The human-in-the-loop experiments (pilots and controllers) enable an understanding of the impact of airborne spacing on human activity, effectiveness and safety. The model based experiments were intended to complement the validation of airborne spacing by enabling prototyping as well as the collection of a large amount of data under varying conditions. The series of model-based experiments described in this report aimed at: (i) prototyping spacing guidance algorithms for human-in-the-loop experiments; (ii) understanding the intrinsic dynamics of sequences of aircraft under normal and extreme operating conditions (varying entry conditions, wind turbulence and aircraft types); (iii) evaluating the effects of air-air surveillance transmission quality (e.g. ADS-B, Automatic Dependent Surveillance Broadcast, update rate, latency and accuracy) on the performance of airborne spacing.
Two complementary operational airborne spacing applications were studied: 'Merge' (aircraft on converging trajectories) and 'Remain' (aircraft on same trajectory). From the three high level objectives introduced above specific objectives were derived to be studied separately. For the 'Merge' application, different distance based guidance laws were developed and compared. The most robust was capable of merging multiple aircraft in descent under turbulent wind conditions.
This guidance law was selected for studying the effects of initial distances and speeds on the ability of an aircraft to descend and establish a stable spacing behind another by a given merge way point. For the 'Remain' application the effects of ADS-B transmission quality, time based spacing criteria, mixed aircraft types and varying wind conditions on the ability of aircraft to maintain a given along-track spacing (distance or time) behind a descending lead aircraft were investigated.The results presented in the report, based on normal operating conditions, are consistent with the hypothesis that the airborne spacing 'Merge' and 'Remain' applications are robust. The results based on extreme conditions may be useful to evaluate the limits of applicability for 'Merge' and 'Remain' applications.