Supplier Quality Guide
Supplier Corrective Action Requests (SCAR): Templates, Examples, and Practical Guidance
Everything quality engineers need to issue, manage, evaluate, and close supplier corrective action requests.
Fundamentals
What is a SCAR?
A Supplier Corrective Action Request (SCAR) is a formal document a customer issues to a supplier when nonconforming product or a process failure is found. It requires the supplier to contain the defect, identify the systemic root cause, implement permanent corrective action, and verify the action worked.
SCARs exist because email threads and verbal commitments do not survive audits. Aerospace (AS9100), automotive (IATF 16949), and medical device (ISO 13485) quality systems require documented supplier corrective action with traceable evidence.
A SCAR is the external trigger for the supplier's internal CAPA process. It usually originates from a nonconformance report (NCR) opened on the receiving floor, a customer complaint, or a supplier audit finding.
Triggers
When should a SCAR be issued?
Not every defect needs a SCAR — single-piece scrap with an obvious cause can be handled by an NCR alone. Issue a SCAR when the issue is repeating, systemic, safety-related, or required by the quality system.
Aerospace example: A casting supplier ships three lots with porosity exceeding ASTM E155 acceptance. Receiving inspection rejects on radiographic review. Issue a SCAR — repeated defect, special process (foundry), and a documented escape from supplier final inspection.
For the customer
How to issue a SCAR
- 1
Define the issue
Part number, lot, date code, quantity, defect description, drawing/spec reference, and the requirement violated. Vague problem statements ('quality issues') produce vague responses.
- 2
Collect evidence
Photos with scale, measurement data, retained samples with traceability, inspection reports, and the receiving paperwork. Evidence travels with the SCAR.
- 3
Define expectations
State explicitly what response format is required (8D, your own SCAR form), what tools are acceptable (5 Whys, Fishbone, Fault Tree), and what evidence must be attached.
- 4
Set due dates
Initial response + containment: 24 hours. Root cause + corrective action: 10 business days. Effectiveness verification: 30 to 90 days based on production cadence.
- 5
Require containment
Suspect inventory at supplier, in transit, at your dock, on your line, and at your customer. Containment without quantities is not containment.
- 6
Evaluate responses
Score with the rubric below. Reject and return — do not accept weak responses to clear the metric. A weak SCAR closure is a problem you will see again.
- 7
Verify effectiveness
Audit the next N lots, check process data, walk the supplier floor if warranted. Verification is a positive confirmation, not the absence of new complaints.
- 8
Close the SCAR
Document the closure with date, verifier name, evidence summary, and any conditions (e.g., 100% inspection for 5 more lots). File for audit.
For the supplier
How to respond to a SCAR
Most SCAR guides only cover how to issue one. If you are on the receiving end — and most quality engineers spend time on both sides — your response determines whether the customer escalates, removes you from approved suppliers, or closes the loop and moves on.
Initial response
Acknowledge within 24 hours with a named owner, target dates, and confirmation that containment is underway. Silence is the worst response — it signals you do not have control of the process.
Containment
Identify and segregate suspect material at every location (supplier, transit, customer, end-customer). Communicate quantities. If you can sort, sort. If you cannot determine boundaries, treat the population as suspect.
Investigation
Use a structured tool — 5 Whys for simple issues, Fishbone (Ishikawa) for multi-cause issues, Fault Tree for complex or safety-critical failures. Document eliminated causes, not just the surviving one.
Root cause expectations
Reach a systemic cause. 'Operator error' is rarely root cause — the real cause is the missing control. Customers in aerospace and automotive will reject 'human error' without a system explanation.
Corrective action expectations
Permanent actions tied to each root cause. Update the PFMEA, control plan, work instructions, and training records. Poka-yoke beats inspection; inspection beats nothing.
Verification
Explicit verification plan with quantitative criteria and a date. 'We will monitor going forward' is not a verification plan. State what data, what threshold, and who signs off.
Common mistakes suppliers make
- Submitting the response on day 10 with no interim updates.
- Repeating the customer's problem statement as the root cause.
- Adding '100% inspection' as the only corrective action — inspection is containment, not correction.
- Updating one work instruction but not the PFMEA or control plan.
- No read-across to similar parts, fixtures, or operators.
- No retained samples to prove the defect characteristics.
- Closing without a verification plan, then reopening the same SCAR 60 days later.
Evaluation
SCAR response scorecard
Score each category from 0–10. A response below 35/50 should be rejected and returned. Use the same rubric every time so suppliers learn what 'acceptable' looks like.
| Category | What good looks like | Score |
|---|---|---|
| Containment | Suspect inventory identified at supplier, in transit, at customer, and at end-customer with quantities, dates, and disposition. | / 10 |
| Root Cause | Structured analysis (5 Whys, Fishbone, Fault Tree) reaching a systemic cause, not 'operator error.' Cause is supported by objective evidence. | / 10 |
| Corrective Action | Permanent actions that address each identified root cause. Updates to PFMEA, control plan, work instructions, and training records. | / 10 |
| Verification | Effectiveness check with quantitative criteria (zero defects in next N lots, Cpk improvement, audit closure). Plan and dates are explicit. | / 10 |
| Read Across | Review of similar parts, processes, and product families that could share the same failure mode. Actions extended where applicable. | / 10 |
| Total | Accept ≥ 40 · Conditional 35–39 · Reject < 35 | / 50 |
Watch outs
Common reasons SCARs are rejected
Root cause is 'operator error'
Operators work inside a system. 'Operator error' is a symptom — the real cause is missing fixture, ambiguous work instruction, no error-proofing, or inadequate training. Ask 'why was the operator able to make that error?'
