A Simulation Model for Aircraft Maintenance in an Uncertain Operational Environment

1
A Simulation Model for Aircraft Maintenance in an
Uncertain Operational Environment

• Ville Mattila, Kai Virtanen and Tuomas Raivio
• Systems Analysis Laboratory
• Helsinki University of Technology

2
Objective

• Modeling and simulation of flight and maintenance
  operations of the aircraft fleet of the Finnish
  Air Force (FiAF)
• Prediction of supportability requirements and
  fleet performance
• Effect of operating conditions
• Effect of operating policies and supposed system
  improvements
• Special interest in conflict operations
• Uncertainty involved in the operational
  environment

3
Development
Early considerations in FiAF, static failure
models
Initiative for simulation of aircraft
maintenance, joint project between FiAF
and Systems analysis laboratory
Discrete-event simulation as approach, Arena
software as tool
Simulation model of one airbase
Model with multiple airbases, normal and conflict
operations
A simulation tool for FiAF
Introduction in FiAF
Simulation of helicopter maintenance
Scheduling of aircraft maintenance
2000
2004
4
Discrete-event simulation

• Widely applied in analyzing logistic systems
• Conceptually simple approach
• Intuitive consideration of uncertainty
• Allows the inclusion of highly complex
  processes and interactions in a model
• Possibilities for visualization
• Powerful software tools for model
  construction and analysis, flowchart modeling

5
Aircraft availability

• Maintenance
• resources
• operating policies
• environment

• Reliability
• Deterioration
• Preventive measures

• Flight activities
• modes of flying
• intensity
• selection of aircraft

• Battle damages
• threat scenarios
• tactics

6
Conflict operations

• Limited knowledge on how the presence of the
  enemy affects the fleets operations
• Unpredictable flight pattern
• Battle damage rates
• Changed maintenance requirements
• Decentralization of airbases
• Material supply
• Assaults on airbases

7
The simulation model
Aircraft availability
8
Construction and validation of the model

• Based on incomplete information
• Emphasis on expert knowledge
• Conversations with FiAF representatives
• Presentations to maintenance professionals
• Available data on normal operations, exercises
  and contingency plans
• Affects the way the model can be used
• Definition of input data
• Interpretation of results
• Sensitivity analyses

9
Utilization of the model

• Implemented with Arena -software
• Appears as a stand-alone tool to the user
• Customized user interface and simulation reports
• Simulation analyses for maintenance designers
• Allocation of maintenance personnel, spare parts
  and equipment
• Comparison of flight and maintenance policies
• Effect of reliability improvements...
• Applicable for training of maintenance personnel
• Demonstrates the significance of maintenance and
  support logistics to performance of the fleet

10
Example analysis

• Change of maintenance policy during a dynamically
  evolving conflict
• Periodic maintenance is suspended to release
  aircraft to flight activities
• At what time should this occur?
• A scenario with 4 phases
• Increased flight intensity
• Further increase in flight intensity,
  decentralization of airbases
• Aerial battles
• Decreased flight intensity due to losses

11
Example analysis results
12
Conclusions

• A simulation model for the aircraft fleet of FiAF
• Quantitative assessment of supportability
  requirements and fleet performance
• Diverse operating policies and conditions
• A tool for maintenance designers and training of
  maintenance personnel
• Introduced to Air Force units