Browse Topic: Risk management
Research into the feasibility of a scaled rim-drive propulsion product to enable ultra-heavy vertical lift (UHVL) is ongoing at the University of South Carolina in partnership with KRyanCreative, LLC, a start-up aerospace small business. The research team is advancing a superconductive design concept for a rotor system that delivers significant performance gains and flight envelope expansion disruptive to the vertical lift transportation sector. The team has conceived a novel electric tip-driven ducted propulsor to guide architectural and engineering investigations that improve hover and acoustic performance over current practice without penalty to weight and cost. This paper summarizes the data and assumptions that emerge from the systems engineering process of requirements decomposition for product realization. Requirements are categorized as to whether they are explicit (programs of record) or implied (comparable business case or as an alternative to a program of record). Risk reduction enroute to technical feasibility is addressed with a methodology that applies predictive analytics aided by artificial intelligence that will accelerate prototype fabrication by 2030 and fast track market incentives for multiple aviation technologies.
The Research Aircraft for eVTOL Enabling TechNologies (RAVEN) Subscale Wind-Tunnel and Flight Test (SWFT) model is a subscale aircraft built for flight dynamics and controls research demonstrated in wind-tunnel and flight-test experiments. The intent of this paper is to provide a summary of past, current, and future efforts being pursued by the RAVEN-SWFT project. Initially, vehicle development guidelines were crafted by a multidisciplinary team to ensure that the RAVEN-SWFT vehicle was well suited for research in multiple areas, including aero-propulsive modeling, flight controls, and autonomy, among others. The vehicle has been used to obtain extensive wind-tunnel data, enabling aero-propulsive model development across the transition flight envelope and validation of computational tools. The vehicle will be used to conduct flight testing in order to evaluate modeling strategies and flight control logic. The RAVEN-SWFT model also serves as a risk reduction activity for a conceptual, full-scale vehicle in the 1000-lb class. The next steps in the project are to successfully demonstrate free flight in hover, transition, forward flight, and the reverse thereof, utilizing custom control laws integrated onto the RAVEN-SWFT avionics hardware. The project intends to publicize all of the geometry, data, and methods in future reports.
When the target value of functional geometrical specification is too tight, its cascade of tolerances is at the feasibility limit of production. In this case, the geometrical Tolerancing method loses its benefits and generates an excessive level of non-Conformity which induces additional costs that are not acceptable. The aim of this paper is first to introduce the background concerning chain of dimension method and tolerances capabilities based on test specimen results. Secondly, demonstrate ability to apply statistical calculation. Thirdly extend conventional chain of dimension in one dimension to multi-holes system installation. And, then analyze potential effect by stress evaluation. And confirm the demonstration of improvement on Tolerancing installation calculations, by onboarding all stakeholder (design, manufacturing, stress) early in design phase (interfaces maturation) and by analyzing more in detail installations constraints. This method should be applied first on "non-critical" junction, because it needs to be further matured and so it is not yet mature enough for primary structure and associated quality checks. In conclusion, as a result, it is possible to increase tolerance specification of parts and manage risks of non-assembly. In conclusion, tolerances for holes localization could be approximatively multiplied by two compared to basic calculation method.
