Lidija Tomić, Olja Čokorilo, Ljubiša Vasov and Branimir Stojiljković
The paper aims to investigate the compatibility of manned-aircraft airborne collision avoidance systems (ACAS) for use on unmanned aerial vehicles (UAV).
Abstract
Purpose
The paper aims to investigate the compatibility of manned-aircraft airborne collision avoidance systems (ACAS) for use on unmanned aerial vehicles (UAV).
Design/methodology/approach
The paper uses the Fault Tree method for defining ACAS model adapted for the UAV operations, with the aim of showing the presence of certain factors that configure in such ACAS system, and whose failure can lead to an adverse event – mid-air collision.
Findings
Based on the effectiveness analysis of ACAS solution adapted for the UAV operations, for given inputs, it can be concluded that the probability of ACAS failure is on the order of 10–4, as well as that in the case of autonomous ACAS solution for the UAV, the probability is reduced to 10–5. The most influential factors for the failure of the UAV’s ACAS are as follows: technical implications on the UAV, human factor, sensor error, communication and C2 link issue.
Practical implications
The established model could be used both in the UAV’s ACAS design and application phases, with the aim of assessing the effectiveness of the adopted solution. The model outputs not only highlight the critical points of the system but also provide the basis for defining the Target Level of Safety (TLOS) for the UAV operations.
Originality/value
The developed model can be expected to speed up the design and adoption process of ACAS solutions for the UAVs. Also, the paper presents one of the first attempts to quantify TLOS for the UAV operations in the context of collision avoidance systems.
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Milica Milovanović, Olja Čokorilo, Ivan Ivković, Branimir Stojiljković and Ljubiša Vasov
Accidents occur in all transport modes and can cause significant material damage and loss of life. To efficiently allocate resources that enable the reduction of accidents, it is…
Abstract
Purpose
Accidents occur in all transport modes and can cause significant material damage and loss of life. To efficiently allocate resources that enable the reduction of accidents, it is necessary to estimate the value of a statistical life (VSL). This study aims to show how the statistical value of human life in air and road traffic is determined.
Design/methodology/approach
This study examines and applies recent empirical evidence aimed at clarifying the basic concept of the VSL and defining the reasons for its importance in evaluating public policies in aviation safety and road traffic safety. The research focuses on the principal equity indicators, both theoretical and empirical, that must be confronted to provide a credible estimate of the VSL.
Findings
Previous research shows that the VSL could have a considerable range of possible values. This study emphasizes that risk reduction funds need to be distributed in a consistent and equitable manner to achieve the best outcomes for society as a whole.
Practical implications
This research will guide future research efforts towards understanding the impact of the estimated statistical life value on air and road safety implications.
Social implications
This study strengthens awareness of the importance of the VSL in evaluating public policies in the field of aviation and road safety.
Originality/value
To the best of the authors’ knowledge, this study is one of the first to compare air and road traffic from the perspective of the VSL evaluation.
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Aleksandar Knezevic, Ljubisa Vasov, Slavisa Vlacic and Cedomir Kostic
The purpose of this paper is to define conditions under which improved availability of fleet of G-4 jet trainers is obtained, and optimization of intermediate-level maintenance…
Abstract
Purpose
The purpose of this paper is to define conditions under which improved availability of fleet of G-4 jet trainers is obtained, and optimization of intermediate-level maintenance through imperfect maintenance model application. This research has been conducted based on available knowledge, and experience gained by performing intermediate-level maintenance of Serbian Air Force aircrafts.
Design/methodology/approach
Analysis of the data collected from daily maintenance reports, and the analysis of maintenance technology and organization, was performed. Based on research results, a reliability study was performed. Implementation of imperfect maintenance with its models of maintenance policies (especially a quasi-renewal process and its treating of reliability and optimal maintenance) was proposed to define new maintenance parameters so that the greater level of availability could be achieved.
Findings
The proposed methodology can potentially be applied as a simple tool to estimate the present maintenance parameters and to quickly point out some deficiencies in the analyzed maintenance organization. Validation of this process was done by conducting a reliability case study of G-4 jet trainer fleet, and numerical computations of optimal maintenance policy.
Research limitations/implications
The methodology of the availability estimation when reliability parameters were not tracked by the maintenance organization, and optimization of intermediate-level maintenance, has so far been applied on G-4 jet trainers. Moreover, it can be potentially applied to other aircraft types.
Originality/value
Availability estimation and proposed optimization of intermediate maintenance is based on a survey of data for three years of aircraft fleet maintenance. It enables greater operational readiness (due to a military rationale) with possible cost reduction as a consequence but not as a goal.
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Branimir Stojiljković, Ljubiša Vasov, Olja Čokorilo and Goran Vorotović
The purpose of this paper is to present novel recursive expressions for modelling the replacement costs of aircraft engine life-limited parts during shop visits to assist engine…
Abstract
Purpose
The purpose of this paper is to present novel recursive expressions for modelling the replacement costs of aircraft engine life-limited parts during shop visits to assist engine operators in both evaluating their decisions regarding the applied life-limited parts management strategies and tracking the replacement costs consistently throughout the life of the engine.
Design/methodology/approach
The replacement costs of aircraft engine life-limited parts are modelled analytically in this research, which strives to quantify the costs of used and unused lives of the replaced parts, incurred during engine shop visit events. Inputs for this model include the list price of life-limited parts, the replacement decisions made on all previous shop visits and the number of cycles the engine has operated at different thrust ratings on all previous operating intervals.
Findings
The average annual escalation rate of life-limited parts list prices was shown to range from 5% to 7%. The presented model is not only suitable for calculating the costs of used and unused lives of life-limited parts during past engine shop visit events but also for application in the life-limited parts replacement cost forecasting and optimisation models.
Originality/value
Uniquely derived recursive expressions represent the final result of the developed model which, to the authors’ knowledge, had not been studied elsewhere in the academic literature. The analysis of aircraft engine life-limited part list prices carried out to account for the average annual escalation rate enables the prediction of replacement costs during subsequent shop visits.