FAA Grounds 787s
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
I experienced one catastrophic electrical failure (marine) last year, involving a wiring problem.
The system was deactivated, rewired, and reactivated, the system had one short, and a loss of polarity. The heat, smoke and damage was breathtaking.
Lithium Ion......
The extent of the damage to a battery that is so well known suggests a major, and not entirely unknown, fault.
If Elemental Lithium plates out, and shorts a cell, there is a chaotic loss of polarity, as well as major discharge.
So the prominent suspect remains dendrites, causing dead short, polarity diffusion, heat, fire and smoke.
I think that is why such emphasis is placed on tomography, and chemical analysis of the remnants of the APUBATT by NTSB. These batteries burn, the record is clear. Boeing and FAA knew (know) this, and the Lithium requirements in the considerations are outdated.
Regulatory/certification, construction/monitoring, integration/mitigation, maintenance/service life....
Dendrites? Sound easy? I don't think so....
Hersman impresses, she has my confidence. LaHood and Huerta, not at all.
The system was deactivated, rewired, and reactivated, the system had one short, and a loss of polarity. The heat, smoke and damage was breathtaking.
Lithium Ion......
The extent of the damage to a battery that is so well known suggests a major, and not entirely unknown, fault.
If Elemental Lithium plates out, and shorts a cell, there is a chaotic loss of polarity, as well as major discharge.
So the prominent suspect remains dendrites, causing dead short, polarity diffusion, heat, fire and smoke.
I think that is why such emphasis is placed on tomography, and chemical analysis of the remnants of the APUBATT by NTSB. These batteries burn, the record is clear. Boeing and FAA knew (know) this, and the Lithium requirements in the considerations are outdated.
Regulatory/certification, construction/monitoring, integration/mitigation, maintenance/service life....
Dendrites? Sound easy? I don't think so....
Hersman impresses, she has my confidence. LaHood and Huerta, not at all.
Last edited by Lyman; 24th Jan 2013 at 21:54.
Join Date: Feb 2008
Location: UK
Posts: 94
Likes: 0
Received 0 Likes
on
0 Posts
it would seem the FAA has the `devils alternative` in regards to the 787 - whatever choice they now make , someone will get rather upset about it... they ground it till its fixed , airlines come down on boeing , possibly cancel orders or even go bankrupt (look at LOT)
if the FAA allow it to fly and 1 catches fire in the air - lots of legal action against both boeing and the FAA , and consideration that the FAA is ` unfit for purpose`.
just some rambling thoughts that is all.
if the FAA allow it to fly and 1 catches fire in the air - lots of legal action against both boeing and the FAA , and consideration that the FAA is ` unfit for purpose`.
just some rambling thoughts that is all.
Join Date: Nov 2006
Location: Scotland
Posts: 56
Likes: 0
Received 0 Likes
on
0 Posts
Qoute from the NY Times:
What are the financial implications for Boeing and its customers should the above prediction prove to be correct?
“It means that the 787 is going to be grounded for an indefinite period — whether that’s two months, four months or six months, the 787 is not going to get back in the air soon,” said Scott Hamilton, managing director of the Leeham Company, an aviation consulting firm in Issaquah, Wash.
Join Date: Jan 2013
Location: UK
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Hello
I am new to posting anything on pprune, but I have actively read pprune forum threads for several years.
I am an engineer but not in aviation. At one stage in my career I was an EMC engineer (electromagnetic compatibility), and I spent some time actively trying to break military comms systems as well as studying their EMC behaviour.
I have no doubt that aviation EMC requirements are stringent before anything gets bolted in to an aircraft and that is right and proper.
I would however like to mention that if software and hardware upgrades are made to any system then the performance of a system may change and unintended electrical signals could be generated. EMC testing is intended to evaluate systems to make sure nothing unintended takes place that is detrimental to the correct operation of a system. If there is a problem then EMC control measures are employed which might be filters, shielding material etc. If it is a big problem then redesign might be required.
The above is a general statement but it is clear that a battery fire when an aircraft is in flight is a big problem. On the 787 the battery charging system will no doubt be studied to see if any changes have altered it's behaviour. The real issue is the extent of the 'system' boundary in EMC terms. This might be the whole aircraft or just a bit of it.
I'll be interested in the outcome of the 787 investigation.
I am new to posting anything on pprune, but I have actively read pprune forum threads for several years.
I am an engineer but not in aviation. At one stage in my career I was an EMC engineer (electromagnetic compatibility), and I spent some time actively trying to break military comms systems as well as studying their EMC behaviour.
I have no doubt that aviation EMC requirements are stringent before anything gets bolted in to an aircraft and that is right and proper.
