Unauthorized Changes to Special Process Execution
Published .
Applicable Standards
AS9102Applicable Sections
- ✓Form 2 — Product Accountability
- ✓Form 3 — Characteristic Accountability
Related
- AS9100
- AS13100
- Nadcap
Topics
- special-process
- configuration-management
- process-control
- supplier-quality
- nadcap
- frozen-process
- unauthorized-change
- engineering-change
A supplier was contracted to perform manufacturing that included a special process, such as chemical conversion coating or brazing, defined on the engineering drawing. During production, the supplier identified a potential alternative material or a different class of coating for a touch-up application, believing it was functionally equivalent.
Without obtaining formal engineering authorization from the customer, the supplier proceeded with the substitution. This unilateral change violated the "frozen process" requirements dictated by the drawing and associated specifications, as the output of a special process cannot be fully verified non-destructively.
Key Takeaways
- The deviation was discovered during a quality audit, resulting in a product non-conformance and a formal corrective action request.
- This led to production delays and required a formal engineering disposition for the affected hardware.
- Without obtaining formal engineering authorization from the customer, the supplier proceeded with the substitution.
Common Mistakes
- Drawing notes not captured as characteristics.
- Treating a design change as a full FAI re-accomplishment instead of a partial/delta.
Best Practice
Suppliers must strictly adhere to all specified materials, parameters, and procedures for special processes as defined by the engineering authority. Any proposed change or substitution requires explicit, documented approval from the customer's engineering function prior to implementation.
Reflects the recommended position based on community discussion and expert review.
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