Optimization Of Aircraft Approach Wake Time-based Separation Under Strong Headwind Conditions

With the continuous development of air transportation industry,because of its rapidity and convenience,the proportion of air transportation is increasing in the whole transportation industry day by day,and the number of aircraft is also increasing rapidly.However,the growth of aircraft is limited by the airspace capacity,and the aircraft wake separation is the key factor hindering the improvement of airspace capacity.Therefore,the aircraft wake separation has become an important factor restricting the improvement of air transportation efficiency and threatening the safety of air transportation,especially in the final approach stage,the influence of wake separation is more prominent,and the safety problems and operation efficiency decline caused by it should not be underestimated.Generally,the distance separation between two aircraft is not less than the current wake distance separation standard.During the final approach,the headwind will cause the ground speed of the aircraft to decrease,the successive landing time between the aircraft will be prolonged,and the runway capacity will be greatly reduced.Under headwind conditions,while ensuring safe operation,how to reduce the landing time separation between aircraft and improve the aircraft approach efficiency has become the focus of scholars and aviation control departments at domestic and abroad.Based on the research results at domestic and abroad,converting the current wake distance separation standard into wake time separation standard is one of the important means to alleviate the impact of headwind on aircraft landing efficiency in the final approach stage,and it is also a powerful driver to improve the runway capacity under headwind conditions.The advantage of Time-Based Separation(TBS)is the ability to ensure the safe operation between approach aircraft and improve the runway capacity under headwind conditions.Firstly,this thesis combed and analyzed the current distance-based wake separation standard and timebased wake separation research at domestic and abroad.According to the characteristics and evolution mechanism of aircraft wake during the final approach,combined with the headwind conditions in the final approach stage,the evolution model of wake vortex circulation and rolling torque has been established under headwind.Combined with the aircraft wake time separation under static wind calculated by the current wake distance separation standard,the time separation calculation model has been established under headwind by integrating the factors such as wake intensity,minimum distance separation standard and runway occupation time.The time separation was transformed into equivalent distance for visualization.In order to verify the safety and rationality of the time separation,an improved air traffic flow separation analysis model based on LWR model was proposed.Through the idea of density distribution,the dangerous value profiles at different positions before and after the aircraft are established,and the dangerous critical value index between the two aircraft is specified.By calculating the comprehensive dangerous value when maintaining the time separation under different headwinds,it is compared with the specified dangerous critical value index to verify the rationality and safety of the time separation.Finally,according to the 210 day actual operation data and meteorological data since the operation of Qingdao Jiaodong airport,the runway capacity operated according to the time-based wake separation mode has been calculated.Compared with the actual runway capacity,it was concluded that the time-based wake separation operation mode can significantly improve the operation efficiency of the airport under headwind conditions.It laid a good theoretical foundation for the implementation of wake time separation in the final approach stage of the airport with strong headwind prevailing in China.Finally,a time-based wake separation calculation software is developed on the matlab development platform,and an auxiliary decision-making tool is developed for approach and tower controllers.This makes the time-based wake separation operation mode play a greater advantage in improving the runway capacity.