Just a hypothetical question.
What if both flight deck were incapacitated and a pair of dead heading, type rated, current, P1 qualified pilots from another airline were summoned from business class
to take over.
Woudl the 'In charge' be in charge, in the same way that an observer in the fleet air arm could be the a/c commander?
I know the probability of this happening is about 0.000000001p, but I would be interested to know if SOPs in 'big iron' cover this sort of eventuality.