An Agent-based Approach for Structured Modeling, Analysis and Improvement of Safety Culture

Safety culture is broadly recognized as important for operational safety in various fields, including air traffic management, power plant control and health care. Previous studies addressed characterization and assessment of safety culture extensively. Nevertheless, relations between safety culture and formal and informal organizational structures and processes are yet not well understood. To address this gap, a new, formal, agent-based approach is proposed. This paper shows the application of the approach to an air navigation service provider, including structured modeling, analysis and identification of improvement strategies for the organizational safety culture. The model results have been validated using safety culture data that had been achieved by an independent safety culture survey study. © 2011 The Author(s)

QUANTITATIVE SAFETY ASSESSMENT OF AIR TRAFFIC CONTROL SYSTEMS THROUGH SYSTEM CONTROL CAPACITY

Quantitative Safety Assessments (QSA) are essential to safety benefit verification and regulations of developmental changes in safety critical systems like the Air Traffic Control (ATC) systems. Effectiveness of the assessments is particularly desirable today in the safe implementations of revolutionary ATC overhauls like NextGen and SESAR. QSA of ATC systems are however challenged by system complexity and lack of accident data

Safety Return on Investment (ROI): The Broader Adoption of Rotorcraft CFIT-Avoidance Technology

This dissertation provided a method of estimating the potential return on investment (ROI) that could be achieved if operators were to adopt the readily available controlled flight into terrain (CFIT) avoidance technology more broadly. Previous research explored the costs and benefits of different safety initiatives but did not evaluate from an operators’ perspective. For the operators, a private ROI that excludes societal costs and benefits was therefore considered the suitable metric. For the rotorcraft industry, the ROI estimation methodology was not readily available, and this study sought to fill that gap. The purpose of this study was to estimate the potential ROI by determining the costs associated with the outcomes of CFIT-accidents, the costs of adopting the technology, the current accident rate, the benefits expressed as costs avoided through a reduction in the number of accidents, and application of the appropriate ROI formula. The dissertation was conducted as a mixed method study that used qualitative data from historical CFIT-related accident reports to identify the accident outcomes and estimate the associated accident costs plus the available quantitative data to estimate the CFIT-avoidance technology adoption costs. The accident cost categories were based on categories used in airline research and modified for the rotorcraft industry. Using the formula, ROI = Net benefits divided by safety technology adoption costs, ROI values were generated in multiple iterations of the Monte Carlo simulation. The net benefits were evaluated as the difference between the potential accident costs avoided with a reduction in CFIT accidents and the technology adoption costs. The simulation results for the three rotorcraft categories showed that the turbinesingle would experience the highest ROI, followed by the piston category and the twinturbines. When all rotorcraft categories were considered, the ROI was positive but could turn negative if the technology adoption costs grew by a factor of more than three. The broad range in the ROI values for both the piston and single-turbine categories were largely driven by the high variation of the individual cost categories, especially the direct costs: occupant death and injuries, aircraft damage, and leasing costs. From the results of the study, it was recommended that CFIT-avoidance technology should be more broadly adopted by piston and single-turbine rotorcraft operators. For twin-turbines, the adoption should be evaluated against the impact of the regulatory changes for helicopter air ambulance (HAA) operations, which may reduce the number of accidents and generate a positive ROI before further action from operators. Future research should focus on validating the methodology by using it as a starting point for evaluating the ROI for safety initiatives that have already been implemented, whether technology or operational programs. The industry should also improve the methodology by defining or proposing better processes for estimating rotorcraft accident costs, especially indirect costs estimated to be the of the same magnitude as the direct costs. The rotorcraft industry should find ways to make costs data, such as accident investigation costs, more accessible in order to apply the ROI estimation methodology to achieve more accurate results

Lennonsuunnitteluun liittyvän turvallisuusriskin mallinnus suoritusarvoluokkaan B kuuluvien lentokoneiden kaupallisessa operoinnissa