No objective evidence
Photos, measurement data, process capability studies, fishbone with eliminated causes, retained samples. A narrative without evidence is an opinion.
Corrective action does not match root cause
'Retrained the operator' when the root cause was a missing poka-yoke. The action must directly address each cause identified in the analysis.
No effectiveness verification
A corrective action without a measurable verification plan and a date is a promise, not a fix.
No read-across
If the same fixture, operator, raw material lot, or program touches other parts, those parts share the risk. Read-across is mandatory in aerospace and automotive responses.
For a deeper look at root-cause technique, see the root cause analysis guide and the fault tree generator.
Worked example
SCAR example: casting porosity
Aerospace casting supplier delivers parts with excessive porosity. This is what a strong response looks like end-to-end.
| Problem | Three lots of aluminum investment castings (P/N 47812-A, lots L24-118, L24-121, L24-126; 1,840 pieces total) failed radiographic inspection for porosity exceeding ASTM E155 Class 3. Defects found at the gate area on 23 of 60 sampled parts (38%). |
| Containment | Supplier quarantined remaining inventory (412 pieces). Customer segregated 1,200 pieces at receiving and 228 pieces at the machining cell. End-customer notified — no parts shipped past final assembly. 100% radiographic inspection applied to existing inventory; 188 conforming parts released. |
| Root cause | Fishbone analysis isolated the gating system as the dominant cause. 5 Whys: porosity → turbulent metal flow at the gate → gate cross-section reduced 12% in the most recent tooling refurbishment → refurb spec did not call out gate dimensions → tooling refurbishment work instruction is silent on gating geometry → no PFMEA linkage between tooling maintenance and casting integrity. |
| Corrective action | 1) Tooling restored to original gate geometry, verified by CMM. 2) Tooling refurbishment work instruction updated to require gate dimension verification. 3) PFMEA updated — tooling refurbishment added as a process step with gating dimensions as a special characteristic. 4) Operators trained on revised work instruction (sign-off attached). 5) Read-across: 6 other part numbers run on similar tooling reviewed, 2 received the same refurb update. |
| Verification | Next 5 production lots subjected to 100% radiographic inspection (acceptance: zero Class 3+ porosity). Lots L24-134 through L24-148 passed (2,210 pieces, 0 rejects). Sampling plan returned to AQL 1.0 with quarterly radiographic audit. Verification signed by supplier QA Manager and customer SQE. |
| Closure | SCAR closed 47 days after issue. Conditions: quarterly radiographic audit retained for 12 months; PFMEA revision attached to closure record. Filed against supplier scorecard with positive corrective action credit. |
Downloads
Free resources
SCAR Template
Free PDF SCAR template, 8D-aligned. AS9100, IATF 16949, ISO 13485 ready.
OpenCorrective Action Plan Template
Standalone CAP document — problem, root cause, actions, verification.
OpenCAPA Guide
Corrective and preventive action process explained end-to-end.
OpenNCR Template
Document nonconformances with disposition, containment, and CAPA trigger.
OpenRoot Cause Analysis Template
Full RCA worksheet — problem statement through CAPA closure.
OpenFault Tree Generator
Excel-based fault tree builder for structured root cause analysis.
OpenFAQ
Frequently asked questions
What is a supplier corrective action request?
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A Supplier Corrective Action Request (SCAR) is a formal document issued by a customer to a supplier requiring them to contain a quality issue, identify the root cause, implement corrective action, and verify that the action is effective. It creates a documented record of supplier nonconformance and the actions taken to prevent recurrence.
Who issues a SCAR?
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SCARs are typically issued by the customer's Supplier Quality Engineer, Quality Manager, or Supplier Development Engineer. In larger organizations they may be initiated by receiving inspection, the manufacturing floor, or the customer of your customer (cascaded SCARs).
How long should a supplier have to respond?
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Industry practice is 24 hours for initial response and containment, 10 business days for root cause and corrective action, and 30 to 90 days for effectiveness verification. Aerospace (AS9100) and automotive (IATF 16949) programs often use shorter timelines for safety-critical issues.
What is the difference between a SCAR and CAPA?
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A SCAR is an external request issued to a supplier. A CAPA is an internal corrective and preventive action process that any organization runs against its own quality events. A SCAR usually triggers the supplier's internal CAPA, and the SCAR response is the visible output the customer receives.
Can a SCAR be rejected?
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Yes. Customers commonly reject SCAR responses for weak root cause (operator error without a system explanation), no objective evidence, corrective actions that do not address the root cause, missing effectiveness verification, or no read-across to similar parts and processes.
What should be included in a SCAR response?
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A complete SCAR response includes immediate containment with quantities and locations, a structured root cause analysis (5 Whys, Fishbone, or Fault Tree), corrective actions tied to each root cause, preventive actions and read-across to similar products, an effectiveness verification plan with data, and document updates (PFMEA, control plan, work instructions).