I would however like to mention that if software and hardware upgrades are made to any system then the performance of a system may change and unintended electrical signals could be generated. EMC testing is intended to evaluate systems to make sure nothing unintended takes place that is detrimental to the correct operation of a system. If there is a problem then EMC control measures are employed which might be filters, shielding material etc. If it is a big problem then redesign might be required.
The above is a general statement but it is clear that a battery fire when an aircraft is in flight is a big problem. On the 787 the battery charging system will no doubt be studied to see if any changes have altered it's behaviour. The real issue is the extent of the 'system' boundary in EMC terms. This might be the whole aircraft or just a bit of it.
I'll be interested in the outcome of the 787 investigation.
Last edited by old dawg; 25th Jan 2013 at 16:21.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
EMC/EMI
Hi, old dawg
787 EMI/EMC certainly were a big issue in the design. ("non metal" body and extensive use of new electric solutions)
Welcome to the Thread(s).
A lot of questions to you...
(I was at Phoenix area for a seminar in this complex subject many years ago.)
787 EMI/EMC certainly were a big issue in the design. ("non metal" body and extensive use of new electric solutions)
Welcome to the Thread(s).
A lot of questions to you...
(I was at Phoenix area for a seminar in this complex subject many years ago.)
Last edited by RR_NDB; 25th Jan 2013 at 13:06.
Join Date: Dec 2001
Location: England
Posts: 1,389
Likes: 0
Received 0 Likes
on
0 Posts
If that NY Times article is correct....
Here is a comparative study of different types of Lithium-Ion Batteries dated 2010 that mentions lithium cobalt oxide batteries...
http://www-scf.usc.edu/~rzhao/LFP_study.pdf
My bold.
Another comparison of different Lithuim cell types
Types of Lithium-ion Batteries
Here is a comparative study of different types of Lithium-Ion Batteries dated 2010 that mentions lithium cobalt oxide batteries...
http://www-scf.usc.edu/~rzhao/LFP_study.pdf
Lithium Cobalt Oxide Manufacturing
Current manufacturing of lithium cobalt oxide batteries is highly automated. This is because speed and quality is desired, and because some of the chemicals used are either toxic or known carcinogens. The process starts by creating a cathode paste (LiCoO2+binders). This paste is thinly spread onto both sides of a sheet of aluminum foil. Similarly, an anode paste (graphite) is created and spread onto both sides of a sheet of copper foil. Next, a separator (polymer film) is sandwiched between the anode and cathode sheets. This sheet is then wound up and placed into a cylindrical housing. Then, the cell is filled with an electrolyte (lithium salt) and the cell contacts are connected. Finally, the cell is sealed. Usually, a circuit is attached to each cell to control charging and discharging. These circuits prevent discharge past a set voltage to prevent being discharged too deeply.
snip
Though lithium cobalt batteries are equipped with safety electronic devices
along with the safety shell on its body, still they are not fully used in cars and other vehicles because of the safety concerns as they can catch fire or explode due to the extreme heat, overcharging or thermal runway.
Current manufacturing of lithium cobalt oxide batteries is highly automated. This is because speed and quality is desired, and because some of the chemicals used are either toxic or known carcinogens. The process starts by creating a cathode paste (LiCoO2+binders). This paste is thinly spread onto both sides of a sheet of aluminum foil. Similarly, an anode paste (graphite) is created and spread onto both sides of a sheet of copper foil. Next, a separator (polymer film) is sandwiched between the anode and cathode sheets. This sheet is then wound up and placed into a cylindrical housing. Then, the cell is filled with an electrolyte (lithium salt) and the cell contacts are connected. Finally, the cell is sealed. Usually, a circuit is attached to each cell to control charging and discharging. These circuits prevent discharge past a set voltage to prevent being discharged too deeply.
snip
Though lithium cobalt batteries are equipped with safety electronic devices
along with the safety shell on its body, still they are not fully used in cars and other vehicles because of the safety concerns as they can catch fire or explode due to the extreme heat, overcharging or thermal runway.
Another comparison of different Lithuim cell types
Types of Lithium-ion Batteries
Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2)
The Lithium Nickel Cobalt Aluminum Oxide battery, or NCA, is less commonly used in the consumer market; however, high specific energy and power densities, as well as a long life span, get the attention of the automotive industry. Less flattering are safety and cost.
Figure 8: Snapshot of NCA
High energy and power densities, as well as good life span, make the NCA
a candidate for EV powertrains. High cost and marginal safety are negatives.
The Lithium Nickel Cobalt Aluminum Oxide battery, or NCA, is less commonly used in the consumer market; however, high specific energy and power densities, as well as a long life span, get the attention of the automotive industry. Less flattering are safety and cost.
Figure 8: Snapshot of NCA
High energy and power densities, as well as good life span, make the NCA
a candidate for EV powertrains. High cost and marginal safety are negatives.
