Method and system for computing a trajectory for landing an aircraft

A trajectory generation method for generating a trajectory for bringing an aircraft in flight from a current position to a georeferenced runway, the method being implemented by an automatic trajectory generation system formed of electronic circuitry on board the aircraft, the method comprising:

• obtaining a procedure, called a STARI procedure, which is suited to the georeferenced runway and which provides a final trajectory for the approach to the runway that is flyable by the aircraft in order to land, regardless of a performance of the aircraft, and such that, from the entry point of the final trajectory or any point above it, a holding loop pattern of a predefined shape is flyable in order to dissipate energy if necessary;
• computing a lateral trajectory, avoiding any terrain relief, meteorological obstacles and military no-fly zones, between the current position of the aircraft and the entry point or a point above it, based on performance adapted to an operational state of the aircraft;
• providing an overall trajectory in order to bring the aircraft to landing on the runway, by linking the computed lateral trajectory and the final trajectory provided by the STARI procedure, including one or more iterations of the holding loop pattern if necessary;
• wherein, for obtaining the STARI procedure, the method comprises:
• when a STARI procedure has been defined beforehand for the runway and has been stored in a database, reading the STARI procedure from the database;
• when the database does not store any STARI procedure for said runway, establishing the STARI procedure in real time as follows:
• constructing a final approach trajectory;
• and
• searching for an appropriate entry point of the STARI procedure that complies with the following conditions:
• a flyable trajectory to an entry point of the constructed final approach trajectory exists;
• and
• the holding loop pattern is safely flyable by the aircraft from said entry point of the STARI procedure in order to dissipate energy;
• wherein, for searching for the appropriate entry point of the STARI procedure, the method comprises:
• evaluating whether it is safe to implement the holding loop pattern, based on information about the elevation of the terrain surrounding the runway, by placing the entry point of the STARI procedure on the entry point of the final approach trajectory and by aligning the holding loop pattern with the final approach trajectory;
• considering the entry point of the STARI procedure to be appropriate when it is safe to implement the holding loop pattern in light of the information about an elevation of the terrain surrounding the runway;
• and
• performing a backward search for an entry point of the STARI procedure, from the entry point of the final approach trajectory by applying a descent slope, when it is not safe to implement the holding loop pattern in light of the information about the elevation of the terrain surrounding the runway.