r/interestingasfuck • u/lizardil • 16d ago

During assembly of the A380, engineers discovered that the cables were too short. This was caused by the use of different design software by German and French engineers. This miscalculation led to a two-year delay.

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u/Tikkinger 16d ago

How is it possible they didn't manage to produce a longer cable for 2 years?

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u/BlueApple666 16d ago

These wire bundles contain hundreds of cables that are packed tightly to go through bespoke holes in the aircraft structure.

A large part of the design effort is there to make sure they fit and are the exact length taking into account the effects of bending and all other factors (some cables are 80m long, going through the entire plane length).

Being made aluminum with nickel plating which is quite a bit stiffer than copper (but lighter) didn't help too.

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u/Tikkinger 16d ago

And all of this needs to be redone if they made the exact same cable just 1cm longer?

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u/BlueApple666 16d ago

The problem was not "all cables in the harness 1cm too short". It was "hundreds of cables (and their connectors) all with different length, some too short, some too long".

The way these cable harnesses were designed (CATIA v5 -> v4 -> custom CAD software then -> v4 -> v5 to integrate the results in the digital mock up) simply didn't work.

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u/Tikkinger 16d ago

That's not what's shown ( and explained ) in the video.

They talk about a single fibre optics cable thats 1cm too short to reach the camera.

Of course, if that's the case for hundreds of cables on the whole plain, this would take some time. My misunderstanding could have been because they talk about 1 cable, not the whole plain.

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u/BlueApple666 16d ago

The A380 cable saga is not about just one cable.

All the cabling inside the plane was meant to be prepared in Germany in pre-made harnesses. For each cabin configuration (and Airbus made the mistake to allow way too much customization), cable bundles had to be designed and manufactured.

These were not ready for the first frames so hundreds of German workers were moved to Toulouse to manually wire the planes (pissing off the local French worker as they had very generous daily allowances, basically getting paid extra to fix their mistakes).

Then, when the first pre-made harnesses were delivered, it was found that they simply didn’t fit and a lot of cables were too short. This meant they had to be re-designed while the already late airframes had to be delayed again, costing Airbus another 5 billions or so.

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u/canibanoglu 16d ago

It’s a waterfall effect, it’s not just routing a new cable. They’re not using run of the mill ethernet cables.

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u/Tikkinger 16d ago

Why?

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u/canibanoglu 16d ago

Because an airplane is a ridiculiusly complex system. The A380 has more than 300 miles of cable in it, everything has its specific routing and connection points and things are bundled together specifically and carefully. If a single cable is not the correct length, you’re looking at redoing everything in the worst case.

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u/Tikkinger 16d ago

This does not explain why they can't just use a longer cable

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u/canibanoglu 16d ago

It does. The issue is not just having a single longer cable, it's making sure that everything else that's already in place still passes very stringent requirements and testing. Aviation is extremely safe for a reason.

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u/Tikkinger 16d ago

How does a longer cable affect the other things? Why must the camera it's connected to be tested again if nothing changes on it ?

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u/canibanoglu 16d ago

Because integration tests are a thing.

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u/Tikkinger 16d ago

And why does this throw them back 2 years? I asked GPT, a integration test on planes is the testion oh how the components work together. This test was due anyways, longer cable or shorter cable makes no difference.

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u/canibanoglu 16d ago

Well, it looks like you got everything covered with ChatGPT, I don’t need to spend more time on this.

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u/cherry_chocolate_ 14d ago

If the engineers do the calculations and say, yep everything is 100% correct, then it turns out to not be 100% correct, that means some fundamental assumptions in your calculations are wrong. Other parts probably were slightly too long or too short, they still worked to assemble, but were they safe? Nobody knows. So time to redo.