Reachability analysis of landing sites for forced landing of a UAS in wind using trochoidal turn paths

This paper details a method to ascertain the reachability of known emergency landing sites for any fixed wing aircraft in a forced landing due to engine failure in steady uniform wind conditions. With knowledge of the aircraft’s state and parameters, and landing site location and landing direction, the minimum height loss path can be defined. This uses glide performance calculations and a trajectory planner to give a minimum height loss to each landing site. Based on the aircraft’s initial altitude it can calculate if the site is reachable, and how reachable it is. The path definition takes into account wind and uses a geometric shape called a trochoid to define the gliding turns in wind. This method is generic enough for use by any aircraft in any wind conditions.