In the early days of quality management, prior to 1980s, the focus seemed to be on "Quality Control" or "Quality Assurance". Emphasis was placed on inspection and testing. Quality was about conformance to specification. Non-Conformance Reports were representative of quality control. Our understanding of quality management has evolved, largely based on the Toyota Quality and Concurrent Engineering Approach of moving it off the production line for Integrated Product and Process Development (IPPD) [1]. In the late 1980s industry experienced similar difficulties in understanding and adopting quality management. The ideas behind managing quality are quite abstract. Quality is primarily about understanding and satisfying a customer's expectations. This includes implicit expectations, as well as explicit expectations. The techniques of specification, inspection and testing only make sense in that wider context. Formal risk management was developed in the late 1980s and throughout the 1990s. Risk management principles are now widely understood and applied. Functional Safety Management (FSM) simply applies quality management to systems that are designed to control risk. [2] The standards for FSM and Development Assurance (DA) are relatively new. SAE ARP 4754 and ARP 4761 for complex aircraft systems were introduced in 1996 and DO-178 for software in 1998. In 2010 ARP 4754A [3] was created for movement from federated avionics systems to distributed integrated avionics systems which set the stage for Integrated Modular Avionics (IMA) in DO 297 [4]. The Army identified IMA as a critical technology in its Joint Common Architecture (JCA) Final Report [5] and is seeking to provide a Modular Open Systems Architecture (MOSA) approach to its Future Vertical Lift (FVL) programs. [6] The aim is to build and upgrade FVL mission systems without expensive proprietary interfaces. New capabilities from a choice of developers will adapt to emerging threats. The mission system architecture demonstration (MSAD) Program has awarded six contracts to avionics vendors to develop MOSA tools and rules. A capstone demonstration wraps-up this December 2020 and will generate a final report and provide guidance for Future Attack and Reconnaissance Aircraft (FARA), FLRAA and FUAS architectures. MOSA flexibility and economy come to legacy helicopters with the Aviation Mission Common Server (AMCS), which transitions the legacy fleet from single-purpose/single-vendor architectures to more adaptable modules and components. Nonproprietary, government-controlled, open system standards interface new software applications without going to each platform maker for integration. [6] This paper will review FSM, DA, and Open IMA in these civil aircraft standards, compare them with Army Aviation's current Army Military Airworthiness Certification Criteria (AMACC) [7] and recommend a Civil Military FSM DA Framework for FVL and on how AMACC could be modified for FVL Open Systems Architectures (OSA) Certification using a Modular Open Systems Approach (MOSA). [8]
Quantitative Risk Assessment has become essential in rotorcraft safety risk management. Measures of risk include Cumulative Fleet Risk (also called Risk Factor), Risk per Flight, and Risk per Flight Hour. Each measure applies to a different situation and can produce the same or different predictions of future risk. Risk for a large fleet of aircraft might be accurately predicted by Cumulative Fleet Risk, whereas Risk per Flight or Risk per Flight Hour might be best for a small fleet of rotorcraft, a flight test program, or a fleet with low flight hours. Calculating risk per flight hour seems as simple as dividing the number of previous occurrences by the flight hours for the total fleet, but this is appropriate only in the case of random distribution. Most failures that lead to hazards are not random because the failure mechanism has a specific cause. A more appropriate method is to develop the future event forecast using Quantitative Risk Assessment, then divide that by the future fleet hours. The simple division process requires only two numbers and can be completed quickly, but with a possibly inappropriate or misleading result for anything but a random distribution. The approach presented here results in a risk prediction that is appropriate for hazard rates that are increasing, decreasing, or constant, and for non-random distributions, which could prevent misleading or unconservative risk management decisions.
This document addresses measurement uncertainty and consumer risk as they relate to AS8879 thread inspection. It describes the rationale, theory and methodology used to generate the technical content of the AS5870. The document describes how to calculate measurement consumer risk. It documents all of the calculation methods which industry employs today to calculate what is commonly called measurement uncertainty (Appendices A, B, C, D, E and F). These, in turn, are used to calculate measurement uncertainty ratios which are required inputs to calculate measurement consumer risk. Users of this document can apply the information described herein for the evaluation of the capability of their measurements based on the measurement consumer risk. It involves the analysis of the measurement (product) distribution and biases of both the product and measurement system distributions. It protects the consumer from the worst case distribution results.
