Identification of Speed Brake, Air-Drop, and Landing Gear Effects from Flight Data

Applying system identification methodology, an aerodynamic database covering the entire operational flight envelope, was estimated from Transall flight data. We emphasize the modeling and identification of some of the Transall specific operational characteristics such as the ramp door and dropping of heavy loads. In addition, aerodynamic effects because of speed brakes and landing gear are determined applying a nonlinear maximum likelihood parameter estimation method. The identification results indicate that the speed brakes function as pure drag generators only for the retracted landing flaps. For extended landing flaps, applying speed brakes affects the aircraft pitching motion. The landing gear is found to affect both the longitudinal and lateral-directional aircraft motion. Opening of the ramp door results in an effectively enlarged fuselage, affecting mostly the lateral-directional motion. It is demonstrated that the load dropping can be adequately modeled by properly accounting for the variations in the aircraft mass characteristics.