United States National Airspace System Research Articles

The Role of Human Factors in Evaluating and Updating Requirements for Flight Deck Displays and Controls

The remarkable level of safety of aviation operations is due, in part, to Federal Aviation Administration requirements and guidance that govern civilian aviation activities in the United States National Airspace System. At times, these requirements and guidelines need reevaluation and updating—for example, due to a known change in the pilot workforce or with flight deck technology. This paper provides examples of when this may be necessary, and explains the role that human factors research plays in this process. One objective of this paper is to make the case that it is necessary to periodically review and update requirements and guidance, even if the equipment or technology haven’t changed; often the human operators have changed or additional information is now available. Additionally, the process described here may be applicable to international aviation authorities, other federal agencies, and the private sector, as a best practice and critical safety initiative.

Probability of Trajectory Deviation of Unmanned Aerial Vehicle in Presence of Wind

Incorporating unmanned aerial vehicles (UAVs) into the United States National Airspace System would demand enhanced airspace safety technologies for the safety of the UAVs, people, and property on the ground. One of the safety-critical factors to consider is the risk of a UAV deviating from its planned trajectory, which may result in loss of separation between other vehicles or obstacles or may cause early depletion of battery power. In this paper, we studied the effect of wind on UAV trajectory deviation by incorporating wind velocity as a drag component in a six-degrees-of-freedom trajectory simulation comprising a rotorcraft lumped-mass model. Both steady-state wind and wind turbulence effects were investigated. We validated our approach using real flight data from UAV experiments conducted at NASA Langley Research Center. The proposed approach would enable risk-informed decision making by timely mitigation of current and future collision events in an uncertain and dynamic environment.

Exploring the Use of Geographic Information Systems to Identify Spatial Patterns of Remote UAS Pilots and Possible National Airspace Risk

The proliferation of Unmanned Aircraft Systems (UAS) in the United States National Airspace System (NAS) has resulted in an increasing number of close encounters between manned aircraft and UAS, which correlates with the increasing number of remote pilots in the Federal Aviation Administration (FAA) airmen database. This research explores spatial patterns of registered airmen using Geographic Information Systems (GIS) analyses that provide notable spatial distribution patterns of pilots and how they relate to UAS sightings and airspace categories. The application of GIS to these aviation data may assist safety practitioners with identifying geographic patterns, areas of higher risk, and ultimately improve safety management. The authors analyzed publicly available airmen data to examine spatial distribution patterns, data correlations, and inferences. Airmen addresses were first geocoded into ArcPro 10.4 GIS software as a vector data layer containing attribute values of the database. The spatial analysis tool set was then utilized to establish clustering, density patterns, and spatial relationships between various categories of registered airmen. These density analyses revealed implicitly that commercial registered pilots tend to have the highest clustering near major commercial use controlled airspace, yet registered remote (UAS) pilots are also clustered in these and other densely populated areas. UAS sighting data were also geocoded using zip code values of the reported city to potentially correlate UAS sighting with registered remote pilots, yet the lack of spatial precision in the database made establishing any type of spatial relationship ineffective. The implicit spatial relationships between commercial and remote registered pilots revealed further research is needed to integrate UAS safely and effectively into the national airspace. The poor quality of UAS sighting data also demonstrates the need to better utilize GIS to monitor and track UAS flights within the context of an Unmanned Traffic Management System.

Dissecting lightning strike hazard impact patterns to National Airspace System facilities in the contiguous United States

Lightning strikes pose a severe threat to the United States (US) National Airspace System (NAS). Although the US Federal Aviation Administration (FAA) implements lightning protection practices and procedures to protect personnel, electronic equipment, and structures within the NAS, many lightning-induced outages still occur. To date we found that most research on lightning-induced facility outages has focused on understanding the physical processes of lightning strike effects on aircraft and airport ramp operations. Very little research has been done on examining the overall patterns and characteristics of such hazards to aviation from a geo-spatial standpoint. To bridge this gap, we analyze nationwide lightning strike spatiotemporal data and FAA airport facility outage records from 2009 through 2020 and apply innovative pattern recognition methods to identify key characteristics of lightning strike hazards. Our results uncover the complexities of lightning strike hazard impact patterns to NAS facilities, identifying five distinct typologies with climatological signatures critical to creating better hazard mitigation strategies.

Integration of Unmanned Aircraft Systems into the National Airspace System-Efforts by the University of Alaska to Support the FAA/NASA UAS Traffic Management Program

Over the past decade Unmanned Aircraft Systems (UAS, aka “drones”) have become pervasive, touching virtually all aspects of our world. While UAS offer great opportunity to better our lives and strengthen economies, at the same time these can significantly disrupt manned flight operations and put our very lives in peril. Balancing the demanding and competing requirements of safely integrating UAS into the United States (US) National Airspace System (NAS) has been a top priority of the Federal Aviation Administration (FAA) for several years. This paper outlines efforts taken by the FAA and the National Aeronautics and Space Administration (NASA) to create the UAS Traffic Management (UTM) system as a means to address this capability gap. It highlights the perspectives and experiences gained by the University of Alaska Fairbanks (UAF) Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) as one of the FAA’s six UAS test sites participating in the NASA-led UTM program. The paper summarizes UAF’s participation in the UTM Technical Capability Level (TCL1-3) campaigns, including flight results, technical capabilities achieved, lessons learned, and continuing challenges regarding the implementation of UTM in the NAS. It also details future efforts needed to enable practical Beyond-Visual-Line-of-Sight (BVLOS) flights for UAS operations in rural Alaska.

