Doesn’t the captain “own” the whole decision, in the legal sense, always? Even if PNF (pilot not flying). In GA you don’t have the PF and PNF concept so you have the PIC and he should “own” the whole decision.
It seems to me that the common issue is that the PIC (and I am sure that the PIC virtually always knows perfectly well who is the PIC) derogates his responsibility to a passenger (a non-PIC PPL) who seems (or is) much more experienced. Or is just more assertive; a lot of syndicates suffer from assertive individuals on the ground and one would expect this to carry through into the cockpit.
This would also be more likely to happen to fresh PPL holders because they have just spent some 50-60 hours sitting next to a “passenger” who was the PIC. Accordingly, many pilots start to screw up badly when they have an instructor as a passenger. Happens to me, too, at 2400+hrs, and I have to consciously force myself to disregard who the passenger is.
I’ve become PIc on a few flights when the low-hours syndicate member handed me control. I have said “I have control” as the aircraft developed an increasing PIO, or, on two occasions, left the runway.
Our Jodel syndicate includes an instructor at present, previously had an examiner, and earlier an instructor.
I always have my biennial “flight with an instructor” in a school plane. It avoids problems.
My last “one- hour- with-instructor” was in a Pa38 with the instructor who shares the Jodel. I’ve far more Jodel hours than him.
Flying with fellow part-owners, if they’re unhappy with the weather, I’d usually divert/turn back.
