Why are loose-fitting blades used on the first several stages of large compressors?

Correct Answer: Option A — To minimize vibration while the engine is passing through critical speed ranges.

Loose-fitting blades, often called 'shingled' or 'loose-mounted' blades, provide mechanical damping. By allowing slight movement, they absorb energy and minimize resonant vibrations as the compressor accelerates through critical speed ranges, preventing fatigue failure and structural damage to the rotor assembly during transient operation.