In ECT ratings, which label indicates no prop fracture during testing?

• A. ECTPV (Upon isolation)
• B. ECTN## (No prop fracture)
• C. ECTP## (Prop across ec)
• D. ECTX (No)

Answer: (B)

In ECT ratings, the outcome of interest is whether the prop fractured during testing. When the prop stays intact and shows no fracture, the rating label that reads “No prop fracture” is used. This is the best answer because it communicates explicitly that there was no fracture observed in the prop, which is exactly what the question asks. The numeric cues (like the two hashes) are just identifiers for a specific test instance and do not change the meaning. The other labels describe different conditions or failure modes (such as fractures under certain conditions or other ambiguous states), so they do not match the requirement of indicating no fracture.