Adaptive Stress Testing of Airborne Collision Avoidance Systems

This paper presents a scalable method to efficiently search for the most likely state trajectory leading to an event given only a simulator of a system. Our approach uses a reinforcement learning formulation and solves it using Monte Carlo Tree Search (MCTS). The approach places very few requirements on the underlying system, requiring only that the simulator provide some basic controls, the ability to evaluate certain conditions, and a mechanism to control the stochasticity in the system. Access to the system state is not required, allowing the method to support systems with hidden state. The method is applied to stress test a prototype aircraft collision avoidance system to identify trajectories that are likely to lead to near mid-air collisions. We present results for both single and multi-threat encounters and discuss their relevance. Compared with direct Monte Carlo search, this MCTS method performs significantly better both in finding events and in maximizing their likelihood

Analyzing aviation safety: problems, challenges, opportunities

a b s t r a c t This paper reviews the economic literature relating to aviation safety; analyzes the safety record of commercial passenger aviation in the United States and abroad; examines aviation security as a growing dimension of aviation safety; and identifies emerging issues in airline safety and challenges for aviation safety research. Commercial airline safety has improved dramatically since the industry's birth over a century ago. Fatal accident rates for large scheduled jet airlines have fallen to the level where (along many dimensions) aviation is now the safest mode of commercial transportation. However, safety performance has not been evenly distributed across all segments of commercial aviation, nor among all countries and regions of the world. The finding that developing countries have much poorer safety records has been a persistent conclusion in aviation safety research and continues to be the case. Unfortunately, operations data are not available for many of the airlines that experience fatal accidents, so it is not possible to calculate reliable fatality rates for many segments of the worldwide aviation industry. Without more complete information, it will likely be difficult to make substantial improvements in the safety of these operations. Challenges to improving aviation security include: how much to focus on identifying the terrorists as opposed to identifying the tools they might use; determining how to respond to terrorist threats; and determining the public versus private roles in providing aviation security. The next generation of safety challenges now require development and understanding of new forms of data to improve safety in other segments of commercial aviation, and moving from a reactive, incident-based approach toward a more proactive, predictive and systems-based approach

Computational Mechanics for Aircraft Water Entry and Wind Energy

In this thesis, two problems in computational mechanics, namely aircraft water entry and wind energy, have been studied together with description of related theory and methodology. Fluid calculations are carried out with proper schemes and computational techniques, including the use of dynamic mesh with OpenFOAM as the platform. Subsequent analysis of the data provides valuable information for these real world problems. First, algorithms and numerical methods to solve the equations related to the problems are proposed. Model problems are solved to test these methods. Then, in the aircraft water entry problem, the complex and dynamic process of aircraft water entry problem is simulated under several cases. External loading data has been analyzed to estimate the severity of structural damage. The main finding is that the vertical diving case is actually a reasonable theory regarding the final moments of flight MH370 given the currently available information. In the wind energy problem, blade resolved simulations of wind turbines are carried out. The proper orthogonal decomposition analysis is shown to be capable of extracting dominant features of the turbulent flow. Interaction between wind generators are studied to find out that contra-rotating turbines can better capture energy in the wind. It has been demonstrated that the computational approach is advantageous in saving long and expensive processes of laboratory setup and measurements, while providing valuable information to the subject problem

Civil aviation safety in Indonesia

The aim of the research described in this thesis is to identify factors that contribute to incidents/accident in the Indonesian civil aviation industry. Three studies were undertaken. The first study comprised of an analysis of 97 official accident investigation reports, and was aimed at capturing the nature of the incidents/accidents. The key results are that Indonesia suffers a relatively high accident rate, with the most prevalent accident types being non-fatal Runways Excursions of jet aircraft at main airports, and Controlled Flight Into Terrain accidents in the highlands, these often being fatal. The second study implemented and analysed the results of a survey of 205 professional pilots currently flying in Indonesia, who have four different flight training backgrounds, being expatriate pilots flying for the Indonesian industry, Indonesian commercial pilots, Indonesian ex-military pilots and Australian pilots. The three pilot survey constructs (cockpit management attitude questionnaire/CMAQ, power distance index/PDI and approach and landing attitudes/ALA) are analysed to compare the four groups of pilots, and it is found that Indonesian national pilots from commercial and military backgrounds have a more cavalier and less consistent approach to safety than expatriate and Australian pilots. The last study comprised an analysis of interviews with 27 senior managers of the Indonesian aviation industry, including managers from regulatory bodies, air operators, training schools, the national transportation safety committee/NTSC and the national aviation weather agency. The manager surveys confirm that a substandard safety culture is believed to exist at all levels of management and agency, as well as in airline operations and training. The three following methods: descriptive, analysis of variance (ANOVA) and thematic analysis are applied for each of the study. To triangulate and discuss the core results of the studies, the Human Factors Analysis and Classification System (HFACS) conceptual model is applied, and the Indonesian system is found to have safety deficiencies at all levels including Organisational Influences, Unsafe Supervision, Preconditions of Unsafe Acts and Unsafe Acts. The combination of bad weather and relatively poor pilot training and operation appears to be prevalent

Safety culture: a legal standard for commercial aviation.

Although a link between organisational safety culture and human behaviour is well established within academic literature, ambiguity about the actual nature of the causal relationship has inhibited its practical application. This thesis aims to establish a legal standard of safety culture by producing a model which describes the relationship between organisational safety culture and potential corporate liability. The model, called d3SC, attempts to promote a defence of due diligence to potential prosecution by improving an organisation’s safety culture. The thesis consists of three sequential studies. The first study comprises of twenty-six accident case studies from which data is developed into a prototype model through a process of grounded theory. The subsequent studies then take the emergent model from a construct to a risk management tool that was applied and tested against a real-world data from commercial aviation and law. In attempting to develop a model, d3SC, the thesis has adopted a predominantly functionalist approach. However, it is recognised that the complexities of culture and causation are not sufficiently represented without adopting some methods of real world analysis. This recognition of the need to dig deeper into organisational dynamics is manifest in the use of qualitative methods in the thesis to triangulate the output of the d3SC process. It is also represented in the units of measurement or case studies from which safety culture is frequently described. The quality of safety culture is often described in terms of organisational performance yet a consistent theme in both the literature and the data collated in these studies, shows that aggregating organisational safety culture as a singular measurement can be misleading. Contrasting the data from different departments and hierarchical levels within an organisation gives a much deeper and contextual understanding of internal dynamics and influences. This is of particular relevance to corporate liability in the aftermath of an accident. Prosecuting agencies will not focus their investigation on the adequacy of overall metrics of organisational assessments, but on the perceived causal links between an accident and the weaker areas of organisational safety culture. By improving the visibility and understanding of the causal links between corporate liability and corporate culture it is hoped that this research can contribute to enhancing safety standards in commercial aviation.PhD in Transpor