I have learned from pilots that when they board an airplane for their flight, the pilots are required to have a bag loaded with several documents, booklets, textbooks, and user manuals. Pilots are required to have this loaded bag with these important documents always by their side for a successful flight.  The loaded bag serves as an essential kit in case if anything goes wrong with the airplane, the pilots quickly have a chance to repair it, solve it, or enhance it.  As long as the pilots are are on the plane and in the pilot’s seat, they are required by law to always have this bag with these resources with them and the bag should never leave their side.