Japanese Probe Finds Miswiring of Boeing 787 Battery 201
NeverVotedBush writes in with the latest installment of the Dreamliner: Boeing 787 saga. "A probe into the overheating of a lithium ion battery in an All Nippon Airways Boeing 787 that made an emergency landing found it was improperly wired, Japan's Transport Ministry said Wednesday. The Transport Safety Board said in a report that the battery for the aircraft's auxiliary power unit was incorrectly connected to the main battery that overheated, although a protective valve would have prevented power from the auxiliary unit from causing damage. Flickering of the plane's tail and wing lights after it landed and the fact the main battery was switched off led the investigators to conclude there was an abnormal current traveling from the auxiliary power unit due to miswiring."
Re:Yay, time for finger pointing (Score:5, Insightful)
Outsourcing contractor.
Re:Yay, time for finger pointing (Score:4, Insightful)
Really? I am actually quite impressed. The degree of investigation over lighting failures and back up safety systems and all that is pretty awesome. Putting aside my condemnation of corporations like Boeing, this mess isn't damning, but rather assuring. Any finger pointing should be met with a reminder that the plane landed just fine. Granted, I'd be annoyed if my flight was grounded for this nonsense but degree of blame should reflect the problem caused.
Re:Yay, time for finger pointing (Score:4, Insightful)
Themselves? [dilbert.com]
Re:What? (Score:2, Insightful)
Yes, but commercial airliners aren't built with plugs and sockets. For weight savings, everything is directly hardwired. At least, in pretty much every airliner prior to the 787, and I can't imagine Boeing changing that. Military aircraft are built with plug and socket connectors, but both sides of the connection are big bulky heavy metal components. When your plane is a cockpit and wings strapped onto a giant oversized turbine, you basically don't care about weight, but commercial airliners are the exact opposite. They're obsessed with weight savings, so the miswiring happened during initial assembly and their quality control procedures were too poor to catch it. Boeing has fallen a loong long way.
Someday, people are going to look back on the outsourcing mania of core competencies by MBAs over the past generation as sheerest idiocy.
Re:Yay, time for finger pointing (Score:1, Insightful)
I was just thinking that..the media will now have their blame game but at the end of the day it was a plane mishap that didn't include charred bodies strewn on the countryside. It was a glitch, that was easily fixed. I could have been much worse.
Re:Yay, time for finger pointing (Score:4, Insightful)
I was just thinking that..the media will now have their blame game but at the end of the day it was a plane mishap that didn't include charred bodies strewn on the countryside. It was a glitch, that was easily fixed. I could have been much worse.
This whole idea of a wiring error sounds fishy and it seems to be based on flimsy evidence. These kind of things are proven by hard inspection of the aircraft, drawings, and designs not by observing flickering lights. Somebody in Japan wants these aircraft in the air really bad, and I'm betting they managed to talk Japan's version of the NTSB into this idea.
I'm waiting for the final report on this... Before I decide to get on one of these.. Because if this flimsy sounding reason is what I think it is, another plane is going to have a battery fire pretty soon and this time we might not be so lucky.
Re:What? (Score:5, Insightful)
Yes, but commercial airliners aren't built with plugs and sockets. For weight savings, everything is directly hardwired. At least, in pretty much every airliner prior to the 787, and I can't imagine Boeing changing that. Military aircraft are built with plug and socket connectors, but both sides of the connection are big bulky heavy metal components
Do you have a reference for that? It doesn't make sense that field replaceable parts are hardwired in - you'd have to clip the wires to take it out, and every time you clip the wire it gets shorter, so eventually you'd have to run a new wire back to the source.
Even for parts that aren't replaced often, it seems that hardwiring would just increase the chance of error - if everytime they replace an engine someone has to sit down and manually splice 200 separate wires, that seems a lot more trouble prone than plugging in a dozen connectors that were wired in at the factory and tested on the factory test harness to be sure every wire was connected to where it should be.
Re:Yay, time for finger pointing (Score:5, Insightful)
During my tenure in aerospace, I had witnessed more and more of a disregard for detail work. What used to be a good thing called "attention to detail" started being regarded negatively as "being a perfectionist".
The devil is in the details. Thousands of things work perfectly. One does not. This is the inevitable result of overlooking just one detail.
Re:Yay, time for finger pointing (Score:4, Insightful)
Re:Yay, time for finger pointing (Score:5, Insightful)
The length of the wires isn't a useful metric - it's the complexity of the wiring that causes miswiring.
Re:Yay, time for finger pointing (Score:4, Insightful)
At a guess, I'd say the total length of wiring might be indicative of complexity. The machines that I have worked on that have only a few hundred feet of wiring are generally less complex than machines with thousands of feet of wiring in them.
For comparison, find an old Farmall or John Deere tractor, and compare the wiring to your modern automobile. An elementary school child can figure out the wiring on an 50 to 80 year old tractor. Good luck with your car - experience mechanics have problems chasing down problems, especially intermittent shorts.
Re:Yay, time for finger pointing (Score:4, Insightful)
Only if you assume the topology is the same. The 747 is likely to be much more of a "star" topology with traditional circuit breakers. The 787 is more of a "bus" topology with solid-state relays.
Re:Yay, time for finger pointing (Score:4, Insightful)
Then compare a "modern" car with a very modern car. The huge mess of wires is being replaced by CAN and LIN buses.
Re:Yay, time for finger pointing (Score:5, Insightful)
I agree.
It shouldn't have been possible to "miswire" an aerospace battery, the connectors should have been coded, the wires, and the inspectors should have seen and tested this. Battery failure is still a process failure. Unfortunately, process failures are the most systemic failures possible. Lets hope I'm wrong....
andy
Re:Yay, time for finger pointing (Score:5, Insightful)
A big chunk of the blame should go to whoever designed the connectors. For safety critical systems, it should be physically impossible to connect them in an unsafe configuration.
Re:Yay, time for finger pointing (Score:5, Insightful)
And I don't mean adding stupid spoilers and boost chips and sillyness, I mean stuff like adding an extra pair of high beams that can be operated with the same button as the regular high beams. That will take some serious hacking on a modern car. If car manufacturers were good at making things, this wouldn't be a huge problem, but modern cars do so many things wrong that it's infuriating. Like putting lambertian leds in places where they should have put batwing ones, forcing me to put a diffuser in front of it so that my daughter is able to sleep in her car seat. Or making it a fifteen-minute job to remove the battery for charging it during the winter, when it should take two minutes. Or putting the light that activates when you open the trunk in the far left corner of the trunk, so that it doesn't light up anything if you actually have something in the trunk. I could go on about this for a while...
Re:Yay, time for finger pointing (Score:5, Insightful)
a wiring problem could be as simple as using an incorrect thermistor on a Li-ion pack or not wiring a thermistor in at all. These are often used to alter charge/discharge rates in response to the battery pack temperature. A battery will still work in every other respect, except it won't respond accordingly in response to overheating. This is a fairly simple example of what could go wrong to cause a fire that would not stop the battery from working (until it failed by going on fire). The trouble with Li-ion packs is that if this happens (and it does) then the fire can very easily spread to the surrounding cells. I can see how this could cause short voltage spikes that would overcome resistance in a line to "flicker" a light.
I'd just like to add, I may be totally wrong, but I thought I'd weigh in for the fair minded rather than the conspiracy theorists on this one. Also, before anyone assumes I'm a Boeing employee, I'm not. I'm just a bloke who works with Li-ion batteries and who has seen faults similar to this in the past.
Re:Yay, time for finger pointing (Score:5, Insightful)
Q: What is worse than a dumb guy?
A: A dumb guy with initiative.