What is Unit Load Device?
A unit load device (ULD) is a device for grouping and restraining cargo, mail and baggage for air transport, either an aircraft container or a combination of an aircraft pallet and an aircraft pallet net. ULDs interface directly with the aircraft's cargo loading and restraint system, so certified ULD types require airworthiness certification, which the manufacturer obtains from the competent civil aviation authority. Each unit carries an IATA ULD ID code of 9 or 10 characters: a three-letter type code, a four- or five-character serial number and a two-character owner code. The first letter of the type code shows the category, such as A for a certified container, P for a certified pallet and R for a certified temperature-controlled container, the second letter the base dimensions and the third the contour or pallet certification. Special types include temperature-controlled and fire-resistant containers, horse and cattle stalls, and garment-on-hanger units.
Why it matters for forwarders
Forwarders that build up their own ULDs must respect the contour, weight limits and restraint requirements for the aircraft position, or the airline can reject or rework the unit at acceptance. Air freight is often priced per ULD for built-up units, so matching cargo dimensions to the right ULD type can lower the cost per kilogram compared with loose cargo. Damage is expensive: IATA puts annual ULD repair costs at about USD 330 million, with 80% of the damage avoidable. ULDs are tracked by their ID code in messages between airlines and handlers, so wrong codes on manifests cause loading and reconciliation errors. The IATA ULD Regulations (ULDR), updated annually by the IATA ULD Board, are the reference for specifications, handling and build-up.