The Rubric requires compliance with applicable parts.
More generally though, Part 61 (esp 61.3) and 91 (700 series) are clearly and unambiguously drafted from the perspective that the USA asserts its right to control the basis on which N-registered aircraft are operated whilst outside the USA - irrespective of the crew licence on which the flight is conducted.
We might disagree as to whether this is practical, enforceable, desirable or otherwise, but it is exceptionally clear.
MY OPINION, is that I believe that the UK CAA would defer to the FAA on such points, should a case arise, in a way that other third party CAA's might not. Such statements as they have made in public would tend to support this view.
Like so many Pprune discussions on such points of fine detail, these things are only ever really tested in court, or by insurers. A court case is highly unlikely unless a very specific complaint is brought. An insurance glitch is much more likely. You take a view and roll the dice.
I go with the cautious route, others differ. If we all agreed, Pprune would become as dull as the average air law argument.
