Home » Building Airline ULDs: What You Need to Know

Building Airline ULDs: What You Need to Know

by | Sep 15, 2021 | Blog Post

If you’re shipping air freight, your main concern is getting the freight where it needs to be, and fast. You’re not necessarily concerned about the equipment used and exactly how the freight moves from origin to destination.

Truckers, forwarders and air carriers take care of those details and keep you in the loop. But the container types used and who actually prepares the cargo can actually have a big impact on what you pay, how fast your shipment moves through airports and customs agencies, and the damage that could occur in transit.

Those things you do care about. That’s why it helps to have at least a basic understanding of air freight containers and pallets and how those are prepared for shipment. In this article we’ll answer some basic questions about what goes on behind the scenes as air cargo moves from your dock to your customer.


ULD Basics

Q: What is a ULD?

Building Airline ULDA unit loading device (ULD) is the air freight equivalent of the ocean container. It allows for the safe, fast, efficient transit of freight on passenger and cargo aircraft. A steamship line can put upwards of 20,000 stacked containers on one vessel. With airplanes, it’s a different story. Loading spaces are small and irregularly shaped. That’s why there are many different ULDs, in different sizes and shapes, to make the best use of the available space.

There are two basic types of ULD: a closed metal container that houses freight inside and a metal pallet onto which cargo can be loaded. Cargo on pallets is covered with a net and secured under the ULD. Whether you’re moving pallets of merchandise or cars or expensive equipment, ULDs are secured to the body of the aircraft to keep the freight from shifting, even during the most turbulent flights.

Air cargo can be tendered to the carrier either loose or already containerized. Once loose freight is checked in, it is loaded by the carrier into a ULD.


Q: When would you use a container or a pallet?

Containers have the following advantages:

  • Make loading and unloading faster and easier
  • Protect against any kind of weather – do not require the extra wrapping that you’d want for the palleted cargo
  • Protect better against damage ­– no need for corner guards or other special protective packaging
  • Prevent unauthorized access to the cargo

ULD pallets, sometimes referred to in the industry as “cookie sheets,” are cheaper to use than containers. Other advantages:

  • Accept oversized cargo that won’t fit in a container
  • Take up less room than containers since they are flat and can be stored efficiently and returned by plane
  • Have more options for how to build the pallet (size and shape) depending on where on the plane the airline ULD pallet is being loaded

As a shipper, the choice of ULD is typically made for you, by the airline or your freight forwarder. It’s a little different if you’re shipping temperature-sensitive cargo. You’ll want a specialized, temperature-controlled airline ULD.


Q: What are the all the various types of airline ULD equipment?

Dimerco has actually created an airline ULD specification guide for your reference.



How ULD Loading Can Impact Freight Cost, Speed and Risk

As a shipper, you’re not doing the final preparation of cargo. That’s handled by freight forwarders and airlines. There’s a real science to the ULD building process, especially when it comes to building pallets, since the width and height will depend on the weight of the shipment and where on the aircraft the pallet will be loaded.

But far more important than how airline ULDs are built is who does the building – the freight forwarder or the airline. This can influence many things, from securing freight capacity to how long you must wait to receive or deliver the cargo.


Q: How is your ability to secure reliable air freight capacity affected by airline ULDs and who builds them?

Passenger airlines often overbook and then must ask some people to deplane and travel on a later flight. That happens with air cargo, too!  Especially in the current market where freight capacity is constrained. The potential for your freight to be offloaded is lessened if you work with a freight forwarder that has Block Service Agreements (BSAs) with the airline. Larger forwarders essentially pre-purchase airline cargo space well before they have customers for that space. These BSAs correspond to a certain volume of cargo (metric tons) over a certain time in certain lanes. It’s common to achieve most of this committed tonnage through fully built-up ULDs. So, if your cargo is moving with a forwarder that builds the ULD and tenders it to the airline, the space is secured. On the other hand, if the cargo is tendered loose to the airline, the airline builds the ULD, mixing your cargo with freight from other forwarders. In this case, the air carrier is not obligated to transport this freight on a particular flight as part of any existing BSA. So, if the carrier has accepted more freight than it can fit, it can offload your cargo.


