For the record, the designations foxtrot and ultra were replaced because we tried to match the letter to the first letter of the colour assigned to each designation.

So bravo is blue, victor is violet, sierra is silver and tango is tan.

Admittedly, we're stretching the point with some of those.

But the other consideration with colours is to ensure they don't conflict with other colours in use on the console and that they're easy to tell apart, even if there are no other colours to compare them to. For example, it can be hard to tell which of a particular shade of blue is being displayed unless the others are also displayed to compare it to. That limits the colours we have to choose from.