BS ISO 21785:2020 Air cargo unit load devices — Load distribution model.
1 Scope
This document defines the industry agreed model for load distribution on air cargo unit load devices
(ULD) bases to apply the maximum allowable centre of gravity (C.G.) eccentricity.
Its purpose is to establish a common reference load distribution algorithm for:
a) comparable and repeatable ULD testing methods, or equivalent numeric simulations;
b) aircraft structure and cargo systems design assumptions, consistent with existing airframers practices; and
c) definition of operators unit load devices utilization rules and cargo build-up training programs.
It applies to all types of unit load devices intended for use on board civil transport aircraft and airworthiness approved in accordance with the performance requirements and testing parameters of either ISO 21100 or, as applicable, ISO 8097.
It also applies to non-airworthiness approved (non-certified) containers as defined in ISO A118, the utilisation of which is controlled by the provisions of the aircraft type’s Weight and Balance Manual and other airframe manufacturer’s documents.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO_a091, Aircraft — Minimum airworthiness requirements and test conditions for certified air cargo unit load devices
ISO 10254. Air cargo and ground equipment — Vocabulary
ISOIIIO.0. Air cargo unit load devices — Performance requirements and test parameters
3 Terms and definitions
For the purposes of this document, the terms and definitions of ISO 10254 and the following apply:
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at
— IEC Electropedia: available at h.ttpJ/ ISO 21785 pdf download.