ULD Types — Air Cargo Containers & Pallets

A Unit Load Device is the container or pallet an airline loads cargo into before it goes on the aircraft. Loading a whole ULD rather than loose pieces is what lets a widebody be turned around in hours, and it is why air cargo is quoted, weighed and tracked per unit.

The first letter gives the type — A for a certified aircraft container, P for a pallet, R for a refrigerated container, K for a livestock unit. The second gives the base size and the third the contour, which is the shape the ULD has to be cut to so it fits the curve of the fuselage. AKE is the LD-3, the most widely used lower-deck container of all.

Lower-deck ULDs go in the belly holds under the passenger cabin, so they are short and contoured to the fuselage. Main-deck ULDs go on the cargo floor of a freighter or a combi and are far taller and heavier — an M-2 takes 11,340 kg where an LD-3 takes 1,588 kg.

Tare weight is the empty ULD itself; maximum gross weight is the ULD plus everything in it, as certified for the aircraft. Payload is the difference between the two, so a heavy refrigerated unit carries less cargo than a plain container of the same size.

No. Each type is certified for a specific set of aircraft, and some only through one door — an HMA livestock stall loads through the nose cargo door of a 747F and nowhere else. Every page in this reference lists the aircraft its ULD is loaded on.

Track the shipment rather than the unit: enter the air waybill number in the air tracking app and every milestone from acceptance to delivery comes back as one timeline. The same lookup is one REST call in the API reference.