Manju Nag

Graduation Semester and Year




Document Type


Degree Name

Master of Science in Aerospace Engineering


Mechanical and Aerospace Engineering

First Advisor

Kamesh Subbarao


In this research, we propose to support the development of a queuing model for the National Airspace System (NAS) by providing distributions for the various phases of flight, accounting for the uncertainties in flight trajectory which includes factors such as weight, power factor, lift co-efficient. In addition to this, a detailed study is done on the impact of weather on flight routes and two days in 2006 are compared to show the effect of weather on flight times. The research develops from a good understanding of the NAS and its requirements to implement a system capable of dealing with issues regarding airspace capacity and air traffic. The need for this emerges from the Next Generation Air Transportation System (NGATS), a system when implemented should be able to handle air traffic and capacity ranging from 150 % to 250% of the current traffic and capacity. NGATS proposes a few changes in the existing system to overcome the drawbacks and is studied in detail. Air traffic delays are identified and classified and a case study is done on the Dallas- Fort- Worth International airport The Base for Aircraft Data (BADA) database for aircraft performance is used to characterise flight phases in various phases of flight and is developed and maintained by the European Organization for the Safety of Air Navigation ``Euro control Experimental Center". Factors affecting time during various phases of flight such as climb, cruise and descent is identified and the sensitivity of these were investigated for variations in key operation related parameters such as weight at take off, aerodynamics and power. An aircraft performance calculator was developed on MATLAB, which, when the aircraft category and suitable inputs are specified, calculates the time taken by the aircraft in each of its phase. Monte Carlo experiments are conducted for these parameters and a distribution of time for different phases of flight is obtained. Future ATM Concepts Evaluation Tool (FACET) is a simulation tool developed by NASA to analyse, implement and test new air traffic management and operational concepts. Cruise uncertainty was studied using FACET and the results obtained validated the previous uncertainty model developed using the aircraft performance calculator. Weather uncertainty was studied using the National Convective Weather Diagnostic (NCWD) data. The impact of weather on air traffic was analysed using Enhanced Traffic Management System (ETMS) data. ETMS data gives the radar positions of any aircraft detected in the NAS and based on this, the air traffic and flight routes were compared for a good weather day and a bad weather day. Queuing models offer an efficient replacement to Monte Carlo simulations. To develop and implement a system which should be capable of handling 250% of the current capacity, the NAS has to be tested for flaws in the operational procedures and procedural, structural and operational changes have to be made to realise the objectives of NGATS. Queuing models offer this capability with development, analysis and implementation of traffic flow models. This research proposes to aid the realisation of NGATS by identifying distributions to develop the queuing model. Chapter 6 introduces us to topics which can be incorporated into the uncertainty model. Traffic flow patterns are identified and the impact of weather on traffic flow, service times are observed.


Aerospace Engineering | Engineering | Mechanical Engineering


Degree granted by The University of Texas at Arlington