Novel Air Traffic Procedures: Investigation of Off-Nominal Scenarios and Potential Hazards

The paper demonstrates the development of simulation-based models through which off-nominal conditions in air traffic can be investigated and the corresponding potential hazards can be assessed quantitatively. Primarily, those hazards are studied as they arise due to the introduction of new types of vehicles and novel operational procedures within the Next Generation Air Transportation System; the focus is on the combined effect of new vehicles and new procedures that specifically accommodate those new vehicles. These models are intended to complement any hazard assessment of air traffic that may be conducted qualitatively or via simplified or reduced-order analysis due to limited knowledge at the early stages of research. Such models can provide inputs into the system-level quantitative safety and risk analyses that facilitate developing recommendations for any appropriate new regulatory guidance and standards for vehicles and procedures to be adopted for future air traffic implementation. Two specific scenarios are explored in detail: a helix descent in the presence of failed autopilot, and a steep-descent approach of a slower vehicle sandwiched between two regular approaches with vertical navigation failing during the descent.