Under ICAO rules, a pilot wishing to operate an aircraft which has a different State of Registry to the state that issued that pilot’s licence must have a validation from the relevant authorities.
This means that flight crew carrying a non-UK CAA licence, issued by an EASA Member State or Switzerland who operate UK-registered aircraft must carry a ‘general validation’ with their licence. This is issued by the UK CAA.
Find enclosed the link:
Click here - Validation link