Airport Surface

Airport Configuration Planning

Current airport efficiency is limited by a number of factors. “Choke points” in the system appear in the three primary components of the airside design; the runway environment, taxiway intersections, and the ramp area. Intersecting runways or extended runway centerlines significantly reduces the capacity of the airport due to the limited number of straight in approaches available for all runways. This reduced capacity is caused by traffic interference between these runways. Once the aircraft is on the ground, the next leading cause of delay for an aircraft is active runway crossings. An aircraft which has landed on an outer runway must usually cross an active departure runway before it may taxi to parking.

Taxiway congestion is caused by various operations including fixed queues, taxiway crossing points, aircraft engine run-ups, and delays in departure releases. Fixed queues refer to the single file line which aircraft must sustain once they have left the ramp area for departure. Bottlenecks on the ground occur at run up areas near a departure runway where aircraft complete their final takeoff checklist and hold for departure release. If this area is not large enough to accommodate multiple aircraft or if it does not leave enough space for aircraft to bypass other aircraft, the entire ground control system begins to congest, as all subsequent aircraft must wait for the first to depart.

Taxiway congestion may also be caused by terminal delays. Currently, amount of gate space is the limiting factor affecting efficiency of airports. Also, with one lane of two-way traffic, the ramp becomes vulnerable to congestion. The pier concept of terminal design is commonly used to promote gate capacity. This concept however leads to longer taxi times and distances.

To create an airport there are many constraints to consider in addition to the few listed above. The delicate relationship between the airport and the environment around it must be carefully maintained. Noise and emissions must be controlled for minimal residue outside the airport environment. The design and verification of a “Perfect Airport”, using computer drafting and simulation software will help to alleviate the lasting problem of airport traffic flow efficiency. Instead of attempting to improve existing airport layouts that have inherent flaws. “The Perfect Airport” will provide a baseline for designers to design an airport with inherent maximum efficiency for its operations. From this baseline, designers can account for topographic, political, and environmental constraints to maximize capacity for their specific airport design.

The ATL is also developing algorithms to determine the optimum taxiway, ramp, and regulation of start and take-off roll for fixed airport configurations, given uncertainties in airline operations.

Runway Operations Planning

The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful runway operations planning (ROP) is required if runway utilization is to be maximized. Thus, runway operations planning (ROP) is a critical component of airport operations planning in general and surface operations planning in particular. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, may be incorporated into the ROP solution subject to constraints introduced by air traffic control (ATC) procedures.

Our current work aims to change possible flight arrival schedules based on weight class so that the arrival schedule becomes a part of the optimization process rather than an input. This schedule inclusion may require examination of the current division of roles for various air traffic controllers (local, center, and Tracon), with communication and coordination mechanisms between them. The next step will be to formulate a stochastic program to generate a schedule of operations (arrivals, crossings and departures) that are close to optimal as possible while taking into account uncertainties in pushback and taxi operations. Successful implementation of these schedules will minimize departure inefficiencies related to such factors as wake vortices, downstream constraints, workload limitations and intersecting runways.

About Evan McClain