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."
A protective valve? (Score:3, Informative)
What is a power diode [slashdot.org]
Re:A protective valve? (Score:5, Informative)
"Valve" is a generic term, slightly archaic for an electronic switch. Some vacuum tubes are called valves.
http://en.wikipedia.org/wiki/Vacuum_tube [wikipedia.org]
Since a transistor is simply a crystal triode, the terminology is reasonable.
http://www.beatriceco.com/bti/porticus/bell/belllabs_transistor.html [beatriceco.com]
Re:What? (Score:2, Informative)
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
Re:Yay, time for finger pointing (Score:5, Informative)
You do realize that the flickering lights pointed investigators in a particular direction. THEN, after more analysis, they discerned the problem lay in miswiring. The flickering lights are not prima facie evidence of a wiring fault.
A bit more detail would be welcome. As it is, one cannot tell what happened or how many aircraft are affected.
Re:User error (Score:4, Informative)
Actually from my admittedly limited experience, FAA and airplane mfgrs are downright obsessive about making connections idiot proof and failsafe. It's pretty difficult to find places in an airplane where it's possible to plug the wrong things together or backwards. FAA has been dealing with Murphy for a very long time. In this case, if that's what happened, then it's one that slipped through the design and development process. FAA will mark this as a design failure and require Boeing to make it impossible to connect wrongly.
Looking at that Japanese powerpoint [mlit.go.jp], it looks like that may be exactly what happened. The battery cells are rectangular with a stud on each side of the top. Not even any prominent markings to indicate polarity, though the two studs seem to be mounted with different colored rivets. You'd think they'd at least have different diameter studs for the positive and negative, and jumpers with holes to match.
Re:Yay, time for finger pointing (Score:3, Informative)
A valve is also another term for a diode, which only allows current to flow in one direction.