ANA 787 makes emergency landing due 'battery fire warning'

[Speed of Sound]

BBC News now reporting that an ANA Dreamliner has made an emergency landing at Takamatsu due to a 'battery fire warning'.

BBC News - A Boeing 787 plane makes an emergency landing in Japan (http://www.bbc.co.uk/news/business-21038128)

[asc12]

Goodness. We're going to need a new forum for these threads.

Can anyone tell if the airplanes with battery problems are the same planes, or even the same batteries on different aircraft? A single battery seems like a much more tractable problem than if the (alleged) overheating is taking place on different batteries.

:ouch:

[GuilhasXXI]

Why do I suspect it was anything else but the batteries... ? :ooh:

[Speed of Sound]

At least two different planes as one JAL and the other ANA.

JAL 787 still on ground in BOS. As all we know is that tonight's landing was prompted by a 'battery malfunction warning', we won't know what battery it is.

I suspect that this was probably an over-reaction to something that must be at the back of the minds of all 787 flight crew. If it was a genuine battery malfunction then we have to start considering whether there is any significance in the fact that so many incidents have occurred in Japanese operated 787's.

Is there something in the 'customer electrical specification' of the of the planes built for JAL and ANA that could be initiating these fires/warnings?

Just a thought. :cool:

[Undertow]

All Nippon Airways grounds all Dreamliners in fleet after emergency landing — RT (http://rt.com/news/ana-grounds-dreamliner-emergency-landing-089/)



All Nippon Airways has grounded all 17 Boeing 787 planes in its fleet for emergency inspections after a malfunction on board forced one of the Dreamliners to make an emergency landing at Takamatsu Airport in the west of Japan.
*A battery malfunction on one of ANA’s Boeing 787 Dreamliners forced an emergency landing at Japan’s Takamatsu airport on Wednesday morning.

[FlightPathOBN]

Japan’s ANA grounds 17 Dreamliners | Business & Technology | The Seattle Times (http://seattletimes.com/html/businesstechnology/2020139494_787emergencyxml.html)

ANA Dreamliner makes emergency landing -NHK WORLD English- (http://www3.nhk.or.jp/daily/english/20130116_13.html)

[Ranger One]

SoS I think it was a little more than a 'battery warning'; landing was due to smoke on flight deck and was followed promptly by a full evac...

http://si.wsj.net/public/resources/images/OB-VZ792_0115bo_F_20130115205952.jpg

[bubbers44]

Bad batteries, nothing to do with aircraft type? How can you blame Boeing on this?

[DozyWannabe]

No-one's blaming anyone at this point, bubbers. Wait and see, eh?

[Phalanger]

I suspect that this was probably an over-reaction to something that must be at the back of the minds of all 787 flight crew.
I don't think that would be the case, the fact that they are reporting smoke in the cockpit is a good indication that this is a real problem. Even if it is in the minds of all 787 crew, then that means there is a problem that needs to be fixed and fixed quickly.In flight the pressure should push the smoke away from there, but once you're back down it will change. That could by itself set of a quick reaction.

[silverknapper]

BBC News - Japan's ANA grounds Dreamliners after emergency landing (http://www.bbc.co.uk/news/business-21038128)

[Squawk-7600]

No-one's blaming anyone at this point, bubbers. Wait and see, eh?

I for one would be very surprised if they weren't grounded as a result of this last event. Maybe too soon for such a call, but we'll see

[Old Fella]

Phalanger. Don't know what your background is, but your statement that inflight the pressure should push the smoke away from the cockpit is pretty "Broad-Brush". Depending on the source of the smoke and how it is entering the cockpit it may not always be possible to evacuate the smoke from the cockpit area immediately. Until the source can be isolated and removed the smoke will continue. Once this is accomplished the "Smoke Evacuation Procedure" would follow.

[DozyWannabe]

@Squawk-7600 - That's not the same thing as "blaming" Boeing though, is it?

As is invariably the case these days, the components have come from all over the world, and from various suppliers - it's no different for Airbus. If ANA ground their B787s then that's a matter for them and Boeing to hash out in terms of responsibility - it's not a given that Boeing themselves are responsible for the problem, just as it's not a given that Airbus are solely responsible for any issues on their types.

[EDIT : Tempting as it may be to engage in "schadenfreude", it just makes the person that does so look like as much of an arse as the folks who do so when the boot is on the other foot. Be a grown-up - don't fall into that trap!]

[FlightPathOBN]

Actually, the inflight movement would create denser air at the tail of the aircraft, and any smoke would move forward.

(put a helium balloon in your car and accelerate, it will move forward)

[Lyman]

Post JAL/BOS, Boeing reported that "cockpit pressurization" would keep smoke out if the cockpit....And cabin.

Squawk7600

I think the authority is about to put an end to further "flight test" with pax aboard....

Wasn't ANA debut operator?

[Phalanger]

The idea is it should move with the flow. Same reason smoke goes up from a fire, heat creates an airflow that it follows. So while you may not get none, it should be moving concentrations away from such areas (unless they are generated in those areas).

[archae86]

Al-Jazeera reports both All Nippon and Japan Airlines have "grounded" their 787 fleets.

Boeing 787 makes emergency landing in Japan - Asia-Pacific - Al Jazeera English (http://www.aljazeera.com/news/asia-pacific/2013/01/20131161112528514.html)

[Weeds round the prop]

'Flight' is considering the case of a container under accelleration. I don't have a helium balloon handy, but I suspect that it would move aft, relatively, due to the inertia of it's mass. The aircraft in question would likely have velocity but not accelleration in flight.

[camel]

ANA and JAL have grounded all 24 of their 787's.

[Robert Campbell]

In the DC-3s we opened the cockpit windows to cool the cabin. The air flowed forward. One wide open cockpit window created quite a strong wind. Two open windows was too strong a breeze.

I would think that any fire would get worse in such a breeze.

[EEngr]

Anyone know how 'old' these planes are? And if they were some of the earlier ones off the production line, how long they might have been sitting around through some of the initial rework? With batteries installed?

[FlightPathOBN]

ANA took the first deliveries...

[NWA SLF]

ANA plane reportedly delivered January 2012. If so one of the oldest in the fleet.

[Squawk-7600]

DozyWannabe
@Squawk-7600 - That's not the same thing as "blaming" Boeing though, is it?

As is invariably the case these days, the components have come from all over the world, and from various suppliers - it's no different for Airbus. If ANA ground their B787s then that's a matter for them and Boeing to hash out in terms of responsibility - it's not a given that Boeing themselves are responsible for the problem, just as it's not a given that Airbus are solely responsible for any issues on their types.

[EDIT : Tempting as it may be to engage in "schadenfreude", it just makes the person that does so look like as much of an arse as the folks who do so when the boot is on the other foot. Be a grown-up - don't fall into that trap!]

I have no idea why you're addressing this to me, or even what the schadenfreude reference is in relation to. As a result of this latest incident I said that I would be surprised if the aircraft isn't grounded and have just heard on the radio that 2 operators in Japan have done just that. I get no pleasure from seeing aircraft sitting on the ground I assure you!

[dabrat]

Qatar has a few 787's and if it is the battery it will be fun to see what happens there in the Summer in the Desert. It will be 50 degrees Celsius outside, 70 degrees in the E&E compartments, those babies will be Boiling!!Could be a Fireworks display if not fixed soon!:O

[Dan Winterland]

''Bad batteries, nothing to do with aircraft type? How can you blame Boeing on this?''

Quite easily. I question the wisdom of encasing so many lithium-ion batteries in a plastic fuselage. If it's Boeing, I'm not going!

[FlightPathOBN]

Both ANA and JAL have now grounded their 24 aircraft.

[2dPilot]

Have Boeing just been too agressive in their power & weight demands of the L-ion batteries? Most battery fires appear to be caused by overly thin insulation (reduced weight) and squeezing the last milli-watt of charge (the last few percent) into the battery - necessay for mobile phones & laptops, but for planes?
Would a few grams more weight and a few hunderd less mill-watt hours per battery really make a difference on a plane?
How long do Boing expect their craft to operate in-flight without main generators, or on the ground without an APU?

[Green Guard]

Boeing 787 Dreamliner makes emergency landing in Japan - World News (http://worldnews.nbcnews.com/_news/2013/01/15/16533328-boeing-787-dreamliner-makes-emergency-landing-in-japan?lite)

..both the passengers and the pilots "smelled something strange" !?

I wonder... was it before that "battery smoke" message or ~1 min after

[BobnSpike]

Whoever used the term "over reaction" may not have keyed in on the presence of smoke in the cabin. Smoke in the cabin, or the smell thereof, especially when the source is unknown or inaccessible, is an immediate and dire emergency.

In a pressurized airplane, smoke will travel to the outflow valve(s). The route it will take depends on the design of the pressurization system and the configuration of the valves, but that is the only place it is going.

[Sober Lark]

Only a year after launch I believe there are around 49 Boeing 787s in service. Compare this to the A380 where there were only a handfull in service and problems were fixed as they happened. All 787s problems appear to be happening together. From a public confidence point of view perhaps a softer launch of the 787 would have been less damaging to Boeing.

[BRE]

Good thing the smoke event occured on a domestic flight rather than somewhere above Siberia or the Pacific with the next diversion airport hours away.

Since I have a seat on the HND to FRA flight little more than a week from now, I am curious as to whether ANA will cancel flights or have enough 777s to fill the gap, or worse be tempted to resume flights before the issue has been fully understood.

[golfyankeesierra]

Fleetwide grounding? Don't think so, it's a Boeing. FAA don't ground boeings...
But it surprises me that it remains ETOPS.

BTW if you look at the picture in this link worldnews.nbcnews (http://worldnews.nbcnews.com/_news/2013/01/15/16533328-boeing-787-dreamliner-makes-emergency-landing-in-japan?lite) , don't the slides look steeper then on older types?

[ATC Watcher]

If I remember correctly Apple had a similar problems with its very first iPhones 3, (batteries exploding and catching fire..) very quickly the company found a fix and I have not heard the problem coming back since ( or it is well kept away from news).

So it would look like a technical solution does exists.

For those discussing the way smoke moves inside an aircraft cabin/cockpit , you may want to read through some of the pages of the final report of SR111.

[Spooky 2]

You guys have to stop believing everything you read or hear from the media. By now one would think you all would know better.:=

There is no battery fire warning EICAS message in the 787 or for that matter any Boeing airplane that I know of.

In addition, the flight deck is slightly over pressurized on both the 777 and 787 so as to keep smoke and fumes out. The flight deck does not use a recirculated air source for the same reason. It actually uses 100% fresh air at all times. If there are smoke and fumes present on the flight deck, most likely the source is there as well. The battery is a long ways back in the aft EE compartment, so smelling it on the flight deck is unlikely.

The Cabin Air Compressors (CAC) have been know to overheat. Just say'n!

[Volume]

If talking about smoke from a L-ion battery, what does it consist of ? How poisonous is that smoke ? Does the "non-toxic" requirement for burning aircraft interior apply to batteries as well ? After all, Lithium is a strong drug!

[Love_joy]

There is no battery fire warning EICAS message in the 787 or for that matter any Boeing airplane that I know of.

Likely that is true, but it would be very unusual to omit a BATT HOT caution, or similar measurement of unusual temperature from a modern airliner.

On my fight deck, unusual smell and a battery temp caution would lead me to believe my battery is getting warm. Couple that with a recent history of on-type battery over temp incidents and my minds made up

[TURIN]

If there are smoke and fumes present on the flight deck, most likely the source is there as well. The battery is a long ways back in the aft EE compartment, so smelling it on the flight deck is unlikely.




APU battery is in the aft EE compartment. The Main Aircraft battery is a lot further forward. (I think the forward EE Compartment)

Apparently the batteries are supplied (manufactured) by a Japanese company. Oh the irony. :hmm:

[Spooky 2]

In either case it's highly unlikely you would smell them. Read my post again:ugh:

[RTM Boy]

Overheating and even exploding batteries are actually quite common. HP had to recall somewhere in the region of 170,000 Li-Ion laptop batteries in 2009 and 2010 because of 40 spontaneous fires. A couple of years before that Sony had to do the same for its batteries supplied to other laptop makers...

I'm assuming that the 787 batteries are Li-Ion type(?)

[TURIN]

Stop being so touchy Spooky. My remark was for info not to criticise your knowledge. Jeeesus some people. :ugh:

[911slf]

One less risk.

[DingerX]

At this point, any sort of in-flight electrical problem, particularly involving batteries, on a 787 will be accompanied by the smell of smoke. There could have been smoke, but it's what passengers, crew and the press are expecting.
Event, non-event, or not even a non-event, they will all look the same at this point.
It's called a "screaming metric", I believe.

[glenbrook]

Love_joy: Would you deploy the slides if all it was a bad smell and a warning light? I'm guessing it was more than that, probably significant smoke in the cabin, as rumours have it. I really hope it's not a systemic problem with Li-Ion batteries, or else Boeing may have a very expensive problem.

[BRE]

How many LR/ETOPS 787 does ANA operate vs. short haul?

I suppose SH can be replaced by 737 and 767.

Any idea if they have enough 777s to fill the LH gap or whether there will be flight cancellations?

[BRE]

Update from BBC website:
"Earlier reports that smoke was seen in the cockpit were inaccurate, ANA said. The pilots saw a warning on their computer screen telling them there was smoke inside one of the electrical compartments, the airline said. The source of the smoke is not yet known.

The pilots also received a warning that there was a fault in the battery system. ANA said the battery in the forward cargo hold was the same type as the one involved in a fire on another Dreamliner at a US airport last week."

[bsieker]

From what I could find quickly, there's no overheat or fire warning for batteries; the only EICAS warning I could find was smoke detection for the equipment cooling systems. There are three: forward (including flight deck), aft (where the APU battery is) and "misc" for all other stuff spread over the aircraft.

In normal operation fans pump air through the forward E/E equipment and flight deck equipment and dump it overboard or into the cargo hold (for heating) by means of more fans.

Setting the forward equipment cooling system to "override" mode can be used to help clear smoke from the flight deck; in this mode, suction from an overboard venturi pulls air from the flight deck through the equipment in reverse flow, thus sucking air/smoke from the flight deck as well. I cannot tell from the pictures if in normal operation, flight deck cooling exhaust air goes into the flight deck.

