Aerospace NDT (SNT-TC-1A) Compliance for Inspection Service Providers

Aerospace NDT compliance applies to manufacturers, MRO shops, FAA Part 145 repair stations and NDT suppliers that certify personnel for aerospace work under an SNT-TC-1A written practice. Certification is employer-based, so a contracted ASNT Level III can write and sign the written practice and administer examinations, and the customer's flow-down and Nadcap AC7114 decide what that practice must add.

Engine and airframe shops, casting and forging suppliers and independent NDT houses on approved-supplier lists add their customers' flow-down requirements to that written practice, and Nadcap audits the result under AC7114 when a prime makes accreditation a purchase-order condition. 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.

Aerospace NDT (SNT-TC-1A) at a glance — authority, scope and what it demands
Item	What applies	Why it matters
Authority	ASNT publishes SNT-TC-1A; the employer's NDT Level III approves the written practice. Primes flow requirements down in purchase orders, PRI audits suppliers to Nadcap AC7114 and the FAA oversees Part 145 repair stations.	The body that issues, audits and can withdraw
Applies to	Aerospace manufacturers, MRO shops, FAA Part 145 repair stations and NDT suppliers certifying personnel for aerospace work	Whether this binds your firm at all
Personnel certification	Employer-based — the firm certifies its own, under a qualified Level III	Decides whether an outsourced Level III can sign for you
Renewal	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.	Track the dates the regime sets, not from memory
Methods in scope	PT, MT, UT, PAUT, RT (film), RT-D / digital radiography	Each method needs its own procedure and qualified personnel
Industries	Aerospace manufacturing, Aviation MRO and overhaul, Engine components, Castings and forgings, Defence aviation	Where this regime shows up in contracts

Who does Aerospace NDT (SNT-TC-1A) apply to?

Aerospace manufacturers, MRO shops, FAA Part 145 repair stations and NDT suppliers that certify NDT personnel for aerospace work under an SNT-TC-1A written practice. Engine and airframe shops, casting and forging suppliers and independent NDT houses on approved-supplier lists add their customers' flow-down requirements to that written practice, and Nadcap audits the result under AC7114 when a prime makes accreditation a purchase-order condition.

Can an outsourced Level III sign for Aerospace NDT (SNT-TC-1A) compliance?

Yes. Aerospace NDT (SNT-TC-1A) accepts employer-based certification, which places the obligation on the employer and allows a contracted Level III to write and sign the written practice, approve procedures and administer examinations. The Level III must be qualified in each method they sign for, and the employer still owns the records.

What documents does an Aerospace NDT (SNT-TC-1A) audit ask for?

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. Auditors open records before they open manuals, because a manual describes intent while records show practice. The most common failure is a documented system that does not match what the technicians actually do.

How often is Aerospace NDT (SNT-TC-1A) renewed?

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.

What are the most common Aerospace NDT (SNT-TC-1A) findings?

Self-audit not performed, or performed without all applicable job audits, consistently among the most-cited AC7114 nonconformances, Required pre-audit package not sent to the auditor 30 days before the audit, Corrective actions from the previous Nadcap audit no longer implemented at the following audit, Calibration requirements not flowed down to subcontracted calibration or subcontracted NDT services. These recur because they are records problems rather than capability problems — the work is being done correctly and the evidence is not being kept.

Which NDT methods does Aerospace NDT (SNT-TC-1A) cover?

PT, MT, UT, PAUT, RT (film), RT-D / digital radiography, ET. Each method in scope needs its own approved procedure and personnel qualified in that specific method; a Level III qualified in ultrasonics cannot sign for radiography.

Personnel certification under Aerospace NDT (SNT-TC-1A)

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.

The audit sequence

Confirm which requirements apply: the prime's flow-down, the AC7114 base checklist and the slash checklists for the methods and techniques actually performed
Apply through PRI's eAuditNet and complete the self-audit against those checklists, including all applicable job audits; send the required package to the auditor 30 days before the audit
On-site audit covering customer and procurement requirements, internal NDT audits, the written practice and certification files, examinations and vision testing, Level III responsibilities and inspection status control, plus live job audits on real parts
Auditor raises nonconformance reports; the supplier responds with root cause and corrective action, reviewed by PRI staff engineers
The Nadcap NDT Task Group votes on accreditation
First reaccreditation audit within twelve months of the initial audit; the Supplier Merit Program can extend later intervals to 18 or 24 months based on audit performance

Documents an auditor asks for

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

Findings firms get against Aerospace NDT (SNT-TC-1A)

Self-audit not performed, or performed without all applicable job audits, consistently among the most-cited AC7114 nonconformances
Required pre-audit package not sent to the auditor 30 days before the audit
Corrective actions from the previous Nadcap audit no longer implemented at the following audit
Calibration requirements not flowed down to subcontracted calibration or subcontracted NDT services
Written procedure and observed practice disagree during a job audit: the technique the operator ran is not the technique the procedure specifies
Experience carried in from a prior employer accepted without the Level III's documented evaluation
Written practice not re-approved by the current Level III after a personnel change
Process timing steps missed during a job audit; PRI's published lists cite eddy current step-one timing among the recurring job-audit nonconformances
A customer flow-down requirement, such as a practical examination on the customer's own parts, missing from the written practice, so certifications meet SNT-TC-1A but not the purchase order

Meet this requirement without the paperwork pile-up

Atlantis writes the procedures and Level III documentation this requirement calls for, trains the technicians, and Atlantis ERP keeps certifications and procedure revisions in one place.

Speak to an ASNT NDT Level III

Discuss your inspection requirements with Atlantis NDT. Include the asset, method, location and documents you need reviewed.