Liquid Penetrant Testing (PT) Requirements Under FAA Part 145 (NDI limited rating)

Consumables are batch-controlled: certificates for each batch, contamination checks, and the sulphur and halogen limits where the material demands it. FAA Part 145 (NDI limited rating), enforced by Federal Aviation Administration, Flight Standards Service; day-to-day oversight sits with the repair.: Employer-based, and the FAA says so plainly.

An auditor examining PT asks for penetrant, developer, cleaner and emulsifier batch records, plus the light meters for the inspection environment. 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.

Liquid Penetrant Testing under FAA Part 145 (NDI limited rating) — procedure, personnel and evidence
Item	What applies	Why it matters
Regime	Title 14 Code of Federal Regulations Part 145 — Repair Stations, with the limited rating for nondestructive inspection, testing, and processing	Enforced by Federal Aviation Administration, Flight Standards Service; day-to-day oversight sits with the repair station's responsible Flight Standards office
Method	Liquid Penetrant Testing (PT)	Needs its own procedure and its own qualified personnel
Procedure approval	The employer's Level III, qualified in this method	The signature an auditor traces
Other methods in scope	MT, UT, RT, ET, VT, Eddy current array and phased array where covered by the approved specification and the written practice	Each needs separate qualification
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.	Applies to the personnel certification behind this method

Does FAA Part 145 (NDI limited rating) require a separate procedure for PT?

Yes. Every method in scope needs its own written procedure, approved by someone qualified in that method, describing technique, equipment, calibration, scanning or coverage, acceptance criteria and reporting. A single combined "NDT procedure" covering several methods is a finding under every regime that names procedures individually.

Who can approve a PT procedure under FAA Part 145 (NDI limited rating)?

A Level III qualified in PT. Because FAA Part 145 (NDI limited rating) accepts employer-based certification, that Level III may be contracted rather than employed — but their own qualification must cover PT, and an auditor will check that before accepting the signature.

What PT records does a FAA Part 145 (NDI limited rating) audit sample?

The approved procedure, the technician's PT certification on the date of work, and the equipment evidence — penetrant, developer, cleaner and emulsifier batch records, plus the light meters for the inspection environment. The auditor works backwards from a finished job, so every item has to reconcile with the report and its stated acceptance criteria.

What is the most common PT finding at audit?

Batch certificates missing for consumables used, or dwell time not recorded. It is a records failure rather than a technique failure — the examination was performed correctly and the evidence supporting it cannot be produced, which under FAA Part 145 (NDI limited rating) is recorded the same way as not having done the work.

Can a technician certified elsewhere perform PT under FAA Part 145 (NDI limited rating)?

Not automatically. Employer-based certification ends when the holder leaves, so the new employer must certify them under its own written practice. Prior training and documented experience transfer as evidence; the certificate itself does not.

What equipment evidence does PT need under FAA Part 145 (NDI limited rating)?

Calibration status traceable to the day of use, covering the instrument and its accessories — probes, cables, blocks and reference standards for ultrasonics; sources and densitometers for radiography. An in-calibration instrument with an out-of-calibration reference block fails the same way as an uncalibrated one.

How do PT requirements differ from the other methods in FAA Part 145 (NDI limited rating)?

Scope, qualification and evidence are method-specific, so the differences are real rather than administrative. FAA Part 145 (NDI limited rating) also covers MT, UT, RT, ET, VT, and each carries its own procedure, its own personnel qualification and its own equipment evidence.

Personnel certification for PT

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.