NADCAP Audit Preparation Checklist for Aerospace Subcontractors
I sat in on a heat treat shop preparing for its first NADCAP audit. They had spent eight months building documentation and training procedures. Two weeks before the audit, the quality manager discovered that the pyrometry surveys for the four production furnaces had been signed off by a calibration technician whose certification had expired four months earlier. The audit was rescheduled. The shop lost three months of revenue from contracts that depended on the certification.
NADCAP audit preparation checklist work is not a formality. It is the documented evidence that the shop's special process meets the AC7000-series audit criteria, and a single missing record or expired certification can fail the audit even when the underlying process is sound. This guide walks through the documentation, training, calibration, and audit-day items that subcontractors preparing for a NADCAP heat treat, NDT, chemical processing, or composites audit should have in place.
For the relationship between NADCAP and AS9102 FAI, see NADCAP special process requirements AS9102 FAI.
What NADCAP Audits Cover
NADCAP (National Aerospace and Defense Contractors Accreditation Program) audits assess whether a subcontractor's special process meets the technical requirements of an industry-standard audit criteria document. The audit criteria documents are called AC7000-series checklists, and each covers a specific process family.
AC7102 covers heat treating. AC7114 covers nondestructive testing (NDT) operations including penetrant, magnetic particle, radiographic, ultrasonic, and eddy current. AC7108 covers chemical processing including anodize, conversion coating, plating, and chromate. AC7118 covers composites manufacturing. There are several other AC checklists for specialized processes such as welding (AC7110), coating (AC7109), and materials testing (AC7101).
The audit is performed by a NADCAP auditor (a credentialed independent assessor) over a one to three day on-site visit, and the audit findings are reviewed by a task group of customer representatives who decide pass or fail. The audit reviews documentation, observes the actual process operation, and interviews operators and supervisors.
NADCAP Audit Preparation Checklist: Documentation
The single largest preparation effort is the documentation set. NADCAP auditors review documentation extensively, and missing or out-of-date documents are the most common finding category.
Quality manual. The shop's quality manual must explicitly identify the special process scope (such as "heat treatment of aluminum and titanium aerospace alloys") and reference the controlling industry specifications. The same scope language must align with the shop's AS9100 quality management system, which we covered in AS9100 certified shop quoting best practices.
Procedures. Each operation in the audit scope needs a written procedure with revision control. For a heat treat audit (AC7102), this includes furnace operation, pyrometry instrumentation, load patterns, time-temperature profiles for each alloy and condition, and quench operations.
Work instructions. Operator-level instructions for each routine task, posted at the work station or accessible to the operator. Work instructions reference the procedures and translate procedures into shop-floor actions.
Records. Furnace charts, pyrometry survey records, calibration certificates, training records, deviation logs, and customer-specific records (such as the AMS 2750 reports for heat treat or AMS 2700 for passivation). Records must be retained per the shop retention policy and per customer-flow-down requirements.
Material certifications. Incoming material certificates for any consumable that affects the process, such as quench oils, plating bath chemistries, NDT consumables, and shielding gases.
A documented index of where each required document is stored, with a current revision number, eliminates the audit-day scramble that produces missing-document findings.
Calibration and Pyrometry Requirements
Calibration of process instrumentation is one of the highest-rejection categories on NADCAP audits across all process families.
For heat treat (AC7102), pyrometry must conform to AMS 2750 with all instrumentation calibrated, instrument calibration certificates current, temperature uniformity surveys (TUS) within the calibration intervals required for the furnace class, system accuracy tests (SAT) current, load thermocouples calibrated, and survey results signed off by qualified personnel.
For NDT operations (AC7114), instrument calibration includes the eddy current and ultrasonic equipment calibration certificates, the magnetic particle gauss meter, the penetrant ambient lighting meter, and the reference standards used for sensitivity verification. Each must have current calibration and traceability to a national standard such as NIST.
For chemical processing (AC7108), calibration includes the temperature controllers on plating tanks, the ammeters and voltmeters for plating current, the pH meters and conductivity meters for bath chemistry, and any titration equipment for bath analysis.
Calibration intervals are typically driven by the AC7000-series checklist and by the underlying industry standard. Internal calibration programs must have qualified calibration technicians whose certifications are current at the time of the audit.
Training and Operator Qualification
NADCAP audits review whether the people operating the process are qualified to do so.
