What does AD do?
 

What is AD responsible for on the plan. Can anybody give me the accurate directions and what AD should do on the plan???

I assume you are talking about an Assistant Director?

The AD is responsible for directing "extra's" on set. If I'm not mistaken he (or
she) is also yelling "silent, sound, rolling" etc. However I could be wrong on that.

From what I have seen on Project Greenlight, the AD is THE person that keeps everything moving and everyone on schedule. The director works with the DP and the main actors, the AD does everything else.

This may help.

http://www.skillset.org/film/jobs/article_3649_1.asp

Job titles are less defined, the further you get from "hollywood" level productions. But strictly speaking, the AD "bosses" the set. He is the voice and arm of the director, freeing him up to be creative. When the caterer arrives on set, and needs to know where to set up, and who will write the check, the AD takes care of it, so the director is not disturbed. He keeps the show running on schedule. He reminds the director, ever so politely, when they are running behind. He makes sure the actors are standing by and ready to go on when their call comes up. IN short, just about everything an "indy" director wishes he wasn't doing while making a movie, an AD does for him on a larger set.

Oh, I see Imran has posted a nice link... that's a good summation.

(I've been a 1st AD, and the expression "Busier than a one-armed paper hanger" comes to mind.)

Okay so what does the second second AD do ? LOL

He's the other arm. Shiva would be popular on most sets.

First Assistant Directors generally run the set from a logistic and time management point of view, they are often involved in scheduling the day's shooting and making sure the film stays on schedule and under budget during the shooting stage. In fact they are responsible to the producer and the production manager rather than the director. If principle photography goes over budget and/or over schedule the 1st AD is often the first one replaced, whereas he or she is not responsible for post schedules and budgets.

The 2nd AD organises and liaises with the cast, will often be in charge of call sheets and getting the talent to the set on time. They will also look after cast paperwork and itinerary, make sure contracts are up to date, and may arrange accomodation and travel for key actors.

The 3rd AD (who is sometimes called the Second Second AD) is in charge of extras, unless it's a pretty demanding action sequence (battle scenes etc.) when the stunt co-ordinator or a more senior AD may step in to organise the more technically demanding background action work.
At least this is the "Hollywood" model, and generally the model around the world now.