How does the modern autopilot system work for commercial airliners?

http://www.google.com/search?source=ig&hl=en&rlz=1G1GGLQ_ENUS374&q=autopilot+system+commercial+airliners&aq=f&aqi=&aql=&oq=&gs_rfai=

Well, I never knew that autopilot can be used to give the real pilots a break during their flight in order to check the plane's systems (ex. hydraulics, air pressure)and scout for traffic. But for overnight flights, the pilots can use the autopilot so they can go to sleep.

I have some questions relating to this.

1) How do they scout for air traffic?

2) How is a flight plan altered?

Use the autopilot so they can sleep? I sure hope not!!!

http://www.bls.gov/oco/ocos107.htm

Are you sure?!?!?!!? All the pilots are expected to fly overnight and stay awake from midnight to 6 am?

I sincerely HOPE they're awake up there, autopilot or not!!

Remember what happened when some pilots were distracted?
http://www.nytimes.com/2009/12/17/us/17pilot.html
They weren't even asleep, just distracted, which is bad enough!

Asleep? Yikes!!

AL -- where have you been? Many people work overnight shifts -- police, fire fighters, doctors, nurses, EMTs, cleaning staff, some fast food employees, assembly line workers, etc.

Al, you are absolutely right; however,........ People who work at night usually do NOT go to sleep. Their employers are not paying them to sleep; people are expected to work during those hours. They sleep on their own time; that is, during the daylight hours if they work the midnight to 8 am shift. The shifts are rotated at the oil refineries where I live. Doctors and nurses at the hospitals who work the midnight shift sleep during the day and NOT on the job at night. I grant you that sometimes things don't go well and someone may try to sneak off and sleep in an unoccupied room BUT if they are found sleeping on the job it is not unusual for them to be fired. I don't know about aviation rules; it may be allowable on long overseas flights for ONE pilot to catch some shuteye while the other is awake. Why don't you take that on as a research project? I suggest talking to someone in the pilot's union. They will know the rules. See especially the last site below about the rules.

http://www.usatoday.com/news/nation/2007-11-07-airfatigue_N.htm

http://www.militaryphotos.net/forums/showthread.php?136731-Air-India-pilots-caught-sleeping-on-the-job-!

In the following, scroll down to "As a General Rule" portion and read where flights taking longer than an eight hour period must provide sleeping quarters AWAY FROM THE COCKPIT which mans, by implication at least, that those flights must contain more than one set of crew members and they can switch places during the flight.
http://answers.yahoo.com/question/index?qid=20100324091550AAJbRT6