Ice accumulation on propeller blades during flight most directly causes which of the following effects?

• A. Increase in fuel efficiency
• B. No change
• C. Increase in thrust and smoother operation
• D. Thrust decreases and excessive vibration

Answer: (D)

Ice on propeller blades changes the blade surface and weight distribution, which disrupts the aerodynamic flow and balance. The ice roughens and thickens the airfoil, increasing drag and reducing the effective lift the blade can generate at a given engine power. That means the propeller produces less thrust. At the same time, the uneven ice buildup around each blade creates dynamic imbalance, causing more vibration in the propeller hub, drive train, and airframe. So the combination is lower thrust and excessive vibration. The other ideas don’t fit because ice accumulation does not improve propulsion, and it typically causes some change rather than none.