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Reliability of the air transportation system heavily depends on the performance of communication, navigation, and surveillance facilities in the National Airspace System (NAS). These facilities are prone to outages caused by convective weather, such as lightning. Current lightning safety standards and risk assessments focus solely on lightning occurrence and omit the effect of lightning intensity from hazard characterization. We propose methods that incorporate lightning intensity and occurrence parameters to better understand the impact of lightning strike on the NAS using the National Lightning Detection Network and Federal Aviation Administration NAS facilities and equipment outage databases. Spatial analysis and clustering reveal different exposure profiles for 436 U.S. airports. Kernel Density estimation and Hot Spot analysis show that regardless of lightning intensity, Southern state airports are the most exposed to lightning hazards. K‐means clustering reveal five different lightning exposure profiles that mimic the spatial patterns produced by the Kernel Density estimation and Hot Spot analysis. A scoring system ranks all airports according to their exposure profile taking into consideration lightning occurrence and intensity. It is complemented with a rising trend exposure analysis, which identifies airports whose exposure could be underestimated under the current standards, identifying airports with fewer lightning occurrences but higher intensities. Finally, a comparison between the exposure patterns and lightning‐induced outages provide insights into U.S. lightning impact patterns. Similar patterns between lightning exposure and outages indicate that the results of the proposed lightning hazard assessment provide useful information for prioritizing airport hardening investments at the national scale and reducing lightning risk. [ABSTRACT FROM AUTHOR]

Safe integration of Unmanned Aircraft Systems (UAS) into airspace generally occupied by manned aircraft and other aviation stakeholders is a pressing global challenge. In the United States, efforts are being made to integrate small and large UAS into the National Airspace System (NAS). Whereas regulations for the civil operation of small UAS (25 kg and lighter) have already been adopted, those for larger unmanned systems are still being crafted. Thus, a two-part mixed methods study was conducted to examine three pivotal issues in the safe operation of large UAS: (1) What kind of visual observer skills are needed to execute safe UAS operations; (2) Should visual observers involved in UAS operations receive formal training; and (3) Should visual observers be required to pass a certification exam? In the first phase, subject matter experts identified various vigilance, trajectory estimation and communication skills that were vital to performing visual observer duties successfully and elaborated on their training regimens. In the second phase, survey participants were approximately evenly split on the need for formal classroom/online and hands-on visual observer training. Furthermore, participants generally favored visual observers having to pass a classroom/online certification exam, whereas they were against a practical (hands-on) exam. [ABSTRACT FROM AUTHOR]

Flight on-time performance is one of the most important issues in the National Airspace System, a very complex and dynamic system. To avoid negative impacts to the aviation industry, the Federal Aviation Administration has set a long-term objective of understanding and mitigating flight delays. Building an effective and accurate prediction model of flight-delay incidents will help airport executives make the best decisions in delay scenarios. This article utilized two advanced prediction methods to predict the probability of a flight-delay incident--data mining using the decision tree and data mining using Bayesian inference. Prediction models were built using flight on-time performance data collected from different sources. The results indicated important airport-related factors and their effects on the flight on-time performance. [ABSTRACT FROM AUTHOR]

Safe integration of Unmanned Aircraft Systems (UAS) into airspace generally occupied by manned aircraft and other aviation stakeholders is a pressing global challenge. In the United States, efforts are being made to integrate small and large UAS into the National Airspace System (NAS). Whereas regulations for the civil operation of small UAS (25 kg and lighter) have already been adopted, those for larger unmanned systems are still being crafted. Thus, a two-part mixed methods study was conducted to examine three pivotal issues in the safe operation of large UAS: (1) What kind of visual observer skills are needed to execute safe UAS operations; (2) Should visual observers involved in UAS operations receive formal training; and (3) Should visual observers be required to pass a certification exam? In the first phase, subject matter experts identified various vigilance, trajectory estimation and communication skills that were vital to performing visual observer duties successfully and elaborated on their training regimens. In the second phase, survey participants were approximately evenly split on the need for formal classroom/online and hands-on visual observer training. Furthermore, participants generally favored visual observers having to pass a classroom/online certification exam, whereas they were against a practical (hands-on) exam.

