TY  - JOUR
AU  - Stojiljković, Branimir
AU  - Vasov, Ljubiša
AU  - Cokorilo, Olja
AU  - Vorotović, Goran
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3505
AB  - 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.
PB  - Emerald Group Publishing Ltd, Bingley
T2  - Aircraft Engineering and Aerospace Technology
T1  - An analytical model of the replacement costs of aircraft engine life-limited parts
EP  - 782
IS  - 5
SP  - 776
VL  - 93
DO  - 10.1108/AEAT-12-2020-0297
ER  - 

@article{
author = "Stojiljković, Branimir and Vasov, Ljubiša and Cokorilo, Olja and Vorotović, Goran",
year = "2021",
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.",
publisher = "Emerald Group Publishing Ltd, Bingley",
journal = "Aircraft Engineering and Aerospace Technology",
title = "An analytical model of the replacement costs of aircraft engine life-limited parts",
pages = "782-776",
number = "5",
volume = "93",
doi = "10.1108/AEAT-12-2020-0297"
}

Stojiljković, B., Vasov, L., Cokorilo, O.,& Vorotović, G.. (2021). An analytical model of the replacement costs of aircraft engine life-limited parts. in Aircraft Engineering and Aerospace Technology
Emerald Group Publishing Ltd, Bingley., 93(5), 776-782.
https://doi.org/10.1108/AEAT-12-2020-0297

Stojiljković B, Vasov L, Cokorilo O, Vorotović G. An analytical model of the replacement costs of aircraft engine life-limited parts. in Aircraft Engineering and Aerospace Technology. 2021;93(5):776-782.
doi:10.1108/AEAT-12-2020-0297 .

Stojiljković, Branimir, Vasov, Ljubiša, Cokorilo, Olja, Vorotović, Goran, "An analytical model of the replacement costs of aircraft engine life-limited parts" in Aircraft Engineering and Aerospace Technology, 93, no. 5 (2021):776-782,
https://doi.org/10.1108/AEAT-12-2020-0297 . .

TY  - JOUR
AU  - Stojiljković, Branimir
AU  - Vasov, Ljubiša
AU  - Mitrović, Časlav
AU  - Cvetković, Dragan
PY  - 2009
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/875
AB  - This paper presents an application of the root locus technique for the design of a feedback control system of an F-104A aircraft. The analysis of the longitudinal aircraft stability was performed for the jingle Input Single Output (SISO) open-loop system, using linearised equations of aircraft motion and aerodynamic derivatives of an F-104A aircraft taken from the NASA report [1]. The dynamical behavior of the open-loop system was unsatisfactory and led to the introduction of the feedback control system. The closed-loop system was designed using the root locus technique, developed by Evans in 1948. The transfer function parameters of each element of the feedback control system are determined according to previously set design requirements. Although, the analysis of the closed-loop step response showed that all of the design requirements were realised, the controller designed within the proposed control system structure is not the only one, and there are different controller designs that lead to a satisfactory solution.
T2  - Strojniski Vestnik/Journal of Mechanical Engineering
T1  - The Application of the Root Locus Method for the Design of Pitch Controller of an F-104A Aircraft
EP  - 560
IS  - 9
SP  - 555
VL  - 55
UR  - https://hdl.handle.net/21.15107/rcub_machinery_875
ER  - 

@article{
author = "Stojiljković, Branimir and Vasov, Ljubiša and Mitrović, Časlav and Cvetković, Dragan",
year = "2009",
abstract = "This paper presents an application of the root locus technique for the design of a feedback control system of an F-104A aircraft. The analysis of the longitudinal aircraft stability was performed for the jingle Input Single Output (SISO) open-loop system, using linearised equations of aircraft motion and aerodynamic derivatives of an F-104A aircraft taken from the NASA report [1]. The dynamical behavior of the open-loop system was unsatisfactory and led to the introduction of the feedback control system. The closed-loop system was designed using the root locus technique, developed by Evans in 1948. The transfer function parameters of each element of the feedback control system are determined according to previously set design requirements. Although, the analysis of the closed-loop step response showed that all of the design requirements were realised, the controller designed within the proposed control system structure is not the only one, and there are different controller designs that lead to a satisfactory solution.",
journal = "Strojniski Vestnik/Journal of Mechanical Engineering",
title = "The Application of the Root Locus Method for the Design of Pitch Controller of an F-104A Aircraft",
pages = "560-555",
number = "9",
volume = "55",
url = "https://hdl.handle.net/21.15107/rcub_machinery_875"
}

Stojiljković, B., Vasov, L., Mitrović, Č.,& Cvetković, D.. (2009). The Application of the Root Locus Method for the Design of Pitch Controller of an F-104A Aircraft. in Strojniski Vestnik/Journal of Mechanical Engineering, 55(9), 555-560.
https://hdl.handle.net/21.15107/rcub_machinery_875

Stojiljković B, Vasov L, Mitrović Č, Cvetković D. The Application of the Root Locus Method for the Design of Pitch Controller of an F-104A Aircraft. in Strojniski Vestnik/Journal of Mechanical Engineering. 2009;55(9):555-560.
https://hdl.handle.net/21.15107/rcub_machinery_875 .

Stojiljković, Branimir, Vasov, Ljubiša, Mitrović, Časlav, Cvetković, Dragan, "The Application of the Root Locus Method for the Design of Pitch Controller of an F-104A Aircraft" in Strojniski Vestnik/Journal of Mechanical Engineering, 55, no. 9 (2009):555-560,
https://hdl.handle.net/21.15107/rcub_machinery_875 .