A UT Level III is more than a technician; they are a technical authority. They write procedures, train and supervise personnel, interpret complex codes, and act as the final word on challenging inspections. Making the wrong hire can impact project timelines, client trust, and operational safety. A rigorous, multi-faceted interview process is essential to ensure you’re bringing a true expert onto your team.

This guide provides a comprehensive framework for interviewing and vetting UT Level III candidates. It’s broken into three critical parts: technical questions to probe their expert knowledge, situational questions to assess their leadership and problem-solving skills, and a guide to conducting a non-negotiable practical screening.

Why Hiring the Right UT Level III is Critical for Your Business

The responsibilities of an NDT Level III are extensive. They are certified to develop, qualify, and approve NDT procedures, establish and validate techniques, and ensure all operations comply with relevant codes and standards. In many organizations, particularly smaller ones, the UT Level III also functions as a “Working Level III,” directly supervising and training Level I and II technicians and performing inspections.

Hiring a proficient UT Level III directly impacts your bottom line. Their expertise ensures the quality and integrity of your products or assets, prevents costly failures, and maintains your company’s reputation with clients and regulatory bodies. A great Level III is a pillar of your quality program, while a weak one can become a significant liability.

Part 1: Technical & Code-Based Interview Questions

This section is designed to move beyond basic definitions and test the candidate’s deep, nuanced understanding of ultrasonic testing principles.

Procedure & Technique Development

A primary function of a Level III is to write and approve NDT procedures. Their ability to create clear, effective, and code-compliant documents is paramount.

1. Walk me through your process for developing a new UT procedure for a complex geometry, from initial client consultation to final approval.
   • What to listen for: A systematic approach. They should mention reviewing the client’s specifications, understanding the part’s manufacturing process, identifying potential flaw types, selecting the right equipment (transducers, wedges, instrumentation), determining scan patterns, establishing calibration requirements, and defining acceptance criteria based on the relevant code.
2. Describe a time you had to create a scan plan for detecting a specific, challenging flaw type, like stress-oriented hydrogen-induced cracking (SOHIC) or high-temperature hydrogen attack (HTHA).
   • What to listen for: An understanding of advanced UT applications. They should discuss the selection of appropriate angles, the use of specialized techniques like Phased Array (PAUT) or Time of Flight Diffraction (TOFD), and the reasoning behind their choices.
3. How do you determine the appropriate frequency for an inspection? Describe a scenario where you would choose a lower frequency over a higher one, and vice-versa.
   • What to listen for: Knowledge of the trade-off between penetration and resolution. Lower frequencies offer better penetration for thick or coarse-grained materials, while higher frequencies provide better resolution for detecting smaller discontinuities.
4. Explain the concept of beam spread and its impact on flaw sizing. How do you account for it in a procedure?
   • What to listen for: An understanding of ultrasonic physics. They should explain that the sound beam widens as it travels, which can affect the accuracy of amplitude-based sizing techniques. They might mention using DAC curves or an AVG/DGS method to compensate.

Code & Standards Interpretation

A Level III must be fluent in the language of codes and standards like ASME, AWS, and API.

1. A client wants to use a procedure based on ASME Section V, Article 4 for a job, but you believe a different code or technique is more appropriate. How do you handle this?
   • What to listen for: Professionalism and communication skills. The ideal answer involves educating the client, explaining the technical reasons for their recommendation, documenting the conversation, and ultimately ensuring the correct, most effective inspection is performed.
2. Explain the key differences between qualification and certification as defined by ASNT’s SNT-TC-1A.
   • What to listen for: A precise understanding of personnel qualification (PQ) standards. They should articulate that qualification demonstrates that an individual has the required training, experience, and has passed exams, while certification is the written testimony of that qualification, typically issued by the employer.
3. Describe the function of a Distance Amplitude Correction (DAC) curve. What are its limitations?
   • What to listen for: A deep understanding of calibration. They should explain that a DAC curve plots the amplitude of reflectors of the same size at different distances. They should also mention its limitations, such as its sensitivity to transducer variations and its primary use for sizing based on amplitude comparison.

Advanced UT and Data Analysis

The field of UT is constantly evolving. A top-tier Level III stays current with advanced technologies.

1. What are the primary advantages and disadvantages of using Phased Array (PAUT) versus conventional UT for weld inspection?
   • What to listen for: Familiarity with modern techniques. They should cite PAUT’s advantages like speed, multiple angle inspection from a single position, and superior data imaging (S-scans, C-scans). Disadvantages could include higher equipment cost and more complex procedure development.
2. You are reviewing UT data that shows several recordable indications near the acceptance threshold. What is your process for final disposition?
   • What to listen for: Meticulous attention to detail and sound judgment. The process should include verifying the calibration, re-scanning the area to confirm the readings, using multiple sizing techniques if possible, carefully reviewing the acceptance criteria, and creating a detailed, defensible report of the findings.
3. Explain the basic principle of Time of Flight Diffraction (TOFD). In what situations is it most effective?
   • What to listen for: Knowledge of complementary UT techniques. They should explain that TOFD uses the transit time of diffracted signals from the tips of a flaw for highly accurate sizing. It’s particularly effective for weld inspection, especially for detecting and sizing vertical defects like lack of fusion and cracks.