The success of the flight mission is closely related to a wide set of factors that must be taken into consideration. Combining all these elements together, the risk associated to the flight can raise significantly, eventually resulting in a situation in which the flight should be cancelled, unless some mitigation of the risk factors are applied. The aim is the understanding of the expectable human abilities and limitations, in correlation with the aircraft status and all the external elements related to the flight. Following the guidance contained in Ref.1, this knowledge has being applied in the definition of a standardize approach for the design of the risk assessment procedures and software requirements. For the safety of the flight, it is essential that the pilot is able to discern in advance between a low and a high risk flight. With a Flight Risk Analysis Tool (FRAT) the pilot can proactively identify the hazard with a visual representation of the risk, applying an evaluation process and risk mitigation strategies, as described in Ref. 2. Moreover to better support this analysis the tool shall be enough complex to consider all aspects, but at the same time, easy to use and simply accessible (i.e. usable by an application installed on the portable device). SkyFlight has been developed to support the flight planning activities for the rotorcraft mission, being the optimal offaircraft mean to carry out the evaluation of the flight, ensuring a thorough Safety Assessment. Pilots have SkyFlight application installed on their portable devices to access the service. As presented in Ref.3, SkyFlight gives to the Pilot a deep understanding of the current situation and the involved dynamics, to anticipate changes and future developments, and to clearly understand the consequences related to the flight. The features are designed to positively increase the Pilot Situational Awareness and reduce mission risks. The Safety is spread within all functionalities, starting from simple and common concepts, to a finer level with a deep performance calculations and what-if analysis. To further increase the safety, the latest developed functionality is the Flight Risk Assessment, which has been developed following the EASA and FAA standards, discussed in Ref. 4 and 5, and embedding the EHEST pre-departure Risk Assessment Checklist, provided in Ref. 5. The predefined set of checklist is available to support different types of flight (Training, HEMS, passenger, etc.) and each list is based on the PAVE (Pilot, Aircraft, Environment, External pressure) areas. In addition to the pre-departure Checklists, also In-flight and Post-flight Checklists have been shaped, following the approach discussed in Ref. 6. Through SkyFlight the pilot is able to fill the Risk Assessment Checklist, inserting mitigations where applicable and view the total score. The filled checklist can be saved and shared. It is also possible to export them in a pdf format and to send automatically via email to one or more email addresses. In addition to this, which reflects the state of the art for FRAT, some other peculiar features have been designed. Indeed, to better support the different rotorcraft missions and to meet the process of each operator, the Risk Assessment Checklists will be completely customized by the company safety manager. The functionalities have then being further enhanced with software developments to add value to the tool with both small and big features. For example, the order of the multiple choice answers changes every time the pilot access to the checklist, to guide her/him to read carefully the answers before the selection. More complex functionalities have been inserted to connect the flight planned with SkyFlight to the hazard evaluation, showing the weather data and all the notifications associated to the flight (NOTAMs, Warning/restrictive Airspaces infringements ...). AW SkyFlight application can be installed on personal portable devices and the Flight Risk Assessment functionality can be used for free, to let every pilot from the general aviation to access to the safety enhancements above described. The FRAT capabilities, usability and utility have been then tested with the Leonardo Helicopters Division pilots as well as a set of specific customers pilots as representatives of the different types of operations (in the Executive and Private transport, Medical and Rescue services, Offshore operations, Security services and Utility).
This paper presents the unique perspective and role of the test pilot in helicopter design and test risk reductions efforts. The system safety process provides a framework to show points of contribution during design and risk reduction (mishap prevention) in developmental, engineering and production rotorcraft flight operations. Taking a historic perspective of risk reduction during test, chief engineers who were also test pilots had an intuitive understanding of the risks and mitigations present during flight testing. With the specialization of both engineering disciplines and test pilot skills, a gap has emerged in the mutual understanding between the two roles. Using the system safety process can help fill that gap and provides an opportunity to highlight risks and mitigations in aircraft design and test. The intent of this paper is to encourage use of the system safety process and specifically early and frequent test pilot participation in risk management strategies during the design and test phases of aircraft development.
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