An aircraft forced to change course abruptly could soon be given a clear passage within seconds, without manually reorganizing all the surrounding traffic.
Researchers have developed a method called Plan-and-Avoid to coordinate several aircraft around a declared priority trajectory. This priority may concern an aircraft in difficulty, an aircraft with limited maneuverability or a specific mission. The principle is simple: its route must remain clear, so the other aircraft adapt.
Illustration: Pixabay
To understand how it works, the system first calculates the trajectory the priority aircraft must follow. It then predicts the future positions of nearby aircraft. If it detects that two trajectories may pass too close to each other, it prepares a modification for the other aircraft. This instruction takes the aircraft's movement capabilities into account.
The method therefore does not merely seek to avoid an imminent collision. It maintains a predefined safety distance between aircraft. It also accounts for uncertainty about their positions and movements, since a real trajectory never follows a calculated line perfectly.
The researchers tested their system with real air traffic data recorded around Washington, United States. They simulated more than 900 emergency landings, representing over 140 flight hours. These scenarios produced 575 distinct situations in which trajectories conflicted.
In all these cases, the program found feasible instructions for the aircraft that had to move aside. The complete processing took no more than 5.7 seconds on a personal computer. This time even included one simulated second for the exchange of information between the aircraft and the system.
This time is particularly important in an emergency situation. A route to a suitable landing site may cross traffic already in the area. Manually modifying flight plans one after another would take time. Here, cooperating aircraft directly receive an adapted instruction to clear the way.
The next step will notably focus on delays caused for aircraft diverted from their route. Their scale and operational consequences will have to be measured before considering the use of such coordination under real-world conditions.