Standards Forum

in Vol. 24 - September Issue - Year 2023
Supplier Audits and Nadcap


In the Aircraft manufacturing industry quality and reliability are obvious matters of extreme importance, and the industry works hard to ensure the product delivered meets only the highest possible standards.  A key element in the achievement of this goal, is the systematic auditing of the supply chain, especially of, but not restricted to special processes.  Nadcap is a key third party certification that is designed to reduce the OEM Supplier Quality Department’s loads and consequently costs. 

The Nadcap program was introduced as a globally accepted method to ensure processes in terms of manufacturing and processing quality control are consistent across the industry, and of the highest quality possible.  Achievement of certification to Nadcap requirements is considered a significant accomplishment, particularly, when Merit is achieved.  Merit is awarded when very low non-conformance numbers are achieved.  It is then that the auditing frequency is permitted to be extended from 12 months to 18 months and even to 24 months.

Although the Nadcap program has been highly successful and adopted by almost all major manufacturers of aircraft, there has been a shift away from a complete reliance on this method of certification and to qualify the suppliers on the OEM’s ASL (Approved Supplier List).  The principal reason for this change, which is being adopted by an increasing number of OEMs, is that there are many specialised safety critical requirements, that are unique to the individual OEM.  A Nadcap audit could still result in those specific requirements not being audited, and existing issues to remain undetected especially when special processes are involved.   A special process is generally one that cannot be confirmed as being correctly applied, without rendering the component that has been processed and subsequently tested, unfit for purpose.

The ever evolving and improving standards defined by the OEM’s can be efficiently flowed down to the supply chain via the relevant specification.  The supplier specification review system reviews the resulting changes for continued compliance and ensures that product integrity is achieved.  It is not practical to flow down such changes into the Nadcap process without significant delays being incurred.  Where a requirement which is unique to a particular OEM is incorporated in a checklist it then has to be uniquely identified as being non-applicable to the requirements of the other OEM’s.

When product being audited does not belong to an OEM that has flowed down a special requirement into the Nadcap checklist, it is possible that the requirement never becomes effectively audited.  This can occur when there is not a relevant product present on the premises at the time of the audit.  Steps are taken to try to prevent such a situation from occurring by the use of a matrix which is updated and maintained at the time of the audits by the Nadcap Auditor on which the identification of the OEM, Part Number, Machine and Operator is recorded.  The next audit then has to avoid re-auditing the previously audited areas by referring to the Matrix.  This in turn helps ensure a wider variety of product is audited.

It is crucial that the auditor is experienced in the specific requirements in order to perform an effective audit.  While Nadcap auditors are highly trained top-level experts in their particular discipline, they cannot be expected to be experts in the explicit requirements that are unique to a particular OEM.  It is important to consider that the reintroduction of audits on the supply chain by OEMs will not result in the demise of the Nadcap methodology.  Instead, the OEM auditors will be well aware of the areas covered by the Nadcap process thus preventing a duplication in effort.  They will then be able to focus on their own special requirements.  

Another crucial factor in this changing landscape is an increasing importance for transparency and traceability in the supply chain. OEMs are facing mounting pressure from consumers, regulatory bodies, and stakeholders to ensure their products are sourced and manufactured ethically and sustainably.  An area that is not covered by Nadcap and by conducting their own audits on the supplier base, companies can confirm that their suppliers are adhering to relevant social, environmental, and ethical standards. This helps ensure that risks associated with non-compliance are mitigated and their valuable reputation is protected.

To conclude, the concept of an audit conducted by an appointed third-party organisation, to a series of checklists which meets or exceeds the requirements of all OEMs has potentially been challenged by the ever-changing dynamic in the aerospace industry.   However, the overall goal of a deep and detailed audit, using checklist compiled by a consortium of OEMs working together has been spectacularly achieved.  The re-introduction of supplier audits to assure the appropriate control of OEM specific requirements is now filling a previously exposed gap in the overall concept.  This is now resulting in a more effective auditing regime than had previously been achieved.

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MFN Contributing Editor