<p dir="ltr">I conducted an in-depth analysis of the frequency and severity of external load accidents involving Chinook helicopters over a period of 30 years. The literature review encompassed General Aviation (GA) and ground-based safety organizations, while the data analysis predominantly relied on secondary data from the Army Combat Readiness Center (ACRC). In conducting this study, I aimed to identify key trends, causes, and effects of these accidents, particularly emphasizing material failures, human errors, and the substantial impact of rotor downwash as horizontal wind velocities in proximity to the ground. The study's goal was to improve safety and operational efficiency in Chinook external load operations by identifying frequency and severity of accidents over a 30-year period. The hope was that this would provide valuable insights for improvements in risk mitigation techniques.</p><p dir="ltr">By using an exploratory secondary data analysis of both publicly available U.S. Army accidents and accident data provided by the U.S. ACRC, I found that Chinook rotor downwash, which manifests as horizontal wind velocity when in close proximity to the ground, is the most significant and underreported factor. Based on the findings of this research, I recommend improved classification and documentation of such accidents. The findings highlighted the urgency of updating training and operational procedures to effectively address the unique challenges posed by rotor downwash and high gross weights in proximity to the ground, typical of Chinook external load Pickup and Landing Zone (PZ/LZ) operations. Implementing these recommendations is expected to enhance safety measures in both training and practical operations, ultimately reducing future accidents and improving safety standards in the aviation industry.</p>

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / The Aircraft Research and Development Unit (ARDU) of the Royal Australian Air Force (RAAF) is the only agency in Australia that performs the full spectrum of military flight testing and is the new custodian of the instrumented weapons range at Woomera. Receiving early attention will be the upgrade and integration of ARDU's telemetry systems with the meteorological and tracking data acquisition capabilities at Woomera to minimize overhead and data turnaround time. To achieve these goals, maximum modularity, extensibility, and product interoperability is being sought in the proposed architecture of all the systems that will need to cooperate on the forecast test programmes. These goals are also driven by the need to be responsive to a wide variety of tasks which presently include structural flight testing of fighter and training aircraft, weapons systems performance evaluation on a variety of combatant aircraft, and a host of other tasks associated with all fixed and rotary wing aircraft in the Army and Air Force inventory. Of all these tasks however, ARDU sees that responsiveness to future testing of F-111Cs fitted with unique Digital Flight Control Systems along with USAF standard F-111Gs may place the most significant demands on data handling —particularly in regard to providing an avionics bus diagnostic capability when performing Operational Flight Programme (OFP) changes to the mission computers. With the timely assistance and advice of Loral Test & Information Systems, who has long-term experience in supporting USAF F-111 test programmes, ARDU is confident of making wise design decisions that will provide the desired flexibility and, at the same time, minimize life-cycle costs by ensuring compliance with the appropriate telemetry and open systems standards. As well, via cooperative agreements with the USAF, the potential exists to acquire proven software products without needing to fund the development costs already absorbed by the USAF. This paper presents ARDU's perception of future needs, a view by LTIS of how best to meet those needs, and, based on ARDU data, a view of how LTIS' proposal will satisfy the requirement to provide maximum extensibility with minimum life-cycle costs.

Dans les systèmes embarqués critiques, assurer la sûreté de fonctionnement est primordial du fait, à la fois, des exigences en sûreté dictées par les autorités de certification et des contraintes en sûreté de ces systèmes où des défaillances pourraient conduire à des évènements catastrophiques, voire la perte de vies humaines. Les architectures de ces systèmes sont aujourd'hui de plus en plus distribuées, s'appuyant sur des réseaux numériques complexes, ce qui pose la problématique de l'intégrité des communications. Dans ce contexte, nous proposons une approche bout en bout pour l'intégrité des communications, basée sur le concept du " canal noir " introduit par l'IEC 61508. Elle utilise les codes détecteurs d'erreurs CRC, Adler et Fletcher. Selon le niveau de redondance des systèmes, nous proposons une approche multi-codes (intégrité jugée sur un lot de messages) pour les systèmes dotés d'un niveau de redondance important et une approche mono-code (intégrité jugée sur chaque message) pour les autres cas. Nous avons validé ces propositions par des expérimentations évaluant le pouvoir de détection intrinsèque de chaque code détecteur et la complémentarité entre ces code en termes de pouvoir de détection, ainsi que leurs coûts de calcul avec une analyse de l'impact du type de leur implémentation et de l'environnement matériel (standard et embarqué : processeurs i7, STM32, TMS320C6657 et P2020). L'approche mono-code a été appliquée à un cas d'étude industriel : les futurs systèmes de commande de vol d'Airbus Helicopters. / In critical embedded systems, ensuring dependability is crucial given both dependability requirements imposed by certification authorities and dependability constraints of these systems where failures could lead to catastrophic events even loss of human lives. The architectures of these systems are increasingly distributed deploying complex digital networks which raise the issue of communication integrity. In this context, we propose an end to end approach for communication integrity. This approach is based on the "black channel" concept introduced by IEC 61508. It uses error detection codes particularly CRC, Adler and Fletcher. Depending on the redundancy level of targeted systems, we propose a multi-codes approach (integrity of a set of messages) for systems with an important redundancy level and a single- code approach (integrity per message) for the other cases. We validated our proposals through experiments in order to evaluate intrinsic error detection capability of each error detection code, their complementarity in terms of error detection and their computational costs by analyzing the impact of the type of implementation and the hardware environment (standard or embedded: i7, STM32, TMS320C6657 and P2020 processors). The single-code approach was applied to an industrial case study: future flight control systems of Airbus Helicopters.

