Graham Lake discusses factors affecting runway throughput
An airport’s aircraft throughput capacity, demand and delay are three interdependent elements. Capacity refers to the theoretical peak traffic density the airport can absorb, while the demand corresponds to the number of aircraft operations planned in relation to the airport’s declared capacity.
Capacity and demand are linked by the flight delays which result from any exceedance of demand over available capacity for a particular time period. This excess demand might occur for a wide range of reasons very often beyond the control of the airport, aircraft operator or ANSP. The operational challenge to be addressed by planners and operational decision makers is how to strike a balance between these three elements. How much delay is acceptable to accommodate demand? How might specific measures to increase capacity be identified, justified and implemented and, how much capacity resilience should be planned into runway usage to accommodate the inevitable and unplanned demand exceedance?
Flight delays which compound through the day can lead to EU261 passenger compensation liability for the airline, although neither the ANSP or airport operators have similar obligations to passengers. The airline sector and its users are the most exposed to the negative effects of a failure to adequately balance demand and capacity.
There is no universal method for the calculation of an airport’s capacity, commonly considered factors include the airports airside infrastructure; the layout of the runway(s), and associated taxiway, apron, parking gates, terminals, and local airspace constraints, as well as ATC procedures, environmental performance obligations (including night flight restrictions) economic factors, and lastly, local prevailing weather characteristics.
Airports seek to resolve demand/capacity imbalances, with those routinely operating close to theoretical capacity, experiencing the largest delay effects. As a result of airport demand/capacity balancing, the ‘excess traffic’ demand will be ‘pushed’ through the capacity bottlenecks (constraints) at the various planning stages and flight phases. Balancing will be achieved in different ways, based on the phase of flight and specific local circumstances.
Five Aero Directors using a thorough understanding in the interdependence of both the challenges and solutions have helped several major European airports and airlines to identify and resolve demand/capacity balancing challenges, creating opportunities to improve both capacity and performance.