Core model status Core model status

The Core model  Committee Draft (CD/TS) successfuly balloted at ISO in March 2021

About 50 comments have been received and are currently in resolution process.

Next step will be the publication of the Core model as an ISO Technical Specification (ISO/TS 10303-4000).

Core Model Technical Report Core Model Technical Report

ISO STEP Core model Technical Report available 

The “Core model” is an essential component of the STEP Extended Architecture. The Core model, developed in SysML, provides a set of data interoperability capabilities harmonised and shared between STEP Application Protocols (AP242, AP243 MoSSEC, AP239 PLCS).

Understand the work done these last years and assess the completeness and maturity of the result achieved by downloading:

  • the STEP Core model Technical Report (pdf file)
  • and its annex: Core Model HTML documentation - working draft (27 Gb zip file to be unziped on your computer to navigate in Core model documentation).

Published in March 2020

Second AP239 ed3 project at ISO Second AP239 ed3 project at ISO
The two phases of AP239 ed3 development:
  • The first phase of the AP239 ed3 project has been focused on harmonization work, developing the harmonized Core model. The harmonized Core model is an essential component of the STEP Extended Architecture, and is intended to be shared by all STEP Application Protocols in the future (starting from AP239 and AP242).
  • The second phase is aiming at developing AP239-specific components and to build the AP239 ed3 Draft International Standard, to be turned into an International Standard (ref. ISO process).
From an administrative viewpoint, the first phase has been linked to a first ISO AP239 ed3 project, and the second phase will be associated to a second ISO AP239 ed3 project (due to the time needed to perform the harmonization work). 
During the AP239 ed3 workshop in Asheville, NC (USA) in March 2019, the AP239ed 3 Steering Committee has then made the decision to propose a New Work Item at ISO for the second AP239 ed3 project. This NWI will be balloted at ISO in Q1 2021.
STEP AP239 ed3 White Paper STEP AP239 ed3 White Paper

The STEP AP239 ed3 "PLCS" White Paper was submitted as an accompanying document of the related ISO New Work Item in November 2015.

You can download the White Paper here.

Introduction to STEP AP239 ed3 project Introduction to STEP AP239 ed3 project

ISO 10303-239 “Product Life Cycle Support” Edition 3 project


“Our product information lives for more than 50 years, and we need to understand how to manage that over time”.

Enterprises today are more aware that data and information assets represent significant values, with direct influence on their financial performance and operational capabilities. Poor quality and poor management of data and information resources are recognized as major cost drivers and a significant obstacle to business performance and improvement.

ISO standard 10303 STEP with its Application Protocols, Methods and Models represents a viable alternative to the current chaos of multiple, fragmented standards and proprietary data formats, and is a proven way to ensure fast, reliable data exchange between partners and suppliers using different systems. STEP supports engineering, manufacturing, electrical/electronics, architecture and product life cycle information.
AP 239 PLCS has proven its capabilities for maintenance and support data exchange across the whole lifecycle of complex products like those in focus by A&D Industry. Nevertheless, complex EXPRESS implementations of edition 1 and edition 2 resulting in big files, the deprecation of OASIS DEXlib and discussions/arguments of OASIS PLCSlib based on edition 2 and the non-standardized Reference Data Library (RDL standardized in OASIS but not at an ISO level) have hampered further potential implementations.

STEP AP 239 edition 3 project objectives

Considering above status, and after analysis of requirements from A&D industries (ASD SSG, ASD ILS DMEWG, SAE LOGSA, LOTAR, OASIS PLCS members) and from MoDs and Defense bodies (US, UK, Swedish, Norwegian and French), it is clear to all stakeholders that a new version of STEP AP239 (named “edition 3”) is needed to secure past investment in PLCS and to answer to new business needs from Industry and from Operators.

The proposed STEP AP 239 edition 3 project was formalized end of 2015 through a White Paper (ref).

The main objectives of STEP AP 239 edition 3 are:

  • Realization of an efficient Integrated Logistic Support (ILS), by integration of the different logistic disciplines, covering all aspects of supportability over the entire life cycle of a product. In particular AP 239 edition 3 intends to ensure the full support of ASD-AIA ILS S-series specifications based on information needs identified by ASD-AIA ILS DMEWG and also GEIA-STD-0007.
  • Minimize the cost and the delay of development of interfaces based on AP 239 :
    • Ease the understanding of the standard.
    • Facilitate the mapping with business specifications (in particular with the AIA/ASD ILS Suite and the GEIA STD 0007) by providing high level business objects (template concept).
    • Propose simpler and performance implementation methods of AP 239, based on main stream technologies, taking into account lessons learnt from AP 242, OASIS PLCS PSM/PLCSlib, ASD DMEWG, DoD requirements in GEIA-STD-0007 rev C.

A normative XML schema is the priority – based on the core model (and related derived XSD) of the new STEP architecture, across all STEP APs.
Web based implementation methods (SOA services and linked data/OSLC) shall be developed in addition to P21 and XML methods.

  • Ability for manufacturing Industries and their customers to manage design, product and service information throughout the product lifecycle, including rigorous configuration management and the long term retention of information, where the data is ‘created once and used many times’, by ensuring interoperability of AP 239 ed3 with other STEP APs (incl. AP 242), and providing unambiguous implementation methods within the common new STEP architecture.
  • Contribute to a reliable and harmonized ISO/TC 184/SC 4 information model through the product life cycle and across domains thanks to the finalization of the harmonization between AP 239 and AP 242.
  • Preserve legacy investment (current AP 239 based systems) thanks to upward compatibility (as far as possible) with former standard edition, and a mapping between PLCS PSM and AP 239 ed3.
  • Improve interoperability within domains and across domains thanks to a mechanism for sharing common information semantics (e.g. classification and reference values defined in common Reference Data Libraries) managed at an international level.

Consistency with other standardization projects

This standard will be consistent with the ISO 10303 STEP modular Application Protocols described in the following figure:


As illustrated in the next figure, the STEP series of standards has been designed to cover the entire life cycle of product data across all functions throughout the supply network.

Together these STEP Application Protocols will be the foundation for ILS specifications, for developing the support solution based on product design data and support requirements, to maintaining the product and providing feedback to Aerospace and Defence industries. This should extend the use of STEP by the main manufacturing industries and the support by PLM software suppliers and integrators.

The project will take also into account close coordination with other related standardization projects (e.g. LOTAR, STEP AP 242 ed2, STEP AP 209, STEP AP 210, STEP AP233, PDM-IF / Future PLCS Implementor Forum).


The project plan is described in the following figure, with a final result (AP239 ed3 International Standard) expected to be published by ISO in 2022:

Call for participation

Don’t miss the opportunity to build the ISO standard that will enable the future product support services, to be used from design of product support to operation!

Join the international consortium, by contacting Yves Baudier and Patrick Walsh (project co-leaders).