Boeing 787 battery fire was difficult to control
Source: AP-Excite
BY JOAN LOWY and JOSHUA FREED
WASHINGTON (AP) - Firefighters and mechanics tried repeatedly to put out a battery fire aboard a Boeing 787 Dreamliner through smoke so thick they couldn't see the battery, according to documents released Thursday that portray the incident as more serious than previously described.
The Jan. 7 fire at Boston's Logan International Airport is under investigation by the National Transportation Safety board, which released laboratory analyses, interviews and other data it has gathered so far. It still hasn't been able to pinpoint the cause.
Federal Aviation Administration officials are expected to make a decision in the next few days on whether to approve a plan by Boeing to revamp the 787's lithium ion batteries to prevent or contain future fires. Once the plan is approved, Boeing hopes to swiftly test the reconfigured batteries and get the planes back in the air.
Dreamliners worldwide have been grounded since a second battery incident led to an emergency landing in Japan nine days after the Boston fire. The incidents have raised questions about the safety of using lithium ion batteries, which are more susceptible to igniting if they short-circuit or overheat than other types of batteries. The episodes also have called into question the FAA's process for certifying the safety of new aircraft designs.
FULL story at link.
Read more: http://apnews.excite.com/article/20130308/DA4SJGSO1.html
In this Jan. 24, 2013 file photo, Joseph Kolly, director National Transportation Safety Board (NTSB) Office of Research and Engineering, holds an fire-damaged battery casing from the Japan Airlines Boeing 787 Dreamliner that caught fire at Logan International Airport in Boston, at the NTSB laboratory in Washington. An investigation of a battery fire aboard a Boeing 787 shows mechanics and firefighters made repeated, unsuccessful attempts to put out the blaze through smoke so thick they couldn’t see the battery. The documents released Thursday by the National Transportation Safety Board paint a more dangerous picture of the Jan. 7 fire than previously portrayed. (AP Photo/Manuel Balce Ceneta, File)
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Knowing how supremely complex their systems are is another. I've built model airplanes and real ones. From balsa to litium ion - there's all degrees of complexity and chance. The average rube - airline traveller - who gripes about seat size - would have something else bother them if they were given a look into the electronics bay (or any other "inner workings area"
of a modern flying bus.
The point I'm getting at is that when a new design takes to the skies, it can take time for the fallibility of human engineering to surface. Look at that cargo door mis-engineering some years back - or the shorted wire over the center fuel tank on 747s. Both those instances involved what was really old technology simply applied shortsightedly. But this Dreamliner - with a fair amount of cutting edge technology incorporated - it's got an even higher than normal quotient of risk built in.
If we held back and waited for THE perfect conveyance to come along, we'd still be cowering in caves and clubbing mammoths.
The great majority of the posters there seem to think the problem is likely a combination of things with picking the most volatile lithium chemistry for these cells being the prime cause.
Evidently the Battery Management System (sometimes known as the Battery Murder System) was set to exceed some ratings of the cells in the batteries in question, ratings that were established by the cell manufacturer.
Drawing 580A from cells rated at 325A is not good practice. Discharging lithium cobalt cells to 2.5V is also bad practice, anything below 2.7V is just asking for trouble with them, unlike nicads lithium cells really don't like to be discharged completely and sometimes respond to this sort of abuse by catching on fire. As you can see from the graph below, 3.0V is just about completely discharged.
