Why are blade tip clearances important, and how are they typically controlled or monitored?

• A. Tip clearances can be ignored as they do not impact engine performance.
• B. Tip clearances affect efficiency and prevent rubbing; controlled by active clearance control, shrouds, and thermal/mechanical balancing with monitoring via sensors or borescope.
• C. Tip clearances are set only at manufacturer and cannot be adjusted.
• D. Tip clearances influence only blade weight distribution.

Answer: (B)