NDT Technician Interview Questions
& Model Answers, 2026

Establish the probe's exit point and refracted angle on the calibration block, set the screen distance range using the known radii or notches, then set sensitivity and construct the distance-amplitude correction or reference level from the specified reflectors, applying transfer correction for surface condition differences between the block and the part. Record the calibration and re-verify at the required interval and at the end of the examination — if it has drifted outside limits, everything scanned since the last valid check must be re-examined.

By location, response behaviour and corroboration: plot the indication's depth and surface distance and compare it with the joint geometry, root, counterbore or backing bar, move the probe to see how the signal behaves with angle and position, and check the drawing. Confirm ambiguous cases with a second angle or a complementary method. A technician who calls every echo a defect creates unnecessary repairs, and one who dismisses them creates escapes.

Clean and dry thoroughly, apply penetrant and allow the specified dwell without letting it dry on the surface, remove excess correctly — with a damp cloth for water-washable or solvent methods rather than flooding the surface, which washes penetrant out of the discontinuity — dry, apply a thin even developer coat, allow developing time, then inspect under the correct light and intensity within the time window. The classic failures are over-washing, too heavy a developer coat, and inspecting too early or too late.

It detects surface and slightly subsurface discontinuities in ferromagnetic material by leakage fields, and it only finds indications lying at a useful angle to the field, so you must magnetise in two roughly perpendicular directions. Verify field adequacy with the specified indicator — a pie gauge or shim — check equipment output, control particle concentration and lighting for the visible or fluorescent method used, and demagnetise afterwards where the specification requires it.

Survey before, during and after with a calibrated meter, establish and physically control the restricted and high radiation boundaries at the calculated dose rates, post signage, use the correct collimation and source-to-object geometry, confirm the source has fully returned to the shielded position by survey rather than by the crank position, wear and read dosimetry, and maintain the source and transport records. Say that you would stop a shoot if the boundary could not be controlled, no matter what the schedule demands.

A Level I performs calibrations and specific examinations under a written procedure and records results, but does not independently interpret or accept and reject. A Level II sets up and calibrates, interprets and evaluates against the code, and reports and can supervise Level I work. A Level III establishes and approves procedures and techniques, interprets codes, and certifies personnel. Working beyond your level invalidates the examination even if the technical call was correct.

Both directions are instructive: a call that proved bigger or deeper than reported, or a repair excavation that found nothing. Describe what the follow-up taught you about the technique, the calibration or the geometry, and what you changed. Technicians who claim perfect correlation with excavation results are not being credible about a method with real interpretation limits.

Give the concrete answer: you cannot compress dwell times, developing times or calibration checks without invalidating the examination, and reducing scan coverage means the report must state the reduced coverage. Describe explaining that to the client and offering the legitimate options — more technicians, a different method, a re-sequenced schedule — rather than quietly cutting corners.

Scaffold and elevated work, confined spaces, night shoots, live plant, extreme weather. Describe the permits, the atmospheric testing, the standby person, the radiation boundary management and how you coordinated with other trades who had to be cleared from the area. Field NDT injuries and overexposures happen when a technician tries to work around other crews rather than clearing the area.

Concrete practices: recording readings and calibration data at the time, sketching or mapping indications with reference to a datum on the part, photographing where useful, and writing reports the same day while the examination is fresh. Say that you would rather report reduced coverage honestly than imply full coverage that was not achieved — that single habit is the difference between a defensible report and a liability.

Anchor and qualify. The BLS OEWS May 2025 median for inspectors, testers, sorters, samplers and weighers is $48,570 a year ($23.35/hr), with the top 10% above $77,860; that broad series includes general production inspection, and certified NDT technicians — particularly multi-method Level II with ultrasonics and radiography — sit toward the top of it. Argue on the methods and levels you hold and your field experience.

Field NDT is heavily travel-based, so ask the per-diem rate and whether it applies on travel and weather days, whether lodging is booked or reimbursed, how travel time is paid, the call-out minimum for night shoots, and the overtime structure during outages. Also ask about the split between shop and field work, because a mostly-shop role pays and lives very differently from a travelling one.

Employer-funded certification and renewal in additional methods and levels, the training and documented experience hours needed to move up a level, annual eye examinations, dosimetry and medical monitoring, calibrated equipment and consumables supplied, and PPE. Ask specifically what support exists to add a method, because each additional method materially increases your market value.