In recent years, more stringent aviation regulations have demanded commercial air operators to put more emphasis on quantitative risk analysis methods as part of their safety management systems. The objective has been to promote aviation safety by identifying the risk factors applicable to the operations and mitigating their effectivity based on the risk analysis results. In particularly, the importance of proper flight preparation has been underlined by European Aviation Safety Agency for the commercial operation of single-engined turbine aeroplanes in instrumental weather conditions and at night. Yet, there are still not many comprehensive analysis methods, which would examine a flight as an entirety. The aim of this thesis was to make a research about different risk analysis methods and find suitable means to develop new kind of risk models for the case examples, which were aerodrome and landing site determination and flight planning. Under particular interest were the questions of how much risk can vary between aeroplane types and in which extent is the overall risk mitigatable. The risk models are also supposed to be a basis for a risk tool that operators could utilise in their actual flight planning processes in the future. This risk tool would primarily be applicable to the operators of single-engined turbine aeroplanes but it is utilisable for other performance class B aeroplanes as well. As an outcome, a novel weighted fuzzy hierarchy method was developed based on previous research. It calculates an individual risk level for each aerodrome and landing site along the route and an overall risk level for the entire planned flight. As a base, it uses risk models, which are hierarchical structures of each case example’s applicable risk factors. An individual weight and set of membership functions were established for each risk factor in order to receive rational results. The weights and the membership functions were defined using the combination of expert judgement and statistics. Various example calculations showed that there are distinct variations in the risk levels of different kinds of operations. From the risk mitigation perspective, it was also noticed that the flight crew related risk factors have the most significant effect to the risk level. The method proved to be a usable and convenient tool to assess risk objectively and therefore further development and validation of this risk analysis method is recommended.Yhä tiukemmat ilmailuvaatimukset ovat viime vuosina vaatineet kaupallisia lento-operaattoreja panostamaan enemmän määrällisiin riskianalyysimenetelmiin osana heidän turvallisuudenhallintajärjestelmiään. Tarkoituksena on ollut ilmailun turvallisuuden parantaminen tunnistamalla operaatioihin liittyvät riskitekijät ja pienentämällä niiden vaikutusta riskianalyysin tuloksien perusteella. Euroopan ilmailuturvallisuusvirasto on painottanut riittävän lennonvalmistelun tärkeyttä erityisesti yksimoottoristen potkuriturbiinilentokoneiden kaupallisessa operoinnissa mittarilentokelillä ja yöaikaan. Silti ei ole olemassa montaa riskianalyysimenetelmää, joka ottaisi huomioon lentoa kokonaisuutena. Tämän diplomityön tavoitteena on tutkia erilaisia riskianalyysimenetelmiä ja löytää sopivat keinot kehittämään uudenlaiset riskimallit esimerkkitapauksille, jotka ovat lentokentän ja varalaskupaikan määrittäminen ja lennonsuunnittelu. Erityisenä mielenkiinnonkohteena ovat kysymykset, kuinka paljon riski voi vaihdella riippuen lentokonetyypistä ja missä määrin kokonaisriski on pienennettävissä. Riskimallien on tarkoitus myös toimia perustana riskityökalulle, jota operaattorit voisivat tulevaisuudessa käyttää todellisissa lennonsuunnitteluprosesseissaan. Tämä riskityökalu olisi pääasiassa tarkoitettu yksimoottoristen potkuriturbiinilentokoneiden operaattoreille, mutta se on sovellettavissa myös muihin suoritusarvoluokkaan B kuuluviin lentokoneisiin. Aiemman tutkimuksen pohjalta kehitettiin uudenlainen, sumeaa logiikkaa ja painokertoimia hyödyntävä hierarkkinen menetelmä. Se laskee yksilöllisen riskitason reitin varrella oleville kullekin lentokentälle ja varalaskupaikalle ja kokonaisriskitason koko lennolle. Pohjana se käyttää riskimalleja, jotka ovat hierarkkisia rakenteita esimerkkitapausten riskitekijöistä. Yksilöllinen painokerroin ja sarja jäsenfunktioita määritettiin kullekin riskitekijälle, jotta saataisiin rationaalisia tuloksia. Painokertoimet ja jäsenfunktiot määriteltiin sekä asiantuntija-arvioiden että tilastojen avulla. Useat esimerkkilaskelmat osoittivat, että erilaisilla operaatioilla on selviä eroja riskitasoissa. Riskin pienentämisen näkökulmasta huomattiin myös, että lentomiehistöön liittyvillä riskitekijöillä on kaikkien suurin vaikutus riskitasoon. Menetelmä osoittautui käyttökelpoiseksi ja sopivaksi menetelmäksi riskin arvioimiseen objektiivisesti ja tämän johdosta tämän riskianalyysimenetelmän jatkokehittämistä ja validointia suositellaan