Which of the following is NOT an effect of icing?

Icing does indeed have several significant effects on aircraft performance and operation, but increased fuel efficiency is not one of them. When ice accumulates on an aircraft, it changes the aircraft's aerodynamic properties, which can lead to an increase in drag. This increased drag often requires the engines to work harder, resulting in reduced fuel efficiency rather than an increase.

In contrast, ice accumulation can lead to a loss of proper operation of control surfaces, as the weight of the ice affects their function and responsiveness. It also can obstruct the pilots' outside vision due to ice buildup on windshields. Additionally, icing can interfere with radio communications because it may cause distortion or attenuation of signals. These factors collectively demonstrate the detrimental impacts of icing on flight safety and operations, making them critical considerations for pilots.