems at all three airport control towers, at Brisbane, Gold Coast, and at Sunshine Coast.

Next steps to waypoint DMAN

Allowing a DMAN system to also manage waypoint capacity demand at points like APAGI would ensure that aircraft are metered in passing through the waypoint only to the level of airspace capacity the waypoint can accommodate.

To get to that point, it is necessary to first quantify the Australian airspace capacity. It is also important to quantify the dynamics of demand in both normal and adverse conditions, such as when the ATC system is at degraded capacity due to poor weather or other issues.

Once the airspace demand has been properly quantified, the next step is to build a DMAN capability that works beyond the usual boundaries. Such a system needs to function beyond individual airports and Airport CDM systems to include enroute constraint points.

In case you missed Part 1 of this blog series on demand management in growing aviation markets, you can read it here.

Photo by Ishak Ahmed


About To70. To70 is one of the world’s leading aviation consultancies, founded in the Netherlands with offices in Europe, Australia, Asia, and Latin America. To70 believes that society’s growing demand for transport and mobility can be met in a safe, efficient, environmentally friendly and economically viable manner. To achieve this, policy and business decisions have to be based on objective information. With our diverse team of specialists and generalists to70 provides pragmatic solutions and expert advice, based on high-quality data-driven analyses. For more information, please refer to


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