Operator training records. Each operator working in the special process must have a documented training record showing initial training, periodic refresher training, and proficiency verification. The training program references the shop's procedures.
Operator qualifications. For NDT operations, operators must be certified per ASNT SNT-TC-1A, NAS 410, or the customer-flowed equivalent (such as PWA 13 for Pratt and Whitney) at the appropriate level (typically Level II for routine inspection, Level III for procedure approval). For welding (AC7110), welders must be qualified per the relevant AWS or BAC specification.
Supervisor qualifications. Process supervisors and quality personnel must have documented technical training in the process. For heat treat, this typically includes formal metallurgy training. For NDT, supervisors are typically Level III certified.
Training matrix. A current document showing which operators are qualified for which operations, with effective dates and renewal dates. Auditors check this against the production floor staffing to verify that only qualified operators are running the process.
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Process Control Evidence
The audit reviews how the shop demonstrates that the process is in control during routine production. The evidence is statistical and historical, not theoretical.
Statistical process control charts for key process variables (furnace temperature, plating thickness, weld penetration, NDT sensitivity readings) showing the variation over time and the response to out-of-control signals.
Deviation log documenting every excursion outside the procedure-required limits, the root cause, and the disposition of affected product.
First piece and first article records showing that production starts with verified-correct setup. These records link to the AS9102 FAI for parts that have a first article requirement.
Periodic process audit records showing that the shop's internal quality system audits the special process at the procedure-required frequency.
The NADCAP auditor will sample several production lots and trace each one back through the records to verify continuous control. Gaps in the historical records, especially during periods of high production or staff turnover, generate findings.
Audit-Day Logistics
The audit day itself has predictable failure modes that shops with otherwise solid preparation still hit.
Personnel availability. The auditor will need to interview operators, supervisors, calibration technicians, training coordinators, and the quality manager. Schedule these people for availability during the audit window. Auditors who arrive and find that the calibration technician is on vacation will note it.
Process running during audit. The auditor wants to observe the actual process operation, not a simulated demonstration. Schedule production work in the audit scope during the audit day so the auditor can see the operation, ask the operator questions, and observe the records being generated in real time.
Document accessibility. Documents requested by the auditor should be retrieved in minutes, not hours. A shop that takes 30 minutes to find a specific calibration certificate has effectively failed that document review. An indexed and electronically searchable document repository solves this.
Findings response. The audit closeout meeting will list any findings. The shop's response (typically due within 30 days of the audit) must include a root cause analysis, a corrective action, and an objective evidence completion plan. The same framework covered in common AS9102 Form 3 rejection reasons applies here.
NADCAP Audit Preparation Checklist for Specific Process Families
The general NADCAP audit preparation checklist work above applies to all process families. Each AC7000-series checklist adds family-specific items.
For AC7102 heat treat: AMS 2750 pyrometry conformance is the highest-attention area. TUS, SAT, instrument calibration, load thermocouples, and the relationship between furnace class and pyrometry frequency must all be current. Heat-treat operations frequently appear as Boeing flag notes pointing to BAC5605 or AMS 2759, which we covered in Boeing flag notes interpretation.
For AC7114 NDT: Operator certification under NAS 410 or ASNT SNT-TC-1A, written procedures for each method (penetrant, magnetic particle, ultrasonic, radiographic, eddy current), reference standards, and sensitivity verification records are the high-attention items.
For AC7108 chemical processing: Bath chemistry control records, water quality records, rinse effectiveness records, and the specific specification conformance evidence for each plating type (such as MIL-A-8625 for anodize or BAC5009 for cadmium plating) are the high-attention items.
For AC7118 composites: Material control of pre-preg, oven and autoclave instrumentation calibration, lay-up procedures, and cure cycle records are the high-attention items.
What Mavlon Does for NADCAP-Related Documentation
Mavlon is not a NADCAP audit preparation tool, but the special process callouts on aerospace drawings (BAC plating, AMS heat treat, BSS NDT specifications) get extracted and surfaced during drawing review. For a shop preparing a NADCAP audit, the catalog of process specifications cited across recent quoted work is a useful input to the audit scope definition. For shops that flow special processes to subcontractors, Mavlon captures the cited specification on AS9102 Form 2, supporting the audit-day documentation trail.
Want to see how Mavlon catalogs special process callouts across your quoted work? Book a 30-minute demo and bring a sample of your recent aerospace RFQs.