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Japanese Probe Finds Miswiring of Boeing 787 Battery
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."
Who will it be? Maintenance? Boeing?
So basically, the user reached back behind the power supply while fiddling and bumped the 110/220V switch, and it caught fire. Naturally, they didn't say anything to the tech after setting the switch back besides, "It just caught fire! All by itself!"
The user in this case is a giant airline company, and tech support would be Boeing. The FAA, of course, is the QA manager, who reviewed the call, and after reading the ticket closure notes, facepalmed, leaned back into his chair, and took a deep draft of coffee.
#fuckbeta #iamslashdot #dicemustdie
Can't they make an idiot proof power plug?
Because idiots are much more resourceful than ordinary people.
#fuckbeta #iamslashdot #dicemustdie
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.
Because idiots are much more resourceful than ordinary people.
Behold!
It's the damned metric +/- that causes all the confusion.
"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"
What is a power diode
AccountKiller
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.
When you say "Japanese Probe" I had an entirely different idea in my head regarding what this story was about.
Slightly different, but my friend works for a company that makes in-flight video systems for planes including Lufthansa. While not mission critical, they still have to follow FAA and other regulations... one of which is some of the plugs they use plug in and then are secured in place with 12 to 16 screws even though the signals being passed are just network/video/audio.
I don't see why they couldn't use plugs of the same fashion instead of hard wiring everything
AFAIK you are completely incorrect. Just using the 787 for example, the entire thing is built in modules including wiring and all, that are built and tested by subcontractors and then plugged and bolted together at the Boeing assembly plant. All commercial aircraft that I am aware of at least since the 1940s has had connectors. The biggest problem with connectors is not the weight but the unreliability. Each connector is a potential point of failure, so aircraft electrical connectors are actually heavier - they have positive scraping between the two parts of each connection, often have moisture resisting / sealing. and have a threaded ring that holds them together. Then (IIRC) there is an additional set of tabs through which a wire is threaded and itself positively bound - used to be twisted, now I think they use a mechanical crimp. The wire assures that the threaded ring can not unscrew itself due to vibrations.
The most expensive cost for a commercial aircraft after fuel is the cost of downtime - time spent fixing things costs thousands of dollars per hour. Therefore everything on an aircraft is designed to be removed and disconnected quickly, efficiently and safely - including things like wings, tail fins, etc. FAA is not going to allow the mechanics to cut wires and fasten them back together, so again the connectors are designed so that each one can only go one way.
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
I'm sorry; but, you're wrong. Work for a sensor manufacturer that sells to the aerospace industry and I can tell you, commercial aircraft cabling is full of connectors. Same kind of locking connectors found on military aircraft.
The original
Questions raise, answers kill. Raise questions to stay alive.
Never underestimated the ingenuity of dumb. I gave a guy a hard drive to replace the one in his computer. He 'knew all about it' and I knew he had the knowledge to format and reinstall his OS no problem.
He brought the drive back to me, claiming it didn't work, in fact the power cables would not fit till he took his dremel to them, so it must not have been the right drive for his machine.
He had shaved off the corners of a standard hard drive power connector so he could fit it upside down in a used 512 MB IDE hard drive. Which of course killed the drive, but I also determined it killed that connector on the motherboard's IDE bus.
The reason for this mistake?
His computer had been built with some oddball brand of hard drive (I can't remember... Paladin or Palladium? I think it started with a P) which put the controller board on TOP of the drive instead of on the bottom.
I see that the discussion here is based on a sketchy summary from the originally Japanese press conference. More coherent information is available if you could read Japanese but I know it's too much to ask for...
Here is the latest update of the on-going investigation from the JTSB issued 20 Feb, 2013; this mentions the mis-wiring:
http://www.mlit.go.jp/jtsb/flash/JA804A_130116-130220.pdf
More in-depth information is given at
http://www.aviationwire.jp/archives/16032
According to this article, the mis-wiring was in the original specs/design, and the design had been corrected. The aircraft in question was manufactured in accordance to the earlier specs but no modification was made to comply with the new ones. One can infer that the bug was considered insignificant to compromise the safety of the aircraft. The JTSB currently does not think this mis-wiring was the cause of the battery incident although they will keep looking into it as a potential cause of anomalous voltage readings.