Newcomers to air freight often regard "pallet loading" simply as placing goods onto flat pallets, yet the actual operation is far more complex. Anyone with experience operating main-deck freighters knows aircraft ULD pallets are no ordinary industrial trays; they constitute an integral part of the aircraft safety system.
The pallet model, cargo nets, outer contour dimensions, locking fittings, airworthiness status, together with the envelope limits of the aircraft cargo hold, collectively determine whether a shipment can be loaded onto the aircraft. This article elaborates on all these key points one by one.
ULDs Are Not Ordinary Pallets, But Certified Aircraft Components
The International Air Transport Association (IATA) has laid out a clear definition for Unit Load Devices (ULDs): ULDs refer to air cargo unit load devices, encompassing aircraft pallets with cargo nets and air cargo containers alike. IATA further stipulates that ULDs are removable aircraft components subject to stringent airworthiness regulations.
Airworthy ULDs are mandatory to secure cargo loads and safeguard aircraft onboard systems and fuselage structures.
This principle is critical for freight forwarders. Many forwarding agents, manufacturing plants and warehouses mistakenly treat ULDs as disposable, borrowed large pallets, which poses severe safety risks.
| Standard Pallet | Aircraft ULD Pallet |
|---|---|
| Mainly used for warehousing and handling | Integral to flight safety |
| Limited consequences upon damage | Damage may compromise aircraft airworthiness |
| No mandatory standard identification number | Assigned ULD ID & subject to strict airworthiness requirements |
| Cargo can be secured arbitrarily | Must comply with airline and IATA regulations |
Overview of Common Air Cargo Pallet Types
Different airlines, aircraft models and regional markets adopt varying ULD specifications. Freight practitioners frequently encounter designations including PMC, PAG and PLA. The exact applicable type shall comply with each carrier's operational regulations; the following content serves solely for practical reference.
| Pallet Type | General Explanation | Typical Application |
|---|---|---|
| PMC | Standard air cargo pallet, dimensions: 96 × 125 inches | Widely adopted on main decks and lower holds; subject to aircraft type and contour limits |
| PAG | Standard air cargo pallet, dimensions: 88 × 125 inches | Commonly used on wide-body aircraft with varying positional and height restrictions |
| PLA | Half-width pallet (approx. 60.4 × 125 inches) | Lower cargo holds of passenger aircraft, mails, express shipments, etc. |
| P6P / P1P & others | ULD pallet specifications designated under IATA industry codes | Usage determined by individual airlines and aircraft models |
Instead of memorizing pallet codes mechanically, beginners should master three core metrics: base dimension, usable contour space, and aircraft compatibility.