sankaps From United States of America, joined Jan 2008, 2237 posts, RR: 2 Reply 3, posted (10 months 1 week 5 days 22 hours ago) and read 34064 times:
Some of the comments in the previous thread before it was locked are unbelievable!
"When has the FAA or NTSB ever been proactive?"
Well -- they are being proactive right now! Grounding the battery system and thereby the aircraft until they can be sure the root cause issues are identified and fied, before something disastrous occurs.
"It is all just politics".
In other words, Obama is to blame. Right. Boeing is based primarily in two states which helped Obama get re-elected -- Washington and Illinois. But Obama wants to screw them?
Guys -- we need to take a step back, read the NTSB statement, and just calm down and accept that the grounding wasa prudent, proactive step given the two incidents just 9 days apart, involving a new system and technology that had only recently been certified but hadn't really stood the test of time and extensive usage yet. That is exactly the right thing they did. And I love Boeing and its products as much as anyone else.
Braybuddy From Brazil, joined Aug 2004, 5476 posts, RR: 34 Reply 4, posted (10 months 1 week 5 days 22 hours ago) and read 33978 times:
Quoting RottenRay (Reply 1): And, frankly, positing a battery meltdown followed by severe turbulence is something best left to Hollywood.
Murphy's Law. And aviation probably supplies one of the best (or worst) examples of same with the KLM/Pan Am collision at Tenerife in 1977: a bomb had exploded earlier at Las Palmas and the aircraft were diverted to Tenerife. Then you had the fog, the absence of ground radar, the misheard ATC instructions and the blocked-off taxiway. Had one of those events not occurred there would have been no collision.
DocLightning From United States of America, joined Nov 2005, 17900 posts, RR: 57 Reply 6, posted (10 months 1 week 5 days 21 hours ago) and read 33910 times:
Quoting RottenRay (Reply 1): Doc, you've taken blood samples - they're thinner than the electrolyte goo you're talking about. This stuff is not magically sticky in a picture and later capable of gymnastics in turbulence.
Do you know the consistency of this material over all temperature ranges? If so, how do you know? Also, blood is not terribly viscous and it gets all over everything. Are you saying this stuff is like blood?
Quoting Braybuddy (Reply 4): Murphy's Law. And aviation probably supplies one of the best (or worst) examples of same with the KLM/Pan Am collision at Tenerife in 1977: a bomb had exploded earlier at Las Palmas and the aircraft were diverted to Tenerife
Yup. Just about every major aviation disaster in history has occurred because of an unlikely chain of events all coinciding (leaving aside intentional sabotage).
Quoting liftsifter (Reply 2): Has John Leahy made a comment at all about the grounding and how it may affect the A350 program?
Even Mr. Leahy is smart enough to know to keep his mouth shut.
Anyway, it is far too early in the investigation to determine whether Airbus will actually need to make changes to the design of the A350, but you can rest assured that some people at TLS are watching these proceedings with great interest. And you can rest assured that none of them are gloating about it, because they know that if they are not careful, their new A350 might be next.
AirlineCritic From Finland, joined Mar 2009, 667 posts, RR: 1 Reply 7, posted (10 months 1 week 5 days 21 hours ago) and read 33789 times:
First, I'd like to thank once again CM, tdscanuck, rcair1 and others for informative posts. I would also like to welcome b2319 to a.net, your post certainly got me thinking about containment and relief valves as far more complex beasts than I had thought before. Thanks.
Second, I have a plea that this thread would not descent into political speculation or accusing NSTB or FAA of misbehaviour. They are one of the most respected organizations in the world in this area, and it would be, IMO, unthinkable that they would be misbehaving any way. They are the true experts. They have all the information that we do not have here in a.net. Exact state of containment systems and other equipment in the bays, for instance. If they say they need to ground the plane, they have a reason to do so. Even if it is just not being certain that no other damage occurs in some (perhaps obscure) other scenario than the one played out in the two incidents. Let them do their work.
And now to the topic of my post. I'm trying to understand different scenarios for lifting the grounding.
Scenario 1: Operational changes
ETOPS limitations, in-the-ground inspections, lower thresholds for diversion, perhaps some battery usage/charging changes in flight. If these procedures would be sufficient, the grounding could have been over in days. I can only conclude that either these procedures are insufficient, or that the NTSB does not understand the events well enough to allow the grounding to be lifted yet. Obviously, the root causes need to be found.
Scenario 2: Battery manufacturing quality
A problem is discovered in battery batches and/or manufacturing process, the issue is fixed and the planes start to fly again. If this was the solution, we could see the end of the grounding in weeks, particularly if defective batteries can be found by testing.
I think this is somewhat unlikely as the only fix, as I suspect the NTSB wants to understand how well the containment works in the eventual cases that even with high-quality batteries, there can be a thermal runway in one of them some day.
