Mon Mar 12, 2018 8:16 pm
This is something I too have wondered about, and I work on 767 freighters for FDX as a structures tech. The lower cargo doors on our 767s are about the same size as the main deck doorway. The answers as stated above make sense. We also see another benefit in that the doorways don't get damaged as often on the 767s as they do on other types such as the MD10s. The 10s usually have a smaller width doorway and the rubber seal are around the fuselage side of the doorway, thus they get hit by the containers when loading along with the under lying structure sometimes.This is a common maintenance write up when the plane comes in for a letter check. On the 767s the rubber seals are on the door itself and the depressor is mounted around the doorway on the fuselage. Also, the wing-to-fuselage fairings on the 10s and MD11s extend back over the center (some call it the aft) cargo doorway and, being of composite construction, are continually getting beat up and needing repair.