FAA Part 145 (NDI limited rating) Compliance for Inspection Service Providers
NDT firms whose inspection results are used to return civil aeronautical articles to service. A standalone NDT house needs its own repair station certificate carrying the §145.61(b)(9) limited rating for nondestructive inspection, testing, and processing. Personnel are qualified under employer-based certification, so a contracted Level III can sign the written practice and administer examinations for the firm.
Alternatively the firm works as a noncertificated contractor to a repair station, in which case the repair station must qualify and surveil it under its own quality control system. Covers aircraft, engines, propellers, accessories and components. Part 145 does not describe NDT techniques; it regulates the organisation that performs them. The FAA issues a limited rating for 'Nondestructive inspection, testing, and processing' under §145.61(b)(9), and §145.61(c) requires the repair station's operations specifications to name the specification used for the specialized service — either a civil or military specification currently used by industry and approved by the FAA, or one the applicant develops and the FAA approves. Around that sit §145.151 personnel, §145.155 inspection personnel proficiency and English literacy, §145.163 an FAA-approved initial and recurrent training program with records kept at least two years, and §145.211(c) a quality control manual that must describe how inspection personnel proficiency is established and maintained and how measuring and test equipment is calibrated, including intervals.
Source: 14 CFR §§145.51, 145.55, 145.59, 145.61, 145.151, 145.155, 145.163, 145.211 as published in the electronic CFR via Cornell LII, current text including Docket FAA-2016-8744 Amdt. 145-31 (81 FR 49163, 27 July 2016) for §145.61 and Amdt. 145-32 (83 FR 9176, 5 March 2018) for §145.163. FAA Advisory Circular 65-31B, 'Training, Qualification, and Certification of Nondestructive Inspection Personnel,' dated 2/24/14, initiated by AFS-300, cancelling AC 65-31A of 25 April 2003, read in full — paragraphs 3, 5d, 5u, 6, 8, 9, 10, 11 and 12. Accessed 21 Aug 2026.
| Item | What applies | Why it matters |
|---|---|---|
| Authority | Federal Aviation Administration, Flight Standards Service; day-to-day oversight sits with the repair station's responsible Flight Standards office | The body that issues, audits and can withdraw |
| Applies to | NDT firms whose inspection results are used to return civil aeronautical articles to service. | 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 | Under §145.55(a) a certificate or rating issued to a repair station located in the United States is effective from the date of issue until surrendered and accepted for cancellation, or suspended or revoked — there is no periodic expiry. Under §145.55(b) a certificate issued to a repair station located outside the United States expires on the last day of the 12th month after issue and the FAA may renew it for 24 months; renewal must be requested no later than 30 days before expiry and the prescribed fee paid, otherwise the full §145.51 application procedure applies. Personnel recertification runs on the AC 65-31B intervals: Level I Special not exceeding one year, Levels I and II not exceeding three years, Level III at five-year intervals, with requalification also triggered by six months of inactivity in the method or an expired vision examination. | Diarise from the certificate date, not from memory |
| Methods in scope | PT, MT, UT, RT, ET, VT | Each method needs its own procedure and qualified personnel |
| Industries | Commercial aviation MRO, Airlines and part 121/135 operators, Engine and component overhaul, Aerospace parts distribution and repair, Business and general aviation | Where this regime shows up in contracts |
Who does FAA Part 145 (NDI limited rating) apply to?
NDT firms whose inspection results are used to return civil aeronautical articles to service. A standalone NDT house needs its own repair station certificate carrying the §145.61(b)(9) limited rating for nondestructive inspection, testing, and processing. Alternatively the firm works as a noncertificated contractor to a repair station, in which case the repair station must qualify and surveil it under its own quality control system. Covers aircraft, engines, propellers, accessories and components.
Can an outsourced Level III sign for FAA Part 145 (NDI limited rating) compliance?
Yes. FAA Part 145 (NDI limited rating) 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 a FAA Part 145 (NDI limited rating) audit ask for?
Application for a repair station certificate and rating, with the attachments required by §145.51(a), Operations specifications containing the specification used to perform the specialized service, per §145.61(c), Repair station manual, and the quality control manual required by §145.211(c) covering preliminary, hidden-damage and final inspection, establishing and maintaining proficiency of inspection personnel, current technical data, qualifying and surveilling noncertificated persons who perform maintenance, calibration of measuring and test equipment including intervals, and corrective action on deficiencies, FAA-approved employee training program under §145.163(a), submitted per §145.51(a)(7), with individual training records documented and retained a minimum of two years, Written NDI qualification and certification program — the written practice — describing training, examination, qualification, documentation, proficiency maintenance, and the steps to decertify, retrain or recertify (AC 65-31B paragraph 9a). 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 FAA Part 145 (NDI limited rating) renewed?
Under §145.55(a) a certificate or rating issued to a repair station located in the United States is effective from the date of issue until surrendered and accepted for cancellation, or suspended or revoked — there is no periodic expiry. Under §145.55(b) a certificate issued to a repair station located outside the United States expires on the last day of the 12th month after issue and the FAA may renew it for 24 months; renewal must be requested no later than 30 days before expiry and the prescribed fee paid, otherwise the full §145.51 application procedure applies. Personnel recertification runs on the AC 65-31B intervals: Level I Special not exceeding one year, Levels I and II not exceeding three years, Level III at five-year intervals, with requalification also triggered by six months of inactivity in the method or an expired vision examination. Firms that diarise renewal from the certificate date rather than from the last audit avoid the lapse that forces a full reapplication.
