Originally Posted by
ChickenHouse
Now we come to penny-pickin'. The 61.75 license may be valid on the basis of a 3rd class medical - if ever anybody issues that on such constellation -, but as the underlying foreign license has to be valid to execute the rights on the 61.75 and I never heard of any foreign license granted execution rights on the basis of the non-ICAO US 3rd class medical, you need the appropriate medical of the underlying license to render that valid.
A pilot flying on the strength of his 61.75 has the choice of which medical is valid from an FAA standpoint. 61.75(b)(4) could not be more transparent and requires no interpretation.
When a pilot is flying outside the US, in reliance on his 61.75 licence (such as a pilot on a UK PPL and FAA 61.75 flying an N-reg outside the UK) the same principle applies. The underlying UK PPL is not rendered invalid by reason of the absence of a UK medical. If the pilot has the correct FAA medical, then he has a valid licence.
Where that pilot seeks to do something which relies on his UK licence (such as exercising the privileges of an IMC rating whilst in UK airspace), then his UK licence needs to be valid, up to and including his UK medical.