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The 787 Dreamliner's charred battery  (Source: nycaviation.com)
The battery will be sent to Tokyo for a deeper inspection

An opening investigation into the safety of Boeing's 787 Dreamliner is complete, and with the focus primarily on the 787's battery, more safety checks are on the way.

Boeing, the Federal Aviation Administration (FAA), the U.S. National Transportation Safety Board (NTSB) and Japanese officials have completed their initial investigation into the 787's battery problems in recent weeks. A battery that was involved in this week's incident will be sent to Tokyo for further investigation.

A Japanese safety official mentioned that the battery associated with this week's incident was charred, and that excessive electricity could be the reason it overheated. The battery looked like a burnt metal box that had liquid spilling from the inside.

Boeing uses rechargeable lithium-ion batteries for its main electrical system. GS Yuasa Corp., which makes the lithium-ion batteries used in the 787s, said the problem could be the battery, the power source or the electronics system.

Just this week, a 787, which was an All Nippon Airways (ANA) flight to Tokyo, had an issue with its main battery only 15 minutes into a 90-minute flight. After 40 minutes, a burning smell made its way into the cabin and cockpit, and the plane made an emergency landing at Takamatsu Airport on the southern island of Shikoku. This issue caused all 787s to be grounded in Japan, the U.S. and India until a safety investigation was conducted and the problems were corrected.

Unfortunately, this incident isn't where the 787's problems started. Early last week, a 787 operated by Japan Airlines had experienced an electrical fire at Boston's Logan International Airport after coming in from Tokyo. According to the National Transportation Safety Board, a battery in the auxiliary power unit suffered severe fire damage.

Just one day later, a Boeing 787 operated by the same airline at the same airport suffered a fuel leak. The fuel leak was discovered at 12:25 p.m. ET right after the 787 left the gate for a trip to Tokyo. The flight was cancelled, and the plane was towed back to the gate where passengers were instructed to exit and stay in the airport. No one was injured.

As it turns out, about 40 gallons of fuel had leaked from the 787. The plane ended up being delayed four hours before leaving for Tokyo.

On Friday of last week, two more issues occurred.
It was discovered that a 787 Dreamliner with All Nippon Airways (ANA), which had arrived at the Matsuyama airport in western Japan from Tokyo on Friday, developed a web-like crack in the cockpit window. The pilot found it about 70 minutes into the flight, but no one was injured. In a separate incident on Friday, but also with ANA, another 787 Dreamliner had an oil leak after traveling to the Miyazaki airport in southern Japan. It is unclear how much oil had leaked.



Source: Reuters



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RE: Excessive Electricity
By m51 on 1/18/2013 1:52:29 PM , Rating: 3
It's misstatement, misquote, or mistranslation.
It should be excessive electrical current.


RE: Excessive Electricity
By drycrust3 on 1/18/2013 4:11:36 PM , Rating: 1
You are right, but do you know how much is "excessive current"? 5 Amps! True ... well if what Yuasa say is true. Yes, I know, that's barely enough for a light bulb, but I am not kidding.

I found the spec sheet for the cell Yuasa claim ... sorry, PROUDLY claim is the cell used to make the Dreamliner battery. You can download it from this website:
http://www.gsyuasa-lp.com/aviation-lithium-batteri...

When you down load it, look at the maximum discharge rate. The spec sheet claims the maximum discharge rate for each one is just 5 amps . If that is correct, and I would say it is (because this is a spec sheet), then there is no way a battery composed of this type of cell, even if several cells are "paralleled" together, would be suitable for an aircraft unless it was used purely as a backup for some low powered electronics.
From Yuasa's website:
quote:
GS Yuasa’s lithium ion cells will play a key role in on-board power, providing both Auxiliary Power Unit start and emergency power back-up capabilities.

Unless this Auxiliary Power Unit is some tinsy winsy motor, which I doubt, there is no way a battery made with these cells can be reliably expected to provide the current needed to start it and to provide an emergency power backup capability.
As I see it, if the Auxiliary Power Unit requires anything like your car engine does, a burst of several hundred amps, then it is only matter of time before battery composed of this type of cell will fail.
The remedy is simple: use some car batteries.


RE: Excessive Electricity
By SunLord on 1/18/2013 5:18:39 PM , Rating: 2
The battery if used to start the on board APU which is a small turbine engine in the rear of the jet. If you look at the rear of most if not all modern jets you'll notice a hole at the very rear tip of the jet that's where the APU exhausts from


RE: Excessive Electricity
By drycrust3 on 1/18/2013 6:21:44 PM , Rating: 2
So how much current does starting it draw? 5 amps?
The Auxiliary Power Unit on a Dreamliner is the Hamilton Sundstrand APS5000. Here is what the Hamilton Sundstrand website says about this little beauty:
quote:
The APS 5000 APU is rated at 1,100 shaft horsepower and is designed to start and function throughout the full range of the 787 operating envelope up to 43,000 feet. Hamilton Sundstrand Power Systems, based in San Diego, currently has more than 13,000 APUs in commercial and military service.

Apparently some APU's use a compressed air system to start them, but I haven't been able to determine whether the APS5000 uses that method or not. If it did, then maybe 5 amps is all that is needed to start the APU.
It seems to me the compressed air starting system is the most likely way the APU is started, but even if so, I still think this is the wrong sort of cell to use within an airliner battery.


RE: Excessive Electricity
By Keeir on 1/18/2013 6:00:59 PM , Rating: 5
Ugh.

#1. Amps are not a measure of Power. Amp x Volt = Watt. Watt is a measure of power. Not surprizingly the -same- electronics work just as well in Europe on 1/2 the Amps as they do in NA. Why? The Voltage is twice as much!

#2. Car batteries are linked to a system where Voltage is regulated to be very very low. ~12V in most cases. That means that a car battery needs to output 10 times the Amps compared to a wall socket and 20 times a European Wall socket.

#3. Having read the sheet. Your entirely wrong. CA does not stand for A! It really means that the maximum rate is X times the Capacity. This battery is 3.7 Volts with a maximum rate of 325 Amps. The sheet even showns 250 AMP results.

Each of these batteries is roughly capable of a short burst of 1.3 kW and wieght ~6 lbs each. A 60 lb car battery is capble of producing around ~8kW in short bursts. 60 lbs of these produce around 12 kW ... hmmm


RE: Excessive Electricity
By drycrust3 on 1/18/2013 7:36:14 PM , Rating: 2
quote:
The sheet even showns 250 AMP results.

Duh! It does too. Well, there you go, I got it all wrong.
My apologies to Yuasa.


RE: Excessive Electricity
By drycrust3 on 1/18/2013 8:47:41 PM , Rating: 2
... and apologies to Boeing.


RE: Excessive Electricity
By AntDX316 on 1/20/2013 4:32:01 AM , Rating: 2
boeings electrical engineers should be the best in business

surely there is a reason for an overlook

probably due to lack of adequate testing for the items they choose to use such as zero type failure of their battery selection at previous electrical rate

I'm saying they never could really test at that high rate for pro long period under every condition and assumed its checked ok but then again it could be but slight defect in that one battery is stereotyping everyone to say they are all bad

also other isolted incidents where its only one not all so they should realize not to fix and/or change great products for small defects out of production that really appear to be big


"Young lady, in this house we obey the laws of thermodynamics!" -- Homer Simpson














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