NTSB: 787 battery in Boston not overcharged
Members of the Japan Transport Safety Board hold a main battery removed from an All Nippon Airways Boeing 787, at Takamatsu Airport in Kagawa Prefecture, Jan. 17, 2013. The Dreamliner had made an emergency landing the previous day. / Yomiuri Shimbun via AP Images
WASHINGTON The battery that caught fire in a Japan Airlines Boeing 787 in Boston earlier this month was not overcharged, but government investigators said there could still be problems with wiring or other charging components. Japanese investigators had asserted in a similar incident on an All Nippon Airways 787 flight in Japan the battery there had been overcharged.
An examination of the flight data recorder indicated that the battery didn't exceed its designed voltage of 32 volts, the National Transportation Safety Board said in a statement.
This Jan. 17, 2013, photo provided by the Japan Transport Safety Board shows the distorted main lithium-ion battery of the All Nippon Airways' Boeing 787 which made an emergency landing on Wednesday, Jan. 16, 2013 at Takamatsu airport in Takamatsu, western Japan.
/ APNTSB investigators are continuing to look at the battery system. They plan to meet Tuesday with officials from Securaplane Technologies Inc., manufacturer of the charger for the 787s lithium ion batteries, at the company's headquarters in Tucson, Ariz., said Kelly Nantel, a spokeswoman for the board.
"Potentially there could be some other charging issue," Nantel said. "We're not prepared to say there was no charging issue."
Even though it appears the voltage limit wasn't exceeded in the case of the Japan Airlines 787 battery that caught fire on Jan. 7 in Boston, it's possible that the battery failures in that plane and in an All Nippon Airways plane that made an emergency landing in Japan last week may be due to a charging problem, according to John Goglia, a former NTSB board member and aviation safety expert.
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Too much current flowing too fast into a battery can overwhelm the battery, causing it to short-circuit and overheat even if the battery's voltage remains within its design limit, he said.
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"The battery is like a big sponge," Goglia said. "You can feed it with an eye dropper or you can feed it with a garden hose. If allowed, it will soak up everything it can from the garden hose until it destroys itself."
There are so many redundancies and safeguards in aviation that when an accident or mishap occurs, it almost always is the result of a chain of events rather than a single failure, he said.
The Japan Airlines plane caught fire Jan. 7 while it was sitting on the tarmac at Boston's Logan Airport. In a separate incident on Jan. 16, an ANA flight made an emergency landing in western Japan after a cockpit message warned of battery problems and a burning smell was detected in the cockpit and cabin. An investigator in Japan said Friday that the burned insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.
Since then, all 50 787s that Boeing has delivered to airlines' fleets have been grounded, and the manufacturer has halted deliveries of new planes until it can address the electrical problems.
The batteries in two incidents "had a thermal overrun because they short-circuited," Goglia said. "The question is whether it was a manufacturing flaw in the battery or whether it was induced by battery charging."
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FAA has authority to conduct and verify a system test result on the flight box.
By adding some tempreture sensors on the battery, monitor current flow in and out of the box.Turn on the lightingload, turn motors load to observe
temperature rise.
Setting the starting voltage on the Charging system
higher than 80.00% of full charge to save battery life and reduce heat rise.
Will FAA allows battery package from 747 production line to install and keep 787 flying until the problem get fixed?
power demends from motors and lighting during the landing phase. We can not tell the battery is over stressed. But over stressed battery will get
hotter and hotter. Charging cycle will induce heat to the battery.
To prevent fire, we much address the heat rising in the battery in confined box. Are there any heatsink and cooling fan attached to the battery to reduce the rise. Increase mass of the battery to provide more amperes will reduce the stress.
second issue is the battery voltage to start charging.It should not be lower than 80.00% of the full charge voltage. Airline has reported few battery can not be recharged back to normal. That indicates the battery drain out too much energy and can not be recovered. We dont know what start charging voltage battery
charging system set at.What they set at is too low to induce battery failure.
They just need to prevent the batteries from charging in the air to prevent them from catching fire in flight, but the real solution probably isn't far behind either.
What is the problem here? How could something so simple be causing a problem and have made it through testing??
They DID test it, right?
lol