Q: How is shipping speed affected by who builds the ULDs?

In air freight, flight times are predictable; handling times are not.

If you want to minimize total transit time, you may be better off working with a freight forwarder to build ULDs at origin and then receive and deconsolidate ULDs at its container freight station (CFS) near the destination airport.

The reason is simple: congestion at airport cargo facilities. Bottlenecks are caused by high freight volumes combined with COVID-related circumstances – mainly manpower shortages, as we have experienced in PuDong Shanghai airport (PVG), for example.  Check out this video for an example of how Dimerco leverages its own bonded warehouse near PVG to speed the process of disinfecting imported cargo (a Chinese government requirement).

At origin, ULDs built by a forwarder and sent, as ready-to-ship units, to the airline are called BUPs (Bulk Unitization Program). These BUPs greatly reduce handling time at the cargo terminal by combining lots of separate items into a single unit. For that reason, BUPs benefit from preferential conditions and more rapid handling at the airport.

At destination, BUPs are turned over to the forwarder for unloading. These BUPs can be available up to 3-4 days faster than airline-loaded ULDs. Let’s take an example.

A flight arrives at LAX from China at midnight. If your goods ship as loose cargo with the airline, that means the airline and its handling agent are responsible for processing the inbound freight. Under normal market conditions, the earliest it might be available, if you are lucky, is some time the next day. If there is a congestion delay, as we have experienced over the last year, it could be up to a week. In contrast, if your goods arrive as a BUP shipment from China, your forwarder could likely pick up its own cargo by noon, bring it back to the CFS and, if the consignee is nearby, deliver the next day.


Q: How is the timing of customs clearance affected by who builds the ULDs?

In the US, the Transportation and Safety Administration (TSA) requires that all air cargo be screened before it is loaded onto a passenger flight. To keep goods flowing, the TSA certifies independent cargo screening facilities to screen cargo prior to providing it to airlines. This Certified Cargo Screening Program (CCSP) allows shippers to avoid long waits at airport Customs facilities by having a qualified forwarder with BUP capability build ULDs and pre-screen the cargo.

A pre-screened BUP can save at least 6–8 hours compared to screening at the airport.


Q: How is product damage or loss affected by who builds the ULDs?

Cargo handling at airline terminals is more about speed than quality. Typically, shipments must be tendered to the airline 6 hours before departure. For a Boeing 747-400 freighter, which can fit cargo volumes equivalent to five semi-trucks, that’s a lot of ULDs for cargo handling agents to build in a very short amount of time. When you rush, you get careless and the damage percent increases.  An experienced forwarder that is being paid to build BUP shipments does not operate under the same time pressures. And it typically has people trained to follow careful procedures around proper loading and securing of airline ULDs. Those people are incented for a job well done and will be held accountable for errors that lead to lost inventory or damage. You rarely see the same structure and discipline with airport cargo handling operations.


Q: When corrective action is required, is it better to be working with a freight forwarder or the airline directly?

Few things erode the trust of a shipper more than damaged cargo. When it comes to addressing issues, complaints lodged with an airline rarely result in fast action and resolution. It’s different if you work with a forwarder that manages a global, company-owned forwarding office network and is building its own ULDs.

Let’s say you manage a semiconductor product supply chain and wet cargo becomes an issue on the Hong Kong-to-Chicago lane. In response, the forwarder’s office in Chicago might communicate to its sister office in Hong Kong “We’ve been seeing wet cargo upon arrival. During the typhoon season, you must change your procedure and add three layers of plastic over the cargo instead of two.” Because one forwarder controls the entire global shipping process, such initiatives will be monitored to ensure the proper steps were taken and that results improve.


Rely on Air Freight Experts

You don’t need to be an expert in air freight to ship effectively. But it helps to understand the basics about how airline ULDs are built, who builds them, and how these decisions impact the cost and speed of your cargo. After that, you can leave the details to an expert.

To discuss how Dimerco can help manage your time-critical air freight, contact one of our international shipping specialists to start a discussion. Our strong relationships and block space agreement with all top Asia-based, global airlines help bring you the capacity you need for ongoing and emergency freight.

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