what is a ULD and how to load and unload air freight

Aircraft ULDs are indispensable in aviation and logistics because they make it easier to transfer air freight from one plane to another or from one vehicle to another. Operators can consolidate bulk cargo into a single unit, which makes it easier to handle, bolsters process efficiency and increases process safety. Ultimately, a ULD’s main purpose is to streamline cargo loading. Operators can load and unload faster, protect the cargo and optimise the cargo space.

Equally as important is a ULD’s other purpose: safety. ULDs secure the load from take-off right through to landing, especially during turbulence, and enable even weight distribution in the aircraft. An unsecured, unrestrained load could damage the aircraft. Worse still, it could cause the aircraft’s weight to shift, the pilot could lose control and the plane could crash. In all cases, a cargo plane must be equipped with a roller floor, straps and fittings to hold pallets and containers in place. 

The three-letter codes indicate different types of ULD. The first position is always a letter and defines the ULD category. The most common letters you’ll find are:

• A: Certified container
• P: Certified pallet
• B: Noncertified container
• R: Certified temperature-controlled container

There are 15 main categories of ULD

The third letter refers to the ULD’s contours, which are shaped to fit the inside of the plane’s body. In the case of pallets and nets, they also describe the restraint system the unit is classified in. ULD contours are designed to allow as much cargo volume to be carried as possible.

The contour also depends on whether the ULD is positioned in the aircraft’s main deck or the lower one. The different contours and their classification are:

You’ll see various ULD types used in logistics. Here are some of the most frequently used ones:

ULD manufacturers must provide clear instructions for ULD usage. Airlines must also create instructions on ULD usage for anyone who must load or unload ULDs onto aircraft. Although instructions may vary slightly, several will be common:

• Always check the ULD for any damage that could render it unusable.
• Load cargo or baggage evenly, paying attention to maintaining the centre of load gravity with the 10% of centre the base.
• Secure the container doors after completing loading.
• Don’t use a certified ULD unless its manufacturer’s plate/marking is clearly visible. and legible. The plate is an authority requirement and is a legal requirement.
• Always secure container doors closed or secure them in an open position.

These are just some of the main guidelines on correct ULD use. You’ll find more information on our ULD Storage page, where we discuss correct ULD usage in further depth. There we also discuss:

• the loading of air freight containers;
• the loading and unloading of pallets and nets;
• ULD handling;
• and storage of loaded ULDs and empty ULDs.

ULDs come in two main types: pallets and containers. A pallet is a platform that operators will stack cargo on and then pull a net, which is attached to the rim of the pallet, over the cargo to restrain it. Ultimately, the pallet is a specific type of ULD, whereas ‘ULD’ refers to pallets and containers.

Structural and functional differences

Whereas pallets are more of a platform for stacking, containers are lightweight structures, often made of aluminium and comprise a base, a frame, side and roof panels and, normally, a solid door. Some containers are collapsible, some insulated, some ventilated and some refrigerated.

The speed, reliability and global connectivity of air freight means lots of industries make the most of air freight as a means of transportation.

• eCommerce: due to the pressure for speedy logistics that eCommerce businesses encounter;
• Manufacturers: especially those whose use of JIT production forces them to rely on timely, efficient delivery of crucial components;
• Pharmaceutical: because these items are often time sensitive and need handling carefully;
• Food: where there are lots of perishable goods, including vegetables, fruit and seafood, and quick transportation is necessary;
• High-value goods industries: such as jewellery, electronics and artworks, because of the greater security air freight offers.

You’ll also see cargo handling locations such as airports and cargo handling hubs making the most of air freight transportation.

Thanks to our Air Freight Equipment, you can minimise manual ULD handling and ease the pressure on your ground personnel and logistics teams.

The Modular Roller Bed System: Air Cargo

The Modular Rollerbed System (MRS): Air Cargo is ideal for handling ULDs, whether containers or pallets, and is one of the top choices for anyone in the air cargo industry. It’s possible to install the system into any van or trailer, transforming it into a specialised unit for ULD handling without needing major modifications to the vehicle itself.

This system, which features a pneumatic rise-and-fall roller bed, is also suitable for road feeder services (RFS) that want to upgrade their air cargo handling capabilities. The versatile system is easily transferable from one trailer to another, and its modular design allows easy customisation and scaling to suit the operator’s needs.

We offer a range of Air Cargo Handling, Ground Support Equipment, and ULD Storage Equipment to support cargo handlers.

In terms of ULD Storage Equipment, we offer:

• Pallet storage racks for storing PMC and PGA pallets;
• Pallet storage stillages for vertical stacking of pallets;
• Container storage racks for empty containers.

Regarding Ground Support Equipment & Air Cargo Handling systems, we offer:

Dolly Dock Systems are advanced cargo handling solutions that streamline the transfer of ULDs and pallets between dollies, warehouses and vehicles. This aircraft handling equipment optimises workflows by reducing manual handling, ensuring precise alignment, and improving efficiency in high-demand logistics and air cargo environments.

A Castor Deck is a versatile cargo handling system that facilitates the easy movement and positioning of heavy loads through a manual or semi-manual cargo system. This system consists of a deck equipped with heavy-duty castors, providing efficient mobility for unit load devices (ULDs), pallets or other heavy cargo items.

It is essential for operations that require the flexible movement of goods across various environments, including warehouses, loading docks, and air cargo terminals. The freight can be rotated in tight spaces so that logistics teams can push or pull the product in any direction required.

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