How should you express a frequency of 118.50?

The correct way to express a frequency of 118.50 in air traffic control communication is "one one eight point five zero." This phrase precisely conveys the frequency in a clear and standardized format that is easy for pilots and ground controllers to understand, minimizing the chance of miscommunication.

In ATC, each number in a frequency is articulated distinctly to ensure that there is no confusion. Saying "one one eight" clearly communicates the numbers 1, 1, and 8, while "point five zero" specifically indicates the decimal point followed by 5 and 0. This method adheres to aviation communication protocols, which prioritize clarity and precision.

Other expressions like "one hundred eighteen point five" may create ambiguity, as the system used in ATC prefers individual digits over numbers combined in a larger format. Saying "eighteen point fifty" may also be misleading, as it does not specify the higher numbers leading to the frequency and could potentially confuse the listener about which frequency is being referenced.