Cargo Container Sizes
As the fuselage diameter increases with passenger load, the under-floorboard space can be used for cargo and baggage transportation. With operating costs becoming
Figure 4.22. Typical container shapes
more competitive, the demand for cargo shipment is increasing, to the extent that variant aircraft are being designed as cargo aircraft (e. g., no windows and a lower level of cabin pressurization). An attractive variant is the “combi” design, which can convert the cabin layout according to the sector payload, in which the passenger load is smaller and the cargo load is higher. The combi layout can quickly reconfigure the cabin interior for passengers in the forward part and cargo in the rear, which facilitates passenger loading and unloading through the front door.
Cargo and baggage could be handled more efficiently by keeping items in containers (Figure 4.22) and having both destination and interior-space management. At the destination, the entire container is unloaded quickly so the aircraft is free for quick turnaround utilization. Container sizes are now standardized to fit in the fuselage and are internationally interchangeable.
The term unit load device (ULD) is commonly used when referring to containers, pallets, and pallet nets. The purpose of the ULD is to enable individual pieces of cargo to be assembled into standardized units to ease the rapid loading and unloading of airplanes and to facilitate the transfer of cargo between airplanes with compatible handling and restraint systems.
Those containers intended for below-floorboard placement (designated LD) need to have the base smaller than the top to accommodate fuselage curvature. Those containers have rectangular cross-sections and are designated “M.” Figure 4.22 shows typical container shapes; Table 4.6 lists standard container sizes, capacities (there are minor variations in dimensions), and designations.