Design Analysis of Corridors-in-the-Sky

Corridors-in-the-sky or tubes is one of new concepts in dynamic airspace configuration. It accommodates high density traffic, which has similar trajectories. Less air traffic controllers workload is expected than classic airspaces, thus, corridors-in-the-sky may increase national airspace capacity and reduce flight delays. To design corridors-in-the-sky, besides identifying their locations, their utilization, altitudes, and impacts on remaining system need to be analyzed. This paper chooses one tube candidate and presents analyses of spatial and temporal utilization of the tube, the impact on the remaining traffic, and the potential benefit caused by off-loading the traffic from underlying sectors. Fundamental issues regarding to the benefits have been also clarified. Methods developed to assist the analysis are described. Analysis results suggest dynamic tubes in terms of varied utilizations during different time periods. And it is found that combined lane options would be a good choice to lower the impact on non-tube users. Finally, it shows significant reduction of peak aircraft count in underlying sectors with only one tube enabled

Safety roads: the analysis of driving behaviour and the effects on the infrastructural design

Road design should ensure the correct behaviour of drivers in terms of speed and level of attention. Nevertheless, in some cases users are not able to visualize the carriageway enough correctly, owing to the misled road layout or the loss of visibility. In this research, road safety management was assessed with the driving and visual behaviour of users, considering the impact of different configurations of pedestrian crossings and road signs in order to reduce accidents. Even if users focus their attention on the zebra crossing (60%) and the vertical sign (24%), 16% of them have had no perception of the pedestrian crossings. This result shows how pedestrian crossings represent critical points that could compromise the safety of vulnerable users also in relation to speed. In fact, driving behaviour highlights 50 km/h of the average speed at 100 meters before the crosswalk, which allows having a too short time to stop the vehicle in safety. Moreover, the maximum speed underlines that users drive beyond the limit imposed by the road’s rules. It is thus necessary to require the implementation of road infrastructure so as to modify the driving behaviour. Starting from the Road Safety Review, it was then possible to detect the critical issues and correlate a visual and kinematic analysis so as to intervene accurately

Descent strategy comparisons for TNAV-equipped aircraft under airplane-preferred operating conditions

Three 4-D descent strategies were evaluated which were employed by TNAV-equipped aircraft in an advanced metering air traffic control environment. The Flow Management Evaluation Model (FMEM) was used to assess performance using three criteria when traffic enters the simulation under preferred cruise operating conditions (altitude and speed): throughput, fuel usage, and conflict probability. In comparison to an evaluation previously performed under NASA contract, the current analysis indicates that the optimal descent strategy is preferred over the clean-idle and constant descent angle (CFPA) strategies when all three criteria are considered

The effective bandwidth problem revisited

The paper studies a single-server queueing system with autonomous service and $\ell$ priority classes. Arrival and departure processes are governed by marked point processes. There are $\ell$ buffers corresponding to priority classes, and upon arrival a unit of the $k$th priority class occupies a place in the $k$th buffer. Let $N^{(k)}$, $k=1,2,...,\ell$ denote the quota for the total $k$th buffer content. The values $N^{(k)}$ are assumed to be large, and queueing systems both with finite and infinite buffers are studied. In the case of a system with finite buffers, the values $N^{(k)}$ characterize buffer capacities. The paper discusses a circle of problems related to optimization of performance measures associated with overflowing the quota of buffer contents in particular buffers models. Our approach to this problem is new, and the presentation of our results is simple and clear for real applications.Comment: 29 pages, 11pt, Final version, that will be published as is in Stochastic Model

Observation and Analysis of Departure Operations at Boston Logan International Airport

The Departure Planner (DP) is a concept for a decision-aiding tool that is aimed at improving the departure operations performance at major congested airports. In order to support the development of the DP tool, the flow constraints and their causalities in the departure process - primarily responsible for generating inefficiencies and delays- need to be identified. This thesis is an effort to identify such flow constraints and gain a deep understanding of the underlying dynamics of the departure process based on field observations and data analysis at Boston Logan International Airport. It was observed that the departure process is a complex interactive queuing system, where aircraft queues form as a manifestation of the flow constraints. While departure delays were observed in all airport components (runways, taxiways, ramps and gates), it was concluded that the flow constraints manifest mainly at the runway system, which exhibits the largest delays and queues. Major delays and inefficiencies were also observed due to downstream flow constraints, which propagate back and block the departure flow from the airport. It was also observed that the airport system is a highly controlled system as the air traffic controllers manage the flow constraints. The air traffic controllers were, therefore, identified as another flow constraint due to their workload and their main strategies in managing the flow constraints were observed. Based on the observations, a core departure process was identified consisting of two main elements: a queuing element generated by the flow constraints and a control element representing the air traffic controller actions. This core process was abstracted using a controlled queuing framework, where the air traffic controller actions are represented by blocking the flow of aircraft in order to maintain safe operation of the airport resources according to the ATC rules and procedures and regulate the outbound flow to constrained downstream resources. The controlled queuing framework was used to analyze the departure process highlighting the queuing dynamics and the control behavior for different flow constraint examples. In conclusion, a number of implications for the Departure Planner and other improved methods for departure operations are inferred from the observations and analysis.This work was supported by the National Aeronautics and Space Administration Ames Research Center under grant NAG 2-1128

Technical approaches for measurement of human errors

Human error is a significant contributing factor in a very high proportion of civil transport, general aviation, and rotorcraft accidents. The technical details of a variety of proven approaches for the measurement of human errors in the context of the national airspace system are presented. Unobtrusive measurements suitable for cockpit operations and procedures in part of full mission simulation are emphasized. Procedure, system performance, and human operator centered measurements are discussed as they apply to the manual control, communication, supervisory, and monitoring tasks which are relevant to aviation operations