Safety Of National Airspace System Research Articles

Aircraft post-upset flight risk region prediction for aviation safety management

Flight trajectory prediction is a vital tool for enhancing the national airspace system (NAS) safety management, especially with the rapid increase in flight density. In-flight uncertainties during aircraft upset events significantly impair the flight path trajectory prediction, hence a robust uncertainty quantification study is needed for realistic flight path risk region construction upon such upset events. The NASA transport class model (TCM) is implemented as a high-fidelity flight dynamics simulator to mimic post-upset aircraft response. Take-off and high-altitude stall scenarios are considered, due to their major contribution to aircraft loss of control in-flight incidents, where stochasticity is introduced in the TCM upset-triggering parameters. Automated recovery algorithm is developed and applied into TCM framework to control the rate of elevator surface deflection and/or throttle level, leading to flight path nominal conditions recovery. Monte Carlo simulations are performed to estimate a stochastic risk region in terms of confidence ellipsoid for both non-recovery and recovery simulated cases, where a relatively larger uncertainty level is observed during the recovery process. Additionally, a data-driven deep-learning surrogate model is developed to enhance the computational feasibility of such risk region estimation, which is essential for in-situ NAS safety assessment. Finally, the wind speed effect on the risk region and flight dynamics response prediction during high-altitude post-upset recovery cases is investigated.

Information Fusion for National Airspace System Prognostics

Expanding Prognostics and Health Management (PHM) from an equipment-centric view to complex large-scale engineering systems is a challenging problem. One example for a large engineering system is the next generation national airspace system (NAS), which is a fully coupled cyberphysical- human system. This paper presents an overview of a NASA University Leadership Initiative (ULI) project which aims to address the safety needs and their technology solutions for future NAS. The ULI is a 5-year collaborative project in which researchers from several universities and commercial entities work together to advance real-time airspace safety concepts. The underlying premise is that it is imperative to be able to assess and predict the evolution of the airspace’s safety state. Towards that end the work envisions to address the following issues: modeling of the airspace using both data-driven and physics based approaches; quantifying and managing uncertainty; advancing prognostics and information fusion algorithms; and understanding and modeling human computer interface. A comprehensive simulation environment is being built that allows for assessment of performance and verification and validation. The paper discusses the various activities and places them into the context of overall NAS safety.

The Design of the UAS Ground Control Station: Challenges and Solutions for Ensuring Safe Flight in Civilian Skies

Growing civil demands for uninhabited aircraft systems (UASs) are creating pressure to determine minimum design standards and required capabilities for UAS ground control stations (GCSs). This panel will discuss recent and ongoing research initiatives, regulatory guidance, and lessons learned from military UAS operations and mishap reports to shed light on the potential for GCS designs to support safe and non-disruptive UAS operations in the national airspace system (NAS). As part of this discussion, panelists will present GCS design challenges related to the preservation of NAS safety and traffic flow and will suggest strategies for overcoming them.

Safety of Efficiency: Link Between Operational Performance and Operational Errors in the National Airspace System

Safety and efficiency are two of the most important goals of the national airspace system (NAS). However, these goals are typically viewed as competing or independent, rather than complementary. The complementary aspect of safety and efficiency is illustrated from the point of view of human factors and ergonomics. Statistical methods were used to analyze safety and efficiency performance measurements, operational errors, and daily flight time index (DFTI). Factors related to weather and complexity were found to be more likely on days with poor operational performance as measured by DFTI. The results indicate a positive relationship between NAS safety and efficiency and imply that NAS safety performance may be improved by increasing efficiency, and vice versa.

Impact of Air Traffic Controllers' Strike on the Safety of National Airspace System

The findings of the study performed for FAA/DOT Office of Aviation Safety are presented. The level of safety of performance in the ATC system after the strike of August 1981 was analysed. There were two parameters of interest, viz. 1, near mid air collisions, 2, operational error reports, of these, the operational errors related more directly to the performance of ATC and was analyzed in detail. The data consisted of 54 weekly frequency counts of operational errors and the volume of operations covering the periods from January 1980 to July 1982. The model used a linear autoregressive process, but the parameters were estimated using a derivative-free non-linear least squares estimation method. The post-strike operational error data normalized to the volume of operations were found to be lower than the same rate for the pre-strike period. The analysis of operational errors of the Air Traffic Controllers reported during comparable periods before and after the strike date of August 3, 1981 showed that there was a lack of degradation of safety of the National Airspace System in the post-strike period. This was found to be true both for terminals and the air route traffic control centers.