Abstract. The August 2005 Helios 522 accident may end up demonstrating that the reductionist model we apply to understanding safety and risk in aviation (taking systems apart and checking whether individual components meet prespecified criteria) no longer works well. Through a concurrence of functions and events, of which a language barrier was a product as well as constitutive, Helios 522 may have been pushed past the edge of chaos, that area in non-linear dynamics where new system behaviors emerge that cannot be anticipated using reductive logic. Complexity theory, in contrast, encourages us to fix on higher-order system properties if we want to gain confidence about the resilience of a system, i.e. its ability to recognize, adapt to, and absorb a disruption that falls outside the disturbances the system was designed to handle
