Method and system for monitoring a safety level of a trajectory of an aircraft and for generating a corresponding alert

A method for monitoring a safety level of a trajectory followed by a flying aircraft, implemented by a Trajectory Conflict Detection and Alerting (TCDA) system comprising electronic circuitry on board the aircraft, the method comprising:

• defining a set of integration points positioned along a trajectory, downstream of a current position of the aircraft on the trajectory;
• a monitoring phase comprising at least one iteration, by initially selecting an integration point at a position farthest from a current position of the aircraft, with each iteration comprising:
• determining whether the position of the selected integration point is different from a position of the integration point closest to the current position of the aircraft, otherwise establishing a failure to compute a contingency trajectory;
• when the position of the selected integration point is different from the position of the integration point closest to the current position of the aircraft:
• checking whether part of the trajectory, called common part, extending from the current position of the aircraft to the position of the selected integration point is safe if:
• (i) no conflict between an obstacle and the common part is detected, and (ii) a contingency trajectory exists from the position of the selected integration point,
• otherwise carrying out a new iteration of the monitoring phase by selecting a next integration point toward the current position of the aircraft,
• and the method further comprising:
• establishing a safety level for the trajectory, with the safety level either corresponding to the position of the integration point at which failure to compute the contingency trajectory was established, or to the position of the integration point at which the common part is safe.