False Indication

A false indication is an NDT response not caused by an actual material discontinuity, instead produced by contamination, technique error, magnetic writing, or instrument artifacts.

Definition

Common false indications include penetrant trapped under loose scale, magnetic writing on hardened steel, dirt on the radiograph, or transducer ringing. Eliminating false indications is a primary inspector responsibility.

Related terms

Indication — An indication is the response observed during an NDT examination that requires interpretation to determine whether it represents a relevant defect, a non-relevant geometric effect, or a false signal.
Relevant Indication — A relevant indication is an NDT response produced by an actual material discontinuity that must be evaluated against the applicable acceptance criteria for accept/reject disposition.

More data terms

A-Scan · B-Scan · C-Scan · D-Scan · S-Scan · L-Scan · Distance-Amplitude Correction · Distance-Gain-Size · Time-Corrected Gain · Gating

Where this comes up in practice

Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.

Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.

Separate the observation from its cause

First record the indication and the examination conditions. Check equipment function, surface preparation, consumables, geometry and the applicable procedure. A response caused by part geometry is not the same as an equipment artefact, even when neither represents a defect.

Repeat or extend the examination only within the approved procedure. If the result remains unclear, refer it to the responsible qualified reviewer and retain both the original observation and the follow-up evidence.

Use careful reporting language

State what was seen, what checks were performed and the basis for the conclusion. Avoid writing “no defect” where the actual conclusion is that the original response could not be reproduced or that coverage was limited.

A useful record allows another inspector to understand the decision without reconstructing the work from memory. Include the location reference, settings or technique information needed to reproduce the examination.