Is it possible to open the door when the aircraft is pressurised and at such an altitude. We have all seen it in films but a CC friend of mine told me not the case.
Nope.
The door is not locked or anything, however at FL350 typical pressure differential between outside and inside is about 7 PSI.
say the typical aircraft door is about 3 ft wide by 7 feet tall - thats 21 sq ft or 3000 odd square inches.
with 7 lbs or air pressure leaning on each one of those 3000 squares, there is the best part of 21000 lbs 'leaning' on that door - call it 10 metric tonnes.
Its a 'plug' door , so to open it you need to move it inward against that weight - Kinda difficult to pry that open in flight!