not getting info on 'should be' departed flight

Sir/madam,
Flight AI 191 from mumbai to Newark was scheduled to depart from mumbai on 17 mar 2011 at 1.30am.
now after about 5 hrs from this time, i am trying to track it on net. it is still showing as ‘scheduled’ rather than ‘on the way’. when i searched in ‘airborne flights’ it is not showing it in that list. when i contacted on phone no 28318888 ( from mumbai in mumbai) i was told that it has departed in time.
so i want to know why it is not showing in the tracker?
if it is assumed that tracker is not updated; then how it is showing the data of other flights which have departed very recently.
pl let me know as i am worried. my wife has boarded the plane.

AFTER getting more info from FAQ on this related issue it is observed that:

  1. this site is controlled from US and has primary service area around US and UK. The track line appears only within area.
  2. however the site shows data of ‘departed flights’ and ‘air borne flights’ from primary as well as SECONDARY service area like india.
  3. moreover, the my in particular which i was tracking is not still shown in the list of ‘departed flights’ because it was from Air India, another constraint.
    From the above three points it, i have got answer to my own query. Thus, AI 191 from mumbai to NEWARK NJ being from AIR INDIA was not in the list of departed as well as air borne. secondly, since it has not reached in the primary zone yet, the tracker is not showing the path.
    ** Incidently, the return flight because covered in primary area, was shown by its track. The list of all departed flights from mumbai were not showing any AI flight. The air borne list was also not showing the filghts from AI since none was coming in primary area. **. This fact has initially made me confused and scared. It is only when i searched for a similar flight ie from delhi to newyork, whose record was similarly not updated; that i got the clue as stated above; which finally has relieved me after about 3 hrs of struggle.
    i am putting this for the benefit of those who may get confused and panikey like me in same situation.

THUS, by getting more information adds to your worries if are not interpretated correctly