Why Aren't All Frequencies Shown with Six Full Size Digits On Aviation Radios?

The reason all frequencies don't show six full-size digits is to help pilots quickly and easily tell the difference between the older 25 kHz channel spacing and the newer 8.33 kHz channel spacing. This is especially important because there are cases where the frequencies can look very similar.

As you can see in the diagram, with the introduction of 8.33 kHz spacing, there can be a 25 kHz and an 8.33 kHz version of the same frequency. For example, 118.000 and 118.005 both represent a frequency of 118.000 MHz. The "5" at the end tells the pilot that they're on the 8.33 kHz channel. This system was designed to simplify things in the cockpit. Instead of having to remember which spacing to use, pilots can simply tune to the frequency they are given, and the radio knows how to handle the rest.

So, when a pilot is told to switch to a frequency like 118.035, their radio automatically tunes to 118.0333 and uses the correct 8.33 kHz bandwidth. It's much simpler and faster to say and tune "118.035" than "118.0333 with an 8.33 kHz bandwidth," which is a huge benefit when you're flying.

This is an industry-wide standard, not something specific to Icom. It's all about making the process of tuning and communicating as simple and safe as possible for pilots.

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