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Statistical Study of Solar Wind Conditions Prior to Substorm Onsets
Get PDFDue to complex, multi-region, coupled plasma systems, auroral substorm onsets have been historically difficult to predict. The northward turning of the interplanetary magnetic field was considered the primary candidate as an external triggering mechanism for substorm onsets. However, that was later shown to be coincidental in nature. This study is motivated by recent multi-spacecraft observations that show how several magnetosheath jets at the bow shock were heavily correlated to substorm onsets, indicated by a strongly radial IMF interval. In the past, studies have looked at small samples of substorms in order to make large-scale predictions. However in this study, a total of 28 years of solar wind data is analyzed from NASA’s OMNI database to determine if any predictions can be made at all. This thesis investigates statistical differences between parameters before, during, and after substorm onset. This is accomplished using Welch’s t-test to account for differences in distribution means and variances. A time period requirement in-between substorms will also be utilized to show that each parameters’ results are not affected by reoccurring substorms. It is found that Bz, Ey, and |E| are the most significant parameters based off this test
Trust and Confidence in Aviation Safety Oversight: Comparing Scales of Public Perception
Get PDFEffective aviation safety oversight depends significantly on public trust and confidence in regulatory institutions. Understanding the dynamics behind public trust in Civil Aviation Authorities (CAAs) is critical to ensuring compliance, improving safety performance, and fostering legitimacy. This poster presents the preliminary results of a scoping review focused on the mechanisms currently used to measure public trust and confidence in public institutions worldwide. The review examines three scales presented in the literature that could support the analysis of institutional trust in governmental bodies, particularly in public safety-relevant industries such as aviation. The analysis identified some differences in the way the scholarly literature addresses these constructs and some similarities in the methodologies used to measure them. Thes studies also target different participants to collect perception information. The findings support the development of a pilot study supporting the development of new tools for assessing trust in CAAs, which may lead to actionable insights for improving regulatory effectiveness and public perception of aviation safety measures. The outcomes are expected to enhance the theoretical understanding of public trust in aviation oversight and provide practical recommendations for policymakers to reinforce public confidence in safety-related regulatory decisions
Comparing Linear and System-Theoretic Risk Models in Aviation: Insights from the Comair 5191 Accident
Get PDFAviation is one of the safest modes of transportation, thanks to the structured application of safety risk management processes. However, different frameworks offer varying approaches to managing risk. This study compares the effectiveness of two such frameworks: the Bowtie method, a linear approach, and the System-Theoretic Accident Model and Processes – Causal Analysis using Systems Theory (STAMP-CAST), a system-theoretic method, in analyzing the 2006 Comair 5191 accident.
The Bowtie method visually links hazards to consequences, identifying preventive and mitigative controls that either failed or were absent in the sequence leading to the accident. Applied to Comair 5191, the Bowtie analysis reveals how the failure to prevent the aircraft from attempting to take off from the wrong runway resulted in a fatal crash. This method is particularly useful for identifying weaknesses in both preventive and recovery measures, making it easier to propose specific changes to prevent similar accidents in the future.
STAMP-CAST, on the other hand, views safety as an emergent property of the overall system, influenced by its controls, structure, and feedback loops. For Comair 5191, CAST focuses on the broader systemic issues, such as organizational culture, regulatory gaps, and air traffic control management, that contributed to the accident. This approach goes beyond human error, examining how decision-making processes and communication breakdowns within the system created unsafe conditions.
