What is the maximum flap setting with operative boots?

The correct maximum flap setting with operative boots is Flaps 15º. In operations involving aircraft equipped with pneumatic de-icing boots, such as during certain icing conditions, there are specific limitations regarding the use of flaps to ensure safe handling and performance. These limitations are in place because extending the flaps beyond a certain setting while the boots are operational can lead to aerodynamic instability or increased drag in a critical situation.

Flaps 15º is designed to provide adequate lift while maintaining control authority, especially in conditions where ice could accumulate. The use of the boots is intended to keep lift surfaces clear of ice, but with flaps deployed at excessive angles, the risk of stall or control difficulty may increase. Therefore, using Flaps 15º is the safest and most effective option.