ace, you mention that the experienced crew/s tend make mutual assumptions about each other, and that is absolutely correct.
I recall an incident when working for that very company many years back when a particular client required a two pilot operation, but the aircraft wasn't normally 2 crew, nor were the pilots qualified to fly 2 crew.
On downwind, the pilot flying ran through his checklist, changed tanks to the fullest for landing, and sometime after that, the "support" pilot changed tanks (selector on the floor between seats) without mentioning it to the pilot flying, and an engine ran out of steam on short final, in fact over the highway, landing on R36.
That's the reverse of what you mention, but indicates how unsafe an operation can be without the required discipline.
I mention it for no reason other than someone may learn something from the incident. If you're not 2 crew qualified, one must sit on his hands.
Then there's that question,
What are the three most dangerous things in aviation?
The first is two check captains flying together, and one of the reasons is as you state, the other being he's not a dedicated co-pilot.
The other two answers don't require mentioning here.
Last edited by relax737; 25th Mar 2010 at 05:15.