Supplier flow-down is the practice of passing applicable customer, quality, engineering, regulatory, and program requirements from a buying organization to its suppliers and, when needed, to sub-tier suppliers. It helps ensure that external providers understand which requirements apply to the work, materials, parts, services, records, and evidence they provide.
In manufacturing and regulated supply chains, supplier flow-down commonly appears in purchase orders, supplier quality clauses, drawings, specifications, work statements, contracts, and supplier portals. Examples may include requirements for material traceability, approved process sources, inspection records, revision control, counterfeit part prevention, product safety considerations, or notification of nonconforming product.
Supplier flow-down should not be confused with supplier evaluation or supplier approval. Flow-down is about communicating applicable requirements. Evaluation and approval are about assessing whether a supplier is suitable or authorized for the work. Flow-down also does not, by itself, prove that requirements were met; objective evidence, inspection, records, or other controls may still be needed.
In AS9100 and other aerospace or defense-oriented quality systems, supplier flow-down is a common term because requirements often extend beyond the direct supplier to special processors, distributors, subcontractors, and other external providers in the supply chain.