Will be interesting to hear what the actual warning was that they got.

And so far it is not at all clear this one had a battery fire.

EDIT:
ANA said the battery in the forward cargo hold was the same type as the one involved in a fire on another Dreamliner at a US airport last week.
They probably mean the forward E/E bay. I wasn't aware that the main battery located there was also Li-Ion; I thought only the APU battery (in the aft E/E bay) was.

[NSEU]

but it would be very unusual to omit a BATT HOT caution, or similar measurement of unusual temperature from a modern airliner.

If it's like other Boeings, the battery temperature will be monitored and will shut down the battery charger with a resultant charger fail message.

[winter959]

Makes me wondering why all these problems never occured during the test flight phase.

[glenbrook]

Makes me wondering why all these problems never occured during the test flight phase.

No surprise here, it is exactly the kind of issue that shows up in production when you have a number of units in service. During the test phase, there were only 6 aircraft, now there are 50 or so. Boeing have been unlucky to have all these issues show up in a space of a few weeks, but life's like that sometime.

[Uplinker]

Was it the 787 that was overweight during the design phase and weight had to be trimmed from where ever possible?

Are Li-ion batteries lighter than Ni-Cads - I guess they must be?

[Speed of Sound]

Whoever used the term "over reaction" may not have keyed in on the presence of smoke in the cabin.

It was me and at the time there was no mention of the presence of smoke in the cabin.

There still isn't any evidence that there was.

[PiggyBack]

The analysis of these problems needs to look at more than just the direct technical cause. Many processes must have failed or at least not worked well to get to this stage:

1. Specification - is the specifictaion of the components concerned adequate?
2. Risk/safety analysis - battery fires are obvious potential hazards what does the analysis say and what risk control measures are in place? The analysis should have included safety following failures or defects.
3. Verification - The ccomponents concerned and the risk control measures from 2. should all have been verified
4. Life and environmntal testing. The components concerned should have been tested at environmental extremes, shock, vibration and with accelerated aging.

Assuming this is another battery fire then it is suprising to me that they have happened so short into life and so relatively frequently. Safety issues for systems desigend and developed using a safety process are usually complex, multi-faceted involving multiple causes or involve obscure and difficult to predict failure mechanisms. At the moment this does not seem the case. Understanding why this got through the development process is key because if the prcoess is suspect many more areas will need to be looked at.

[re-checked]

Passengers evacuate 787 Dreamliner after emergency landing (http://www.guardian.co.uk/business/video/2013/jan/16/passengers-evacuate-787-dreamliner-after-emergency-landing-video)

[DozyWannabe]

Are Li-ion batteries lighter than Ni-Cads - I guess they must be?

I don't think it's a question of weight. Li-ions are more power-efficient, certainly - but Ni-Cads aren't really made in quantity any more because Cadmium's toxicity makes it a pain to dispose of.

[oceancrosser]

Interesting evacuation video. The APU appears to have been left running from the sound on the video. That is not what I have been taught. Shut everything down before leaving.
At around 00:30 on the video, light smoke can be seen coming from underneath the fuselage where the fwd E&E would be. Equipment cooling exhaust valve?

[BRE]

To answer my own question, there is just four international routes that are served by the 787 (Frankfurt, Beijing, Seattle, San Jose):
Information regarding the Boeing 787-8ER route and flight operation dates?ANA SKY WEB (http://www.ana.co.jp/wws/japan/e/asw_common/inflight/guide/info/b787/)

Out of these, only the Beijing flight is cancelled for today, whereas about 16 domestic 787 connections are cancelled. I suppose they have enought 777 to serve the other 3 international routes.

Interestingly, NH203 which took off about three hours after the emergency landing and arrived on time in FRA, was supposed to take off again as NH204 more than an hour ago. It is not cancelled and showing up as on time in flighttracker. It is hard to believe they could have flown in a 777 as a replacement.

[JamesGBC]

I would say the specs on the battery would be OK, Looking at the size it would seem to be a backup power supply for the instruments, However there are some fake control ICs for charging and current control on the market. I would hope they have been careful in the supply chain. I would be pulling out a few samples from the batch number they would have a few spare now for testing.
Some people have not been in an aircraft with unidentified smoke. I have and looked out the window 400kms from an airfield for a suitable landing area. Asked if we are OK I said yes everything is fine, but that was not in anyway what I was thinking.That day we got lucky.

[davidash]

When one reflects on the concerns and of Airbus that were expressed on this website with the teething problems on the 388, it begs the question why the grounding of the Japanese 788 fleets and the FAA review of the aircraft has elicited such a subdued response.

[jolihokistix]

Just reading the Japanese news and it is being reported that it wasn't smoke but a burning smell, and that the main battery(ies) in the forward electrical compartment have now been discovered to be off-color and discharging a liquid. (Japan Yahoo news in Japanese from TBS and JNN.) My translation.
£Â£·£¸£·¶ÛµÞÃåΦ¡¢¥Ð¥Ã¥Æ¥ê¡¼ÊÑ¿§¤·±Õϳ¤ì(TBS·Ï¡ÊJNN¡Ë) - Yahoo!¥Ë¥å¡¼¥¹ (http://headlines.yahoo.co.jp/videonews/jnn?a=20130116-00000050-jnn-soci)

Evacuation video. »þ»ö¥É¥Ã¥È¥³¥à¡§Æ°²èÆý¸ ¡Ö¥³¥Ã¥¯¥Ô¥Ã¥È¤«¤é±ì¡×¡¢£·£¸£··¿µ¡¤¬¹â¾¾¶õ¹Á¤Ë¶ÛµÞÃåΦ¡á»ëÄ° ¼ÔÄ󶡱ÇÁü (http://www.jiji.com/jc/movie?p=top590-movie02&s=610&y=&rel=y&g=phl)

[shonandai]

NHK news spent 15 minutes on this issue.

Passenger reported a very quick decent with a newspaper falling off a seat and coffee cups sliding forward.

Pilots apparently received several warning messages in the cockpit including generator issues and backup system issues. Smoke was detected in the forward battery /electrical compartment. A burning smell was also noticed.

Battrey was found to be discolored and leaking fluid. Japan air safety authorities said the battery temperature may have been extremely high.

Takamatsu controllers noticed smoke after landing and the pilot then initiated emergency evacuation
Rgds.

[DozyWannabe]

When one reflects on the concerns and of Airbus that were expressed on this website with the teething problems on the 388, it begs the question why the grounding of the Japanese 788 fleets and the FAA review of the aircraft has elicited such a subdued response.

The A388 issues (thus far) don't constitute a fire risk, that's the difference.

Even the most partisan of people in the A v B debate (of which, in spite of reputation, I am not) are likely to recognise that.

[angels]

According to Reuters a Japanese firm makes batteries for the Dreamliner, which is a tad ironic.

The company is GS Yuasa Corp and the shares were hit on the Tokyo bourse, falling nearly 5 percent.

However, the report only says the company makes batteries for the aeroplane, not all batteries. If they don't make the batteries in the forward compartment, fill your boots as the shares will bounce back!

[StoneyBridge Radar]

Interestingly, NH203 which took off about three hours after the emergency landing and arrived on time in FRA, was supposed to take off again as NH204 more than an hour ago. It is not cancelled and showing up as on time in flighttracker.

I don't have the time to search for the statement, but ANA have said words to the effect that "NH203 will continue to FRA and the aircraft will stay there. It will not operate back, nor will it be ferried back."

[glenbrook]

When one reflects on the concerns and of Airbus that were expressed on this website with the teething problems on the 388, it begs the question why the grounding of the Japanese 788 fleets and the FAA review of the aircraft has elicited such a subdued response.

I wouldn't say the response has been subdued. The media response has been quite strong. Until yesterday all the issues were different and the FAA decided on a design review, but not ground the aircraft. That seemed appropriate at the time. Now we have seen two battery fires in two weeks, the Japanese have decided to ground their planes. That also makes sense. I think the FAA should do the same, however hysterical the media get.

It does look bad for Boeing, but they must have contigencies for this sort of thing, And if you are going to have a problem which grounds the aircraft, it is far better that it happens when you have 50 planes in service, not 500.

[BRE]

Well, about four hours after scheduled departure, it is still being shown as departed on time in FRAport and flightaware but there is no position info on flightaware.

I activated email notifications from FRAport for Thursday's NH203/204, and while the showed 787 initially, they were changed to 772 about an hour ago. US flights remain cancelled in flightaware.

[BRE]

�q‹óŒ” —\–ñ�E‹ó�È�Ɖï�E‰^’ÀˆÄ“à�E�‘“à�ü�bANA (http://www.ana.co.jp) now shows tomorrow (Th 17th) cancellations and changes of equipment. It states that all international flights will be operated with different equipment.

I wonder how long they can keep that up?

There was no list of We 16th cancellations on the English ANA website until an hour ago (and there is not now either that the schedule for tomorrow has shown up).

[plt_aeroeng]

The FAA issued a Special Condition for the use of li-ion batteries on the 787. Boeing made several design provisions for control of fire and smoke spread.

Recent incidents suggest these may not have been sufficient.

It will be interesting to see FAA's reaction, and how quickly Boeing can address what may be a significant issue.

Freighters, after several hull losses, can no longer carry these batteries as cargo. It is surprising that even with special provisions the FAA has allowed passenger aircraft to have them designed in.

[BRE]

from today's Japan Times:
"Boeing chose lithium-ion batteries for the 787, which uses five times more electricity than similar jets, because they hold more energy and can be quickly recharged, Mike Sinnett, chief 787 project engineer, said. In a worst-case scenario in which the batteries do burn, they are designed to do so in a way that doesn't threaten the aircraft, Sinnett said.
If the jet is airborne, smoke is supposed to be vented out of the compartment so that it doesn't reach the cabin, he said, and all of the battery cells can ignite without harming the plane's ability to stay aloft."


So that must be a heck of a fire shield...

[Lyman]

"Boeing chose lithium-ion batteries for the 787, which uses five times more electricity than similar jets, because they hold more energy and can be quickly recharged, Mike Sinnett, chief 787 project engineer, said. In a worst-case scenario in which the batteries do burn, they are designed to do so in a way that doesn't threaten the aircraft, Sinnett said."

**********************

So what we see, fundamentally, is a waiver. As such, the elements of impenetrable protection of the airframer....

Sinnett admits the likelihood they will burn, and protects the company from liability via "designed to not threaten the aircraft."

Stop, think..

[bsieker]

BRE,
from today's Japan Times:
"Boeing chose lithium-ion batteries for the 787, which uses five times more electricity than similar jets, because they hold more energy and can be quickly recharged, Mike Sinnett, chief 787 project engineer, said. In a worst-case scenario in which the batteries do burn, they are designed to do so in a way that doesn't threaten the aircraft, Sinnett said.
If the jet is airborne, smoke is supposed to be vented out of the compartment so that it doesn't reach the cabin, he said, and all of the battery cells can ignite without harming the plane's ability to stay aloft."


So that must be a heck of a fire shield...

To be fair, the structural damage caused by the battery fire that did occur was quite limited. The NTSB talked about it being "confined to the area immediately near the APU battery rack (within about 20 inches) in the aft electronics bay".

Perhaps not that big a shield, but only good venting, and thermally resistant materials in the area where the heat is going.

So maybe they did a proper risk analysis after all. The statement did not say that it would leave the aircraft undamaged, only that it "could stay aloft" and wasn't threatened by the fire. The venturi-suction system would have to be able to vent all smoke out of the E/E bay without it entering other parts of the craft. From what I've seen the system is supposedly able to maintain adequate equipment cooling during cruise, but what about a full-blown Li-Ion battery fire during descent?

The venturi system as such is fine, as it requires no moving parts to operate, however it does require moving parts (valves closing and opening, fans switching off), to get it to start working.

I wonder if they did flight-tests, or at least full-size wind-tunnel tests with actual fires.


Lyman,
Sinnett admits the likelihood they will burn, and protects the company from liability via "designed to not threaten the aircraft."

I see that rather as a positive statement, indicating that they did a risk analysis, and considered the likelihood and severity of a battery fire. Doing a proper risk management means that once a hazard has been identified and the associated risk (as far as is possible) quantified, you take measures to either reduce its likelihood, or its severity, possibly by mitigating the effects on people and equipment. If it is well engineered and the regulator agrees that can be acceptable.

I haven't seen the engineering details (and probably never will) so I cannot say that it wasn't adequately done; it seems plausible. The amount of energy that can be set free can be known, the temperature, heat, propagation and duration of a worst-case fire can be estimated, and mitigating technology can be incorporated. I think it depends in large parts on the reliability of the E/E bay ventilaton system entering "override" mode, i. e. passive overboard-venturi suction.


Bernd

[DozyWannabe]

So maybe they did a proper risk analysis after all.

Of course they did. No aeronautical engineering team is going to propose a solution of that sort without performing one if not several. The potential issue is that such analyses and tests are only as good as the pre-existing data, and with new solutions there's only going to be a limited amount of that.

[Lyman]

Gentlemen....

You are "not wrong". Neither of you has stated anything untrue. My assumption is that you expect to have had an effect on the discussion....

I am missing it.....

Can you elaborate? In light of recent events? That will allow my response in presenting an argument that FAA and Boeing are acting incestuously....

[bsieker]

DozyWannabe,

I know they did. My comment was rather tongue-in-cheek to all those saying "how could they do this? Didn't they think of the consequences?"

The development and physical properties of Li-Ion batteriy fires can be estimated quite well. Although maybe they were too optimistic on the likelihood, the mitigating measures may be adequate for the severity.

The probability of failure of the mitigating measure (venting override) of course has to fit the probability the of the original hazard (battery fire), and a redesign may be required in this case.


Bernd

[ORAC]

IIRC correctly from the SAA 747 Combi fire (http://en.wikipedia.org/wiki/South_African_Airways_Flight_295#Combi_design) Boeing did tests for a fire as well. Turned out they used a straw bale and a quickly extinguished fire. When they re-ran them with a high-temp sustained fire after the event the results were drastically different.

The FAA/NTSB may be interested in investigating the test scenarios used against the events to date.

[pax2908]

So they (presumably) are designed to burn with no immediate danger to the a/c. What is then standard procedure in case of burning smell: land ASAP except when it's from the Li-Ion battery?