Last edited by cwatters; 25th Jan 2013 at 13:51.
Join Date: Jun 2010
Location: On the ground too often
Age: 49
Posts: 127
Likes: 0
Received 0 Likes
on
0 Posts
One of the battery spec sheets mentioned in this thread mentioned a maximum operating temperature of 50C. That does not seem right - surely on a hot day the temperature in the EE bay is likely to exceed that.
Join Date: Jan 2008
Location: Denmark
Age: 79
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
Temp. limitations..
The 787 battery is equipped with 8 cells of type LVP65.
Look at this link from an earlier post:
http://www.s399157097.onlinehome.us/...s/LVP10-65.pdf
Look at this link from an earlier post:
http://www.s399157097.onlinehome.us/...s/LVP10-65.pdf
Last edited by grebllaw123d; 25th Jan 2013 at 14:32.
Join Date: Dec 2001
Location: England
Posts: 1,389
Likes: 0
Received 0 Likes
on
0 Posts
http://gsyuasa-lp.com/SpecSheets/LVP65-MSDS.pdf
"Do not expose to high temperatures (50C, 122F)"
Sorry if that's a repost.
"Do not expose to high temperatures (50C, 122F)"
Sorry if that's a repost.
Last edited by cwatters; 25th Jan 2013 at 14:48.
Join Date: Oct 2003
Location: Canada
Posts: 1,852
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jun 2010
Location: On the ground too often
Age: 49
Posts: 127
Likes: 0
Received 0 Likes
on
0 Posts
During any of the press conferences held so far or in any of the statements issued, has the possibility of an act of sabotage been referred to or ruled out?
Given the amount of electronics this thing has, all of it presumably controlled by field upgrade-able software, the possibility of some kind of malware being introduced cannot be ruled out.
I wonder how the aircraft systems are hardened against such threats, though I don't expect this to be information readily shared by the manufacturer or the authorities ;-)
Given the amount of electronics this thing has, all of it presumably controlled by field upgrade-able software, the possibility of some kind of malware being introduced cannot be ruled out.
I wonder how the aircraft systems are hardened against such threats, though I don't expect this to be information readily shared by the manufacturer or the authorities ;-)
Join Date: Jan 2013
Location: UK
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Hi RR_NDB
Thanks for the comment.
I've no doubt that the EMI/EMC design of the 787 was extensive and there will be some interesting technology in there.
I anticipate we'll all learn some more about it this year, although I also note other threads looking in depth at this particular battery design, automated manufacture, and operation.
Thanks for the comment.
I've no doubt that the EMI/EMC design of the 787 was extensive and there will be some interesting technology in there.
I anticipate we'll all learn some more about it this year, although I also note other threads looking in depth at this particular battery design, automated manufacture, and operation.
Join Date: Jan 2013
Location: UK
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Reference posts on the battery temperatures, and a couple of questions.
It would seem that 50 deg. C is the maximun storage temperature which I interpret to be sitting in the store and not wired up.
The Operative Ambient Temperature Range is quoted as -18 deg C through to 65 deg. C
I don't know the answer to the following questions but someone might?
If the temperature in the battery system within the EE bay is towards the end of the hot end of the scale, and the charging system is active, what happens then? My understanding is that the charging system is always active but the extent of charging varies.
What are the factors that govern the charging system?
i.e. Are there particular times when there has been a heavy electrical load on the battery and subsequently the charging system is operating at a peak rate. Do any of these time periods coincide with reported battery incidents?
It would seem that 50 deg. C is the maximun storage temperature which I interpret to be sitting in the store and not wired up.
The Operative Ambient Temperature Range is quoted as -18 deg C through to 65 deg. C
I don't know the answer to the following questions but someone might?
If the temperature in the battery system within the EE bay is towards the end of the hot end of the scale, and the charging system is active, what happens then? My understanding is that the charging system is always active but the extent of charging varies.
What are the factors that govern the charging system?
i.e. Are there particular times when there has been a heavy electrical load on the battery and subsequently the charging system is operating at a peak rate. Do any of these time periods coincide with reported battery incidents?
Join Date: May 2012
Location: SE England
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
There is quite a long piece on this in The Register. Apologies if this has been posted previously.
A lesson was learned decades ago at the time of the grounding of the DC10 following the AA accident at Ohare.
Never ground unless you know the criteria necessary for ungrounding.
This is still a blank to most people at this time
I would bet that 99% of people who read these pages and all the publications linked herein believe that fixing the battery will take care of it.
The problem is that all you can fix is what you know is wrong. That still leaves any aircraft exposed to a yet to be learned unknown cause occuring some day to another battery resulting in similar circumstances. In all this the FAA must have accepted assurances of mitigation should the battery fail. Nowhere have I seen the NTSB findings of these facts against the certification standards set forth in the Special Condition.
