Study On Airport Gates Capacity Assessment Based On Aftereffect Delay Time Analysis

As one of the basic necessities of life since ancient times, transportation has always been an important part satisfying human needs. On the status quo in China, especially for air transport status, the main problem facing us is the contradiction between growing demand for transport and limited transportation resources. To resolve this, many transportation companies only focuses on the short-term benefits, neglecting quality requirements, making substantial reduction in the punctuality, reliability and safety of the transportation services. In fact, to abuse transportation resources may raise the traffic in a short term, but for the long term it should harm the social resources and social benefits. Once a safety incident takes place, the losses will be incalculable.In the background of strained airport gate resources in major airports, this study focuses on the airport gate real capacity or delay-related capacity assessment problem with the request of certain operation order, aiming at the improvement of both airport gate operation order and the transportation efficiency, and the provision of the flight sechdule reference. In present, the study of airport gate capacity is confined only to the maximum or ultimate capacity, with the study field of delay-related capacity to be vacant.This study based upon aftereffect delay propagation theory, formulates the mathematical relation of average aftereffect delay time and average buffer time in three different kinds of the gate conflict mediation policy including no replacement of gate, one replacement between two gates and total replacements between all gates. With this relation, the study then advances the delay-related capacity formulation considering several factors, including airport gate operation order, flights demand characteristics, and the correspondence of gate types with the airplane mix.The main innovation point of the study includes:1. Analyze various factors concerning airport gate capacity, mainly focusing on aircraft delay time and gate adjustment policy. Define five new concepts of delay time and analyze their causes and their relations with the buffer time and with the capacity. Analyze the effect of different gate replacement policy to the gate capacity, and transform the capacity problem to be the queuing syetem problems, including system M/E_k/1, M/E_k/2 and M/E_k/k. 2. Use PERT chart to analyze aircraft turnaround time and study the minimum separation time for aircraft maneuvering in and out of the apron gate. We then use hypothesis test to study the distribution type of the aircraft occupation time, aircraft separation time, buffer time and the delay time in order to make a theoretical preparation for further study.3. Study aftereffect delay time under the no gate-replacement policy. We first study the neighboring aircraft aftereffect delay time aiming at the same priority aircraft pair and different priority aircraft pair respectively. And successively, we study on specific aircraft pair, non-adjacent aircraft pair aftereffect delay time. And finally formulates the first level aftereffect delay time, higher level aftereffect delay time and the total value of the aftereffect delay time.4. We study the aftereffect delay time under the policy of one replacement between two gates. We put forward the concepts of apron gate redundant coefficients and formulate the equality and inequality relation of the interarrival time and the buffer time. Based upon this, we study the best strategy for the gate replacement operation and get the corresponding aftereffect delay time aiming at the same priority neighboring aircraft pair and different priority neighboring aircraft pair respectively. And successively, we study on specific aircraft pair, non-adjacent aircraft pair aftereffect delay time. And finally formulates the first level aftereffect delay time, higher level aftereffect delay time and the total value of the aftereffect delay time.5. By use of the cooperation coefficient, we study the aftereffect delay time relation of the one replacement between two gates and total replacement between all gates. Since then, we can formulate the aftereffect delay time under the policy of total replacement between all gates.6. We study the average buffer time setting standards with the given aftereffect delay time and the given average queue length respectively. We also put forward the average necessary buffer time setting standards and analyze the relation of different factors with the average necessary buffer time. Finally we formulate an optimization model to compute the apron gate capacity considering aftereffect delay time, average queue length, fluctuations in flights number and other factors. We use a real example to justify the validity of the model and make the sensitivity analysis for the improvement of the apron gate capacity.In summary, this study first researches the relation of the buffer time and the after effect delay time under different gate replacement policy. With the consideration of several factors, we formulate the apron gate optimization model. The result not only requests the improvement in apron gate operation order, but also provides the decision makers with the short term effective measures and long term industrial policy for improving actual level of the gate operation.