[Lyman]

pax2908

A serious answer to your question would be, "It's SOP.." Get out the manual.....


My innocent guess is that their is no SOP for onboard fire of any description except to land, immediately....

"If located in either EE bay, (fire).....disregard"

I am hopeful someone will take a very long, hard look at the relationship....

[Asrian]

Don't You say in english "never buy an A-model of something"?

[irgendwer]

Does anyone know if there is an ATC recording of the landing at Takamatsu (or Osaka airspace control) available?

[RR_NDB]

JamesGBC,

Charger and circuitry related to these high tech batteries are critical.

Quality issues indeed a concern.

[BobnSpike]

@SpeedofSound

Next sentence: "Smoke in the cabin, or smell thereof..."

Historically, from the first indication of fire, such as, perhaps, an electrical anomaly accompanied by a smell, to the time people start dying is about 20 minutes.

[FlightPathOBN]

from Boeing land...

2 airlines ground 787 fleets | Business & Technology | The Seattle Times (http://seattletimes.com/html/businesstechnology/2020139494_787emergencyxml.html)

It appears there are two Li batteries on the ac, one at the front in the forward EE bay, and the other in the rear with the APU....

Rumour here has the latest adventure in the forward battery pack...


It also appears that a previous poster is correct, the ac at Logan had previous problems with faulty circuit boards...

[TURIN]

It appears there are two Li batteries on the ac, one at the front in the forward EE bay, and the other in the rear with the APU....



Post #41:ok:

To be fair, the structural damage caused by the battery fire that did occur was quite limited. The NTSB talked about it being "confined to the area immediately near the APU battery rack (within about 20 inches) in the aft electronics bay".



Thats a bit of a worry. If the same happens to the Main (forward) Battery. One of the Common Core Resourse (CCR) Racks is within 20 inches.
CCR is the brain of the beast. :eek:

[FlightPathOBN]

yes Turin...I see that...it really doesnt ever mention that this battery is LI...

the front battery looks significantly larger...

http://operationsbasednavigation.com/wordpress/wp-content/uploads/2013/01/ScreenHunter_06-Jan.-16-10.33.gif

dont see this video anywhere on the thread...from a cell phone camera onboard during the evac....

http://www.youtube.com/watch?v=9ifPCarjAmI

[Lyman]

FPO

It also looks to be readily accessible, externally. Absent a space walk, how to address a fire problem whilst, you know, airborne?

OK. Ceramic vault, with fireproof penetrations, and internal and isolated fire suppression, with cooling.

How did Toyota do it........

Again, Outsourcing may not strictly apply here. Yuasa is a well respected and cutting edge company, who, actually, make batteries, not fire systems or cooling kit....

It is a self-contained unit, requiring only proper install and wiring.

There is "In house", "Sole source", "integrated RFP", and the way Boeing did it.

Prolly not again.....

[grimmrad]

@BRE re Fire shield:

If the battery burns it melts through the composite frame and the resulting decompression ejects the battery entirely, ingenious engineering.:cool:

[Tu.114]

This thread is getting around. I have found it linked to in the German Spiegel Online (http://www.spiegel.de/wirtschaft/unternehmen/pannenserie-bei-boeing-hat-der-dreamliner-ein-echtes-problem-a-877957.html) (German; 3rd non-bold section).

[FlightPathOBN]

Lyman...just added the video...interesting to say the least...difficult to tell, but it does appear to be smoke at front of plane....

I was trying to see what the seatmount screens were saying, and scrolling...

Here is a prius battery
http://blog.toyota.co.uk/wp-content/uploads/2009/07/prius-battery-pack-cooling.jpg

the tesla uses a liquid refrigerant cooling system, about half the car...

http://farm4.static.flickr.com/3291/3065996199_9064c9fbdc.jpg?v=0

Chevy volt uses a liquid cooled battery pack as well....

[Ben_S]

It looks like the screens were rebooting, it seems some of them are showing "Please wait". Only SLF but I would have thought it probably not the best thing to display during an evacuation

[grebllaw123d]

Quote from post #75:

To be fair, the structural damage caused by the battery fire that did occur was quite limited. The NTSB talked about it being "confined to the area immediately near the APU battery rack (within about 20 inches) in the aft electronics bay".

OK, but bear in mind that this incident occured on the ground at a large airport with a very professional Fire Brigade responding within 3 minutes!
Also note that it took about 40 minutes to put the fire out - in other words it must have been a complicated fire.

What the damage would have been if this incident had happened at 35000 feet, that is a good question, which I will not even try to answer.

But one thing is crystal clear: there is no Fire Department at 35000 feet to assist you!

[FlightPathOBN]

Ben... "Please wait"...exactly, probably not the best...
that is what I thought, rebooting...
that in itself is an interesting issue as well...

Looks like Boeing just confirmed it was the main battery in the front. They have cancelled the annual strategy meeting, and have gone into overdrive...

I used to work with the guy Boeing hired to set up the 787 Safety Management System Program...but I am not gonna even try to contact him for a while!

[flyhuzaifa_a380]

Earlier it was JAL and now Nippon airways is in the ring .Earlier also Boeing remains confident when the JAL aircraft was grounded in Boston.
Strange but true ....""32Volts cell battery had accumulated 1.3 million flight hours across the fleet,before a unit exploded on & 7th January.Although Chilean carrier LAN is still satisfied with the type..
Boeing 787 chief Engineer Mike Sennett still unable to address the incident....courtesy:

[Lyman]

Actually, whether deplaning, or evacuating, "please wait", is not ill advised. Vaulting over seats or elbowing folks out of your way, not a good thing....

Don't forget the briefcase, numpty.....(SouthWest)?

[Broomstick Flier]

Freighters, after several hull losses, can no longer carry these batteries as cargo.

Not really.
We carry them almost on a daily basis (between 5 to 20 tons) on both domestic and international sectors, including to/from FAA land. I am sure many other cargo operators do the same. They are not even listed as DGR goods on our NOTOCs.

If the 787 problem is traced to the batteries as main culprit, I wonder how difficult it would be to simply change them from Li-ion to traditional lead batteries. Sounds like the more sensible solution.

[FlightPathOBN]

Broomstick,

Given the way the battery packs are wedged in there, NiCd probably wouldnt fit, and no way for lead-acid amount needed for equivalent...

hopefully, it will just be something with those cells that they have changed since...

IATA recommendations on Li transport...
http://www.ups.com/media/en/lithium_batteries_guidance.pdf

[edmundronald]

Congrats to ANA for a well executed emergency procedure, and for taking decisive action to limit the risks to lives.

Boo to the FAA for hiding behind the word "investigation" in order to delay action.

There's probably an insurance/financial/legal reason why Boeing and the FAA won't address the problem more aggressively and issue an advisory to ground the 787 fleet; this is in fact more disturbing than an issue which is now known and can be solved by replacing a battery by a better battery.

If there are another couple of smoke/fire incidents then I don't think they'll manage to find pilots for these things unless they supply them with ejection seats and parachutes.

[Lyman]

I think the word chosen by FAA is "REVIEW".

There is no way to assess the depth of concern, or scope of the review.

I lean toward calling it a "slow roll". You know it's a roll, but the urgency is lacking.

It is difficult to come up with an answer, the evidence is compelling, only the rate is suspicious.


"The risks were not downplayed; but they may not have received proper emphasis at the operations level...."

"Insufficient internal structure led to overheat, the loss of dissipation capability led to smell, and smoke."

"There is only one occurrence of combustion, Boston, and that was an overload via GPU, not APU...."

etc.

The discouraging thing, is that there is probably way too much concern over how to "play" it, rather than solve it.

[mailinator]

OK, let's say the 787 has no structural problems with a burning accumulator. But that would probably still lead to higher loads on the other one. And what happens to the bird if both of them burn ? I guess it would still stay structurally intact, but if so many systems need electric power how much time remains for the crew to put the thing on terra firma before the emergency bats run out ? What if that happens over the big drink and this aircraft happens to be the first two-engine frame certified for the ocean if I recall properly ? OK, I guess I'm being a bit melodramatic, but some competent answers would be nice :).

[atakacs]

It looks like the screens were rebooting, it seems some of them are showing "Please wait". Only SLF but I would have thought it probably not the best thing to display during an evacuation
My thoughts, exactly.

Also where the engine still spooling down or windmilling ?!

Did I see the pilots leaving before the last passengers ?

Finally I really don't see - at this stage - why everyone gets overexcited about outsourcing. We simply don't know if there is any connection.

[RR_NDB]

dlcmdrx:

Organizational issues... (http://madeinusanews.com/2011/02/22/787-dreamliner-teaches-boeing-costly-lesson-on-outsourcing/)

Kudos for important information presented by a young guy! :ok:

We may expect other issues?

:sad:

[EEngr]

The discouraging thing, is that there is probably way too much concern over how to "play" it, rather than solve it. Maybe not. The typical relationship between Boeing and the FAA is a friendly standoff. The FAA pushes and Boeing pushes back, claiming that the FAA has to abide by its charter to promote aviation. But now they (the FAA) has some ammunition to go in and look around. And while they have Boeing back on their heels, having to deal with a couple of upset customers, they have an opportunity. And not to look at just batteries.

An aviation analyst was interviewed on the radio this morning. In addition to the battery, fuel leak and other problems of the past week, he mentioned the other electrical incidents that the 787 has suffered. And that the FAA will be looking at a possible root cause for all of them. Specifically, a systemic problem in Boeing's engineering process.

Once the customers become dissatisfied with Boeing's performance, this will start to look like the three-way gunfight in The Good, The Bad, and The Ugly.

[YRP]

atakacs:

It appears the video has been edited, changing the order.

You'll notice the pilots waiting at the front slide while some people leave 2nd door. Then it shows the pilots leaving. Then back to some people leaving the 2nd -- with the pilots still at the front exit.

[atakacs]

@YRP: good point (and to be honest given the circumstances I wouldn't expect less).

[YRP]

Question from a non(-professional) pilot:

From the video, the evacuation is on the taxiway. If an evacuation is required, wouldn't they want to stop as soon as possibly and evacuate on the runway?

It seems like the runway is shut down either way, given the passengers and equipment in the area.

This is curiosity not criticism. I recall a recommendation in a Canadian TSB report a number of years ago on a 737 engine fire on takeoff in Calgary.

[atakacs]

Hot of the press: 787 grounded by FAA !

[golfyankeesierra]

If an evacuation is required, wouldn't they want to stop as soon as possibly and evacuate on the runway
Good point , reason is that fire tenders have to get to the aircraft while staying on tarmac. When you are on the taxiway and the fire tenders have to drive around the plane they have to go through the grass with the risk of sinking in and getting stuck in it.

[Fzz]

From the video, the evacuation is on the taxiway. If an evacuation is required, wouldn't they want to stop as soon as possibly and evacuate on the runway?I'm not a professional pilot either, but it seems to me that if you have a potential fire at the front of the aircraft and you have a choice, you wouldn't want to evacuate facing into the wind.

[Agnostique75]

From the Dallas Morning News:

"The Federal Aviation Administration issued a statement ordering operators of Boeing 787s to ground those airplanes until they prove that the batteries onboard are safe.
The action comes after Japan carriers All Nippon Airways and Japan Airlines parked their airplanes temporarily in response to a battery fire on an ANA flight Wednesday:
Here’s the FAA statement:
“As a result of an in-flight, Boeing 787 battery incident earlier today in Japan, the FAA will issue an emergency airworthiness directive (AD) to address a potential battery fire risk in the 787 and require operators to temporarily cease operations. Before further flight, operators of U.S.-registered, Boeing 787 aircraft must demonstrate to the Federal Aviation Administration (FAA) that the batteries are safe.
“The FAA will work with the manufacturer and carriers to develop a corrective action plan to allow the U.S. 787 fleet to resume operations as quickly and safely as possible.The in-flight Japanese battery incident followed an earlier 787 battery incident that occurred on the ground in Boston on January 7, 2013. The AD is prompted by this second incident involving a lithium ion battery.

“The battery failures resulted in release of flammable electrolytes, heat damage, and smoke on two Model 787 airplanes. The root cause of these failures is currently under investigation. These conditions, if not corrected, could result in damage to critical systems and structures, and the potential for fire in the electrical compartment.Last Friday, the FAA announced a comprehensive review of the 787’s critical systems with the possibility of further action pending new data and information.

“In addition to the continuing review of the aircraft’s design, manufacture and assembly, the agency also will validate that 787 batteries and the battery system on the aircraft are in compliance with the special condition the agency issued as part of the aircraft’s certification.

“United Airlines is currently the only U.S. airline operating the 787, with six airplanes in service. When the FAA issues an airworthiness directive, it also alerts the international aviation community to the action so other civil aviation authorities can take parallel action to cover the fleets operating in their own countries.”

[FlightPathOBN]

EEngr,

That is about right. As a regulator, the FAA has no liability. The FAA validates the aircraft manufacturers self certification.

The FAA's job is to look at the data that Boeing submitted, and make sure that it meets or exceeds the criteria, and that the data provided is reasonable for that assumption.

The significant issue here is that the FAA will now look into Boeings processes, testing methods, and certification procedures. The FAA's subject matter subcontractors will be looking at the process as well. It is already noted that the Naval Labs are looking at the batteries.

Agencies in other States will be looking at this as well, so the FAA will have to at least meet or exceed their efforts...given the liability, loss of service claims, and competition significance, the level of detail should be very, very extensive...

This appears routine to the general public, but looking at the engineering and certification process, this is very very significant.

[Prada]

About batteries.
Unlike other battery types, Lithium batteries require electronic monitoring for both charging and discharging. Usually each cell voltages are monitored in order to achieve maximum battery performance and avoid damages and early battery death because of slight difference in battery cells.
If certain limits are reached then battery monitoring system stops or limits battery currents, activates battery cooling or warming. So it is a tricky business with a Li battery in high current applications like in electric cars. Battery usage envelope must be maintained at any cost. If battery monitoring system fails, it should switch off the battery itself or limit battery usage considerably.
If Li batteries are over charged they will start to overheat andat certain point they are not able to contain their own charge and self discharge adds to overheating with rapidly rising temperatures starting to boil highly flammable organic electrolyte which usually burst battery container and creates flames which again usually overheat neighbour cell causing same reaction. if not cooled down fast enough and boiled off organic electrolyte safely vented, the whole battery burns down in a chain reaction emitting huge amount of heat if oxygen is allowed to contact overheated battery parts.
How these problems are solved in aircrafts I do not know. But it seems like huge fire was avoided, as closed Li cells can violently explode and burn. It could be that some of battery cells broke down while being operated in specified envelope. Due to unexpected paremeter change during normal aging. Li batteries can withstand many thousand cycles.

