Scenario. During taxi an engine fire warning occurs. In the Boeing system does the captain or the first officer close down the engine and who pulls the fire switch and fires the bottle? Let's say it is a severe fire and the captain decides to go ahead with a passenger evacuation. Again, which of the two pilots actually closes the remaining start lever and pulls the fire switches. The area of responsibility policy gets a little confused here. In the simulator it has been found that when things happen fast as discussed above, there is often confusion when it comes to area of responsibility actions. Does the captain or the first officer tell the pax and crew to evacuate? Or does it depend on whose leg it was (is going to be)?
What was crystal clear for decades of jet transport flying in terms of checklists, seems now to be a hotch-potch of head scratching in order to hastily recall exactly who is responsible to turning the landing lights off after take off - or who turns off the seat belts - the PNF or PM? These are not particularly good examples I admit - but you get my drift...