How would you phrase the Jackson altimeter of 30.12?

The correct phrasing for the Jackson altimeter reading of 30.12 is "Jackson altimeter three zero one two." This format adheres to standard aviation communication protocols, where altimeter settings are stated in a clear and precise manner.

In this case, "three zero" represents the "30" portion, and "one two" denotes the ".12" part of the reading. This two-part numeric representation eliminates any potential confusion that could arise from decimal points or variations in pronunciation.

Using phrases like "thirty point twelve" would deviate from established phrasing protocols. Similarly, stating things like "thirty one twelve" misrepresents the actual altimeter setting, as it suggests a different value. Clear and unambiguous communication is crucial in aviation for maintaining safety and accuracy, hence the preference for the accepted phrasing structure.