At the same time NiMH batteries are much more forgiving. but are twice as heavy too. And even more expensive.

[green granite]

This Telegraph article about the grounding shows a picture of the battery removed from the Boston aircraft, it's near the end. :

Europe, Japan and India ground Dreamliner indefinitely - Telegraph (http://www.telegraph.co.uk/finance/newsbysector/transport/9807593/Europe-Japan-and-India-ground-Dreamliner-indefinitely.html)

[BRE]

Regarding Wednesday (16th) flights to and from FRA, NH203 operated by a 787 arrived on time, and NH204 that was showing as departed on time by both FRA airport departure messaging and flightaware is now showing as cancelled at ANA. Presumably, there is now a Dreamliner sitting in FRA.


http://www.ana.co.jp/be/fli/certificate/image/space.gif http://www.ana.co.jp/be/fli/certificate/image/space.gif http://www.ana.co.jp/be/fli/certificate/image/title_e_flight_ttl_int_950.gif http://www.ana.co.jp/be/fli/certificate/image/space.gif http://www.ana.co.jp/be/fli/certificate/image/yajirushi03.gif Flight status as of 17:42 (Japan Standard Time)
http://www.ana.co.jp/be/fli/certificate/image/space.gif http://www.ana.co.jp/be/fli/certificate/image/bar_e_flight_ttl_int_950.gif http://www.ana.co.jp/be/fli/certificate/image/space.gif Date Flight No. Departure Airport Arrival Airport 16 January, 2013(Wed) ANA 204 Frankfurt Tokyo(Haneda) http://www.ana.co.jp/be/fli/certificate/image/space.gif To receive Certificate of Cancellation/Delay/Diversion, click flight number.
(Certification of delay will not be provided when delayed time of arrival is within 15 minutes.) Flight No. Flight Status Delay Time Remarks ANA 204 Canceled - Due to inspection of the cause of the Boeing 787 aircraft malfunction


NH203 today was operated by a 772.

[DaveReidUK]

Presumably, there is now a Dreamliner sitting in FRA.

Maybe not.

"Four dreamliner aircraft operated on [ANA] domestic routes have reportedly been grounded, while the remaining two will ground to a halt (sic) on their return from Paris and Frankfurt."

Presumably sans pax.

More Countries Ground Boeing-787 Dreamliners Until Safety Assured (http://www.rttnews.com/2038873/more-countries-ground-boeing-787-dreamliners-until-safety-assured.aspx?type=gn&utm_source=google&utm_campaign=sitemap)

[Dave Gittins]

Fzz - I'm not either but I recall the BA Airtours fire at Manchester and what happened after the off runway stop inadvertently put the fire upwind of the cabin which was rapidly penetrated and destroyed with serious loss of life.

[911slf]

I am not a pilot but it is obvious that in the event of fire stop and get out asap. If this is on the runway so be it.

I once was first on the scene after a serious hang glider crash. Number one priority, separate the pilot from the aircraft (no fire risk but might have been lifted off by the wind).

[Ye Olde Pilot]

The BBC now reporting the Dreamliner is being grounded worldwide.
Dreamliner: Most Boeing 787 planes grounded on safety fears

Leithen Francis, Aviation Week: 'Some 787 operators will ask for compensation from Boeing
What's the impact on Boeing?
Dreamliner plane review ordered

Airlines and regulators have grounded the majority of Boeing's flagship 787 Dreamliner planes amid continuing safety concerns.

Airlines in Chile and India have temporarily halted 787 flights, following a US Federal Aviation Administration (FAA) directive.

European regulators have also followed suit, ordering that planes be grounded.
BBC News - Dreamliner: Most Boeing 787 planes grounded on safety fears (http://www.bbc.co.uk/news/business-21054089)

[SLF3]

Don't prejudge. Decision to evacuate was probably made after the plane had landed (and stopped) when the fire crews saw smoke. So he had no reason to stop on the runway.

If there was a fire in the forward EE bay stopping crosswind on the taxiway was probably a good option anyway.

The video shows a very orderly evacuation with no evidence of 'sauve qui peut' - would be surprising if the pilots were not at the back of the queue for the door.

[davidash]

Imagine the reaction if this had been an Airbus!

[angels]

The battery company said the battery was 'discoloured' after the fire.

Depends on your interpretation of 'discoloured' I suppose.....

NTSB Shows Off Burnt Boeing 787 Battery (http://www.nycaviation.com/2013/01/ntsb-shows-off-burnt-boeing-787-battery/)

Edited to add that the article says the fire authorities had difficulty in getting access to the battery -- this presumably was the reason for thr 45 minutes that was mentioned in an earlier post.

[Ye Olde Pilot]

If the battery company say this is discoloured I would not want to see what a burnt one looks like.http://www.nycaviation.com/newspage/wp-content/uploads/2013/01/jal-apu-battery-ntsb-2-1260-602x401.jpg

[spinnaker]

Hope there's a bit of room for satire.

I can imagine fleet managers and engineers trawling iphone forums looking at solutions for short battery life and devices running a little 'hot'. Boeing carefully studying how steve jobs and Apple would deal with the issue. The bottom line being, deny everything, turn the alleged defect into a feature. Eventually make an announcement that everyone can return the product via 1st. class mail for a refund or new replacement, (please use the supplied jiffy bag).
Personally, I feel its all down to software, if they would use Android jelly bean instead of Ice Ceam Sandwich, the 787 would be a much better 'plane.

[BRE]

NH204 (FRA - HND) for the 16th has now been deleted from the flightaware log. Not sure what plante that would be that was ferried back from Paris. ANA have no Dreamliner service to Paris, and neither does JAL to the best of my knowledge and a quick search effort.

NH203 arrived and NH204 closes on time in Frankfurt today on the 17th. Flightaware is still listing them as 787 but Frankfurt airport has them as 772.

According to FRA airport, NH203 for the 18th is scheduled to be on time whereas they have already posted a delay of nearly 6 hours for the return flight tomorrow. Also, both are listed as 772 whereas the Friday flights are usually operated by 77W (whatever that is).

Are they planning to do scheduled maintenance at an outstation?

[Bagus]

I guess Boeing has made stupid decision,trying to make aircraft more efficient,less fuel,less maintenance ,more outsourcing,all electrics,this is what QF preferred ,but it come at a cost.

[RTM Boy]

Li-Ion batteries are vulnerable to catching fire either because of a fault in the battery itself, or in the charging electronics/circuitry, or the software running the charge program.

Fires have occured widely with Li-Ion batteries in other electronics applications and it known particularly where over-charging takes place, so it is a signifcant risk. I'm surprised that additional safety circuitry either was not installed or failed to prevent such a fire.

[RTM Boy]

OFSO, are you saying that if engineers were paid more this wouldn't happen?

So, I'm a Boeing engineer or a battery engineer and I'm going to be less competent at my job because I don't get paid as much as the marketing director?

Really???

Or, is it that when an engineer gets it wrong, it's never their fault?

It might be better to find out exactly what's caused the battery fire first and how it can be prevented in future so that any further serious incidents can be avoided. It should become clear fairly soon whose 'fault' it was.

[TURIN]

I'm surprised that additional safety circuitry either was not installed or failed to prevent such a fire.

The main aircraft battery wiring has a diode module added to the circuit to prevent back charging of the battery through anything other than the battery charger.

The APU battery circuit has no such module. Considered unnecessary due to the APU battery requirements. IE To start the APU (and nothing else).

Other than that both batteries are identicle.

OFSO, are you saying that if engineers were paid more this wouldn't happen?

So, I'm a Boeing engineer or a battery engineer and I'm going to be less competent at my job because I don't get paid as much as the marketing director?

Really???

Or, is it that when an engineer gets it wrong, it's never their fault?



In that case why are PR people paid so well. Are they going to be less competent at their job if they are paid less?
There is an old saying.
"You pay peanuts, you get monkies".

In my experience the engineers always get the blame regardless of fault. :O

[Sober Lark]

Imagine the reaction if this had been an Airbus

The A380's teething problems with its cracked wings and mid air uncontained engine failure were arguably far more spectacular events. Yet it demonstrates how short public memory is. This time next year I don't think public perception regarding the 787 will be any different.

[GLuis103]

The A380's teething problems with its cracked wings and mid air uncontained engine failure were arguably far more spectacular events. Yet it demonstrates how short public memory is. This time next year I don't think public perception regarding the 787 will be any different.

I agree with this, people tend to quickly forget recent accidents, and that will also happen with the 787...

[RTM Boy]

Turin, so now Boeing and battery engineers are monkeys who get paid peanuts?

Sorry, but we all get paid to do our jobs. If we don't do our jobs competently as a minimum, we stand to lose our jobs.

If an engineer doesn't like their salary, get another job - we keep hearing all the time that "there is a shortage of engineers", so it should be no problem finding work quickly, easily and with better pay.

If, on the other hand, engineers feel underpaid then it indicates that there are in fact plenty of them to spare and they can't command a wage premium. But to imply that this is a valid reason not to do your job properly is ridiculous.

[PiggyBack]

In reply to OFSO as an engineer

1. We are professionals doing a safety related job which we do professionally whatever the pay.

2. If you have worked as and hired engineers you will know pay is very loosely at best correlated with competence. Software developers from financial organisations as an example in my experience are paid very good salaries despite at best poor competence and skill levels. Most senior financial software developers I have interviewed struggle to meet our competence requirments for junior engineers.

3. The development process for safety related systems is multi-levelled so that we do not rely on the competence of one engineer but on a series of analyses and tests throughiut teh development lifecycle. At the end of the day anyone can make a mistake but teh process does not rely on perfection at each stage.

I do believe engineers are often undervalued and underpaid but that is nothing to do with it.

[TURIN]

Turin, so now Boeing and battery engineers are monkeys who get paid peanuts?
No idea. I know nothing of a Boeing engineers remuneration package.
If, on the other hand, engineers feel underpaid then it indicates that there are in fact plenty of them to spare and they can't command a wage premium. But to imply that this is a valid reason not to do your job properly is ridiculous.
Really? I think you are being naive.
This is not the place to get into this spat though. Lots of other threads and bulletin boards for that. :sad:

[mailinator]

Nobody out there to say something about what happens to a 787 when both accumulators go out of business ? I ask this because these things seem to be so important for that aircraft and because I assume that a failing of one accumulator should raise the load on the other one which could then also fail if these things are being used near the edge of their envelope. So ... what remains working on a 787 with both main bats down ? And for how long ? Anybody ?

[LindbergB767]

Maybe Boeing should contact Hydro Quebec They are working on Ion Battery since 30 years and they invented one which do NOT catch fire and have no overheat problem The only thing it is more heavy

[Terego]

Same/ v similar technology is marketed by a company called Valence- they have just settled a patent dispute between them- if you google them you will find a very interesting and spectacular video illustrating the point.

[gums]

From the "light" peanut gallery comes this observation...

- The battery type in question has been known to ignite and once burning is difficult to stop the thing(s). This is more common with the small, dense ones we see in laptops and cellphones, etc. The larger ones seem more safe, but not always. They are still susceptible to overcharging and the ensuing ignition. Which leads me to my observation:

- When the Viper was built, the design team focused upon the flight control computers, as their loss was also loss of the jet and maybe pilot. The elecgtrical system seemed straightforward, so the basic, line engineers came up with a good system with plenty of back ups. The emphasis was upon the whiz kids and the flight control computers. Unfortunately, the computer internal power supplies used solid state voltage regulators of 1970's vintage. They could not handle inputs above 37 volts or so. So uncommanded emergency power that used a simple DC generator with permament magnets could exceed the critical voltage at high power settings ( bleed air powered the thing). The computers would shut down if there was too much input voltage. Sheesh! We fixed the problem, but in the mean time we hot wired the computers and if the input voltagegot too high, then too bad. The computers would fail eventually, but gracefully, one by one. This was much better than having them all ( we had four) just shut down. We proved the point a few weeks later and the pilot flew the thing for 10 or so minutes until all was lost.

- Moral of the story is we seem to overlook some system failures that involve fairly straighforward systems like the battery circuits. The biggies are the aero-mechanical considerations, and they get the most emphasis.

My guess is we'll see a different battery type and better monitoring of the charging circuits.

[Lyman]

Simple and easy are two separate words. We want them to be the same, but frequently they are exclusive....

If this was easy, we would not be writing this thread. Boeing has struggled with monumental problems on this project, and succeeded mightily in almost all of them.

This one is stubborn.... There are enormous forces at work, and to distill this down to R/R power source is simplistic, too easy.

There is a systemic problem, and one or two of several disciplines are struggling.

Nothing fatal, to person or program, imo. We'll see....

[YRP]

I believe that OFSO's point was not the salaries of individual engineers, but rather the number of engineers as a whole. That perhaps having another 10% more design engineering budget or staff would have allowed additional testing.

[FlightPathOBN]

Somewhat OT, but why havent capacitors kept up?
I seem to remember televisions and most electronics had huge capacitors that the power supply fed, and the system drew from. These would stay charged for quite some time.

Is this a viable option to batteries, or could that technology be advanced?

[mailinator]

Power supplies are of course buffered by capacitors and usually in many places - at module level and dispersed over printed circuit boards ect. You wouldn't want to replace accumulators with capacitors because of their size per capacity unit. As the accumulators evolve so do the capacitors, but until now there's no technology which unites the good features of both (small size, low weight, low inner resistance, high capacity).

On the other hand I fail to see any reason to assume that the capacitors in the 787s failed to do their job. What failed was the accumulator ...

[EEngr]

Somewhat OT, but why haven't capacitors kept up? You are referring to supercaps. They work well for short term energy storage as they have a non trivial self discharge rate. Supercaps also have a lower energy density than even SLA batteries. So there would be a significant weight penalty.

