Major 747 repair

A fascinating pictorial of how a Qantas 747 that suffered structural damage in an overrun was repaired… What an engineering job…



The repaired aircraft was put back in service within 9 months of the incident, and flew for Qantas for another 12 years, giving it 22 years service

That is a cool story! I would not have expected that aircraft to make a return to service!

Wow, that’s awesome! Though I think I’m feeling the beginnings of an ulcer just even thinking about planning out that kind of a repair job.

Yeah…the logistics of getting that done is pretty amazing. I’m still scratching my head over how they supported that front nose section by putting those bars through the upper cabin windows. Surely they can’t be just resting on the window frames…there must be some sort of trusses within (?)…

I was wondering about that too- or is that part of the advantage of the monocoque fuselage structure? Einstein’s an Aerospace engineer, right? I

Yes, I are!

I’m not sure about the details of the 747 design, but I’d suspect a semi-monocoque design, which means that SOME of the stresses and loads are transferred through the skin, but not all of it. When you stand on a Coke can and it supports your weight, all the stress is going through the aluminum can skin - this is true monocoque. In a “rigid plane”, there are longerons, stringers, and ribs (oh my!) running throughout the fuselage that give strength underneath whatever skin panels you staple/glue to it - kinda like a skeleton underneath some skin.

The combination between the two (which is called “semi-monocoque” instead of “semi-rigid” due to a trademarking issue with Pfizer) is where you have an internal skeleton, but wrap the skin in tight, so that it carries some of the stresses/loads. You can achieve a stronger airframe with a lighter weight this way, which is what aerospace is all about.

I wouldn’t be surprised if the 747 was specifically designed for this kind of lifting. When you’ve got a huge and expensive aircraft like the 747 you don’t want to throw it away because you broke a landing gear or something trivial, so you make jack points along the fuselage, just like on a car, that enable you to lift it of the main gear and do work on it.

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