The Belfast is primarily a freighter aircraft for the carriage of heavy vehicles and palletized cargo but it also has an emergency troop carrier rôle. As a freighter, the potential loading cases are many and varied, yielding extreme design conditions. The carriage of heavy vehicles, whether on wheels or tracks, imposes severe loads on the floor and floor support structure and the large capacity pay load implies relatively high zero fuel and landing weights which are critical factors in the design of the wing and fuselage.