Depending on the application, one of the best alternatives to battery energy storage would be a flywheel. I haven't worked the numbers for some time, but they might be better than LiON. Definitely better than NiCad.

A flywheel would be useless for an APU start source, where one would expect to be able to 'back start' an airplane that had been parked for a few weeks. But for standby power (to replace the forward EE bay battery), they would work well. The flywheel could be spun up during ground operations prior to flight and kept topped off by main generator power until a complete electrical system loss required their power.

The APU start issue could be addressed by figuring how often an aircraft is parted long term where ground power (maybe just a couple of forklift batteries wired for 24V) can't be brought up to cherge the APU start flywheel. It may be a non issue for many operators.

[EEngr]

There is a systemic problem, and one or two of several disciplines are struggling.Yep. Same disciplines as when I was working on the 747-400.

The question will be: Does the FAA put on blinders and look only at the battery? Or do they chase this problem all the way down (up?) to the root cause?

To be fair, fixing the battery issue should be sufficient to earn the 787 conditional airworthiness. But I wouldn't be surprised to see a battery fix and then the regulators politely shown back to the Boeing gate.

[Lyman]

They can bird dog the problem all they want, they are still dependent on Boeing. Ultimately, as you say, they will see the door. The problem with a battery only solution is that there is such sloppiness in the trail, confidence won't come back. The FAA? Last in, First out.....

Doesn't the 787 have two Flywheels OEM?

[Chris Scott]

Thanks to angels and Ye_Olde_Pilotfor the Boston APU batterypic (http://www.nycaviation.com/2013/01/ntsb-shows-off-burnt-boeing-787-battery/).

Last week on one of these threads, I speculated that the APU battery, and presumably the main elec-sys one(s), would each need to consist of between 6 and 8 cells. I wrote:

“The [GSYuasa] datasheet shows that each cell is rated at 65Ah, with a nominal voltage of 3.7V.Can someone confirm that the low-power DC electrics are the standard 28V DC,implying a 24V battery? If so, would they need a battery pack consisting of 6, 7 or 8 of these cells, connected in series? Each cell is 2” thick, and weighs just over 6lb.”

Looking at the picture, can any sparks expert now say how many cells?

[ECAM_Actions]

Discussions about what was displayed on the passenger displays aside...... why in the hell was the IFE system even powered during an evac due to fire???????

Surely the aircraft should be electrically dead ASAP after landing??

Were they unable to shut it down?

[mailinator]

You got a problem with your forum's software logic ... My messages are being delayed because I'm new, but after having them reviewed by admin they appear at the location where they would have appeared if they had been shown right away. Only that in the meantime other people have already writted a lot of other messages and nobody is going to look back up ... So I'm essentially writing in vain. Makes no sense that way really :-(.

[BOAC]

It was not a full 'emergency' evacuation as I see it - just wanted the pax off quickly and could not wait for steps.

[oceancrosser]

They seemed to evacuate the airplane leaving the APU running. Kinda strange. If they could not shut it down that in itself is a problem.

[400drvr]

I have not really followed the development of the 787 but I am surprised to learn that the FAA allowed Boeing to install these batteries on this aircraft. I know they are not the same ones that power our electronic gadgets but Lithium batteries are nasty once they start to burn. Why do passenger flights require all spare lithium ion batteries be carried with your carry on on not in checked bags?

UN 3090 batteries must be labeled as CARGO AIRCRAFT ONLY when carried into, out of or through US airspace. My company has specific procedures that must be followed when ever these batteries are carried on our cargo fleet. So if Boeing can design an aircraft with these batteries then why bother with all the other regulations on safe transport of same?

:confused:

[sb_sfo]

Having an aircraft battery bolted into place with monitoring circuits attached is a little different than some SLF throwing a couple spare laptop batteries in his checked bags along with god-knows-what else. Or a couple thousand of them in a box, that some forklift-driving yahoo has poked a hole into, then buried in a pallet of who-knows-what else and left in the sun to cook for a couple hours. Still, I take your point.

[Speed of Sound]

I have not really followed the development of the 787 but I am surprised to learn that the FAA allowed Boeing to install these batteries on this aircraft.


It has been said on one of the other threads that this aircraft has significantly higher electrical requirements than other aircraft of similar size. Could it be that when all the design work had been done for all this fancy extra kit, the only realistic battery power to handle the task was from Li-Ion or other similar high energy system. ie a fait accompli.

Were other bigger, heavier, lower energy systems looked at with the associated weight/space penalties or was it a question of 'if you want all this kit you need these batteries'?

Is that how we ended up with Boeing going to the FAA and saying 'to make this work we need these batteries but if you aren't incredibly careful how you look after them, they will burn at 800-1000 degrees C. So the FAA turned round and said "OK we'll let that slide if you can demonstrate that such a fire can be contained long enough to get the aircraft on the ground!

[FlightPathOBN]

It is Boeing designing the aircraft, not the FAA...


In the US, the FAA can only review and validate what has been submitted. It is illegal in the US to design by review.

As noted, the FAA cannot tell Boeing they cannot use LI batteries, if Boeing has submitted all of the required data to show that the issues have been met.

Now, as we can see, the FAA is looking at the Boeing process, from manufacturing down/up, to review if the process and procedures Boeing uses need improvement.

This is not simply about showing Li batteries are safe, this is about Boeing proving their process is safe...

[Lyman]

"AD Requirements
This AD requires modification of the battery system, or other actions, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA."


This is a rule. The manager of the FSDO (Flight Standards Division Office, Seattle) will be the interface for Boeing's work. Boeing must submit a method, (design) for approval. No more cocktail parties, golf games, or monogrammed towels.


This can flexibly be defined as Design/Build, an accepted method for manufacturing. This is a good system, and the possibility for great success is at hand.....

Plugging the bleeds and taking off generation mechanically is a good idea. Composite is mature, and Boeing is the best in the business. And the 787 is a beautiful bird.....

[Speed of Sound]

FlightPathOBN

And that which isn't validated goes back to the drawing board for redesigning, re-testing or whatever and ultimately needs to be validated before it either sees the light of day or is discarded.

And yes, it is all about the process. Li-Ion batteries are neither intrinsically safe nor not safe. It all depends on what you intend to do with them and how you look after them. At this stage there is little that can be done about what is done with them so the solution lies in how you look after them.

This is of course assuming that the problem is systemic to the electrical systems on-board and not just down to a couple of duff batteries that slipped through QC.

[RR_NDB]

Chris Scott:

...how many cells? (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-8.html#post7638727)


Probably 7 cell´s in series. Why?

A LiIon cell typical max charged voltage (4,2 v ea.) for 7 cells means 29,4 V. I´ve heard of a Diode in the circuit (in series, dropping the voltage to ~ 28 V).

Nominal voltage of 25,9 V (7 x 3,7V). Less the Diode drop means ~ 24 V.

Subject to confirm it. Anyway, 6 cells is not enough and 8 is excessive.

(May be multiples of 7 if series parallel config. was used, with higher risks) Will comment on that in a subsequent post.

(8 cell arrangement could be used if the circuitry is designed for). I would design with 7 cell. Quite compatible with aircraft traditional batt. Voltage.

[RR_NDB]

FlightPathOBN:

Is this a viable option to batteries, or could that technology be advanced? (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-8.html#post7638586)

In special cases the mentioned supercaps act as storage. They are costly and NOT SUITABLE to replace chemical batteries. An example: The payphone used in our country has a one Farad supercap "to help" power the microprocessor circuitry under "long line condition". When the telephone line is near the nominal limit between the Exchange and the payphone.

The capacitors used in electronic circuit indeed stores energy but low figures compared to batteries. And the purpose is other.

In electricity they are used for other purposes but again, no replacement for batteries. Could comment further if asked to.

In an aircraft, capacitors NEVER could be used as a replacement for batteries. The same is valid for most designs.

[RR_NDB]

Speed of Sound:

Li-Ion batteries are neither intrinsically safe nor not safe. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html#post7639570)
AFAIK nothing similar to UPS flight #6 (a 744 at DXB) happened (very probably) associated with lead acid or even NiCd batteries.

The experience so far is that these batteries are FANTASTIC. (small, light, efficient, etc.) BUT INFORTUNATELY EXTREMELY DANGEROUS.

A critical device. Will comment later on that.

[Diamond Bob]

Looks like the battery had 8 cells, according to this graphic accompanying a story in the Seattle Times. In another forum someone who seemed to know says that both the APU start battery and the main battery are the same unit.

http://seattletimes.com/ABPub/2013/01/17/2020149445.gif


Lithium-ion batteries pack a lot of energy — and challenges | Business & Technology | The Seattle Times (http://seattletimes.com/html/businesstechnology/2020149254_787batteryexplainerxml.html)

[ItsMe100]

@Diamond Bob

Looking at the High-Res Photos (http://www.ntsb.gov/img/headline/1-7-12_JAL787_APU_Battery.jpg) from the National Transportation Safety Board you could better count them. It seems really to be 8 batteries in a row.

Looking at the the batteries product page (http://www.gsyuasa-lp.com/aviation-lithium-ion-markets) you could find the information that Thales will integrate GS Yuasa batteries (http://www.s399157097.onlinehome.us/SpecSheets/LVP10-65.pdf) into the DreamLiner.

Digging deeper into their LVP 10 65 (http://www.s399157097.onlinehome.us/SpecSheets/LVP10-65.pdf) Data Sheet sheet, you also will find that thai are using Lithium Cobalt Oxide as cathode material. Okay, understandable if you look at Battery University's Types of Lithium Ion sheet. (http://batteryuniversity.com/learn/article/types_of_lithium_ion) Its the
It's got the highest energy density (and maybe the edge on the market - so not so easy to replace).
But looking deeper into their Snapshot of an "average" Li-cobalt Battery (http://batteryuniversity.com/_img/content/li_2(1).jpg) you will find safety of a Lithium Cobalt battery is not their highest inner value.

It seems like they were really trying hard to safe weight. I hope not on the cost of security. (I wouldn't like to breath neither Lithium (which might make me a bit more happy:rolleyes:) nor Cobalt (you will find out on getting it into your lungs, yourself). Maybe the organic solvent smells & feels better. I hope it went well for the Boston and US passengers...

And, I hope it won't be Waterloo II for Thales and it won't get Boeings TraumaLiner.

[Machinbird]

Every time we get airborne in a powered aircraft, we are dealing with combustion processesses that are under careful control, i.e. the aircraft is dealing with fire under carefully controlled conditions. No big deal as long as the engineering is valid.

From the pictures of the battery case of the burned battery in the Boston fire, the case was not burned through although the battery was fully involved. This is indication that Boeing's design concept included an expectation that a fire might occur in the battery and that a concept was developed to mitigate and control the damage.

The design concepts must now be reviewed in light of current experience to make sure that all the design concepts were valid. It appears that among other things, the frequency of battery fires is well in excess of engineering expectations.

The engineering expectations that the design would be sufficient for a battery fire inflight also need to be looked at from the standpoint of adequacy for a fire on ground with the aircraft stationary. This is a more difficult case than the inflight case since the venturi system for exhaust from the E&E compartment would likely not be operational.

My limited experience of intentionally burning a small discharged Lithium cell phone battery left me impressed. The organic chemicals inside the battery are extremely flammable and the flare from the battery fire left me questioning whether or not I was too close to the thing at 5' distance. This was just a very small cell phone battery!

As a betting man, I'll bet that the issue with the battery is actually with the charging system and insufficient feedback from the battery to the charging system regarding cell temperature. The charging system should not continue to charge a battery that is moving in the direction of thermal runaway.

[wooski]

the Cynic in me hopes this is just a simple imperial to metric error.. eg batts sending temp out in celsius but the charger is expecting fahrenheit.

[deptrai]

FYI The Seattle Times illustration claims the batteries have lithium cobalt oxide cathodes. This is what I thought initially as well, as it was the original spec for test/certification aircraft.

However it seems production aircraft may have been fitted with (more safe) lithium manganese oxide batteries, according to Turins anf Fargoos B787 training notes, and an article from 2008.

[Ngineer]

The sealed lead batteries on the B777 (particularly the main battery that seemed to have a higher failure rate) can go into thermal runaway and start smoking.

[RR_NDB]

Machinbird:
As a betting man, I'll bet that the issue with the battery is actually with the charging system and insufficient feedback from the battery to the charging system regarding cell temperature. The charging system should not continue to charge a battery that is moving in the direction of thermal runaway. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html#post7639754)
The closed loop System must use TEMPERATURE and VOLTAGE. Before thermal runaway the cell voltage becomes abnormal. Just a cell is actually critical. When arranging in series or series-parallel the issue becomes complex. And dangerous.

My limited experience of intentionally burning a small discharged Lithium cell phone battery left me impressed. The organic chemicals inside the battery are extremely flammable and the flare from the battery fire left me questioning whether or not I was too close to the thing at 5' distance. This was just a very small cell phone battery!

ScareBatt :mad:

My pilot son before the RTW flight made a lot of dangerous uses of LiPo in the RC models. :E Extra precautions were made here. We simulated how to proceed, just in case after youtube watching. :E

[RR_NDB]

Diamond Bob:

Looks like the battery had 8 cells, according to this graphic accompanying a story in the Seattle Times. In another forum someone who seemed to know says that both the APU start battery and the main battery are the same unit. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html#post7639710)

Thanks bob, this points to another issue. They designed a non conventional circuitry (charger, ETC.) to manage the higher voltage (29,6 V nominal up to 33,6 V "floating" voltage). Aviation uses 24 ~28 V span. A battery replacement would require a redesign, etc. (time consuming) of critical circuitry. :{

I hope for charger issues. (best case scenario)

[RR_NDB]

Ngineer:

The sealed lead batteries on the B777 (particularly the main battery that seemed to have a higher failure rate) can go into thermal runaway and start smoking. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html#post7639797)
For sure! (bold mine)

Batteries are not a simple issue. I had problems with ALL types in my professional life. I remember in first year of academy i read a russian book on batteries. I was amazed how complex were. (1970). Today we need microprocessors to manage them. :mad:

[BRE]

While ANA was quoted on Wednesday saying they expected to by flying again within a few days, it seems they have now changed their mind. Until the wee hours of Friday morning (Japanese time), this is what their reservation change policy read:

"2. Waiver of Date change and Cancellation
Application period until January 23rd, 2013
(1) Date change
One time date change is possible without regardless of the fare rule. The date change is subject to space availability and the new departure date must be until March 31st, 2013. (including arriving Japan on April 1st,2013)
(2) Waiver of Cancellation and Refund charge
Cancellation charges or refund charges will be waived irrespective of the fare rules.
"

The application period has now been extended to March 31st.

