Olja Čokorilo

Aircraft safety analysis using clustering algorithms

In recent years, there have been many cost-benefit studies on aviation safety, which deal mainly with economic issues, omitting some strictly technical aspects. This study compares aircraft accidents in relation to the characteristics of the aircraft, environmental conditions, route, and traffic type. The study was conducted using a database of over 1500 aircraft accidents worldwide, occurring between 1985 and 2010. The data were processed and then aggregated into groups, using cluster analysis based on an algorithm of partition binary ‘Hard c means.’ For each cluster, the ‘cluster representative’ accident was identified as the average of all the different characteristics of the accident. Moreover, a ‘hazard index’ was defined for each cluster (according to annual movements); using this index, it was possible to establish the dangerousness of each ‘cluster’ in terms of aviation accidents. Obtained results allowed the construction of an easy-to-use predictive model for accidents using multivariate analysis.

Managing safety risks in helicopter maritime operations

Nowadays, helicopters have been used in maritime transportation to serve offshore platforms. This paper outlines methodology for assessing safety risks by operating in the vicinity of helidecks. During each flight, decisions must be made regarding the events that involve interactions between the four safety risk elements – the pilot in command, the aircraft, the environment and the operation. This paper evaluates helicopter crash statistics based on region and flight phase. Data collected were used for developing methodology for computing the helicopter impact frequency into facility of interest. The analysis for helicopter impact frequency calculations is based on number of operations, crash rate, frequency, average length of flight and crash area. Furthermore, the conclusion was defined based on future measurements for helicopter accidents mitigation or reduction. The presented paper contributes to safety risk assessment in helicopter maritime operations.

A model of air traffic assignment as part of airport air pollution management system

Abstract The critical concern of modern airports is the air pollution generated by air traffic and its impact on the airport environment. Air pollution is an unavoidable consequence of air traffic, but it can be reduced in numerous ways, including technical innovations in aircraft design and legislation. This paper presents a model of air traffic assignment as a measure to mitigate the concentration of air traffic pollution. The air traffic assignment model was developed specifically for Nikola Tesla Airport but could easily be applied to other airports. The model is based on the categorisation of aircraft according to engine type and the assignment of specific runways for take-off and landing for each aircraft category. It incorporates two basic goals: to increase airport capacity and to reduce the pollution level in the area around the airport. Although these goals are contradictory, it has been shown in the case of Nikola Tesla Airport that the proposed air traffic assignment model successfully creates...

The turbo fan aircraft minimum cost climb technique

Purpose – The purpose of this paper is to define minimum cost technique of turbo fan transport aircraft in the presence of dynamic change of aircraft performance. Results can be practical applicable in airlines for achieving minimal operation costs.Design/methodology/approach – Logarithmic differential is applied for defining conditions in order to achieve optimal Mach number for minimal climb cost. This condition is solved numerically by using Newton‐Ramphson method, to obtain optimal Mach number distribution with altitude. Conclusion about optimal top of climb (TOC) is defined after analyses for different aircraft mass and cost indexes.Findings – Proposed method of minimum cost climb resulting in potential savings up to 5 per cent compared to Aircraft Flight Manual climb law. Proposed method also made correction of climb law and optimal TOC under existence of aircraft performance degradation.Practical implications – Use of defined climb law and optimal TOC will minimize cost of en route flight profile.O...

The estimation of GHG emission costs in road and air transport sector: Case study of Serbia

AbstractThe paper gives special attention on long distance passenger transport and specific emissions related to different transport modes, particularly road and air transport sector. The goal of this research is creation and selection of appropriate methodology for modelling the cost estimation of GHG emissions in road and air transport sector for Republic of Serbia as well as the application of the methodology regarding to detailed calculation by transport mode and sub modes. Input data for road transport sector refer to the 2013 and include road and traffic conditions on the road network. Input data for air transport sector are related to the 2014 and international airport ‘Nikola Tesla’ Belgrade as the main hub point with the highest recorded number of aircraft operations in the Western Balkan countries. The obtained results reveal that, due to realized transport volume, diesel cars have the largest share of the costs of GreenHouse Gas (GHG) emissions within the passenger long distance road transport....

Human factor modelling for fast‐time simulations in aviation

Purpose – The paper aims to present the findings of a research project “Human Factors in ‘Fast‐Time’ Simulation” which was supported by Central European Air Traffic Services – CEATS Research, Development and Simulation Centre (CRDS) EUROCONTROL.Design/methodology/approach – With the aim of improving fast‐time simulations by developing new models related to the air traffic controllers decisions, a simple traffic situation was chosen. It is focused on a pair of aircraft where one aircraft is cruising while the second is requesting clearance for climbing to the same flight level and proceeding flight “in‐trail” whereby flight level is not occupied with other traffic.Findings – In order to determine parameters important to the controllers while making a decision, pilot inquiry was realized in the EUROCONTROL CRDS. The results obtained were used for determining the content and form of the final interview. The model based on the final interview results is designed on the “black box” principle – for certain inp...

The contribution of optimal turbo fan transport aircraft climb schedule to air company economy

Abstract Today airlines are challenging two opposite goals: minimization of flight fuel consumption and minimization of elapsed flight time. A well‐known cost structure and cost generators represent significant pre‐conditions for defining cost optimization strategy in an airline company. Airline company management has a limited set of tools for cost managing, which include the following documents: Performance Engineers’ Manual and Aircraft Flight Manual. In this particular paper review we discuss the problem of vertical flight path of turbo‐fan aircraft, where we point out the impact of the choice of climb technique on the overall en route flight profile costs. In temporary aircraft flight preparation process, there is no stressing out the significance of the climb phase in minimizing costs of this particular flight phase. In the paper we show the procedure of defining optimal climbing resulting minimum costs, but also optimal function operational adjustment to the climb schedule. This way of the approxim...

Bird strikes on an aircraft and bird strike prevention

According to the world accident statistics, air transport is the safest transportation mode, but accidents still could occur. The causes which have brought to the aircraft accident are different, for example, runway excursions, mechanical and structural failures, pilot errors, poor weather conditions, etc. Nowadays, special attention has been given to the accidents caused by bird strikes, although the majority of reported occurrences have minor influence on safe flight realization; a small number of cases which include strikes with large bird flocks, record significant aircraft or engine damage that caused cancel operation. This situation could provide serious damage due to difficult prediction and serious consequences which vary from minor damage to the failure of all engines. The paper gives special emphasis on prevention and contemporary measures for bird strikes mitigation tools development.