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. • Aviation facilities and equipment are prone to lightning-induced outages. • New lightning strike hazard impact patterns identified for airports in the United States. • Lightning strikes beyond current spatiotemporal warning thresholds could still induce outages. • Airports with atypical impact profiles should be prioritized for lightning hazard protection. [ABSTRACT FROM AUTHOR]

In today's National Airspace System (NAS), when an application requires information from another application, a custom application-to-application interface is built. This results in an increasingly complex system, where applications are tightly coupled and expensive to develop and maintain. System-Wide Information Management (SWIM) addresses these shortfalls by implementing a shared infrastructure for managing NAS information. SWIM is based on a service-oriented architecture, a fast growing trend in information technology. It will help the Federal Aviation Administration (FAA) meet the information-sharing needs of the Next Generation Air Traffic System (NGATS) and the federal government's E-government Initiative. SWIM will reduce the cost, complexity, and cycle time for building new applications and help the FAA implement SWIM-enabled applications that increase FAA and user productivity. [ABSTRACT FROM PUBLISHER]

The authors present the communication system architecture for air traffic management and weather information dissemination as viewed within the context of the overall National Airspace System (NAS) and the services it provides. This presents the architecture in the 2015 time frame when the final phases of transition take place from analog voice to digital data exchange of common data via integrated networks. The results of this transition are an integrated collection of systems and procedures that efficiently use the capacity of the NAS while balancing access to all user classes and maintaining the highest levels of safety. Efficient collaboration among users is built on a foundation of common data. This information base provides common situational awareness to all participants. All users are accommodated and will receive benefits commensurate with equipage level. This architecture development provides a technical framework for decision-making, research, and analysis of communication technologies [ABSTRACT FROM PUBLISHER]

The National Institute of Standards and Technology has proposed using the common criteria and system-level protection profiles (SLPPs) to specify security requirements in large systems, such as those used in air traffic management. This article summarizes experience with SLPP and security targets for the US Federal Aviation Administration's National Airspace System. The authors review the FAA efforts, highlight the problems encountered, and offer suggestions for future work, calling for more research on linking systems, software, and security requirements engineering with SLPP; clearer ties between security specifications and system certification; and better guidance on the appropriate use of SLPP as a prerequisite to widespread use [ABSTRACT FROM PUBLISHER]

The acceptance and implementation of advanced digital avionics and flight control systems is dependent on the successful integration of these systems into the current and future National Airspace System (NAS). This paper describes a digital avionics systems research facility known as the Digital Information Facility (DIF) developed to provide researchers with the ground systems and air-to-ground interfaces needed to conduct and document experiments involving a mix of new technologies within the existing NAS infrastructure. The DIF supports four NAS functions: Controller Pilot Data Link Communications (CPDLC), Flight Information Services (FIS), Differential Global Positioning System (DGPS) navigation, and Automatic Dependent Surveillance-Broadcast (ADS-B). The DIF also includes the capability to record pilot and air traffic management interactions and document research participant observations. The DIF capability includes connectivity to flight test and simulated aircraft in a fully immersive Communications, Navigation, and Surveillance (CNS) environment. [ABSTRACT FROM PUBLISHER]

The unstructured traffic environment that is gradually evolving in the National Airspace System may necessitate decision aiding tools to help controllers manage aircraft traffic efficiently and within acceptable safety and workload levels. An experiment was designed to assess the effect of conflict detection and trial planning resolution aids and traffic conditions on the performance of controllers and the efficiency of flight. Twelve controllers participated in a high-fidelity simulation study in the Indianapolis Center dynamic simulation facility using the user request evaluation tool (URET). Study results indicated that URET clearly improves the acceptability of operations and may enhance safety, particularly in the unstructured environment. In addition, the study findings strongly support a shift toward more strategic air traffic control with conflict probe as well as a significant increase in the contribution of the D controller to the primary sector tasks. Because of study limitations, it was not possible to associate any quantitative estimates of airspace user benefits with the potentially more efficient resolution strategies. The results and experimental approach are discussed in terms of their contribution to measurement methods and issues in the evolutionary progression toward a free flight-based air traffic system [ABSTRACT FROM PUBLISHER]

In an effort to accommodate the predicted growth in air traffic, the Federal Aviation Administration (FAA) and the aviation community have developed a concept of operations for the National Airspace System (NAS) called Free Flight. This operational concept has been developed for the midterm time frame (nominally a period of time that centers around 2005). The Center for Advanced Aviation System Development (CAASD) at The MITRE Corporation developed the concept and has conducted laboratory exercises to validate the portion of the concept that applies to the en route domain. The paper describes CAASD's laboratory efforts to begin validating the en route portion of the concept by examining the operational issues associated with the concept and the functional issues related to its evolution to the midterm. The laboratory validation exercises described examine the functionality of possible capability enhancements, but do not address associated detailed human factors issues. Favorable results from CAASD's initial qualitative validation efforts support the need for further quantitative validation activities that include more detailed analyses, further development of operational procedures and computer-human interfaces, and more rigorous exercises involving FAA field controllers [ABSTRACT FROM PUBLISHER]