[mailinator]

Please define "best". I agree with "beautiful". We'll see about composite and "mature" ... I'm sure everybody thinks about the Comets and its nice large windows all the time ... damn shame that one. De Havilland was such a great company.

[YRP]

About the battery voltage, number of cells and such, Boeing might be using various power converters (DC-DC etc) between the batteries and electrical systems. It might well be more efficient to design the battery array at its optimal voltage/configuration, then convert to the optimal voltage for the electrical system. Having said that the burnt battery does look like 8 cells. But it wasn't the main battery was it?

With some of the power figures being talked about (1.4MW in one post -- can that really be right?), I'd expect conversion to high voltages for distribution. Otherwise they would be talking about the airplane being mostly copper rather than composite.



For that matter (just conjecture) it might be interesting to contemplate a "distributed" battery. Rather than co-locating many cells, place single cell (or low cell count) batteries at various places so one cell cannot heat another one. Each one can have an independent charger/controller and can convert its 4V output to 28V (or go 2 cell / 8V if 4V isn't enough headroom for the power converters).

But then maybe you'd have to duplicate the thermal protection / detection systems so perhaps inefficient.

[cwatters]

From the pictures of the battery case of the burned battery in the Boston fire, the case was not burned through although the battery was fully involved.

Are there any photos of the top of the battery? The one I saw had the top missing but was it removed or ??

Edit: This looks like it might be it..

http://media.komonews.com/images/130117_Boeing_787_battery_1.jpg

[Capn Bloggs]

They designed a non conventional circuitry (charger, ETC.) to manage the higher voltage (29,6 V nominal up to 33,6 V "floating" voltage). Aviation uses 24 ~28 V span.
Not so. The battery voltage, under charge, sits at 33v quite often in the older "Boeing" jet I fly. ;)

[Speed of Sound]

That is the charging voltage being measured, not the battery voltage!

If you charge a 28V battery at 28V you will still be waiting for it to be charged next Xmas! ;-)

[shonandai]

See them here in the Yomiuri.
‚V‚W‚VƒoƒbƒeƒŠ�[‰æ‘œŒö•\�A—eŠí“à‘S‘Ì‚ª’Y‰» : ŽÐ‰ï : YOMIURI ONLINE�i“Ç”„�V•·�j (http://www.yomiuri.co.jp/national/news/20130118-OYT1T01121.htm?from=top)

[Speed of Sound]

at least it won't burn.....

I know that is supposed to be a joke but in fact they may eventually burn.

'Charging' at this rate will eventually lead the battery to become completely discharged where we get into another 'danger area' for the Lithium based high energy density system.

Too much charge =risk of thermal runaway.
Too little charge =risk of thermal runaway.
Too high temperature =risk of thermal runaway.
Cell short circuit. =risk of thermal runaway.
Loss of charging voltage regulation =risk of thermal runaway.
Excessive AC ripple =risk of thermal runaway.

To use these batteries in a safety critical situation they not only need to pass strict quality control and be installed correctly, but also require a reasonably complex system of monitoring voltages and temperatures to control charging.

If all this works as it should, then there is no reason for any Li-Ion battery to get anywhere near thermal runaway. Redundancy in this system is the way to go rather than ensuring enough distilled water is available to douse the fire when it does happen.

Boeing will be hoping that the two batteries involved turn out to be from a faulty batch at Yuasa. Redesigning an inherently inadequate charging system is likely to take some time. :-(

[RR_NDB]

Capn Bloggs:

The battery voltage, under charge, sits at 33v quite often in the older "Boeing" jet I fly. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html#post7640537)
Could you check the number of cells (series) in this case?

You can (reducing batt life) keep them more charged. Until a certain point. Excessive gassing (lead acid) or higher temperature (NiCd). Both are NOT CRITICAL like the Lithium counterparts.

In lithium ones you need to monitor carefully temperature and even ea. cell voltage (early warning on impending problems)

[Speed of Sound]

Float current is what you need to keep an eye on with these 'systems'.

[Lyman]

SoS

Hope not a dumb question. I was trained, in utilizing this type of battery, to isolate a cell from concurrent charge/discharge. The system prevented a battery from being used whilst charging. Is that what you mean by "Float"?

thanks

[mickyman]

I wonder if the fault lies with the airlines (Only ANA/JAL aircraft involved) training and maintenance procedures OR with Boeing who may have rushed to deliver aircraft because of previous delays?
Whatever thank goodness we're not scrapping bodies off the tarmac - at least we know the alarm systems are working.

[E_S_P]

Lyman

I 'think' SoS is meaning the charging current would be adaptive to provide the correct optimal charging current for the batteries. Not too little - not too much :)

[Rory166]

Just curious but does anyone have any idea why Boing have not chosen Lifepo4 batteries for their better safety. Ok the energy density is not quite as high but the better safety and longer life would surely outweigh this.

It seems possible to me that the design of the battery system is too focussed on having the new technology mimic the function of traditional batteries rather than making best use of the new technology. Traditional batteries are used to regulate the voltage on the busses. They are able to tolerate overcharging quite well. In my view best use of Lithium technology would involve having a separate voltage regulation system with the battery waiting in reserve, perhaps connected through a diode, to provide power in the event of a generation shortfall below demand. The battery only charged when monitoring deems necessary.

[Lyman]

E S P....

Thanks, I assumed as much. It strikes me that in a very dynamic draw, supply situation, the Generation, load, and "surge" (battery) would have to be balanced in intricate fashion. At times , in load transition, the Battery is passive, merely a conductor, and the relative flow can create temporary overloads, and conversely, wide open draw. My question was meant to attempt to extrapolate a system I became used to, to the current one.

It strikes me that those two batteries are the pinch in a very large pipeline, so I would have expected there to be more than two batteries (each eight cells)...likewise ambient temps would seem to be rather important.

thanks for your response :ok:

[RR_NDB]

Rory166:

Traditional batteries are used to regulate the voltage on the busses. They are able to tolerate overcharging quite well. In my view best use of Lithium technology would involve having a separate voltage regulation system with the battery waiting in reserve, perhaps connected through a diode, to provide power in the event of a generation shortfall below demand. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-10.html#post7641366)

The info we have so far points to the second approach. Not the simpler(old) one.

[FlightPathOBN]

state of the art battery? who wired this up???

Look at that wiring mess on top of the cells....why is there even wiring like that? this looks to me like it was hacked together...

http://seattletimes.com/ABPub/2013/01/18/2020162337.jpg

[RR_NDB]

Bear:

Is that what you mean by "Float"?
(http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-10.html#post7641233)
See Float voltage (http://en.wikipedia.org/wiki/Float_voltage)

Definition: The voltage at which the battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery.

[Rory166]

Flight

The visible wiring is almost certainly the BMS connection. The heavy current connection between cells would most likely be by bars. I imagine the point you are making is that the BMS wiring would have been better tied to a supporting structure rather than draped over the cells where possibly warm metal might damage the insulation and cause a short. It does appear to be formed into a loom away from the terminals and busbars. One would hope the battery terminals would also have insulated covering. In general things often look more of a mess having caught fire than they did before.

[RR_NDB]

FPO:

Look at that wiring mess on top of the cells....why is there even wiring like that? (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-10.html#post7641837)

http://seattletimes.com/ABPub/2013/01/18/2020162338.jpg

The answer is at your RH picture. The plastic plate melted an the harness resisted the heat.

[airman1900]

What puzzles me about these battery events is why they happened when they happened? And why now for, apparently, the first time?

FYI, the ANA aircraft (Line number 9, first flight Jan. 9, 2011) and JAL aircraft (line number 84, first flight Dec. 7, 2012) came off the production line almost two years part. Line Number 1 first flight was Dec. 15, 2009.

My guess: If there aren't serious design problems, is that there are defectively manufactured electrical component(s) involved.

[RR_NDB]

airman1900:

What puzzles me about these battery events is why they happened when they happened? And why now for, apparently, the first time? (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-10.html#post7641889)

Over voltage as reported can explain very well. But why? And the timing for the apparently same problem is intriguing.

:confused:

A software issue? We would need more info on the subsystems "around" the batteries.

NTSB at JAL 787 (BOS):

http://seattletimes.com/ABPub/2013/01/08/2020087644.jpg

[TheRobe]

You know someone at Boeng that pushed for these batteries is having a long talk with a chairman that just lost $50 million in stock options from this fiasco. 'So why didn't we go with Lead Acid batteries?'

'Well uh, well gee, um...'

[UNCTUOUS]

"Helderberg crash IASA Lithium Fire"

Any aviation journalist who googles that will have a wealth of information on the first large aircraft downing due to Lithium Ion battery fires - so many decades ago now. Boeing stopped offering the "cargo in aft section of pax compartment" 747 Combi after that event. The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. That bulk carriage of Li ion batts in air-freight is now banned by IATA and the FAA. Not sure why a bunch of aircraft-powering Li Ion accumulators with an even higher power density is (perversely) OK, yet a properly packed container of segregated tiny watch/calculator/phone batteries is not.

However anybody who's seen the results of the Dell laptop battery fires would have no doubt that it's an issue best ducked. Thermal runaway that doesn't need oxygen and cannot be suppressed? Bad enough in an isolated cargo hold, but in an avionics compartment or an inaccessible APU location?
It's not as if you can make them jettisonable. A main load center/avionics compartment in a 787 is a slightly different proposition to most other aircraft that aren't so "electrical" in nature. It's the heart of what makes it fly, not just the aircraft avionics. Aircraft control becomes an issue.

The 787 was designed to be a nil hydraulics electrically powered beastie. .... so battery capacity and reliability was quintessential to safety. I'm wondering what dispensations and extra requirements specifications were finagled by Boeing engineers in the design approval process (via sympathetic FAA weenies). Maybe the new FAA administrator started looking into this after the fires started, discovered something and then had no choice but to order a "review". More power to his elbow.

If the Lithium Ion battery fires continue or there's an unexplained loss due to a crew having to quickly monitor off busses in a fire and smoke drill? That will be a nightmare for both Boeing and the FAA. It's got all the potential of a NASA Challenger disaster and a denial of leaky seals being a threat to the Space Shuttle.

But one thing is for certain. Boeing will not be giving up on those Li Ion batteries in the 787. There's no viable alternative with the required power density. And a timely fixing of a new aircraft that's both in service and on the assembly line? Burn that midnight oil you Boeing engineers. Whatever you come up with as a fix better be good.

[Romulus]

Any aviation journalist who googles that will have a wealth of information on the first large aircraft downing due to Lithium Ion battery fires - so many decades ago now. Boeing stopped offering the "cargo in aft section of pax compartment" 747 Combi after that event. The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. That bulk carriage of Li ion batts in air-freight is now banned by IATA and the FAA. Not sure why a bunch of aircraft-powering Li Ion accumulators with an even higher power density is (perversely) OK, yet a properly packed container of segregated tiny watch/calculator/phone batteries is not.

Because things have progressed in the last "many decades"?

Boeing and the OEMs will have done their work and believe that they have properly tested this newer technology and that it is safe for aviation specific applications. That's progress. The watch batteries will not have had any such testing done, why would you spend a bucketload of cash for such an incidental part of a spec when you can just use sea freight?

Lithium ion batteries in aircraft will almost certainly become the norm, but the issues need sorting out first. As a new aircraft the 787 doesn't have the luxury of using tried and tested technology, if you did that you'd effectively get a 777, and as good an aircraft as that is the 787 is far better once the bugs are ironed out.

[Rory166]

Having now had the opportunity to view the manufacturers outline spec sheet for the Yuasa Li-Co cells I see the rupture plate is apparently in the side of the battery rather than on top as conventional. This might give the opportunity to place a vent path from this rupture plate to the outside rather than have the emitted chemicals destroy the rest of the contents of the battery case as seems to have happened in the pictures shown on this thread. Clearly the designers of the battery box were confident that the 4 battery management systems (2 in box 2 outside) would ensure that a cell never did rupture.

The requirement for maturity and Aeropspace certification may in this case have been counterproductive in that an older less safe battery chemistry is used in preference to a newer fundamentally safer chemistry.

Does anyone know the pressurisation status of the electronics compartment where the battery is housed. I am slightly mystified as to how the chemicals were vented overboard in one instance and smelled in cockpit and passenger compartment in another.

[Rory166]

Mailinator

The two batteries are for different functions apparently. One as the APU power source and one as a backup for the electronics. So the battery backup has 4 monitoring systems but no backup for itself. Once the backup battery failed there would have been no backup in the event of a power failure. Does the dreamliner have a drop down aero generator anyone?

[DaveReidUK]

But one thing is for certain. Boeing will not be giving up on those Li Ion batteries in the 787. There's no viable alternative with the required power density. Hmmmm. A certainty ? Time will tell.

[DaveReidUK]

Does the dreamliner have a drop down aero generator anyone?http://sitelife.aviationweek.com/ver1.0/Content/images/store/15/3/1f41193b-9f93-478a-a3a3-6556084245e4.Large.jpg

[Swedish Steve]

Does anyone know the pressurisation status of the electronics compartment where the battery is housed. I am slightly mystified as to how the chemicals were vented overboard in one instance and smelled in cockpit and passenger compartment in another
Well one was parked on the ground , and one was flying. In flight the air is extracted from the avionics bays and exits via the outflow valve. On the ground the air exits through openings under the fuselage.
Although there is positive airflow in flight from the cabin to the underfloor it is amazing how crew regularly smell things happening downstairs, even though the airflow is in the other direction.

[glad rag]

From what I can read on the 'net the aft EE bay is the main Electrical distributor point as the 4 main starter/generators and 2 apu generators feed in there.

http://sitelife.aviationweek.com/ver1.0/Content/images/store/0/8/200c7f3e-2451-41b6-b83a-761e9b20d94d.Full.jpg

IF the above picture shows the RAT in it's production location then worryingly does it point to the emergency power distribution system being located in the aft EE bay as well.........all the eggs in one basket?

