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747's Phantom Cables

Posted: Wed Jun 06, 2001 2:19 am
by bio15
I have heard that the control cables and wiring from the cockpit on the 747 run through the upper deck floor. If that's so, then I'm confused in how the connection of these wiring is made with the wings. I mean, the control cables would have to go down through the cabin to reach the wings in some section of the body. Does it happen that way? If not, I would think the 747-400 is FBW which I think is not. Could someone shed some light into this subject please?


RE: 747's Phantom Cables

Posted: Wed Jun 06, 2001 2:34 am
The control cables run from the upper fuselage down through the walls to th wings.


RE: 747's Phantom Cables

Posted: Wed Jun 06, 2001 3:11 am
by bio15
I read on a book, Modern Boeing Jetliners, about the 747-400 program. It said that the -400 had certification problems in Europe with the JAA. The JAA maintained that the upper deck floor didn't meet the lastest specifications for resistance to collapse. It was weird since the 400 held the same specifications as the Classic models.
The specific reason for change was related to resistance to bomb damage in flight. "Under the new rule all wide-body designs had to be able to sustain a 20-foot square hole blown in the fuselage side without sustaining floor damage that would incapacitate the control runs" It seems to me that a 20 foot square hole on the fuselage side would definitely damage wall wiring, and that would leave the JAA with no arguments.
Further resistance must be added to control cables. Do you know something about this JAA issue?

RE: 747's Phantom Cables

Posted: Wed Jun 06, 2001 5:04 pm
by Tuffty
The control cables do run through the upper deck floor for part of their run. Using pulleys and fairleads they are routed down the sides of the aircraft in to the wing leading edges or the body gear bay (depending what they operate) to go out to the valves that they operate in the wings.