Question

can a door of an aeroplanes can be open during flight

Answer 1

NO. Doors of modern aeroplanes close from the inside. When they fly at high altitudes, the air pressure outside is way way less than the air pressure inside the aircraft. This pressure difference seals the door shut from the inside.
If you did want to open the door, you would have to depressurize the cabin to the level outside

Answer 2

how is cabin pressurized would you throw some light on it.i am asking about the mechanism used for pressurizing the cabin

Answer 3

Hey @WAHEEDAHMED, you should take a look at this awesome wiki page under the title 'Mechanics of pressurization' where they say that the compressed air actually comes from the engines' air intake.
http://en.wikipedia.org/wiki/Cabin_pressurization

Answer 4

aah thanks for that rajathsbhat.....it was quite helpful

Answer 5

Lol why you ask?

Answer 6

it is true about eh pressure thing. no they cannot be opened. and why would you anyway. i think they also might have security measures for that.