Airbus have a philosophy of physical separation of primary/secondary and emergency power supply systems with, naturally, a weight penalty.

[bsieker]

As written in a previous post, the reason why it was possible to vent the smoke in cruise, but not on the ground is simple.

Venting is done by an overboard venturi, which only works during flight (it is only used in cases of failure, normal E/E cooling is accomplished using electric fans). On the ground, as in the Boston case, this type of venting cannot work, so smoke was able to enter the cabin.

Glad rag,

The RAT sits under the wings, but feeds into the main circuits in the forward E/E bay.

[DaveReidUK]

IF the above picture shows the RAT in it's production locationYes, the RAT location does appear to be under the centre-section on production aircraft, unlike the photo that I posted earlier, showing one of the prototypes with a RAT forward of the nosewheel.

Here's a clearer photo that shows it deployed:

http://cdn-www.airliners.net/aviation-photos/photos/7/3/6/2177637.jpg

[TURIN]

Unctuous.
Where did you get the idea that the 787 is a "nil hydraulics" aircraft. The only system that is electric instead of the usual hydraulic is the brakes.
Flt ctls, l/gear ops are still hydraulic.
The engines still have directly driven hydraulic pumps on the gear boxes.

[BOAC]

Is the RAT electrics/hydraulics or both? If +electrics, why the need for chunky extra batteries? Does its deployment seriously dent the ETOPS range?

[Chris Scott]

Quote from DaveReidUK:
“Yes, the RAT location does appear to be under the centre-section on production aircraft, unlike the photo that I posted earlier, showing one of the prototypes with a RAT forward of the nosewheel.”

Looking at it again, am not sure if your first pic did show a RAT forward of the nosewheel. Looks aft to me. That panel did at first look like a nose-gear door, but is probably the access panel to the RAT?

Don’t know why RATs are not mounted forward of the nose gear, because at the centre section it’s difficult to avoid any possibility of airflow disruption when the nose gear is down. (That’s why they had to reconfigure the A320 electrical system and FBW downgrade-logic in late-1987, just before type certification.)

Quote from BOAC:
“Is the RAT electrics/hydraulics or both? If +electrics, why the need for chunky extra batteries? Does its deployment seriously dent the ETOPS range?”

Who is calling for “chunky extra batteries”? There is a dedicated APU-start battery, which must help. But I’m not familiar with ETOPS/EROPS requirements. Could you expand on your point?

[BOAC]

If you had electrics on the RAT you might be able to dispense with APU start = 'chunky batteries'? Hence the query on possible detrimental drag on an ETOPS div.

[grebllaw123d]

I found a link which is quite interesting -written by a United pilot, who has taken the 787 course.

The Boeing 787, from a Pilot’s Perspective - View from the Wing (http://boardingarea.com/blogs/viewfromthewing/2012/04/21/the-boeing-787-from-a-pilots-perspective/)

According to him the RAT supplies electricity as well as hydraulic power to flight controls (if needed).

P.S. The last 2 lines in his report read;
"I think the 787 will be a great plane, but there could be some surprises with this level of innovation. Time will tell. "

How true - unfortunately!

[DaveReidUK]

Looking at it again, am not sure if your first pic did show a RAT forward of the nosewheel. Looks aft to me. That panel did at first look like a nose-gear door, but is probably the access panel to the RAT? Yes, you're right, found another photo of it from a different angle, showing the MLG as well: DSC01711 | Flickr - Photo Sharing! (http://www.flickr.com/photos/airlinereporter/4327924913/lightbox/)

[PJ2]

Thanks for the link grebllaw123d. The pilot's enthusiasm comes through well - don't blame him - I'd love to have flown the aircraft!

Bit OT, but he does state that electrical generation is "1.4 Gigawatts" - perhaps he meant Megawatts? But on the question of the RAT, it isn't clear how electrical generation is achieved. Is there a pump and a generator installed in the RAT or is the RAT only a hydraulic pump which then drives a separately-installed hydraulically-driven generator?

edit: by the look of it in the photo provided by DaveReidUK, I'd say the RAT was only a hydraulic pump.

[Avionista]

Hydraulic pump redundancy on the 787 comprises a mechanically driven pump on each engine, powering two separate hydraulic circuits. Each of these separate hydraulic systems also has an electric-motor-powered hydraulic pump connected to the aircraft's electrical system. There is also a third hydraulic system pressurised by two further electric-motor-powered hydraulic pumps. There are two generators on each engine and each of the four electrically driven hydraulic pumps is connected to a different engine driven generator bus. The third hydraulic system can also be pressurised by a pump driven directly by a RAT. (The RAT drives an electrical generator and a hydraulic pump)

Even with a double engine failure ('Sullenberger Scenario'?), electric power from the APU and/or battery should keep the hydraulic systems operational long enough to allow a 787 to descend from altitude to a forced landing/ditching or, hopefully, a suitable runway. Should the APU and battery system also fail, the RAT would provide hydraulic pressure to operate the aircraft's primary flight controls. Therefore, it seems there is a high level of redunancy built into the 787 insofar as the supply of hydraulic pressure to control surface actuators, etc, is concerned.

In addition to hydraulic pressure, actuators also need electrical signals to control their degree and rate of movement in response to pilot/autopilot inputs. After the recent electrical problems experienced by the 787, I wonder if the FAA are worried that, under certain electrical failure scenarios, some of these control signals may be lost due to fire.

[PJ2]

Avionista;

Thank you kindly for the information. Without going into specific differences, the system description is somewhat similar to the A330's system. The A330 RAT provides hydraulic power for one hydraulic system (main one, Green) which powers flight controls (but not the THS) and the hydraulic-motor-generator which provides a certain KVa for basic aircraft electrical services. I'm assuming that this is the way the B787 system is designed as well? (meaning, the RAT itself is only a hydraulic pump).

[RR_NDB]

UNCTUOUS:

The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. (http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-10.html#post7641940)

The container where the investigators focused had computers. (laptops?):

Van Zyl discovered that the front-right pallet was the "seat" of the fire. The manifest said that pallet mostly comprised computers in polystyrene packaging. The investigators said that the localized fire likely came in contact with the packaging and produced gases that accumulated near the ceiling. They also said that gases ignited into a flash fire that affected the entire cargo hold. The cargo fire of Flight 295 did not burn lower than one meter above the cargo floor. The walls and ceiling of the cargo hold received severe fire damage. Van Zyl ended his investigation without discovering why the fire started.[9] (http://en.wikipedia.org/wiki/South_African_Airways_Flight_295)

[wooski]

PJ2;

The way i read it the RAT provides power first, and then hydraulics if required.
Seems if the engines are just windmilling (out of fuel i guess) the PMG's will provide power for the control surfaces (im guessing its generating 270Vdc in this mode ?)

Boeing 787: A Pilots Perspective (http://www.flight.org/blog/2012/06/05/boeing-787-a-pilots-perspective/)

[Avionista]

PJ2:

Earlier this year, Hamilton Sundstrand delivered the first production Ram Air Turbine (RAT) to Boeing for the 787. In the extremely rare case of a loss of engine-generated power, the RAT deploys from the underside of the fuselage to produce both electricity for the cockpit and hydraulic power for the flight controls, allowing the aircraft to land safely. Hamilton Sundstrand is the world's leading supplier of RATs. Since the technology's inception, Hamilton Sundstrand RATs have saved more than 1,400 lives.

The above quote from Hamilton Sundstrand's website suggests the RAT contains both a hydraulic pump and an electrical generator. This may be required because the 787 is a 'More Electric' aircraft than previous Boeing or Airbus aircraft.

[TURIN]

Seems if the engines are just windmilling (out of fuel i guess) the PMG's will provide power for the control surfaces (im guessing its generating 270Vdc in this mode ?)

From memory, the +/-270vDC is a variable output from the big electrical liquid cooled transformer/rectifiers in the aft EE bay. The main engine and APU gennys produce variable frequency 235vAC. Can't remember what the PMGs produce.

[sb_sfo]

1. The RAT is stowed in a compartment aft of the right main landing gear.

2. When commanded, a spring-loaded actuator deploys the RAT into the

airstream.

3. The RAT uses propeller blades that turn in the airstream to turn a shaft.

4. The shaft turns an elecric generator and a hydraulic pump.

- This supplies hydraulic and electric power to critical systems such as flight

contols and primary display system.

5. The RAT system supplies hydraulic pressure to the center hydraulic system.

6. The RAT can extend automatically or manually.

7. The RAT can operate at all flight speeds and altitudes.

8. The RAT door is mechanically linked to the RAT.

- When the RAT deploys, the link opens the door.

[PJ2]

wooski, Avionista thank you for your helpful responses.

"4. The shaft turns an elecric generator and a hydraulic pump."

sb_sfo that clinches it, thank you.

[FlightPathOBN]

My comments from post #191 and #194 were from looking at the wiring connecting the cells.

I cant believe that a 'state of the art' system, the issues with Li, and the importance of this backup, that it is wired up this way....

If the system needs to be perfectly balanced between cells, this doesnt seem the right way to accomplish that....

[gas path]

The four engine driven generators supply the 235v variable freq. That goes to the aft and fwd EE bays. The aft EE bay Auto TRU's convert to +/-270vDC.
The DC is for driving the cabin air compressors, centre hyd. pumps. O/Jett pumps, the ram fans, and the NGS compressor.
The APU battery located in the same bay supplies the APU Hot Batt Bus its charger is supplied from the F/O's instrument bus. APU starter 235vac from the ATRU.
The main a/c battery located fwd. is charged (via a charger) from the capt's instrument bus. This is the only one with a diode pack to prevent the Hot batt. bus from back feeding the battery.
The PMG's only power the eng. EEC's
Windmilling engines will provide some hydraulic power. Enough for flight controls.
The RAT will supply hydraulic power to the centre hyd. system.
The RAT will supply electrical power to the ac busses (with some serious load shedding!) but primarily the backup bus, flt. instrument busses, brake system controllers (130VDC)
I'm tired its getting late..so apologies if I've got something wrong.

[glad rag]

[QUOTE][The APU battery located in the same bay supplies the APU Hot Batt Bus its charger is supplied from the F/O's instrument bus./QUOTE]

EH! :{

[dunwawry]

Machinbird wrote: As a betting man, I'll bet that the issue with the battery is actually with the charging system and insufficient feedback from the battery to the charging system regarding cell temperature. The charging system should not continue to charge a battery that is moving in the direction of thermal runaway.

I can't find his post anymore but wbclay earlier posted a link to a whisteblower case that might offer evidence towards your theory? It was dismissed as the employee appeared to have other good reasons for termination, and most of his whistleblowing related to departure from design specs and a short that was later resolved. However he was top tech engineer on testing the battery until May 2007, and allegedly very good at his job. Here is the relevant portion of transcript of judge's decision, rendered July 2011:

Leon also alleged he engaged in protected activity when he told
Boynton that there was a problem with the thermistor wires in some
BCUs and claimed Boynton forced him to run an Acceptance Test
Protocol (ATP) on these units despite the thermistor problem, knowing
all the units would have to be opened later to inspect the problem. <snip> However, there is no proof Leon communicated his concerns about the
thermistor wires to Boynton or explained he was not completing the
ATP paperwork in order to avoid shipping a potentially defective BCU,
nor that Boynton pressured him to perform an ATP on a unit with a
potential thermistor problem.
pg. 26

http://www.oalj.dol.gov/Decisions/ALJ/AIR/2008/LEON_MICHAEL_v_SECURAPLANE_TECHNOLO_2008AIR00012 (http://www.oalj.dol.gov/Decisions/ALJ/AIR/2008/LEON_MICHAEL_v_SECURAPLANE_TECHNOLO_2008AIR00012_%28JUL_15_2 011%29_172333_CADEC_SD.PDF)_%28JUL_15_2011%29_172333_CADEC_S D.PDF (http://www.oalj.dol.gov/Decisions/ALJ/AIR/2008/LEON_MICHAEL_v_SECURAPLANE_TECHNOLO_2008AIR00012_%28JUL_15_2 011%29_172333_CADEC_SD.PDF)

Physics, and particulary the base hardware portion of electrical circuitry (vs. programming logic, memory/processor architecture, etc.), were my weak suit (one of my three required EE professors accused me of obviously being a CS major, apparently a derogatory label, but ha ha, I got A's in the courses anyways), so I leave you to sort this out.

[patrickal]

All followers of the aviation industry can now rest at ease over the apparent 787 debacle. The US Senate is on the case. All issues should be resolved within days.

Senate to examine FAA approval of Dreamliner battery - Yahoo! News (http://news.yahoo.com/senate-plans-aviation-hearing-faa-approval-787-battery-000233553--sector.html)

Senate to examine FAA approval of Dreamliner battery

WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

U.S., Japanese and French authorities are investigating two separate cases in which lithium-ion batteries on board the new airliner failed. One of the batteries sparked a fire in a parked plane in Boston, while the other forced an emergency landing in Japan.

As a result, authorities around the world last week grounded all 50 Boeing 787s.

The Dreamliner, with a list price of $207 million, is the world's newest airliner, a lightweight, advanced carbon-composite design that has more electrical power than any other aircraft and uses 20 percent less fuel.

"Certainly the issues of FAA certification will be a key component of the aviation safety oversight hearing we're planning," an aide to the Senate Commerce, Science and Transportation Committee told Reuters in an email.

The aide, who was not authorized to speak publicly, said committee chairman Senator John Rockefeller was "following the situation surrounding the Dreamliner and FAA's task force closely and he thinks the FAA and (Department of Transportation)are examining the issue carefully."

The House Transportation and Infrastructure Committee is also keeping a close eye on the 787 investigations and the issue of FAA oversight, congressional aides said, although no formal hearings were planned at this point.

Boeing officials have briefed both oversight committees and other key lawmakers about the matter, a Boeing spokesman said.

The Senate committee had already been planning to conduct "substantial and aggressive oversight" of aviation safety during the first quarter, but would now look closely at the 787 incidents and FAA oversight as part of that process, the committee aide said.

Problems with the 787's lithium-ion battery have sparked questions about why the FAA in 2007 granted Boeing a "special condition" to allow use of the batteries on the plane, despite the fact that they are highly flammable and hard to extinguish if they catch fire.