Scenario 3: Battery charging systems
Or perhaps these systems misbehaved in some way. A fix to them would be an engineering (and re-certification) process. In the best case this would take a few months, in the worst case more. I remember that the battery system manufacturer took seven years to design the current batteries. In my opinion, that is a very long time, and changing a component should be possible in months.
Charging system issues is a possible root cause, but it is looking a bit unlikely perhaps, if the early reports are true that the batteries were not overcharged. That being said, if the per-cell history of events burned down with the batteries, how would we know?
Scenario 4: Containment structures
It is probably not sufficient to fix the containment structures, but if a battery manufacturing fault is found, fixed, and the containment is enhanced to make the NTSB/FAA confident that it works in all cases, then the plane cloud clearly fly.
It is difficult to estimate how long this would take. A steel plate "shower curtain" would be very easy to add. Certification, analysis that it works in all cases would probably take longer. I'd say months.
A more significant modification, such as fluid venting out of the aircraft or even enlarging or moving the battery containment structure could take much longer. Half a year for venting out, years for moving the structure or making the EE bay larger to fit the new containment structure. FWIW, I think the shower curtain is probably going to be sufficient.
Scenario 5: Electrical system
Or maybe there is some issue with the electrical system that is causing trouble for the batteries. If this is the case, it would be very difficult and time-consuming to understand and fix the issues. But as an engineer, I find it difficult to believe this to be the case. Surely the design has voltage and current regulators that isolate the quality of the aircraft electricity from the quality of the electricity fed to the batteries.
But if they need to do something with the electrical system, it could take years. Adding a more high-quality regulation circuitry could be easy, however, maybe only months.
I think the issues are somewhere in categories 2 through 4. If a battery or charging system fault can be identified and a slightly enhanced containment put into place, the plane should fly in 4-6 months, if not sooner, at least as a temporary measure for current frames. And a more intelligent new containment adopted for future frames.
But it is also possible that once the events are understood, the current containment system is deemed adequate (as tdscanuck and CM believed early on in this thread). Then the critical time factor is understanding why the batteries failed, and I'd predict that to take some number of months anyway.
In the other extreme, it is also possible that the containment system needs a significant change. If no intermediate solution can be found, this could drag on for over a year. (Interestingly, according to Wikipedia, A350 should enter service mid 2014. If the worst comes to worst, we could see the 350 fly commercially before the 787 is back in the air. But I do not believe this to happen.)
Finally, I should add that none of this is rocket science. Batteries and charging systems are well understood. And the energy levels for containment are still... small, when you consider the size and energy content of the device. It is some number of times bigger than a car battery, not a nuclear bomb. Boeing engineers know how to enhance it, if it needs enhancing.
sweair From Sweden, joined Nov 2011, 1755 posts, RR: 0 Reply 8, posted (10 months 1 week 5 days 20 hours ago) and read 33666 times:
Just maybe we will have to accept that lion batteries will catch fire, on any airplane that uses them. It will be up to the containment to be able to handle any fire. Or just ban the use of lion in air craft all together. Someone needs to develop a JET-A fueled fuel cell quickly..
seahawk From Germany, joined May 2005, 314 posts, RR: 0 Reply 9, posted (10 months 1 week 5 days 17 hours ago) and read 32257 times:
Looking at the Tesla Roadster electric car for example, I find it interesting that the individual cells are so small in their design, yet they still use an active cooling and heating system to control the individual battery packs. Even the space between each cell seems much larger in relation to the cell size, than in the Boeing solution:
CALTECH From Poland, joined May 2007, 1785 posts, RR: 25 Reply 10, posted (10 months 1 week 5 days 15 hours ago) and read 31312 times:
Quoting B2319 (Reply 260):
I joined a.net because, in part 3 of this thread, someone said the electrolyte "wasn't a liquid, it was a paste". What an absolutely ill-informed post if there ever was one. Anyway, the physical properties of the material to be vented will play a vital part of the safe handling of the release. Some examples of physical properties are density, viscosity, possibly solids content and so on.
How totally incorrect and ill informed the above post is. With out revealing too much information, the paste statement was relayed to us by the manufacturers, you can figure that out for yourself if you'd like, not just a statement put out there by a anet member. But if someone knows more than Boeing and Thales, be my guest, go ahead and post your information. This is why folks are bailing on this thread.
b2319 From China, joined Jan 2013, 145 posts, RR: 0 Reply 11, posted (10 months 1 week 5 days 15 hours ago) and read 31013 times:
Quoting CALTECH (Reply 11): How totally incorrect and ill informed the above post is. With out revealing too much information, the paste statement was relayed to us by the manufacturers, you can figure that out for yourself if you'd like, not just a statement put out there by a anet member. But if someone knows more than Boeing and Thales, be my guest, go ahead and post your information. This is why folks are bailing on this thread.
