Which process is essential in ensuring that an aircraft is ready for inclement weather?

De-icing is the essential process for ensuring that an aircraft is ready for inclement weather, particularly in conditions where ice or snow can accumulate on the wings and other critical surfaces. When an aircraft is exposed to freezing temperatures and precipitation, ice can form, which negatively impacts the aerodynamics of the aircraft and can obstruct important sensors.

The de-icing procedure typically involves the application of heated fluids that eliminate any ice or snow present, allowing for safe operation and performance. This step is crucial before takeoff, as any ice accumulation can significantly reduce lift and increase drag, leading to potential safety issues during flight.

Other processes mentioned, such as taxiing, landing, and takeoff, are routine operations that occur in the normal operation of an aircraft but do not specifically address the preparation for adverse weather conditions. Thus, while important, they do not directly relate to ensuring an aircraft's readiness for inclement weather like de-icing does.