What is blade root distress and how is it detected during inspection?

• A. Cracks or damage at the blade root; detected by borescope inspection, surface NDT such as dye penetrant or radiography, and visual checks.
• B. Root distress refers to finish wear on the blade tip.
• C. The blade root cannot crack; only the mid-span can.
• D. Cracks at the blade root are only detectable by measuring vibration.

Answer: (A)