When converting from true course to magnetic heading, what mnemonic should a pilot remember?

The correct mnemonic for converting from true course to magnetic heading is indeed "East is least and west is best." This phrase serves as a helpful memory aid for pilots dealing with magnetic variation.

When a pilot needs to determine the magnetic heading from a true course, they account for magnetic variation, which is the difference between true north and magnetic north. If the magnetic north is to the east of true north (east variation), the pilot subtracts the variation; hence "East is least" indicates that you are reducing the true course. Conversely, if the magnetic north is to the west (west variation), the pilot adds the variation, corresponding to the phrase "west is best," which indicates that you are increasing the true course to reach magnetic heading.

This mnemonic establishes a simple guideline to help remember the necessary adjustments based on the direction of the magnetic variation, making it easier for pilots to perform these calculations accurately in their navigation tasks.