If you are required to use the radio, you need a LPE on your licence.
Always? Or only for undertaking a flight where the use of English might be required?
I can well imagine that some private pilots in countries like France and Spain, never leaving their country, do all their R/T in local language. Would they still be required to have a valid LPE? Even if they are, I doubt very much whether the requirement would be enforced
