What is the first step of the Winter Correction Formula?

The first step of the Winter Correction Formula is to subtract the airport elevation from the published fix altitude. This calculation is essential because it helps determine the required altitude adjustment needed for safe and accurate flight operations in winter conditions, where atmospheric changes can affect performance and navigation.

By taking the published fix altitude and using the airport elevation in a subtractive manner, pilots can adjust their altitude settings appropriately to compensate for these environmental factors, ensuring they maintain proper altitude during their approach and landing phases, particularly in challenging weather conditions. This adjustment is crucial for optimizing safety and adherence to regulations in Part 135 operations, where precise altitude management is vital.