Originally Posted by
rickair7777
In 91 it might have been legal. Crew are not required to physically occupy their control station at all times and I don't recall anything in 91 prohibiting a non pilot from sitting there (what if he was getting dual given?).
Not to minimize your concern, just talking legalities.
Actually under 91 there is a reg that prohibits a crew member from leaving his station unless nature calls.There is nothing that states that a non pilot cant sit in the pilot seat but we are talking about a high performance jet @ fl410 and the pax is a non pilot who needs more than flight instruction to sit there ..