A Simulation Model for Military Aircraft Maintenance and Availability

1. A Simulation Model for Military Aircraft Maintenance and Availability Tuomas Raivio, Eemeli Kuumola,Ville A. Mattila, Kai Virtanen and Raimo P. Hämäläinen Systems Analysis Laboratory Helsinki University of Technology

2. Outline • Aim of the study • Aircraft fleet operations • Simulation model description • Model validation, results • Concluding remarks

3. Aim of The Study • Development of a simulation model for a fleet of military aircraft • Here Bae Hawk Mk51 jet trainer • Normal peacetime use • Training & patrol flights • Maintenance • Failure repair • Performance measures • Flight and maintenance policy planning • Determine the accuracy needed in modelling such a system

4. Flight operations Maintenance Operations Operations of The Fleet • Complex and dynamic logistic system • Need to understand functioning of the system as a whole

5. Maintenance and Repair Organization

6. The Simulation Model • Discrete event simulation approach • The model describes • The structure and interaction of the maintenance, repair and flight processes • The maintenance capacity in terms of manpower • Outputs from the model • Performance measures (e.g. aircraft availability) • Availability = #operatingAC / total #AC

7. Structure of The Model

8. Modeling Assumptions • Three airbases are aggregated into one airbase • Model describes average operations • Maintenance operations are modeled in terms of maintenance duration and manpower capacity • Other maintenance resources are assumed to be available all the time

9. Input Parameters • Most significant parameters • Maintenance durations and maintenance intervals • Failure repair durations and failure intensities • Maintenance manpower capacities • Flight mission durations and intensities • Reference data collected by the FAF from several airbases • Point estimates and variances, or distributions estimated • Scaling to represent the aggregated base

10. Implementation • ARENA simulation software • SIMAN based simulation engine • Easy-to-use graphical interface • Animation for easy demonstrating • Possibility to create standalone models for nonexpert users

11. Screenshot from Arena

12. Model Validation • Model structure is evaluated together with the maintenance and logistics staff of the FAF • Quantitative validation: • Aircraft availability • Simulated average availability slightly larger than reference value • Maintenance throughput times • Simulated throughput times are0-30% shorter than reference values

13. Simulated Daily Availability

14. Example Analysis

15. Conclusions • ARENA based implementation • Easy what-if scenarios • Illustrative animation capabilities • Stand-alone applications for e.g. maintenance staff training • Rapid estimates for relative effect on system performance in case of • Major changes in maintenance capacity, flight intensity etc. • Aircraft modification programs • Future modelling efforts • Insight to sensitive parts of the system • Easily upgradable platform