The course ends where the loading physically happens: in the holds. This lesson names the three ways cargo travels and what each is good at, works the floor arithmetic that the mass-limits lesson promised, load per area and load per metre, in all three exam directions, and finishes with why and how the load is tied down, because every number computed in thirteen lessons assumes the cargo stays exactly where it was loaded.
The three kinds of cargo
Containerised cargo — freight and baggage packed into unit load devices (ULDs), standard-shaped containers built to the aircraft's own cross-section. Their advantages are industrial: they are packed and weighed away from the aircraft, loaded in minutes on powered roller systems, locked to the airframe by built-in latches so the restraint is automatic, and they protect their contents from weather and handling.
Palletised cargo — loads built up on flat standard pallets, held by a cargo net or straps to the pallet, with the pallet locked into the same roller-and-latch system. Pallets take awkward shapes a closed container cannot, while keeping the speed and positive locking of the ULD system.
Bulk cargo — loose items loaded piece by piece into a bulk hold: late bags, mail, odd-shaped freight. It needs no equipment and fits anything small, at the price of hand labour, slower turnarounds, and restraint that must be built for each load with nets and tie-downs.
The floor arithmetic, all three ways
The mass-limits lesson defined the two intensities, load per unit of floor area and load per unit of fuselage length; the exam asks for each of the three quantities in turn: the area a load needs, the mass an area allows, and the running load a container produces. All three are one division or one multiplication, and the only skill is choosing the right one. The physical cure for either failure is the same hardware: a spreader board or spreader floor under the load, buying contact area against the floor limit and footprint length against the running limit.