Accident risk assessment of simultaneous converging instrument approaches

With increasing traffic there often are environmental and economical reasons to optimise Simultaneous Converging Instrument Approaches (SCIA) without sacrificing the high safety levels realised in air traffic. One of the well known safety issues of SCIA is the risk of a mid air collision due to a double missed approach. The aim of this paper is to show through a working example that there is a clear advantage to evaluate the safety through support of advanced accident risk assessment methodology. In this paper such methodology is applied to a specific example of SCIA at Amsterdam Airport Schiphol. Comparison of the obtained results against FAA established SCIA criteria shows that there are situations in which these FAA criteria are not met; however, the collision risk is not higher than for similar situations that would satisfy these criteria. The implication for Amsterdam Airport Schiphol is that a specific change can be introduced as being risk neutral. The implication for other busy airports with converging runways might be that there is room to develop new or improved SCIA without compromising safety.