Boeing designed a special system that was supposed to contain any such fire and vent toxic gasses outside the plane, but the two recent incidents have raised questions about whether that was a good decision.

It remains unclear what caused the batteries to fail, but when it announced plans to ground U.S.-based 787s, the FAA said both battery failures released flammable chemicals, heat damage and smoke - all of which could affect critical systems on the plane and spark a fire in the electrical compartment.

The FAA has said it will keep the 787s grounded until airlines demonstrate that the battery system is safe and complies with safety regulations.

(Editing by Gary Hill and Sandra Maler)

[m.Berger]

When Comets crashed, they were so important as an export earner that the Government gave orders to blame the pilots (as I have heard reported Airbus still do.) The battery will be redesigned and all will be well until the next minor problem gets blown out of proportion by those who know no better.

[LiveryMan]

When Comets crashed, they were so important as an export earner that the Government gave orders to blame the pilots (as I have heard reported Airbus still do.)..........

Like Habsheim and the A330 Test flight? Both long suspected to be computer glitches but successfully blamed on the pilots.

[toffeez]

"Like Habsheim and the A330 Test flight? Both long suspected to be computer glitches but successfully blamed on the pilots."

What those two had in common was not computer glitches, but inadequate preparation by the crew.

[TURIN]

Excuse my ignorance, but why are the French Authorities getting involved?
Do they mean EASA?

[ATC Watcher]

Thales is a French company , that is possibly the reason .

[TURIN]

Ah yes, of course. Thanks.

[Mac the Knife]

Seven (7) YEARS to design a battery charger?

Even a VERY VERY special battery charger?

JFK's speech about going to the Moon was in 1961, by 1969 they were there.

I'm confused.

[cwatters]

How cold does it get in the bay where the battery is located? I recall reading somewhere that charging when cold can lead to problems with short circuits but I think Li manganese cells can work down to -40C.

[TURIN]

It's a pressurised and conditioned area. Plenty of heat generated in there by the CMSCs etc. Thats why they are liquid cooled.

[syseng68k]

Mac the Knife

Seven (7) YEARS to design a battery charger?In industry, time to proof of concept for a design like that would not be more
than 6 months, using rapid development techniques. Time to market is critical in
industry, where you need to steal a march on your competitors, or just get the
product generating revenue. Safety critical products are shielded from all that in
theory, with very complex processes and audit trails covering every aspect of the
design. 7 years does seem a bit long winded, but we have no info on specification
drift, or how many changes or complete rewrites happened during that time.

Of course, all that process still doesn't mean that the design is fit for purpose,
only that it meets the original spec http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/worry.gif

Turin

One thing I did notice from the battery data sheet was the max temp of 65
degrees C, which doesn't leave much sensing headroom if one or more cells
starts to get hot, assuming a single enclosure temperature sensor.

Max discharge rate is 5C, 325 amps, so they will be limiting the apu starter
current. Typical starter current could be > 500 amps without a starter panel
or other current limiting device.

[EEngr]

FlightPathOBN (http://www.pprune.org/members/351467-flightpathobn) :


My comments from post #191 and #194 were from looking at the wiring connecting the cells.The wiring you are seeing in those photos is for cell voltage sensing. The (unmelted) bundles can be seen through the plastic barrier on the RHS of photo #194. It appears to be bundled, tied and routed neatly, as is common practice in most aircraft electronics.

The high current connections consist of metal straps (probably copper with an insulating coating) between the individual cell studs.

[Chris Scott]

Quote from syseng68k:

"Max discharge rate is 5C, 325 amps, so they will be limiting the apu starter current. Typical starter current could be > 500 amps without a starter panel or other current limiting device."

Yes, and the rest... See my post (http://www.pprune.org/tech-log/505695-787-batteries-chargers-5.html#post7650416) on the "787 Batteries and Chargers" thread:

"The A320 uses its 2 main (NiCd) batteries for APU start if no external power is available. In the 1990s, when starting the APU using external power, I was able to monitor the two TR loads. Initially, they would be off-scale but, IIRC, they reappeared as the current was falling through 350 amps (each). So the peak current delivered by the TRs was in excess of 700 amps. But the main (NiCd) battery was also contributing, so this suggests a peak starter load of the order of 1000 amps."

[syseng68k]

Chris

Agree with everything in that post. I have no professional involvement
with starting issues, but some (murky?) history. There's a loosely connected
group of individuals here in the uk that like to restore and run surplus
gas turbine engines, an offshoot from the historic aviation pastime. Makes
a change from classic cars. One collector in Bristol even has a Derwent that
gets spooled up from time to time. Anyway, my effort was a Rover APU from a
Vulcan a/c, which was remounted in a frame with instruments to run at airshows
such as Bruntingthorpe. I can put up some pics later if anyone's interested,
but that particular engine was quite small, 30Kva + bleed air and 28v electric
start. In a car engine, the starter only runs for a few seconds, while a
turbine engine can take 10's of seconds to spool up, putting a high load
both on starter and battery. On initial testing, measured current was around
700amps, which ran back with increasing speed and rising back emf to
200 or so at lightup. In the Vulcan, the apu had a fairly conventional
starting panel for the time, where the motor was initially started with several
low value resistors in series to limit the current. For those who are old enough
remember trolley busses or trams, there was a tick tick ticjk noise as the tram
accelerated away, progressively shorting out the current limiting resistors.
Same for a turbine engine starter panel, where the series resistors are
progressivly shorted out as the engine spools up.

With modern kit, engines are more fficient and electronics will play a much
bigger role, but if the apu is 1.25Mw rating, ie: a much bigger engine, how do
they manage to get that spooled up within the battery rating of 325A max load
and 65C max temp ?. Quite a technical achievement, however it's done...

[EEngr]

On the 787 is via a starter/generator. That's an AC device, fed from the start battery or other source through a variable frequency inverter. So the start characteristics of this will be very different from an APU that uses a 24 Vdc starter motor.

Variable frequency drives can be programmed to limit locked rotor inrush currents, torque vs speed and other parameters. So comparing the A320 to the 787 is apples and oranges.

[syseng68k]

EEngr:

Thanks for that. Apart from improved controllability, a vfd would increase
efficiency and reduce weight over a dc solution.

One thing that struck me about the main power distribution was the almost
complete use of dc. This would suggest most of the high power rotating loads
are inverter driven. Apart from efficiency savings, there could be significant
weight gains if high frequency (ie: > 400Hz) motors could be used.

Do you have info w/regard to this ?...

[Lyman]

Main power distribution almost all DC?


That is confusing. the generated power is almost exclusively AC, and travels to EEBay fror rectifucation and DC distribution. The ECP motors are adjacent the EEBay, and the wing de ice cabling is AC to the wing?

From a cabling weight perspective alone, is it not the plan to carry distribution in AC power as much as possible?

[Machaca]

http://i337.photobucket.com/albums/n385/motidog/787ElecSys1.jpg

[TURIN]

Power FROM the gennies is 235vAC Frequency Wild.
The output TO the users (starters, hydraulic pumps, Cabin Air Compressors ) is +/-270vDC Variable frequency square wave.
To an old fashioned Airframe/Engine Tech such as myself it's still AC but Boeing insist it is DC.

[hetfield]

+/- 270Vdc in comparison with 28Vdc is strange, indeed....


But batteries wouldn't start to smoke from this....;)

[glad rag]

+/-270vDC Variable frequency square wave.

Quite clever PWM control/matching of load, used in [among others] the conversion/matching of WTG to grid loads along with grid optimisation .......

a pretty bang up to date aircraft electrical system, but how much excess capacity is left??

[syseng68k]

Turin:


Power FROM the gennies is 235vAC Frequency Wild.
The output TO the users (starters, hydraulic pumps, Cabin Air
Compressors ) is +/-270vDC Variable frequency square wave.
To an old fashioned Airframe/Engine Tech such as myself it's
still AC but Boeing insist it is DC.
Looking at the block diagram above your post, all that's in the path
betweeen ac source and 270v bus is a tru, which normally just transforms
and rectifies the ac to provide full wave rectified dc, not a square
wave.

The motor controllers are variable frequency drives, from another post,
which work by chopping (ie: square wave) dc at a much higher frequency
to synthesise a sine wave at the frequency of interest. My guess is that
is what's happening, or do you have other info ?...

[EEngr]

Typically, these take a HVDC input (+/- 270 Vdc) and chop it into three phase, pulse width modulated square waves. Motors are happy enough with square waves, so there is no real need to produce clean sine wave power like inverters feeding some avionics loads do.

While the typical aircraft electric motor has been designed to run on 400 Hz, this has been due to the past use of CSDs driving AC generators at that fixed frequency. Now, with DC distribution, that limitation has been removed. It would be possible to optimize motors and their mechanical loads for higher frequencies (and speeds). Or vary their speed to match mechanical load demands.

The other advantage of a VFD is to 'soft start' a large motor load. By modulating the pulse width and frequency, one can get higher torque out of a motor at zero or lower RPM and then ramp up the frequency as the motor accelerates. This also reduces the voltage drop that would be experienced on a common AC bus by all the other loads sharing it with a line operated motor.

[TURIN]

Chris, that diagram is VERY simplified. Eeng has it about right. The CSMCs alter the output to suit demand. EG. Engine starters. Initial output would be low frequency and as the motor speeds up the frequency gets gradually higher to suit. It can also alter the speed of the hydraulic pumps. So in stable cruise the pumps slow down until a control input is made, the CSMC gets a signal to throttle up the pumps and delivers the required output. Very clever but damn complicated. Posted from Pprune.org App for Android

[syseng68k]

Am familiar with vfd's and they have been used for industrial motor
control for decades. Also pwm, which is a standard technique for
synthesising waveforms from a dc supply.

The question was over your assertion that the 270v dc bus was square
wave, not rectified ac. Usually, individual vfd control electronics
are local to each motor, to provide independent speed and other
control functions. There's no real advantage to have a square wave
on the bus and it would take a lot of added electronics and weight
to generate that from a tru output. Assuming that it's accurate, the
system layout shown in the block diagram is pretty unambiguous.

So, where did the square wave 270v bus come from ?...

[TURIN]

Square wave is how it was explained to us. In truth it will always be rectangular.
And yes, the CSMCs are very, very heavy, large and get very hot if the liquid cooling system fails.

[syseng68k]

If the atru is handling 1Mw, then yes, it would need very extensive
cooling. Liquid cooling allows the cooled unit to be compact and
installed in areas that are not otherwise convenient for the heat
disposal.

Not being pedantic, but trying to understand the system. I still don't
have a definate answer on this 270v bus question.

Anyone else have any info on this ?...

[areobat]

Back in the dark ages (when I had a brain that worked) I used to design AC-DC-AC power conversion systems for very large wind generation systems which were by their nature variable speed/frequency devices like the gen-sets on jet turbines.

I think the +/- 270 VDC buss is rectified, but un-filtered DC, probably 3 wire, bipolar buss derived from a Wye connected gen-set/rectifier. This would have a pseudo AC appearance on a scope. The cost/weight penalty to condition this high power buss would be huge and is really not necessary for driving large motor loads. PWM VFDs are more than capable of dealing with a "dirty" input and large motors are more than happy to run on a dirty output. A bipolar input would reduce the parts count for the VFDs as well.

I think the 115 VDC buss and the 28 VDC buss are both filtered/conditioned (with 28 VDC being the most so), as they serve smaller, more sensitive loads. The cost/weight penalty would be much smaller for theses busses.

One thing that is interesting to me is that all six AC gen sets appear to be paralleled. Phasing gen sets on separate shafts can be a real pain. It would interesting to see how that is handled.

[Uncle Fred]

Good discussion going--particularly since we have some electrical engineers weighing in.

Back up to the view from FL390 but the NYT put this out this morning as to the interplay between Boeing and the FAA:

http://www.nytimes.com/2013/01/24/business/global/boeing-787-battery-was-not-overcharged-japanese-investigators-say.html?_r=0&hp=&adxnnl=1&adxnnlx=1359043905-Qjx+f/CmM84Yu4eo7N2Cpg

Worth a look.

[TURIN]

Chris,
That +/-270vdc is not a single bus supplying the CSMCs. The ATRUs (4 of them) supply various motor controllers.
The output from the motor controller varies depending on user.
I now have access to a better schematic which shows, for example the output to the starter/generator (VFSG) is actually 235vAC. My mistake, I'm not a conehead remember.
However, that AC is still variable frequency.
Hope this helps, I'm still trying to understand it myself.

[syseng68k]

areobat:


I think the +/- 270 VDC buss is rectified, but un-filtered DC, probably
3 wire, bipolar buss derived from a Wye connected gen-set/rectifier.
This would have a pseudo AC appearance on a scope. The cost/weight
penalty to condition this high power buss would be huge and is really
not necessary for driving large motor loads. PWM VFDs are more than
capable of dealing with a "dirty" input and large motors are more than
happy to run on a dirty output. A bipolar input would reduce the parts
count for the VFDs as well.
Thanks for that. From what I remember, 3 phase rectified output looks
like dc with superimposed ripple on top. As you say, it would be fine
for input to a VFD and the bipolar configuration would reduce parts
count elsewhere. Could also cancel any magnetic fields that could affect
things like magnetic compasses, assuming the +/- were tracked together
in the loom.


One thing that is interesting to me is that all six AC gen sets appear
to be paralleled. Phasing gen sets on separate shafts can be a real
pain. It would interesting to see how that is handled.
I guess initially, the shaft speed control must be pretty close. Then
when online, they would tend to lock to each other, just as with the
generators in the national grid. For each shaft, power output is varied
by by fine adjustment of fuel and generator exitation, via some smart
electronics. If you've done this stuff before, correct me if i'm wrong
there.

Wind Generators: With such low blade speeds, do they use step up gearboxes
to get the correct speed for the alternator, viscous couplings etc and how
is it connected to the grid ?. Direct connection as an induction generator,
or via an inverter ?. Off topic, sorry, but just curious...

[EEngr]

syseng68k (http://www.pprune.org/members/302789-syseng68k)

The question was over your assertion that the 270v dc bus was square wave, not rectified ac.Its rectified AC from the engine generators provided by the ATRUs (see #244). By definition, DC doesn't have a waveform, its just a flat line (ignoring some inevitable ripple, of course).