Hi,
Id be happy to explain a little more. On the frieghter 747 we have three outward opening doors. The two lower lobe doors on the right lower side of the fuselage. ( these are the old "baggage compartment" areas from when it was a PAX airplane. There is also a very large outward opening door on the left rear side of the main deck. Per my aircraft flight manual this door is 120" (H) by 134" (L). These are classic numbers, oddly enough my -400 manual dosent say. I assume they are the same. Either way, its a pretty big door. When this door is in the open position it would be right in the midst of the airflow coming from the wing/wing root area. Should this door depart inflight I have no doubt it would contact the tail. Its size would be enough to render the aircraft un-flyable. I would much perfer to slide off the end of a runway (even in EBBR) then to fall out of the sky.
To my knowledge, ( someone correct me if im wrong) there are no cases of a 747 with a main deck cargo door open, flying. Lower lobe, perhaps but I could be wrong.
Would the aircraft fly with this door open? well consider that a fully loaded -400 is tipping the scales at around 870,000 pounds which would give us takeoff and climb speeds even with flaps at the takeoff position of around 200-220. ( assuming after takeoff we maintain what ever our flaps 10 or flaps 20 speed is) These speeds are different for each takeoff, current airport conditions and other variables. Would it fly? maybe, maybe not. I dont want to find out over a crowded city in europe. It all comes back to that judgement thing. Of the 747 operators on this board, what would each person do in this situation? I bet we would get alot of different ideas. For me? I dont want to be guessing during the moment of truth. If a door opens, I stop. Robotic perhaps but in my judgement, its correct. Just to be a bit more clear, if I have already rotated or was about to, well ****, I guess we are going flying and hope boeing makes a good strong door.. Each takeoff is different, the V1 - Vr spread may be 15 knots or better, Im going to think about this spread each time before we aver start engines. Having a plan in this kind of situation or at least having considered it is a far better way to play then to just wing it and hope.
Also, on some 747 freighters we have nose loading doors, in this case the entire nose of the aircraft is hinged and swings up to open. The system is virtually impossible to fail and open on takeoff but if it ever did, total catastrophy.
Just something to think about.
Cheers