background and objectives
background and objectives
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Fast air traffic growth together with limited capacity at major airports are causing frequent flight delays and high costs for airports, airlines, their users, and national and regional economies as a whole. As air traffic is forecasted to keep growing significantly in the future, innovative approaches to airport capacity management will become a prime necessity. In the absence of supply-side opportunities for capacity expansion or operational improvements, enhancements in demand management practices provide one of the most promising approaches to spur capacity utilization and manage congestion at busy airports.
Fast air traffic growth together with limited capacity at major airports are causing frequent flight delays and high costs for airports, airlines, their users, and national and regional economies as a whole. As air traffic is forecasted to keep growing significantly in the future, innovative approaches to airport capacity management will become a prime necessity. In the absence of supply-side opportunities for capacity expansion or operational improvements, enhancements in demand management practices provide one of the most promising approaches to spur capacity utilization and manage congestion at busy airports.
Under the IATA slot allocation process (in place at almost all busy airports outside the United States), airports provide a value of "declared capacity", specifying the number of "slots" available to allocate to the airlines. For each aviation season, the airlines submit slot requests to an independent entity that must allocate the available slots in the most neutral, transparent and non-discriminatory way. The allocation process, described in IATA's World Slot Guidelines, is extremely complex.
Under the IATA slot allocation process (in place at almost all busy airports outside the United States), airports provide a value of "declared capacity", specifying the number of "slots" available to allocate to the airlines. For each aviation season, the airlines submit slot requests to an independent entity that must allocate the available slots in the most neutral, transparent and non-discriminatory way. The allocation process, described in IATA's World Slot Guidelines, is extremely complex.
First, the IATA guidelines specify that slot coordination entities must allocate, in the first place, flights belonging to "series of flights". These are flights that take place at least five times over a season, on the same day of the week and at the same time of the day. Moreover, the series of slots that are requested on several days of the week shall also be allocated together. These considerations create interdependencies between slot allocation decisions made on separate days, and therefore force the allocation to be performed across an entire season at once. This increases greatly the methodological and computational complexity of the process.
First, the IATA guidelines specify that slot coordination entities must allocate, in the first place, flights belonging to "series of flights". These are flights that take place at least five times over a season, on the same day of the week and at the same time of the day. Moreover, the series of slots that are requested on several days of the week shall also be allocated together. These considerations create interdependencies between slot allocation decisions made on separate days, and therefore force the allocation to be performed across an entire season at once. This increases greatly the methodological and computational complexity of the process.
Second, the allocation of slots amongst the requested series of flights must consider sequentially four priority classes. Highest priority is given to historic slots (or "grandfathered" slots), i.e., series of slots already allocated to each airline in the previous equivalent season (winter or summer) and operated at least 80% of the time (known as the "use-it-or-lose-it" rule). Second priority is given to "change-to-historic" slots, i.e., flights for which an airline holds a historic slot, but requests a change (e.g., in timetabling or in aircraft type). Third priority is given to new entrants, which must receive up to 50% of the remaining slots. The definition of a new entrant is based on market penetration (e.g., an airline that holds fewer than five slots in a certain day of the season) and, potentially, other policy considerations (e.g., flights on underserved routes). Finally, any remaining slots are allocated among the remaining requests. The IATA guidelines include many more specifications known as "additional criteria" to differentiate flights belonging to the same priority class.
Second, the allocation of slots amongst the requested series of flights must consider sequentially four priority classes. Highest priority is given to historic slots (or "grandfathered" slots), i.e., series of slots already allocated to each airline in the previous equivalent season (winter or summer) and operated at least 80% of the time (known as the "use-it-or-lose-it" rule). Second priority is given to "change-to-historic" slots, i.e., flights for which an airline holds a historic slot, but requests a change (e.g., in timetabling or in aircraft type). Third priority is given to new entrants, which must receive up to 50% of the remaining slots. The definition of a new entrant is based on market penetration (e.g., an airline that holds fewer than five slots in a certain day of the season) and, potentially, other policy considerations (e.g., flights on underserved routes). Finally, any remaining slots are allocated among the remaining requests. The IATA guidelines include many more specifications known as "additional criteria" to differentiate flights belonging to the same priority class.
At present, no single optimization approach considers all the rules and requirements from the IATA guidelines, probably due to their complexity. Therefore, the first objective of the ASAP project is to bridge this gap in the literature by developing an optimization approach to slot allocation fully compliant with the IATA guidelines, as well as with the other operational and regulatory constraints faced by the airports.
At present, no single optimization approach considers all the rules and requirements from the IATA guidelines, probably due to their complexity. Therefore, the first objective of the ASAP project is to bridge this gap in the literature by developing an optimization approach to slot allocation fully compliant with the IATA guidelines, as well as with the other operational and regulatory constraints faced by the airports.
Based on the optimization approach developed, we will then perform a thorough assessment of IATA guidelines, thus addressing the second gap we identified in the literature review. These guidelines were originally established and then continuously adjusted in a rather ad hoc manner, and the impacts of possible changes to the guidelines on the efficiency of airport capacity utilization were never thoroughly examined. Consequently, the second objective of the ASAP project is to analyze those impacts in a detailed manner. Based on the results, we expect to provide recommendations to the international aviation community on how the current IATA slot allocation guidelines could be improved.
Based on the optimization approach developed, we will then perform a thorough assessment of IATA guidelines, thus addressing the second gap we identified in the literature review. These guidelines were originally established and then continuously adjusted in a rather ad hoc manner, and the impacts of possible changes to the guidelines on the efficiency of airport capacity utilization were never thoroughly examined. Consequently, the second objective of the ASAP project is to analyze those impacts in a detailed manner. Based on the results, we expect to provide recommendations to the international aviation community on how the current IATA slot allocation guidelines could be improved.
In addition to these main objectives, we consider two other, of a different nature but also very relevant: the first is to reinforce connections between the research team and the two international consultants involved in the project, thus contributing to advance the internationalization of the Portuguese R&D system; the second is to consolidate and, in some cases, establish connections between the research team and the industry partners involved in the project.
In addition to these main objectives, we consider two other, of a different nature but also very relevant: the first is to reinforce connections between the research team and the two international consultants involved in the project, thus contributing to advance the internationalization of the Portuguese R&D system; the second is to consolidate and, in some cases, establish connections between the research team and the industry partners involved in the project.
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