Originally Posted by
Mike Flynn
US piggyback licences are issued on the back of UK licences and their restrictions.
In the case of this pilot his eyesight prevented him obtaining a UK night rating because he was colour blind.
So he could not fly at night end of story.
Don't be so sure. He had an FAA Second Class medical without a night flying restriction. To fly an N reg at night, he would only have needed three hours night training with a FAA instructor in his logbook. This would not show up on the 61.75 certificate, because FAA certificates are deemed to include night flying privileges, unless annoted to the contrary.
The difference between CAA and FAA colour vision standards are easy to find online.