What Is a ULD: Unit Load Device in Air Cargo

The ULD: Foundation of Air Cargo Loading The experts at Private Jets Connect break down the key points below.

The ULD (Unit Load Device) is the standardized loading unit that forms the interface between cargo and aircraft. Since the advent of modern air freight in the 1970s, ULDs have transformed cargo logistics by enabling rapid, safe, and optimized aircraft hold loading.

Without ULDs, each package would need to be loaded individually into the aircraft – a time-consuming and risky process. With ULDs, tonnes of freight are pre-assembled on the ground and transferred into the aircraft in minutes using mechanized handling systems.

Containers vs Pallets

ULDs fall into two main families: containers and pallets.

Air Containers

Containers are rigid, enclosed structures profiled to match the aircraft cargo hold shape. They protect goods from weather, impacts, and handling. Walls are made of aluminum or composite, and the base features locking rails.

Air Pallets

Pallets are flat aluminum trays onto which cargo is stacked then covered with a contour net or cover. They offer greater loading flexibility, particularly for oversized packages, but provide less protection than containers.

Main ULD Types

Lower Deck Containers

Main Deck Pallets

Specialized Containers

Certain ULDs are designed for specific uses:

• Thermoregulated containers: Envirotainer RAP/RKN, CSafe, for pharmaceutical freight and perishables
• Animal containers: adapted for live animal transport with enhanced ventilation
• Security containers: blast-resistant (COMAT) for high-security shipments
• Dangerous goods containers: reinforced walls and retention systems

The IATA Coding System

IATA has defined a standardized coding system to identify each ULD:

Type Code (3 characters)

The first character indicates the category (A = certified container, P = certified pallet), the second indicates the base size, and the third indicates the contour.

Owner Code (2 characters)

A two-letter code identifies the ULD owner (airline or leasing company).

Serial Number (5 digits)

A unique number identifies each individual ULD for tracking and maintenance purposes.

Complete example: AKE 12345 AF = LD3 container, number 12345, owned by Air France.

The ULD Lifecycle

Loading

ULDs are loaded in the airport cargo warehouse. Packages are arranged to optimize volume and respect weight limits. Forwarders and handlers manage packaging and securing.

Transfer to Aircraft

Loaded ULDs are transported from the warehouse to the aircraft by forklifts and ground transporters (dollies). Transfer time is a critical factor for temperature-sensitive goods.

Aircraft Loading

Loading is performed through the aircraft’s cargo doors using loaders (elevating platforms). Each ULD is positioned on the hold’s rail system and locked in place. Position is determined by the load plan which respects center-of-gravity constraints.

Unloading at Destination

The reverse process occurs at the arrival airport. ULDs are unloaded, transported to the warehouse, and opened for freight distribution to consignees.

Return and Maintenance

After use, empty ULDs are returned to the owning airline or leasing company. They undergo regular inspections and maintenance to ensure structural integrity and standards compliance.

The Economics of ULDs

ULD Cost

The purchase price of a new ULD ranges from EUR 1,500 for a standard LD3 container to EUR 15,000 for a PMC pallet. Thermoregulated ULDs cost significantly more, from EUR 30,000 to 100,000 depending on technology.

ULD Leasing

Most airlines engage ULD leasing companies (Jettainer, Unilode, ACL Airshop) rather than acquiring their own fleets. Leasing includes management, tracking, maintenance, and repositioning of ULDs worldwide.

ULD Pools

ULD pool systems allow airlines to share a common ULD fleet, reducing repositioning costs and improving availability.

Choosing the Right ULD for Your Freight

ULD selection depends on several factors:

• Aircraft type: each aircraft is compatible with specific ULDs
• Cargo nature: standard, temperature-sensitive, dangerous, live
• Weight and volume: load capacity and available space
• Route: ULD availability at departure and arrival airports

Your broker or forwarder will select the optimal ULD based on these parameters. At Private Jets Connect, we coordinate the provision of appropriate ULDs for every shipment.

Conclusion

ULDs are the invisible yet indispensable foundations of global air freight. Their standardization by IATA enables rapid and safe aircraft loading while protecting goods during transport.

For any questions about ULDs or to organize a cargo shipment, contact Private Jets Connect. Our team selects the optimal loading solutions for every cargo type and flight.

For personalized support, contact Private Jets Connect and get a tailored quote.