What are the two techniques for determining the size of a defect in an engine part?

The correct answer highlights the importance of comparing a defective part to a known standard part, which allows engineers to evaluate the size and extent of any defects in a tangible manner. This method is straightforward and effective, particularly in identifying flaws that may not be readily observable but can be assessed through established standards. Checking safety wire, while important for securing components in an engine, is not a direct technique for measuring defect size but rather contributes to the overall evaluation of the part’s integrity.

The other techniques mentioned often involve more advanced methods that, while effective in their specific contexts, may not directly measure size in the same comparative manner. For instance, visual inspection and thermal imaging can be useful for identifying surface defects, but assessing the actual size of a defect would require additional measurement techniques. Ultrasonic testing and magnetic particle inspection are advanced non-destructive testing methods that effectively locate flaws but do not provide a traditional size measurement comparison. Measuring with calipers and gauging can accurately determine dimensions but is not specifically aimed at defect sizing in the context of part evaluation as compared to a standard. Thus, comparing to a standard part remains a fundamental approach in defect size determination.