When temperatures get below freezing point (see in-game weather via weather panel), planes will request de-icing. You must have a de-icing depot to store de-icing liquid, and then de-icing trucks to bring this de-icing liquid to a de-icing pad. Pads come in three sizes, small medium and large, each handling the respective aircraft. Note that General Aviation (GA) flights will also use your de-icing service. On the de-icing pad, the trucks will de-ice the planes. To get de-icing liquid, you will need to sign a contract with a de-icing fluid provider. Once a contract is signed, a truck will bring the de-icing fluid to your depot. Note: de-icing fluid can be very pricy.
Sizes of Pads
The De-icing pads are 5x5 for small aircraft, 11x11 for medium aircraft, and 16x16 for large aircraft.