600kg will come with a new form of BCAR Section S. No aeroplane will be able to become a 600kg microlight, in either direction, without at-least a paperwork exercise to evaluate the available evidence and determine whether the aeroplane, at the new MTOM, complies with the microlight safety regulations. In most cases, at the very least, there will be some changes to the operating documentation.
It may be simple and pain-free, but it will never be automatic.
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