An OEM should usually issue a supplier NCR when it needs to formally document, segregate, disposition, and trace a specific nonconforming part, lot, document, process output, or delivery. A SCAR should be issued when the OEM needs the supplier to perform root cause analysis and corrective action because the issue is significant, recurring, systemic, escaped, or indicates a breakdown in the supplier’s quality system. The NCR controls the nonconforming condition; the SCAR drives corrective action beyond that individual instance.
Use a supplier NCR for the specific nonconformance
A supplier NCR is normally the right mechanism when the immediate problem is a defined nonconforming condition that must be recorded and dispositioned. That may include dimensional nonconformance, material or certification mismatch, missing required documentation, damaged product, wrong revision, labeling error, or failure to meet purchase order or drawing requirements.
The NCR should support containment, traceability, disposition, and objective evidence. Depending on the program and delegated authority, disposition may involve use-as-is, repair, rework, return to supplier, scrap, or customer approval. In aerospace programs, the authority to disposition nonconforming product is not something to assume; it depends on contract flowdowns, design authority, customer requirements, MRB delegation, and internal procedures.
Use a SCAR when corrective action is required
A SCAR is appropriate when the OEM expects the supplier to investigate why the issue occurred, why it was not detected, and what will be changed to prevent recurrence. It is not just a stronger NCR. It is a corrective action request, commonly tied to RCCA, 8D, CAPA, or supplier quality escalation workflows.
Common triggers for a SCAR include:
- Repeat NCRs for the same part, process, characteristic, document, or supplier site.
- An escape that reached the OEM, customer, installation point, flight hardware, or fielded product.
- A nonconformance affecting safety, fit, function, interchangeability, key characteristics, or regulatory/customer obligations.
- Evidence that the supplier’s inspection, process control, configuration control, or sub-tier control failed.
- Falsified, altered, missing, or unreliable objective evidence, including certificates, test reports, or inspection records.
- Failure to follow approved processes, special process requirements, frozen planning, or revision-controlled technical data.
- A trend showing deterioration in quality performance, even if each individual issue appears minor.
Do not issue a SCAR for every NCR by default
Issuing a SCAR for every supplier NCR can overload suppliers and OEM supplier quality teams without improving control. It can also dilute attention from the issues that actually require RCCA. Many aerospace organizations use thresholds based on severity, recurrence, escape status, risk to product conformity, supplier history, and contractual requirements.
That said, a single severe NCR can justify a SCAR. Waiting for recurrence is not appropriate when the issue suggests a serious process breakdown, unreliable records, unauthorized change, or risk to delivered product.
How the two records should connect
In a controlled process, the NCR and SCAR should be linked, not treated as disconnected quality records. The NCR records the product or delivery nonconformance and its disposition. The SCAR records containment, root cause, corrective action, effectiveness checks, and closure evidence.
In brownfield environments, this linkage is often difficult because NCRs may live in MES or QMS, supplier actions in a supplier portal or QMS, purchase order data in ERP, and drawing or revision data in PLM. If those systems are poorly integrated, teams may rely on manual cross-references, attachments, and periodic reconciliation. That is workable only if document control, audit trails, ownership, and change control are clear.
What is site-specific
The exact decision rule is usually defined by the OEM’s QMS procedure, customer flowdowns, AS9100-aligned supplier quality process, program risk classification, and contractual language. Some customers mandate SCARs for certain defect types or escapes. Some programs require customer notification before disposition. Some suppliers may have delegated authority, while others may not.
No NCR or SCAR workflow by itself guarantees compliance, audit acceptance, or effective corrective action. The records must be accurate, timely, traceable, and supported by competent review. Closure should be based on evidence, not just supplier response text.