# Scheduling of aircraft turnaround operations using mathematical modelling: Turkish low-cost airline as a case study

• Yagmur Simge Gok

Student thesis: Master's ThesisMaster of Science by Research

### Abstract

In recent years, with the phenomenal growth of many low-cost airlines, competitiveness has increased significantly. Within this competition, to achieve an on-time departure performance is a momentous factor; thus providing those airlines with on-time departure performance with a foremost competitive advantage. On-time departure performance is important for airlines to satisfy passengers by departing on adequate scheduled time of departure (STD). The main component of achieving on time departure is being able to complete the turnaround time of an aircraft within its scheduled time. By considering this problem, optimally scheduling of turnaround time was studied in this thesis as a real case of a low-cost company.

One of the Turkish airline companies was facing many delays occurring because of subjective scheduling of turnaround operations. In order to solve this problem a number of on-site visits were conducted and data was collected from the turnaround operations of Boeing 737-800 type of aircrafts from the hub airport of the company. A mathematical model is then developed to find an optimal schedule of operations for four different flight types considering arrival from a domestic or international port and departing to a domestic or international port. The objective of the modelling is to minimise the completion time of the last operation. There are other studies in the literature which were interested to schedule turnaround operations with heuristic approaches and simulation. This study fills the gap of optimisation with integer linear programming (ILP) since there is no other papers used ILP to schedule turnaround operations. The problem was solved using mathematical modelling approach and an optimisation solver (IBM ILOG OPL) to get the results for different scenarios.

The results of the model are then interpreted and Gantt charts of schedules for different flight types are generated. In addition to these, models were also run for different disembarking/boarding styles and the fastest completion time of turnaround time was determined. It was concluded that the minimum time of turnaround operations are in domestic-domestic flight type with using passenger stair for disembarking and airbridge for boarding. Finally, critical path in each schedule were listed to indicate the critical operations needed to be focused.
Date of Award 2014 English Coventry University Ammar Al Bazi (Supervisor)

### Keywords

• aircraft
• integer linear programming
• turnaround operations
• airlines
• optimisation
• airports
• operations scheduling

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