By applying both the Bowtie method and STAMP-CAST to the Comair 5191 accident, this study provides a comprehensive analysis of both direct and systemic causes, offering insights for improving aviation safety. The results demonstrate that while both methods are valuable in assessing safety risks, they address different aspects of system safety, each with its own strengths and limitations. The comparative analysis also highlights the importance of using a multi-faceted approach to risk assessment and underscores the potential for integrating diverse methods to enhance the prevention of aviation accidents
The Influence of Social Achievement Goals on Grit in Aviation Education
Get PDFAviation students have multiple ways of persisting and persevering in their aviation education, and they do not learn in a vacuum. Their social goals may help explain why some aviation students show more grit than others in an aviation education environment. The study examined the relationship and predictive ability of social achievement goals (i.e., social development goal, social demonstration-approach goal, and social demonstration-avoid goal) to predict grit in an aviation education environment. The constructs of social achievement goals and grit have yet to be examined together in motivation research. This paper provides a new predictive model for using the two constructs. Social achievement goals are primarily considered to be motivation in the social domain, while grit has been researched previously in positive psychology. Regression analysis revealed that social development goal was a positively related significant predictor of grit. Social demonstration-approach goal and social demonstration-avoid goal were both negatively related significant predictors of grit. Learning in an aviation education environment involves a social component where students learn in collaboration with their peers in ways that are different than traditional educational settings. Therefore, the aviation education environment is a unique environment in which individuals need to form social bonds with their peers to persevere throughout their education. These findings warrant further exploration. By examining the relationship of grit and social achievement goals, this study contributes insight into the importance of motivation in the social realm to predicting long-term goal attainment in aviation education
Characterization of a Magnetically Contained Hot Filament Plasma Source with a Wide-Sweeping Langmuir Probe
Get PDFIonospheric plasma research in the Space and Atmospheric Instrumentation Laboratory’s Space Plasma Chamber has been hindered by the lack of a suitable plasma diagnostic instrument and understanding of its hot-filament plasma source. This thesis describes efforts made to remedy both problems. A wide-range Sweeping Langmuir Probe was developed with a ±35 V sweeping range to fully analyze ion and electron saturation regions in the entire IV curve. A method was derived to estimate the chamber source’s filament temperatures. The new Langmuir probe was integrated into a refurbished automated system designed in Python to measure plasma parameters for various chamber conditions, culminating in creating several maps of densities and temperatures throughout the chamber. It was shown that the updated source produces plasma within the LEO range of densities and temperatures. The work towards this thesis involved schematic capture in National Instrument’s Multisim, circuit simulation in LTspice, board layout design in National Instrument’s Ultiboard, the board population, calibration, testing, and finally, data analysis of the captured curves. In addition, a filament temperature method was calculated and calibrated, and the framework of a software control system was adapted for automated instrument sampling in the plasma chamber
Contaminated Sweeping Langmuir Probes on Sounding Rocket Platforms
Get PDFSweeping Langmuir Probes (SLPs) are one of the most commonly used probes on sounding rocket missions. They offer measurements of plasma density, electron temperature, and both relative and absolute payload charging. One of the major implementation challenges, however, is contamination on the surface of the probe such that collected IV curves become distorted. This distortion can result in deflated densities, inflated temperatures, and erroneous charging measurements. This dissertation aims to expand our understanding of contamination\u27s impact on SLP data and offer new mitigation methods appropriate for the sounding rocket platform.
SPICE, Simulation Program with Integrated Circuit Emphasis, is used to simulate a contaminated Sweeping Langmuir Probe onboard a sounding rocket. The results are used to characterize regimes of contamination effects and assess the reliability of data analysis techniques for all reasonable contamination layer properties. This work also conducts the first in-depth analysis of charge accumulation across the layer, addressing observed behaviors in SLP in-situ data. The inclusion of this property has major implications on our understanding of contaminated probe behavior, as there are no applied sweep rates that are effective in bypassing all contamination effects. This result also suggests that a lack of apparent distortion is not an appropriate metric for probe cleanliness.
SPICE simulations and in-situ data from the APEP (Atmospheric Perturbations around Eclipse Path) sounding rocket mission demonstrate the impacts of voltage sweep profiles on contaminated probes. These design considerations made prior to launch can have irreversible and detrimental effects on the SLP\u27s behavior. We use simulation results to present the most favorable sweep profile to mitigate these effects.
Finally, methods have been presented in the literature to extract the contamination layer\u27s properties during post-flight analysis, but they rely on underlying assumptions that fail when charge accumulation is considered. We use simulation to test the reliability and practicality of this method for the range of expected layer properties. In most cases, the associated error for both contamination resistance and capacitance is outside acceptable limits, and both values are severely underestimated