What is a major effect of icing on aircraft regarding its weight?

The phenomenon of icing can significantly impact an aircraft's performance, with one of the notable effects being related to its weight. When ice accumulates on an aircraft, it adds additional mass, which contributes to an increase in the all-up weight. This added weight can also lead to increased drag because the ice alters the aerodynamic profile of the aircraft, making it less streamlined.

The accumulation of ice can affect various surfaces, including wings, tail, and propellers, which can lead not only to increased drag but also to potential loss of lift and control. This can make it more challenging for pilots to manage the aircraft, especially during critical phases of flight like takeoff, climb, and landing.

In contrast, the other options do not recognize the full implications of icing. While icing does not lead to decreased overall weight or have no effect on weight, it clearly does not improve balance due to the uneven distribution of ice that can occur. Therefore, the major effect of icing on aircraft weight is the increase in both drag and all-up weight, which is aptly represented by the correct choice.