The Collaborative Colorado–Nebraska Unmanned Aircraft System Experiment

The Collaborative Colorado–Nebraska Unmanned Aircraft System Experiment (CoCoNUE) was executed on 1 March and 30 September 2009. The principal objective of this project was to examine the feasibility of using a small unmanned aircraft operating semi-autonomously with an onboard autopilot to observe atmospheric phenomena within the terrestrial boundary layer covered by the United States National Airspace System. The application of an unmanned aircraft system (UAS; the aircraft along with the communications and logistics infrastructure required for operation) is beset by a number of engineering and regulatory challenges. This article discusses the strategies implemented to meet these challenges. Airmass boundaries served as the target of the flights conducted. These atmospheric phenomena have the fortuitous combination of an across-boundary scale that yields a coherent signal in the in situ meteorological data that can be collected by a UAS and an along-boundary scale that can be easily tracked via the exis...

Remote sensing applications of unmanned aircraft: challenges to flight in United States airspace

The capabilities of unmanned aircraft systems (UAS) have improved dramatically in the past 5 years, and as a result UAS have become increasingly popular among scientists. Missions that require long dwell times and/or are in locations generally too dangerous for manned aircraft are particularly suited to UAS, and scientists are looking more and more to UAS to perform these types of remote sensing missions. Sea ice characterization, mapping of fault lines, hurricane monitoring and satellite calibration/validation (cal/val) are some examples of applications that benefit from the use of UAS. Operations involving UAS have unique challenges compared to manned aircraft. For example, most instruments must be automated and miniaturized. One of the greatest challenges, however, is gaining access to the United States national airspace system (NAS). Currently, access is only granted to government agencies and universities through a certificate of authorization (COA) process. This article will provide a general view of UAS, US NAS, and the COA process. The challenges to flying UAS in the NAS will then be discussed. Finally, example missions will be described in detail with special attention to the specific challenges inherent to the operation.

Robust Air-Traffic Control Using Ground-Delays and Rerouting of Flights

In this paper we demonstrate that nite horizon optimization of ground-delays and rerouting can provide robustness to the performance of the United States National Airspace System (NAS), in the event a center goes down. Our analysis is based on a linear system approximation of the NAS. We use the linear model to analyze the degrading eect of a loss of center on the performance of the ATC. We employ ground-delays and rerouting of ights as mitigation tools and propose optimal sequences of these control actions to restore the performance of the NAS. The optimal sequence is determined by solving a nite horizon optimal control problem. Historical data in the available literature is used to derive the linear approximation of the NAS. From our analysis we observe that both grounddelays and rerouting are able to successfully restore the performance of the NAS. We did not observe signicant dierence in performance between these two methods. However, the computational complexity associated with rerouting is signicantly more than that for ground delays. The simulation plots demonstrate that nite horizon optimization for determining optimal ground-delay or rerouting strategies can mitigate the eects of a center going down in the NAS.

A Scalable Methodology for Evaluating and Designing Coordinated Air-Traffic Flow Management Strategies Under Uncertainty

As congestion in the United States National Airspace System (NAS) increases, coordination of en route and terminal-area traffic flow management procedures is becoming increasingly necessary to prevent controller workload excesses without imposing excessive delay on aircraft. Here, we address the coordination of flow management procedures in the presence of realistic uncertainties by developing a family of abstractions for implementable flow restrictions (e.g., miles-in-trail restrictions, ground delay programs, and slot-based policies). Using these abstractions, we are able to evaluate the impact of multiple restrictions on generic (uncertain) traffic flows and, hence, to design practical flow management strategies. We use the developed methodology to address several common design problems, including the design of multiple restrictions along a single major traffic stream and the design of multiple flows entering a congested terminal area or sector. For instance, we find that multiple restrictions along a stream can be used to split the backlog resulting from a single restriction and use this observation to develop low-congestion designs. We conclude the discussion by posing a tractable NAS-wide flow management problem using a simple algebraic model for a restriction.

Emissions Reductions Enabled by Improved Airport Surface Operations

Capacity constraints in the United States national airspace system (NAS) have coupled with the growth in air traffic to increase congestion in airways, terminal areas and on the airport surface. In this paper, we discuss the growth in aviation emissions from ground operations in the United States from 1995 to 2000 and investigate the potential for emissions reductions under 3 scenarios: improved operations, single-engine taxiing, and use of tow trucks to move aircraft to and from runways. Emissions estimates, unlike with previous models, are based on actual mission times and aircraft types from the Airline Service Quality Performance (ASQP) data, compiled by the US Department of Transportation (DOT) from information provided by the ten largest US carriers. Results indicate that surface emissions have been growing faster than airborne operations or total mission time in domestic US aviation, and may therefore become a constraint on airport expansion. The potential for emissions reductions through improved ground operations and single-engine taxiing is significant. The net environmental benefits from using tow trucks are unclear and should be investigated further.