Nonlinear Simulation of Terminal Maneuvers Including Landing Gear Dynamics, Crosswind and Ground Effect

Terminal flight phases, particularly landing, are among the most critical, due to low altitude, low speed and the possible presence of crosswinds. Tools capable of accurately modeling and simulating these phases are essential for identifying potential issues and assessing airplane safety integrity. This work focuses on the development of a nonlinear flight simulator devised to handle terminal maneuvers, including ground effect and wind. Such a simulator incorporates the six-degree-of-freedom rigid body equations of motion coupled with a landing gear model and with a basic control that emulates the action of the pilot, while the aircraft aerodynamic characteristics are estimated through a dedicated semi-empirical procedure. The proposed simulator is employed to assess the effect of crosswind and approach speed on different performance indicators, considering a general aviation airplane (Ryan Navion). These indicators include ground roll distance, wing-tip clearance and lateral forces exerted on the landing gear. The results demonstrate that landings are achievable even beyond the demonstrated crosswind limits without encountering wing-tip strikes or rollover and that higher approach speeds could be advisable in strong crosswind conditions.