Part 2: Situational & Leadership Questions

Technical skills are only half the equation. A UT Level III is a leader and a problem-solver. These questions assess those critical soft skills.

Problem-Solving and Troubleshooting

1. A Level II technician is on a job site and struggling to get a stable calibration. You are on the phone with them. What are the first three things you ask them to check?
   • What to listen for: A logical troubleshooting methodology. They should suggest checking the basics first: cable connections, couplant application, the condition of the probe and wedge, and the correct settings on the flaw detector.
2. You’ve developed a procedure that works perfectly in the lab, but the field crew reports that it’s not feasible on-site due to physical obstructions. What do you do?
   • What to listen for: Adaptability and collaboration. The best answer involves working with the field technicians, understanding the specific limitations, and modifying the procedure or technique to be both effective and practical.
3. An inspection reveals an indication that you cannot definitively identify using the approved UT procedure. What are your next steps?
   • What to listen for: A commitment to accuracy over speed. They should suggest using other NDT methods for verification (e.g., radiography, magnetic particle), consulting with engineering personnel, and not signing off on the inspection until the indication is fully understood.

Client and Auditor Management

1. An external auditor is challenging one of your signed-off inspection reports, questioning the interpretation of an indication. How do you prepare for and handle that conversation?
   • What to listen for: Composure and defensibility. The candidate should describe gathering all documentation (calibration records, procedure, scan data), calmly and professionally explaining their technical rationale to the auditor, and being open to a constructive discussion.
2. A client is pressuring your team to complete an inspection faster than the procedure allows. How do you respond?
   • What to listen for: Unwavering commitment to quality and safety. They should explain that procedural steps, especially calibration and scan speed, are there for a reason and cannot be compromised. They should be able to articulate the risks of rushing to the client in a firm but professional manner.

Training and Mentorship

1. What is your philosophy on training and mentoring junior technicians? How do you verify their competence?
   • What to listen for: A passion for teaching and a structured approach. They should talk about the importance of hands-on training, providing clear explanations, and verifying competency not just with written exams but with practical, observed performance tests.
2. Describe a time you had to correct a mistake made by a Level II technician you were supervising. How did you approach it?
   • What to listen for: Constructive feedback skills. The goal is correction, not criticism. The ideal approach is to discuss the mistake privately, understand why it happened, use it as a teaching moment, and document any required re-training.

Part 3: The Practical Screening: Verifying Hands-On Expertise

No interview, no matter how thorough, can replace a practical demonstration of skill. This step is non-negotiable for a Level III role.

Why a Practical Test is Non-Negotiable

A practical exam separates candidates who can talk about NDT from those who can do NDT. It allows you to observe their methodology, their efficiency, and their ability to apply theoretical knowledge to a real-world problem. It is the single best way to validate their claimed expertise.

How to Design an Effective Practical Screen

• Step 1: The Flawed Sample: Use a well-characterized test specimen with known, real-world flaws. The flaws should be realistic and include some that are subtle or challenging to interpret. A weld sample with fabricated flaws like porosity, slag inclusions, and lack of fusion is a common choice.
• Step 2: The Task: Provide the candidate with a variety of UT equipment (different flaw detectors, transducers, wedges) and a copy of a relevant codebook (e.g., ASME V or AWS D1.1). The task is clear: “Using the equipment provided, calibrate your system, inspect this sample according to the code, and characterize any flaws you find.”
• Step 3: The Report: The final step is crucial. Require the candidate to write a formal inspection report of their findings, just as they would for a client. The report should be clear, concise, professional, and contain all necessary information (equipment used, calibration details, flaw locations, and characterization).

What to Look For During the Practical Exam

• Methodology: Do they follow a logical, systematic process? Do they select the appropriate equipment for the job?
• Calibration: Is their calibration process efficient and accurate? Do they perform all the necessary checks required by the code?
• Detection & Interpretation: Do they find all the known flaws in the sample? More importantly, how do they interpret the signals and differentiate between geometric reflectors and actual flaws?
• Communication: Ask them to “think out loud” during the process. Can they clearly explain why they are taking certain steps? This provides invaluable insight into their thought process.
• Reporting: Is their final report professional and comprehensive? Does it meet the requirements of the specified code?

Take the Guesswork Out of Hiring Your Next UT Level III

By combining in-depth technical questions, situational leadership challenges, and a robust practical screening, you create a comprehensive evaluation process. This “interview kit” approach allows you to look beyond the resume and certification, giving you a true measure of the candidate’s competence, judgment, and professionalism. Investing this time upfront ensures that the UT Level III you hire is not just qualified on paper, but is a genuine expert who will be a technical pillar for your organization.

Are you a UT Level III looking for your next challenge? Upload your resume to NDT-Jobs.com and let top employers find you.