Don't cut that 'grass'

Introduction: Have you ever noticed the abundance of wildflowers on public open spaces during spring in Cape Town? I suppose some Capetonians would be aware of Rondebosch Common and the astonishing botanical diversity it contains, including many threatened species. However, it appears that very few people are aware of the many other public open spaces that may be just as precious and put on a spectacular spring flower show. But for how much longer

Encouraging and Ensuring Successful Technology Transition in Civil Aviation

Technology transitions are essential to transforming air traffic management to meet future capacity needs. Encouraging and obtaining equipage adoption is one crucial aspect of technology transitions. We propose an approach for developing appropriate strategies to persuade aviation stakeholders to transition to new technologies. Our approach uses cost, benefit, and value distribution across stakeholders and over time to determine which strategies are most appropriate to persuading aircraft operators to adopt new equipage. Equipage that may show an overall positive value can nevertheless fail to provide value to individual stakeholders. Such imbalances in value distribution between stakeholders or over time may lead to stakeholder intransigence and can stymie efforts to transform air traffic management systems. Leverage strategies that correct these imbalances and accelerate the realization of value for all stakeholders can enhance cooperation and increase the likelihood of a successful transition to the new technology. We demonstrate the application of the approach using the case of automatic dependent surveillance-broadcast (ADS-B). The approach is also applicable to a wide range of industries beyond aviation, such as the energy sector and telecommunications

Understanding Current Ways of Reporting Runway Incursion Incidents at Towered Airports

Runway incursions occur when an unauthorized aircraft, vehicle or pedestrian operates on a runway. While most incursions are near-misses, they have the potential of turning into fatal accidents such as the Tenerife accident. Despite various efforts to reduce runway incursions, the number of incursions has been increasing. Learning from past incidents can help us develop effective preventive strategies but lack of in-depth investigations limits our understanding of the causes of incursions. At towered airports, the controller on duty reports the incident to the FAA using a form asking them to describe the incident in their own words. Our research question is whether the current form contributes to the lack of detail in incident reports. To answer this question, we interviewed controllers and asked how they view incident reporting and the factors they consider while doing so. In this paper, we report the results of interviews with air traffic controllers

Analysis of General Aviation fixed-wing aircraft accidents involving inflight loss of control using a state-based approach

Inflight loss of control (LOC-I) is a significant cause of General Aviation (GA) fixed-wing aircraft accidents. The United States National Transportation Safety Board’s database provides a rich source of accident data, but conventional analyses of the database yield limited insights to LOC-I. We investigate the causes of 5,726 LOC-I fixed‑wing GA aircraft accidents in the United States in 1999–2008 and 2009–2017 using a state-based modeling approach. The multi-year analysis helps discern changes in causation trends over the last two decades. Our analysis highlights LOC-I causes such as pilot actions and mechanical issues that were not discernible in previous research efforts. The logic rules in the state-based approach help infer missing information from the National Transportation Safety Board (NTSB) accident reports. We inferred that 4.84% (1999–2008) and 7.46% (2009–2017) of LOC-I accidents involved a preflight hazardous aircraft condition. We also inferred that 20.11% (1999–2008) and 19.59% (2009–2017) of LOC-I accidents happened because the aircraft hit an object or terrain. By removing redundant coding and identifying when codes are missing, the state-based approach potentially provides a more consistent way of coding accidents compared to the current coding system

A new approach to risk analysis with a focus on organizational risk factors

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005.Includes bibliographical references (p. 235-255).Preventing accidents in complex socio-technical systems requires an approach to risk management that continuously monitors risk and identifies potential areas of concern before they lead to hazards, and constrains hazards before they lead to accidents. This research introduces the concept of continuous participative risk management, in which risks are continuously monitored throughout the lifetime of a system, and members from all levels of the organization are involved both in risk analysis and in risk mitigation. One aspect of effective risk management is accurate risk analysis that takes account of technical, human, and organizational factors. This research develops a new approach to risk analysis that improves on event-based models to include risks that do not depend only on component or subsystem failures, and incorporates both human and organizational factors. The approach enables the early identification of risk mitigation strategies, aids in the allocation of resources to best manage risk, and provides for the continuous monitoring of risk throughout the system lifecycle. Organizational factors have been identified as a significant aspect of accidents in complex socio-technical systems. Properly managing and assessing risk requires an understanding of the impact of organizational factors on risk. Three popular theories of organizational risk, normal accidents theory (NAT), high reliability organizations (HRO), and normalization of deviance, are reviewed. While these approaches do provide some useful insights, they all have significant limitations, particularly as a basis for assessing and managing risk. This research develops the understanding of organizational risk factors by focussing on the dynamics of organizational risk.(cont.) A framework is developed to analyze the strategic trade-offs between short and long-term goals and understand the reasons why organizations tend to migrate to states of increasing risk. The apparent conflict between performance and safety is shown to result from the different time horizons applying to performance and safety. Performance is measured in the short term, while safety is indirectly observed over the long term. Expanding the time horizon attenuates the apparent tension between performance and safety. By increasing awareness of the often implicit trade-offs between safety and performance, organizations can avoid decisions that unwittingly increase risk. In addition to this general dynamic, several specific common patterns of problematic organizational behaviour in accidents in diverse industries are identified. While accidents usually differ in the technical aspects, the organizational behaviour accompanying the accident exhibits commonalities across industries. These patterns of behaviour, or archetypes, can be used to better understand how risk arises and how problematic organizational behaviours might be addressed in diverse settings such as the space industry and chemical manufacturing. NASA specific archetypes are developed based on historical accounts of NASA and investigations into the Challenger and Columbia accidents. The NASA archetypes illustrate several mechanisms by which the manned space program migrated towards high risk.by Karen Marais.Ph.D

