Collision risk modeling of air traffic

Air Traffic Management (ATM) involves interactions between multiple human operators, procedures and technical systems, all of which are highly distributed. This yields that providing safety is more than making sure that each of the ATM elements functions properly safe; it is the complex interaction between them that determines safety. The assessment of isolated indicators falls short in covering the complex interactions between procedures, human operators and technical systems in safety-critical non-nominal situations. To improve this situation, this paper develops an approach towards the modelling and assessment of risk of mid-air collision between aircraft.