What is harder - a flightdeck where both are captains, or a flightdeck where both are first officers and no captain is present?
Also, what happens to the legal responsibility and authority of Commander when, on a flight lasting over 8 hours, the commander departs the flight deck in order to occupy a crew rest or passenger seat designated as crew rest? Who lands a plane in Newark or Singapore after having been airborne for 19 hours, and what has he or she been doing for the hours before?