Now we even have congress in the act of reviewing something ? Just what standards are they reviewing against?
If there would be some simple finding of a standard that wasn't met then the timimg to fix it and revoke the grounding would be known. If it is a new realization that the standards are not good enough then this problem grows immensely beyond just a single aircraft model currently being grounded.
Never ground unless you know the criteria necessary for ungrounding.
This is still a blank to most people at this time
I would bet that 99% of people who read these pages and all the publications linked herein believe that fixing the battery will take care of it.
The problem is that all you can fix is what you know is wrong. That still leaves any aircraft exposed to a yet to be learned unknown cause occuring some day to another battery resulting in similar circumstances. In all this the FAA must have accepted assurances of mitigation should the battery fail. Nowhere have I seen the NTSB findings of these facts against the certification standards set forth in the Special Condition.
Now we even have congress in the act of reviewing something ? Just what standards are they reviewing against?
If there would be some simple finding of a standard that wasn't met then the timimg to fix it and revoke the grounding would be known. If it is a new realization that the standards are not good enough then this problem grows immensely beyond just a single aircraft model currently being grounded.
Join Date: Mar 2010
Location: South Korea
Age: 62
Posts: 115
Likes: 0
Received 0 Likes
on
0 Posts
Good point lomapaseo. A few pages back we heard some politician spouting off that he will have to be 1000% sure the 787 is safe before it goes back into service. It seems this has become a vague criteria for ungrounding. Everyone knows 1000% safe is imposible, however 100% safe is also not posible. Unfotunatly nothing is 100% safe. We can probably get to a point where it can be 99.999% safe but with all the hysteria I dont think any politician or FAA official will be brave enough to make that call. Some poor engineer low down in the chain will probably have to make that decision. Just like pilots become the scape goats for any SW assisted flying errors, engineers become the scape goats for any political/media assisted hardware issues .
From what I have read here about Li batteries there seems to be only 2 ways that would come close to meeting the ungrounding critera:
1. Fit a Ni Cad battery.
2. Provide a battery casing which will contain any fire that may happen to occur if the tripple redundant battery managment system fails.
From what I have read here about Li batteries there seems to be only 2 ways that would come close to meeting the ungrounding critera:
1. Fit a Ni Cad battery.
2. Provide a battery casing which will contain any fire that may happen to occur if the tripple redundant battery managment system fails.
Last edited by Cool Guys; 26th Jan 2013 at 02:08. Reason: spelling
Agree with cool guys option 2. Paraphrasing the special conditions listed at #111; the batteries shall not burn except perhaps once or twice in life of aircraft type. If batteries do burn fire must be safely contained and any emission vented overboard. So far the plane has failed on both counts
If batteries do burn fire must be safely contained and any emission vented overboard. So far the plane has failed on both counts
Just take black boxes for instance. They may look burned all to hell on the ouside but the inside is still readable. The batteries are a mirror image of this. It's the harm they cause that is the measure.
As for venting overboard, that is for under-flight-conditions. It sure seemed to vent, but how much vs how much was it certified for?
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
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.
............unquote FAA
1. If the authority knew exactly what was wrong, the issue never would have come up.
2. Likewise, the grounding would not have happened, so,
3. It is not possible to delineate the method of ungrounding (specifIically), prior to grounding
It is vague, not because of some systemic flaw in the wording of the AD, but because there is insufficient data to plot a solution. The onus is on the airframer, not the FAA, nor the manager of ACO.
Boeing is not entirely wrong in claiming the grounding was not necessary, from the standpoint that the special regs. were "met". They were completely in the weeds when their people officially petitioned the FAA to "tell us what we need to do....." the AD explained that in its text.......
ANA could have continued its flight, and the system may have met the parameters, or there may have been a catastrophic blaze in the forward EE Bay, and the a/c might have been lost.
I think the FAA got it right.....
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.
............unquote FAA
1. If the authority knew exactly what was wrong, the issue never would have come up.
2. Likewise, the grounding would not have happened, so,
3. It is not possible to delineate the method of ungrounding (specifIically), prior to grounding
It is vague, not because of some systemic flaw in the wording of the AD, but because there is insufficient data to plot a solution. The onus is on the airframer, not the FAA, nor the manager of ACO.
Boeing is not entirely wrong in claiming the grounding was not necessary, from the standpoint that the special regs. were "met". They were completely in the weeds when their people officially petitioned the FAA to "tell us what we need to do....." the AD explained that in its text.......
ANA could have continued its flight, and the system may have met the parameters, or there may have been a catastrophic blaze in the forward EE Bay, and the a/c might have been lost.
I think the FAA got it right.....
Last edited by Lyman; 26th Jan 2013 at 05:27.