Initiatives in air traffic management both in the United States and in Europe are aimed at providing air traffic controllers with automation tools to separate traffic, meet time constraints required for traffic flow and accommodate route preferences of users such as airlines. These efforts are expected to result in removal of restrictions on users preferred routes without compromising safety. Thus, aircraft will be able to fly optimal routes such as great circle and wind-optimal routes. NASA has developed the design for a new automation tool, referred to as the direct-to tool, which advises the controller on direct time-saving routes for any aircraft irrespective of levels of equipage. In contrast to earlier studies on the potential benefits of direct routes in the National Airspace System, the objective of the paper is to evaluate the benefits based on a controller tool. The paper describes the benefits of applying this algorithm to the 20 air route traffic control centers within the United States. Benefits are measured in terms of the total time savings accrued by flying the direct route. Results are described for three different implementations dependent on the search region bounding each air route traffic control center. The first region exactly encloses the air route traffic control center airspace, the second is the smallest rectangular bounding region while the third is a bigger rectangular bounding region approximately twice as large as the second region. It is shown that the application of the direct-to routing algorithm does not significantly alter the number of conflicts and their spatial distribution compared to the case in which the aircraft fly along the airways. The results presented in the paper suggest that the direct-to routing algorithm can provide significant cost savings to the users without adversely impacting the air traffic management functions [ABSTRACT FROM PUBLISHER]

This paper proposes an application of the Total Airspace and Airport Modeller (TAAM)2 tool for determining the impact of new Communications, Navigation, and Surveillance (CNS) ground-based and avionics technology on the efficiency of the National Airspace System (NAS). TAAM presents an opportunity to attack this problem by simulating aircraft movements using rules that mimic actual operations. The rules can be tailored to represent local procedures, restrictions, and conflict resolution strategies, producing a realistic picture of aircraft movement. This paper describes a novel method for manipulating TAAM output to produce a measure of the voice channel occupancy (VCO) in a sector. This method can be applied for current conditions, where all communications use the voice channel, and for the future case in which Controller-Pilot Data Link Communications (CPDLC) is used to issue controller/pilot instructions. TAAM could then be used to examine the benefits of CPDLC in terms of relieving restrictions or reducing vectoring and holding. Overall system benefits such as reduction in delays or distance traveled could be estimated from the TAAM results [ABSTRACT FROM PUBLISHER]

Reliability of the air transportation system heavily depends on the performance of communication, navigation, and surveillance facilities in the National Airspace System (NAS). These facilities are prone to outages caused by convective weather, such as lightning. Current lightning safety standards and risk assessments focus solely on lightning occurrence and omit the effect of lightning intensity from hazard characterization. We propose methods that incorporate lightning intensity and occurrence parameters to better understand the impact of lightning strike on the NAS using the National Lightning Detection Network and Federal Aviation Administration NAS facilities and equipment outage databases. Spatial analysis and clustering reveal different exposure profiles for 436 U.S. airports. Kernel Density estimation and Hot Spot analysis show that regardless of lightning intensity, Southern state airports are the most exposed to lightning hazards. K-means clustering reveal five different lightning exposure profiles that mimic the spatial patterns produced by the Kernel Density estimation and Hot Spot analysis. A scoring system ranks all airports according to their exposure profile taking into consideration lightning occurrence and intensity. It is complemented with a rising trend exposure analysis, which identifies airports whose exposure could be underestimated under the current standards, identifying airports with fewer lightning occurrences but higher intensities. Finally, a comparison between the exposure patterns and lightning-induced outages provide insights into U.S. lightning impact patterns. Similar patterns between lightning exposure and outages indicate that the results of the proposed lightning hazard assessment provide useful information for prioritizing airport hardening investments at the national scale and reducing lightning risk., (© 2020 Society for Risk Analysis.)

The increasing number of small Unmanned Aircraft System (sUAS) encounters with manned aircraft or airports increases the risk of collision in the National Airspace System. The purpose of this research is to develop and test predictive models for sUAS violation incidents in NAS using machine learning. This research uses machine learning algorithms to predict the risk of sUAS violation incidents using the FAA's UAS sighting data with a sample size of 2088. Three sUAS violation types are identified: flying above 400 feet, flying with 5 miles from an airport, and flying in restricted airspace. Seven machine learning algorithms were used, including classification regression, decision tree, neural network, gradient boosting, random forest, Bayesian networks, and Memory-Based Reasoning. The results show that Gradient boosting produces the best predictive model. This model can predict the sUAS violation incidents with an accuracy of 95.7 percent. Location, distance to the airport, state, sUAs altitude, airport type, and aircraft type are the most influential predictors to the sUAS violation incidents. • This research uses machine learning algorithms to predict the risk of sUAS violation incidents. • The FAA's UAS sighting data was used with a sample size of 2,088 incidents. • Gradient boosting algorithm produces the best prediction model. • The prediction model can predict the sUAS violation incidents with an accuracy of 95.7 percent. • Location, distance to the airport, state, altitude, airport type, and aircraft type are the most influential predictors. [ABSTRACT FROM AUTHOR]