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What’s Up With All The Wires? July 18, 2006

Posted by gordonwatts in computers.

The Farnborough air show is underway right now. This is where airlines and weapons manufacturers show off everything new and cool. Sadly, not so much to people like you and me. I live in Seattle, which means anytime Boeing or Airbus do something I can read about it in all the headlines. The most recent generator of headlines, of course, have been the delays of the A380, the new super-jumbo-jet from Airbus.

Taking a page out of the new PR thing (blogs, etc.), they are trying to let everyone in on why the plane is late (I think this is a great way to do PR). Their excuse?

Tom Williams, an executive vice president at Airbus, offered the company’s first detailed post-mortem on the A380 problems. Most have to do with the wiring, which is more complex than on any existing plane — both because of its size and because of the custom features demanded by Singapore Airlines, Qantas and other carriers.

The A380 has the equivalent of 312 miles of electrical wiring in it. The wires are threaded through the plane in bundles, called harnesses, which can be as thick as a man’s leg.

For all the complexity, the mistakes grew out of relatively simple lapses in communication. Engineers at Toulouse and at the Airbus plant in Hamburg, Germany, tweaked the design of the A380 on a digital blueprint, but sometimes did not update each other on what they were doing.

From this I learn two things. The first one: lack of communication, is a mistake I’ve made more than once and I’m sure I’m destine to make again. System integration is the worst task in a project. You think you’ve got all the bits done and all you have to do is glue them together. And then it takes longer than any single part.

The second thing is interesting: “wires are threaded through the plane in bundles,…, which can be as thick as a man’s leg”. This strikes me as odd. Especially because as you read further on you discover that most of the custom features demanded by the various airlines have to do with entertainment. Now, I can understand for safety and security reasons wanting control lines to be dedicated to particular tasks. But the entertainment lines? Why not just do a network? You could use a combination of fiber and copper. Gigabit Ethernet would be able to ship enough data almost anywhere. This would substantially reduce the weight of the bundles of wire, generating fuel savings. The only thing I could come up with as an reason why not to do this is that you end up with a CPU in each entertainment center that will require power. Perhaps too much power? Given today’s low-power microcontrollers that seems iffy at best. At any rate, it seems like they could do this much simpler using modern networking technology…

Boeing is about to start putting together the 787. I wonder how many problems they will encounter?



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