Does lift of liquid ban raise or compromise the current level of aviation security in the European Union? Simulation-based quantitative security risk analysis and assessment

To protect aviation security against terrorist attacks, air passengers and luggage must be screened for threat items, such as explosives using liquids, aerosols and gels (LAG). This paper treats basic problems of the effectiveness and cost-efficiency of liquid screening within a rigorous methodological framework of quantitative security risk assessment. The risks to be evaluated are measured in terms of statistical distributions of fatalities incurred in in-flight terrorist attacks simulated in computer experiments. The simulations combine 'What-if' attack scenarios involving the use of LAG explosives, LAG explosive detection systems and alternative procedures of security checks of passengers and hand luggage at European airports. The operational constraints and consequences of security incidents are modelled as random events, employing software-based business process-modelling techniques. Frequency distributions of fatalities generated in the computer experiments are evaluated and compared, systematically and in quantitative terms, using risk assessment methods recently developed in the operational sciences. Basic consequences of the lift of the current liquid ban on aviation security in the European Union will be discussed with reference to the results obtained in the risk analysis.