Abstract: In an example, an unmanned aerial vehicle (UAV) is disclosed, which includes an avionics system, a propulsion system, vertical-lift rotors, and a controller. The controller performs operations including, in response to detecting loss of operation of the propulsion system, determining energy and time constraints based on (i) a remaining avionics battery life and (ii) a remaining rotor battery life. The operations also include using a rotor edgewise inflow model stored on the controller, evaluate parameters for a glide descent trajectory and subsequent rotor-powered flight trajectory to a candidate landing site, to determine whether, based on evaluation of the parameters, an estimated energy consumption during the rotor-powered flight trajectory and time needed for the UAV to land at the candidate landing site exceed the constraints.