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

• Simulation of flight and maintenance operations
  of the aircraft fleet of the Finnish Air Force
  (FiAF)
• Importance for maintenance designers
• Predicting supportability requirements
• Evaluating performance of operating policies
• Special interest in operations of crisis
  situations
• Uncertainty due to limited knowledge of such
  circumstances

3
Flight and maintenance operations

• A complex logistic system
• Overall performance greatly influences the
  fleets operational capability

4
Operational environment

• The fleet operates under a threat of an enemy
• Limited knowledge of actual encounters
• Uncertainty of operating conditions
• Uncertainty of model parameters and model form

5
Flight operations in crisis situations

• Increased and uneven flight intensity
• Reacting to enemys actions
• Engagements
• Battle damages

6
Maintenance operations in crisis situations

• Changed maintenance requirements
• Emphasis on battle damage repairs
• Varying intensity
• Decentralization of airbases
• Maintenance facilities threatened by the enemy
• Specialized maintenance personnel
• Uncertain supply of materials

7
Uncertainty in model construction

• Construction based on incomplete information
• Emphasis of expert knowledge
• Experience of normal operations
• Live exercises and contingency plans
• Ambiguity in defining the model
• User is allowed the flexibility to describe a
  variety of operating policies and conditions

8
The simulation model

• Discrete-event approach
• Features
• 3 squadrons operating from own airbases
• Central depot-level maintenance facility
• Periodic maintenance, failure, and damage repairs
• Personnel and material resources
• Implemented with Arena-software

9
Structure of the model
10
Model validation

• Evaluation by subject matter experts
• Assumptions, results
• Various groups of FiAF personnel
• In different phases of the modeling effort
• Comparison of results
• To reference data from normal operations
• To results of an earlier tentative simulation
  study

11
Example analysis

• Changing maintenance policy during a crisis
• Periodic maintenance is discarded to release
  resources to other activities
• How does the change affect aircraft availability?
• A scenario with 4 phases
• Increased flight intensity
• Further increase in the amount of flights,
  decentralization of airbases
• Aerial battles
• Decreased flight intensity due to losses

12
Results

• Change in policy is necessary to sustain
  operational capability

13
Conclusions

• A model for fleet operations in an uncertain
  operational environment
• Quantitative assessment of maintenance policies
  in crisis situations
• Implementation with a graphical simulation
  software
• Easily manageable simulation analyses for
  maintenance designers
• A tool for training of maintenance personnel