What are the most common FAA Part 145 (NDI limited rating) findings?
The specification named in the operations specifications for the NDI specialized service does not match the specification the technicians actually work to, Quality control manual silent on how proficiency of inspection personnel is established and maintained, which §145.211(c)(1)(iv) requires explicitly, Employee training program treated as generic safety training with no method-specific initial and recurrent NDI content, or training records not retained for the full two years required by §145.163(c), Vision examinations lapsed beyond the one-year period, or colour-perception limitations never evaluated and approved in writing by the responsible Level III. 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 FAA Part 145 (NDI limited rating) cover?
PT, MT, UT, RT, ET, VT, Eddy current array and phased array where covered by the approved specification and the written practice. 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 FAA Part 145 (NDI limited rating)
Employer-based, and the FAA says so plainly. AC 65-31B defines certification as 'written testimony of qualification that the employer typically issues' and states: 'In the United States, there is no national certifying agency; therefore, most certifications are employer-based and are not transferrable.' The AC lists acceptable standards — AIA-NAS-410, ATA Specification 105, CAN/CGSB-48.9712-95, ISO 9712, MIL-STD-410E (rescinded but acceptable), ASNT SNT-TC-1A, and prEN 4179. It defines an 'Outside Agency' as an independent body under contract for NDI services, explicitly including consultants and self-employed individuals, and paragraph 9b permits a qualified outside agency to provide NDI training, qualification and testing at the organisation's option and as provided in its written practice.
The audit sequence
- Pre-application discussion with the responsible Flight Standards office to agree the rating sought and the specification that will be named in the operations specifications for the NDI specialized service.
- Formal application under §145.51 with the repair station manual, quality control manual and the employee training program required by §145.51(a)(7).
- FAA review of the submitted manuals and program for compliance with §§145.207, 145.209, 145.211 and 145.163, with revision cycles until they are acceptable to the FAA.
- On-site evaluation of housing, facilities, equipment, materials and data under §145.109, and demonstration that inspection personnel meet §145.155 and that the quality control system is actually being followed.
- Issue of the certificate, the ratings and limitations, and the operations specifications naming the approved NDI specification.
- Continued operational surveillance by the responsible Flight Standards office, with revisions to the quality control manual notified under §145.211(d) and training program revisions submitted under §145.163(d).
Documents an auditor asks for
- Application for a repair station certificate and rating, with the attachments required by §145.51(a)
- Operations specifications containing the specification used to perform the specialized service, per §145.61(c)
- Repair station manual, and the quality control manual required by §145.211(c) covering preliminary, hidden-damage and final inspection, establishing and maintaining proficiency of inspection personnel, current technical data, qualifying and surveilling noncertificated persons who perform maintenance, calibration of measuring and test equipment including intervals, and corrective action on deficiencies
- FAA-approved employee training program under §145.163(a), submitted per §145.51(a)(7), with individual training records documented and retained a minimum of two years
- Written NDI qualification and certification program — the written practice — describing training, examination, qualification, documentation, proficiency maintenance, and the steps to decertify, retrain or recertify (AC 65-31B paragraph 9a)
- Personnel records specifying date, time and place of qualification, employing organisation, level, special qualifications or limitations, and the standard under which the individual is qualified, including a copy of any FAA repairman certificate issued to that individual (AC 65-31B paragraph 12)
- Vision examination records — near vision to Snellen 20/25 or Jaeger #1 in at least one eye, corrected or uncorrected, on a periodic basis not exceeding one year; colour perception evaluated once at initial examination with any limitation approved in writing by the responsible Level III
- Calibration records for NDI instruments traceable to a national metrological institute such as NIST
- Contracting arrangements and evidence of qualification and surveillance for any noncertificated person performing maintenance functions, as required by §145.151(d) and the quality control manual
Findings firms get against FAA Part 145 (NDI limited rating)
- The specification named in the operations specifications for the NDI specialized service does not match the specification the technicians actually work to
- Quality control manual silent on how proficiency of inspection personnel is established and maintained, which §145.211(c)(1)(iv) requires explicitly
- Employee training program treated as generic safety training with no method-specific initial and recurrent NDI content, or training records not retained for the full two years required by §145.163(c)
- Vision examinations lapsed beyond the one-year period, or colour-perception limitations never evaluated and approved in writing by the responsible Level III
- Written practice references SNT-TC-1A or NAS 410 but the recertification intervals actually applied do not match the standard the organisation says it follows
- Outside agency used for training, qualification or testing without that use being provided for in the written practice, as AC 65-31B paragraph 9b requires
- No documented qualification and surveillance of the noncertificated NDT contractor performing work under the repair station certificate
- Calibration of NDI measuring and test equipment performed without stated intervals in the quality control manual or without traceability to a national standard
Related: the FAA Part 145 (NDI limited rating) overview, outsourced ASNT Level III cover, written practice development, NDT procedure development, a programme gap assessment, interim Level III cover.