ISO 21100:2020

Overview - What ISO 21100:2020 covers

ISO 21100:2020, Air cargo unit load devices - Performance requirements and test parameters, defines the minimum airworthiness performance requirements and test parameters for air cargo unit load devices (ULDs) - including containers, pallets and nets - intended for carriage on certified civil transport aircraft. It provides a uniform technical reference and means of compliance for ULD airworthiness approval (TSO-type reference) for airplanes certificated to EASA CS-25 or 14 CFR Part 25 (or equivalent), while explicitly excluding aircraft design and operating requirements (these remain in the aircraft Weight and Balance Manual).

Key facts:

• Applies to certified ULDs for transport-category airplanes.
• Focuses exclusively on ULD airworthiness approval and test parameters.
• Replaces ISO 8097 for new ULD models and updates the 2014 edition.
• Dimensions expressed in mm (inches in brackets); forces in N (lbf shown).

Key technical topics and requirements

ISO 21100 organizes technical requirements and tests into clear sections; major topics include:

• Classification: types, sizes, configurations and form factors of ULDs.
• Materials, fabrication and workmanship: minimum material and construction quality requirements.
• Protection, marking and inspection: identification, inspection provisions and protective features.
• Fire protection and rapid decompression: performance needs related to in-flight conditions.
• Dimensions and tolerances: nominal base dimensions and acceptable variances.
• Strength and restraint criteria: ultimate load criteria, restraint performance, pallet and net specific tests (including pallet track tests for strap compatibility).
• Environmental degradation: durability and ageing considerations.
• Tests and test parameters: defined test methods, parameters and result evaluation.
• ULD configurations and restraint conditions: detailed configuration drawings and recommended restraint condition tests.

Notable updates in the 2020 edition include pallet track tests, added stiffness requirements for container base edges, configuration clarifications (e.g., certain configurations limited to lower-deck use), and adjustments to several restraint-condition procedures.

Practical applications - who uses ISO 21100

ISO 21100 is used by:

• ULD manufacturers and designers for product development and type approval.
• Certification authorities and test laboratories as a means of compliance and as a standardized test reference.
• Airlines, cargo operators and maintenance organizations for procurement, acceptance testing and conformity checks.
• Regulatory bodies and industry auditors for verification of airworthiness documentation.

Benefits include harmonized approval criteria, clearer acceptance testing, and reduced risk of compatibility or restraint failures when ULDs are installed in certified aircraft cargo compartments.

Related standards and references

• ISO 8097:2001 (prior ULD reference; still applicable for sizes/types not covered by ISO 21100)
• EASA CS-25 and 14 CFR Part 25 (aircraft cargo restraint and occupant protection requirements)
• Relevant ISO standards and industry documents on ULD design, load distribution, contours and test methods (see ISO 21100 bibliography).