During a visual inspection, a severely bent and loose fan blade should be replaced instead of repaired. What is the correct action?

• A. Straighten the blade
• B. Re-rivet and straighten
• C. Weld and straighten
• D. Replacement of the fan assembly

Answer: (D)

Severely bent and loose fan blades indicate structural damage and loss of balance that cannot be trusted to be safe after repair. The bend suggests cracks or internal fatigue, and the looseness means the blade-hub connection has been compromised. Straightening the blade would not restore its original strength and could hide cracks or create new stresses. Re-riveting or attempting to reattach and straighten introduces fresh fasteners and changes in clamping that may not hold under operation. Welding the blade involves heat-affected zones that can alter the metal properties, making the blade brittle and more prone to sudden failure. In rotating equipment like a fan, any repair that does not guarantee full structural integrity and proper balance can lead to catastrophic failure at high speed. Replacing the entire fan assembly ensures the blade, hub, mounting, and balance are all within spec and safe to operate.