SPIR

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.Includes bibliographical references (p. 139-140).by Karen Marias.S.M

Developing 3D Virtual Safety Risk Terrain for UAS Operations in Complex Urban Environments

Unmanned Aerial Systems (UAS), an integral part of the Advanced Air Mobility (AAM) vision, are capable of performing a wide spectrum of tasks in urban environments. The societal integration of UAS is a pivotal challenge, as these systems must operate harmoniously within the constraints imposed by regulations and societal concerns. In complex urban environments, UAS safety has been a perennial obstacle to their large-scale deployment. To mitigate UAS safety risk and facilitate risk-aware UAS operations planning, we propose a novel concept called \textit{3D virtual risk terrain}. This concept converts public risk constraints in an urban environment into 3D exclusion zones that UAS operations should avoid to adequately reduce risk to Entities of Value (EoV). To implement the 3D virtual risk terrain, we develop a conditional probability framework that comprehensively integrates most existing basic models for UAS ground risk. To demonstrate the concept, we build risk terrains on a Chicago downtown model and observe their characteristics under different conditions. We believe that the 3D virtual risk terrain has the potential to become a new routine tool for risk-aware UAS operations planning, urban airspace management, and policy development. The same idea can also be extended to other forms of societal impacts, such as noise, privacy, and perceived risk.Comment: 33 pages, 19 figure

Dynamics of Air Transportation System Transition and Implications for ADS-B Equipage

The U.S. Air Transportation Systems faces substantial challenges in transforming to meet future demand. These challenges need to be understood and addressed in order to successfully meet future system needs. This paper uses a feedback model to describe the general system transition process and identify key issues in the dynamics of system transition, with particular emphasis on stakeholder cost-benefit dynamics and safety approval processes. Finally, in addition to identifying dynamics and barriers to change the paper proposes methods for enabling transition through the use of levers such as incentives, mandates, and infrastructure development. The implementation of ADS-B is studied as a pathfinding technology for planned Air Transportation System changes. The paper states that overcoming stakeholder barriers and ensuring efficient safety approval and certification process are the key enablers to the successful implementation of ADS-B.This work was supported by the FAA under the Joint University Program (JUP) [FAA95-G-017] and the National Center of Excellence for Aviation Operations Research (NEXTOR) [DTFA01-C-00030]

Triple probability density distribution model in the task of aviation risk assessment

The probability of an airplane deviation from pre-planned trajectory is a core of aviation safety analysis. We propose to use a mixture of three probability density distribution functions it the task of aviation risk assessment. Proposed model takes into account the effect of navigation system error, flight technical error, and occurrence of rare events. Univariate Generalized Error Distribution is used as a basic component of distribution functions, that configures the error distribution model from the normal error distribution to double exponential distribution function. Statistical fitting of training sample by proposed Triple Univariate Generalized Error Distribution (TUGED) is supported by Maximum Likelihood Method. Optimal set of parameters is estimated by sequential approximation method with defined level of accuracy. The developed density model has been used in risk assessment of airplane lateral deviation from runway centreline during take-off and landing phases of flight. The efficiency of the developed model is approved by Chi-square, Akaike’s, and Bayes information criteria. The results of TUGED fitting indicate better performance in comparison with double probability density distribution model. The risk of airplane veering off the runway is considered as the probability of a rare event occurrence and is estimated as an area under the TUGED

Unlocking and securing ecological infrastructure investments : the needs and willingness to invest and institutional support mechanisms used

CITATION: Mbopha, M.S. et al. 2021. Unlocking and securing ecological infrastructure investments: The needs and willingness to invest and institutional support mechanisms used. South African Journal of Science, 117(9/10)#8666:1-9. https://doi.org/10.17159/sajs.2021/8666.The original publication is available at https://www.sajs.co.za/Ecological infrastructure (EI) is a natural and near-natural functioning ecosystem that delivers a range of essential services to humankind. Examples include mountain catchments, wetlands, coastal dunes, and riparian corridors. In a world where EI is underinvested, rapid degradation and threats such as unsustainable veld-fire regimes, droughts, climate change, and invasive alien plants persist in dominating the ecological landscape. In South Africa, there are government programmes that encourage the restoration, rehabilitation and protection of EI. However, inadequate funding allocations constrain scalingup and thus necessitate the unlocking of public and private sector investments to augment resources for ecosystem-based management interventions. A systematic literature review was conducted at a global scale to (1) understand the drivers behind EI investments, (2) understand the willingness and desire of private landowners and land users to participate and contribute to EI investments and (3) identify institutional support mechanisms used to encourage investments. Results suggest that the need to invest is driven by growing degradation of EI and the urgency to meet environmental sustainability goals. The willingness to invest is stimulated by the use of economic-based policies and compensatory mechanisms. Public–private partnerships, public policy, and market-based conservation instruments are institutional arrangements executed to protect EI. These include processes and systems used by the institutions to legislate and manage interventions towards fulfilling the conservation objective. Our review contributes to the EI investment research agenda by recommending coordinated efforts to encourage EI investment from both public and private partners. These measures will help to secure financial resources and mobilise investments beyond monetary terms by coordinating planning and developing capacity and reform policies.https://sajs.co.za/article/view/8666Publishers versio