Which term describes the phraseology required for stating a magnetic heading of 90 degrees?

The phraseology for stating a magnetic heading of 90 degrees is articulated as "Heading nine zero." This follows the standard communication protocols that ensure clarity and avoid potential misunderstandings in aviation.

When pilots or ATC controllers communicate headings, it's crucial to use a concise format that clearly conveys the direction. The phrase "Heading nine zero" explicitly indicates a heading of 90 degrees, using two digits for clarity. This is important in scenarios where precise navigation and understanding of instructions are vital.

The choice "Heading zero niner zero" does not conform to common phraseology, as the number "zero" is typically omitted when the leading digit is a 9. Furthermore, longer phrases may lead to confusion, especially in high-stress situations.

The option "Heading one eight zero" refers to 180 degrees and is unrelated to the current question about 90 degrees.

Overall, the clear, concise phrasing of directions is designed to promote efficient and unambiguous communication in the aviation environment, making "Heading nine zero" the most accurate representation of a magnetic heading of 90 degrees.