Hi, why is it that the 767 doors are those electrical ones that the MD-11/DC-10/L1011 had?? And also the 777 doors are more like Airbus doors. Why did boeing change the doors from the usual 757/737 etc type??
There are a couple of reasons that I am aware of in the case of the 777:
The slide on the 777 is quite large which makes it difficult if not impossible to have the door fit in the overhead like the 767 and other aircraft types.
The plug type doors on earlier Boeing aircraft work well on smaller aircraft but become unwieldly on the larger ones due to the bigger and thus heavier slide attached to the door. The doors on the 757 are notoriously difficult to close due to their weight and the emergency assist system that helps open the door in an emergency. I am not sure if the 747 has this problem as well since I have limited experience with them.
The doors were designed so that most of the parts making up the door mechanism are interchangeable between the different doors no matter their position. This reduced costs in manufacturing and maintenance.
The doors that slide into the overhead need a mechanism to raise them, usually an electric motor and a system of cables and pulleys, which add weight and complexity to the door system. The doors on the 777 are manual and do not need any mechanical assist.
These are a couple reasons off the top of my head. Others can probably add some more information.
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