The ultimate purpose of a ULD serviceability check is to maintain the continuous airworthiness of ULDs and ensure that only airworthy ULDs are loaded onto aircraft.
During daily operations, every aircraft ULD should be inspected for damage limits before build-up, before dispatch to the aircraft, before aircraft loading, during unloading from the aircraft, after ULD breakdown, during inventory inspections, and before acceptance for interline transfer, interchange, or transshipment (see Section 6, OS 6/00 of the ULDR). These limits are established by the ULD manufacturer as part of the ULD certification process and are included in the manufacturer's Component Maintenance Manual (CMM). Due to the wide variety of ULD equipment types and the fact that the appropriate CMM may not always be readily available, it is necessary to display the ULD operational damage limits directly on the equipment itself. Therefore, the International Air Transport Association (IATA) developed a standard format and content for the Operational Damage Limits Notice (ODLN) applicable to certified aircraft ULDs and restraint straps. The ODLN ensures that the required damage limit information is readily available, enabling effective ULD serviceability inspections and visual detection of operational damage in the field, thereby ensuring that the ULD remains fit for use.
To determine whether a ULD is serviceable, a complete ULD serviceability inspection should be performed by checking all ULD components listed on the ODLN:
- If no damage is found on any ULD component, the ULD remains serviceable.
- If damage is identified on a ULD component, refer to the applicable damage limit specified for that component on the ODLN:
- If the damage falls within the allowable damage limits, the ULD remains serviceable.
- If the damage exceeds the allowable damage limits, the ULD is considered unserviceable.
Once a ULD has been fully built up, conducting a complete serviceability inspection becomes almost impossible because certain ULD components are no longer visible. For example, the ULD base plate and base fasteners may be covered or obstructed by cargo. Therefore, during a specific ULD operational cycle, a complete ULD serviceability inspection should be conducted before ULD build-up when the ULD is empty.
Based on safety risk assessments and mitigation strategies, and in order to reduce the likelihood of unserviceable ULDs arriving at the ULD build-up workstation, a complete ULD serviceability inspection may also optionally be conducted after ULD breakdown and/or before or after ULD transfer, in addition to before build-up.
After confirming that a ULD is serviceable following the complete inspection, regular visual inspections should continue during operations to monitor and verify any detectable damage to ULD components. If visible damage is identified during a visual inspection, the corresponding damage limits specified on the ODLN for that component should be referenced to determine whether the ULD remains serviceable.
1. Pallet Operations
The combination of an aircraft pallet and aircraft pallet net constitutes one form of aircraft ULD. Compliance with applicable standards ensures that they are safe and suitable for use on compatible aircraft. Adhering to the operational standards provided in the ULDR offers reasonable assurance that aircraft pallets comply with the relevant requirements.
2. Pallet Net Operations
Aircraft pallet nets used to cover pallets and restrain cargo are classified as aircraft ULDs under industry standards and must meet airworthiness requirements. The operational standards for pallet nets apply to personnel responsible for securing cargo on certified aircraft pallets where the restraint system is not directly attached to the aircraft structure. Additional pallet net operational standards can be found in the ULD Regulations (ULDR).
3. Pallet Accessory Operations
Aircraft pallet and net operations commonly require the use of aircraft pallet accessories. Some of the most common accessories include:
- Weather protection covers
- Fire containment covers
- Pallet extensions
- Pallet couplers
- Dunnage and support materials
4. Aircraft Container Operations
Aircraft containers used for baggage, cargo, or mail are also classified as aircraft ULDs and must comply with the requirements specified in the ULDR. Aircraft containers must either hold airworthiness certification (TSO C90) or be approved as non-certified units, while also meeting all requirements outlined in the aircraft weight and balance manual and applicable international standards.
