Written Practice for Aerospace NDT (SNT-TC-1A)
The aerospace written practice is the document that defines how the employer trains, examines and certifies its NDT personnel. Built on ASNT SNT-TC-1A (2024), it is approved by the employer's NDT Level III and carries the customer's aerospace flow-down requirements; a contracted Level III can author and sign it.
The finding auditors record against this document is: Written procedure and observed practice disagree during a job audit: the technique the operator ran is not the technique the procedure specifies. For aerospace NDT the personnel standard is the employer's written practice. Built on ASNT SNT-TC-1A (2024), it qualifies Level I, Level II and Level III personnel through training, documented experience, General, Specific and Practical examinations and vision examinations, approved by an NDT Level III. Aerospace work adds what the customer flows down: prime process specifications, ASTM E1417, E1444 and E2375 technique requirements and practical examinations on representative parts. Nadcap AC7114 then audits whether the written practice, the certification files and the job records agree.
Source: ASNT Recommended Practice No. SNT-TC-1A (2024) with Addendum, ASNT standards listing (asnt.org), for personnel qualification, certification and the recommended recertification interval. PRI Nadcap programme material and AC7114 for the audit sequence, the 30-day pre-audit package, recurring nonconformances, the Responsible Level 3 questions (5.5.1 to 5.5.4) and the Supplier Merit Program 12/18/24-month intervals (p-r-i.org), plus Quality Magazine's Nadcap NDT audit perspective. 14 CFR Part 145 and FAA Advisory Circular 65-31B for repair-station NDI personnel and outside agencies. Research checked August 2026.
| Item | What applies | Why it matters |
|---|---|---|
| Regime | Aerospace NDT personnel qualification and certification under an employer written practice built on ASNT SNT-TC-1A, audited through customer flow-down, Nadcap AC7114 and FAA Part 145 | Enforced through customer flow-down, Nadcap AC7114 audits and, for repair stations, the FAA under Part 145 |
| Document | Written Practice | the document that defines how the employer qualifies and certifies its own NDT personnel |
| Owner | the employer's Level III | The signature an auditor traces back |
| Where it is checked | The Nadcap NDT Task Group votes on accreditation; First reaccreditation audit within twelve months of the initial audit;. | Usually against a sampled job, not in isolation |
| Common failure | Self-audit not performed, or performed without all applicable job audits, consistently among the most-cited AC7114 nonconformances | The gap between the manual and the job file |
What must a written practice contain under Aerospace NDT (SNT-TC-1A)?
It has to satisfy Aerospace NDT (SNT-TC-1A) as ASNT publishes SNT-TC-1A; primes, Nadcap and the FAA audit its application. The employer's NDT Level III approves the written practice built on it, primes flow personnel and process requirements down through purchase orders, the Performance Review Institute (PRI) audits NDT suppliers to Nadcap AC7114, and the FAA oversees repair stations under 14 CFR Part 145 with Advisory Circular 65-31B as its guidance on NDI personnel. enforces it: the document that defines how the employer qualifies and certifies its own NDT personnel. The test is not completeness on paper but traceability — an auditor picks a finished job and works backwards to this document, so anything it claims must be demonstrable on that job.
Who signs the written practice for Aerospace NDT (SNT-TC-1A)?
The employer's Level III. Because this regime accepts employer-based certification, that role can be filled by a contracted Level III rather than a staff appointment, provided they are qualified in the methods they sign for.
How does an Aerospace NDT (SNT-TC-1A) auditor test this document?
By sampling. They take a completed job, find the technicians and equipment used, and trace each back through this document to the evidence behind it. A document that reads well but cannot survive that trace is the most common finding across every regime, not just this one.
How long must Aerospace NDT (SNT-TC-1A) records be kept?
Personnel recertification follows the employer's written practice. ASNT describes a recommended maximum interval of five years between renewals, and an aerospace customer can set a shorter interval or extra practical re-examination through its flow-down. Vision examination records must be current on the day of work. The company-level cycle is set by Nadcap: the first reaccreditation audit falls within twelve months of the initial audit, after which the Supplier Merit Program can extend the interval to 18 or 24 months depending on audit performance. Retention is set by the regime and by the client contract above it, and the longer of the two governs. Firms that set one retention period for everything and document it fare better at audit than firms tracking different periods per record type and losing track.
Does a generic template satisfy Aerospace NDT (SNT-TC-1A)?
No. A downloaded template describes a generic firm, and the first question an auditor asks is whether the document describes THIS firm — its methods, its equipment, its people, its actual workflow. Templates are a starting structure; the content has to be the firm's own or the trace fails immediately.
What happens if this document is missing at an Aerospace NDT (SNT-TC-1A) audit?
It is a finding, and depending on the regime it can suspend the certificate rather than merely generate a corrective action. The related finding auditors record most often is: Self-audit not performed, or performed without all applicable job audits, consistently among the most-cited AC7114 nonconformances
Where this sits in the Aerospace NDT (SNT-TC-1A) evidence pack
- Written practice for the training, qualification and certification of NDT personnel, built on ASNT SNT-TC-1A (2024), approved by the employer's NDT Level III and carrying the customer's aerospace flow-down requirements
- Written designation of the Level III responsible for the programme, with that person's ASNT NDT Level III certificates or the outside-agency agreement and credentials
- Individual certification files: training hours, documented experience, General, Specific and Practical examination results on representative aerospace parts, and current vision examination results
- NDT procedures and technique sheets for each method, approved by a Level III certified in that method and traceable to the prime specification and to ASTM E1417, E1444 or E2375 as applicable
- Records retention schedule covering certification files, examination papers and job records for the period the customer contract and the written practice require
- Customer and procurement requirement flow-down records showing which prime specifications apply to which part numbers and jobs
- Internal NDT audit records, plus evidence that corrective actions from the previous Nadcap or customer audit remain implemented
- Equipment calibration, system performance check and process control records, including calibration requirements flowed down to subcontractors
- The completed AC7114 self-audit package, including all applicable job audits, sent to the auditor before a Nadcap audit
Personnel certification context
Employer-based. The employer certifies its own NDT personnel under a written practice built on ASNT SNT-TC-1A and approved by an NDT Level III, and names in writing the Level III responsible for the programme. Nadcap AC7114 calls that person the Responsible Level 3 and accepts an internal or an external (outside agency) Level III, provided documentation on file shows the Level III meets the customer's specified requirements. Aerospace customers add their own conditions through the purchase order, such as practical examinations on representative parts and prime process specifications, so the written practice has to carry them. Atlantis provides ASNT NDT Level III consulting for aerospace written practices, procedures, examinations and audit preparation, can act as the outside agency Level III in UT, RT, MT, PT and VT, and delivers ASNT SNT-TC-1A-based training and NDT inspection for aerospace and aviation work.
Related: the aerospace NDT compliance overview, ASNT Level III consulting for aerospace, aerospace written practice development, SNT-TC-1A-based aerospace NDT training, aerospace NDT inspection, Nadcap AC7114, the SNT-TC-1A overview.
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