RE: Longhaul crews

Two crew longhaul aircraft carry extra crew when operating flights which would/might carry the operating crew over hours. Regulations vary from country to country but, as a rule of thumb, flights of less than 8-10 hours carry 2 crew, 10-12 hours, 3, over 12 hours 4. Where extra crew are carried, there are always 2 Captains and the crew rotate through the crew rest area.