<p dir="ltr">This thesis concentrates on the improvement of the quality of shock-dominated flows in supersonic inlets by controlling shock wave / boundary layer interactions (SWBLIs). SWBLI flow control has been a major issue relevant to scramjet-associated endeavors for many years. The ultimate goal of this study is to numerically investigate SWBLI flow control through the application of steady-state thermal sources --- which were defined to replicate the Joule heating effect produced by Quasi-DC electric discharges --- and compare the results with data obtained from previous experiments.</p><p dir="ltr">Numerical solutions were obtained using both a three-dimensional, unsteady Reynolds-averaged Navier-Stokes (RANS) solver with a Spalart-Allmaras (SA) Detached Eddy Simulation (DES) turbulence modeling method and also a simple three-dimensional, compressible RANS solver with a SA turbulence model. Computations employed an ideal gas thermodynamic model. The numerical code is Stanford University Unstructured (SU2), an open-source, unstructured grid, computational fluid dynamics code. The SU2 code was modified to include volumetric thermal source terms to represent the Joule heating effect of electric current flowing through the gas. The computational domain, source term configuration, and flow conditions were defined in accordance with experiments carried out at the University of Notre Dame. Mach 2 flow enters the three-dimensional test domain with a stagnation pressure of 1.7 bar. The test domain is contained by four isothermal side walls maintained at room temperature, as well as an inlet and outlet. A shock wave (SW) generator, a symmetric 10 degree wedge, is positioned on the upper surface of the test domain. The overall length of the test sections is 910 mm and inlet length of the computational domain is increased prior to the location of shock wave generator in order to allow for adequate boundary layer growth. Volumetric heating source terms were positioned on the lower surface of the test domain in the reflected SW region.</p><p dir="ltr">Experimental results show that the thermal sources create a new shock train within the duct and do not initiate significant additional pressure losses. What remains to be explored is the overall characterization of the 3D flow features and dynamics of the thermally induced SW and the effect of gas heating on total pressure losses in the test section.</p><p dir="ltr">Numerical solutions validate what is observed experimentally, and offer the ability to gather more temporally and spatially-resolved measurements to better understand and characterize shock-dominated flow control in a supersonic inlet or duct. Although thermally driven SWBLI flow control requires additional research, this study alleviates the dependency on experimentally driven data and adds insight into the nature of the complex unsteady, three-dimensional flowfield.</p>

<p dir="ltr">Methodologies for optimizing UAVs' control for varied environmental conditions have become crucial in the recent development for UAV control sector, yet they are lacking. This research focuses on the dynamism of the Gazebo simulator and PX4 Autopilot flight controller, frequently referenced in academic sectors for their versatility in generating close-to-reality digital environments. This thesis proposed an integrated simulation system that ensures realistic wind and gust interactions in the digital world and efficient data extraction by employing an industrial standard control communication protocol called MAVLink with the also the industry standard ground control software QGroundControl, using real and historical weather information from NOAA database. This study also looks into the potential of reinforcement learning, namely the DDPG algorithm, in determining optimal UAV safety distance, trajectory prediction, and mission planning under wind disruption. The overall goal is to enhance UAV stability and safety in various wind-disturbed conditions. Mainly focusing on minimizing potential collision risks in areas such as streets, valleys, tunnels, or really anywhere has winds and obstacles. The ROS network further enhanced these components, streamlining UAV response analysis in simulated conditions. This research presents a machine-learning approach to UAV flight safety and efficiency in dynamic environments by synthesizing an integrated simulation system with reinforcement learning. And the results model has a high accuracy, reaching 91%, 92%, and 97% accuracy on average in prediction of maximum shifting displacement, and left/right shifting displacement, when testing with real wind parameters from KLAF airport. </p>

<p dir="ltr">Cyber-physical-human systems (CPHSs) integrate human cognitive capabilities into the decision and control processes of complex dynamical systems. While artificial intelligence (AI) has shown promise in controlling such systems, it often encounters challenges such as conflict with human behavior and brittleness. Moreover, even successful AI implementations may lead to negative impacts on humans, such as the degradation of manual skills and diminished situation awareness, thereby weakening humans' ability to effectively monitor and intervene in off-nominal conditions as the final decision-makers of the systems. To address these unique challenges within CPHSs, this dissertation proposes three key approaches. First, human behavior modeling approaches are proposed to enhance understanding and prediction of human behavior from the perspective of AI. Accurate modeling enables better calibration of AI's expectations regarding human teammates' intentions and skill-levels. Second, a novel shared control approach is developed to expedite human training for complex dynamic control tasks. An assistant agent supports human novices in emulating human experts by leveraging human behavior models to gauge the human's skill-levels and provide tailored assistance to help improve one's skill. Lastly, human-autonomy teaming (HAT) design is addressed from a resource allocation perspective. A systematic computational simulation approach is proposed to optimize function and attention allocation to manage trade-offs in performance, situation awareness, workload, and other considerations. The proposed frameworks are demonstrated via examples in drone applications. Numerical and experimental results, utilizing simulation platforms and human subjects, validate the efficacy of the proposed approaches. This dissertation presents significant progress in the design and implementation of CPHSs in that it offers insights and methodologies to enhance collaborative interactions between humans and autonomous systems in complex environments.</p>