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Aerospace & Defense

Nadcap Special Process Accreditation: Heat Treating, Welding, NDT & Coatings for Aerospace

Exceleor Editorial Team March 25, 2026 13 min read
Nadcap Special Process Accreditation: Heat Treating, Welding, NDT & Coatings for Aerospace

Nadcap (National Aerospace and Defense Contractors Accreditation Program) is the gold standard for special process approval in aerospace. If you perform heat treating, welding, non-destructive testing, chemical processing, or coatings for aerospace OEMs, Nadcap accreditation is not optional — it is a prerequisite for doing business. We cover the Nadcap audit process, the most common audit findings by commodity, how to prepare your special process documentation, and how Nadcap integrates with your AS9100 certification.

Understanding Nadcap

Nadcap (National Aerospace and Defense Contractors Accreditation Program) is the industry-managed accreditation program for special processes in aerospace. Special processes — heat treating, welding, NDT, coatings, and chemical processing — produce results that cannot be fully verified through subsequent inspection. Quality must be built into the process itself because you cannot inspect it in afterward.

Nadcap accreditation is required by most major aerospace primes including Boeing, Lockheed Martin, Airbus, Rolls-Royce, and GE Aviation. Without Nadcap, you cannot perform in-house special processes for these customers. Understanding Nadcap requirements is essential for aerospace suppliers performing or planning to perform special processes.

Key Special Process Categories

Nadcap covers multiple special process categories. Heat treating includes solution treating, aging, annealing, and hardening of metals. Welding covers fusion welding, resistance welding, and brazing. Non-destructive testing includes radiography, ultrasonic, magnetic particle, penetrant, and eddy current inspection. Coatings encompass plating, painting, thermal spray, and anodizing. Chemical processing covers cleaning, etching, passivation, and conversion coatings.

Each category has specific Nadcap checklists that define the technical requirements, equipment qualifications, personnel certifications, and process control documentation required for accreditation. These checklists are significantly more detailed than AS9100 requirements for special process control.

The Accreditation Process

Nadcap accreditation involves a detailed application, document submission, and on-site audit by a Nadcap-qualified auditor. The audit evaluates your process control documentation, equipment calibration and qualification, personnel qualifications, process parameters, and quality records. Findings must be resolved within defined timelines.

The accreditation cycle is 12 to 18 months for initial accreditation and 12 to 24 months for renewal, depending on audit performance. Merit status — achieved through consistently strong audit performance — extends the audit cycle and reduces oversight requirements. Poor performance shortens the cycle and may trigger additional audits.

Integration With AS9100

Nadcap and AS9100 are complementary programs. AS9100 provides the quality management system framework. Nadcap provides the detailed technical requirements for special processes within that framework. Your AS9100 system should reference Nadcap requirements in your special process procedures and ensure that Nadcap accreditation status is maintained as part of your ongoing compliance program.

Exceleor supports aerospace suppliers in achieving and maintaining both AS9100 certification and Nadcap accreditation. Our active auditing experience in both programs ensures that your quality system addresses the full spectrum of aerospace quality requirements.

NadcapSpecial ProcessesAerospaceAS9100NDTHeat Treating

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