During the flight the pilots make routine checks on all the operating systems, receive and carry out instructions from air traffic control, to which unit, radio contact is maintained from start to termination of flight. It is incumbent upon them to handle and assimilate a mass of information from the instrument panel, maintaining continual vigilance to spot hazards and malfunctions. Take off, climb out, descent and landing are particularly the most difficult and demanding areas of the job requiring concentration on complex procedures. With the exception of small aircrafts, two pilots, a captain and co-pilot are usually needed to operate a large commercial aircraft. The captain, who is the more experienced pilot, is in command and supervises the other crew members on board.
Most large airlines have a third pilot in the cockpit who doubles as flight engineer.
Sometimes the captain or co-pilot may make a brief tour of the cabin talking to passengers, whose concern is one of their key responsibilities. There are set operational procedures for dealing with emergencies but the responsibility for appropriate action rests solely with the pilots. At cruising altitude pilots make periodic position reports enter data in the aircraft log monitor all aircraft systems make announcements to keep passengers updated on progress, weather and other details. Generally, airline pilots work approximately 75 hours flying time each month plus preparation time involving non-flying responsibilities on the ground. All airline pilots are also required to work on weekends and holidays.