The use of expendable countermeasures is still found to be a viable choice for self protection against Man Portable Air
Defense Systems (MANPADS) due to their simplicity, low cost, flexibility, recent improvements in decoy technology,
the ability to handle multiple threats simultaneously and the off-board nature of these countermeasures. In civil aviation,
the risk of general hazards linked to the use of pyrotechnics is the main argument against expendable countermeasures,
whereas for military platforms, the limitation in capacity due to a limited number of rounds is often used as an argument
to replace expendable countermeasures by laser-based countermeasures. This latter argument is in general not
substantiated by modelling or figures of merit, although it is often argued that a laser based system allows for more false
alarms, hence enabling a more sensitive missile approach warning system.
The author has developed a model that accounts for the statistical effects of running out of expendable countermeasures
during a mission, in terms of the overall mission survival probability. The model includes key parameters of the missile
approach warning system (MAWS), and can handle multiple missile types and missile attack configurations, as well as
various statistical models of missile attacks. The model enables quantitative comparison between laser based and
expendable countermeasures, but also a dynamic optimization of the countermeasures in terms of whether to use small
or large countermeasure programs, as well as the dynamic tuning of MAWS key parameters to optimize the overall
performance. The model is also well suited for determination of the contributions of the different components of the
system in the overall survival probability.