I'm bailing too. You can pick up a copy of any physical chemistry textbook and try and understand my point. (I studied using Atkins, though there were others). The scientific terms for the three phases are solids, liquids and gases. Sometimes vapours and gases are interchangable, in some contexts.
From memory, the post was a claim that a paste was somewhat not a liquid or didn't posses a liquid component. In any case, there weren't any links supplied for me to consider the original source.
If you've the ability to determine that my criticism of scientifically-incorrect statements, independent of the source, albeit non-referenced, originated with yourself, well, that's impressive.
My GBP 15.40 experiment with a.net, has been exactly that- an experiment.
I'm bailing from both the thread, and the forum, and have no plans to contribute, nor lurk, again.
art From Lebanon, joined Feb 2005, 3148 posts, RR: 0 Reply 12, posted (10 months 1 week 5 days 15 hours ago) and read 30928 times:
Assuming (a) the cause of the overheating problem were identified (b) a fix had been designed, built and tested to a level where it would be acceptable to FAA (c) a fix for the containment issue had been designed, built and tested to a level where it would be acceptable to FAA, how long would it take the FAA to certify the aircraft as being safe again?
Once the aircraft were certified as safe, how long would it take to put the revised components into production and start installing them on the 787's delivered so far?
Would it be a few weeks between a solution to the problems being found and installation starting? Several (2/3/4) months?
Anyone have any idea how long the aicraft delivered will remain on the ground after a remedy is devised and approved?
CALTECH From Poland, joined May 2007, 1785 posts, RR: 25 Reply 13, posted (10 months 1 week 5 days 14 hours ago) and read 30485 times:
Quoting b2319 (Reply 12): I'm bailing too. You can pick up a copy of any physical chemistry textbook and try and understand my point. (I studied using Atkins, though there were others). The scientific terms for the three phases are solids, liquids and gases. Sometimes vapours and gases are interchangable, in some contexts.
So what you know is learned from a book. Interesting.
Quoting b2319 (Reply 12): From memory, the post was a claim that a paste was somewhat not a liquid or didn't posses a liquid component. In any case, there weren't any links supplied for me to consider the original source.
The memory point is incorrect and way off the mark. No where was it stated that it was not a liquid or didn't posess a liquid component, that has been inserted from a fallible memory. There were no links, it is what has been said by those who work with the batteries. Boeing is where the info comes from. Again, if you have info that shows Boeing has it wrong, please by all means please post it.
Quoting b2319 (Reply 12): If you've the ability to determine that my criticism of scientifically-incorrect statements, independent of the source, albeit non-referenced, originated with yourself, well, that's impressive.
Think It was my post that first brought up that the electrolyte is more of a paste than a liquid such as those found in lead acid batteries. A incorrect post #260 was made in the last thread #5, that was impressive, ' I joined a.net because, in part 3 of this thread, someone said the electrolyte "wasn't a liquid, it was a paste". What an absolutely ill-informed post if there ever was one. '
So excuse me if there is a issue with your "absolutely ill-informed post."
A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?
flyglobal From Germany, joined Mar 2008, 538 posts, RR: 3 Reply 16, posted (10 months 1 week 5 days 13 hours ago) and read 29728 times:
Quoting seahawk (Reply 10): Looking at the Tesla Roadster electric car for example, I find it interesting that the individual cells are so small in their design, yet they still use an active cooling and heating system to control the individual battery packs. Even the space between each cell seems much larger in relation to the cell size, than in the Boeing solution:
And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location).
This requires heating devices and also ventilation and cooling ducts for the batteries.
For Air Planes the design requirements are different - less environmental temperature span at the battery location.
In one of the earlier threads I mentioned that I know that for Chevy it took rather 1/3rd effort for the Cell development and selection its self, 1/3rd for the packaging of the cells and 1/3rd for Power electrics and especially micro controls, software and data calibration.
For Automotive all is about warranty offer. A Chevy, a Toyota and probably as well the Tesla will only charge and discharge between 20 and 80% of capacity, depending on environment etc., charge and discharge is controlled depending on various parameters. Remember the Chevy Volt which caught fire about 2 weeks after a crash test.
A containment and updated procedures after accuidents have been the results.
My gut feel is that we will see something like this as a solution for the Dreamliner:
1) A specific fire and smoke monitoring system, as well as additional temp sensors (probably incl. a camera will be installed)
2) Software, and data cal regarding charging and discharging strategies will be updated in direction of 'more conservative)
3) A regular Battery exchange cycle will be established (like a bottle deposit and return system in Europe)
4) Boeing in the meantime will work on an update of the battery system with a different less risky battery system and get this extensively tested and certified (maybe in 2 years from now) and also will develop a PIP for existing planes for that.
This is what my crystal ball sees coming down the road (air).
DocLightning From United States of America, joined Nov 2005, 17900 posts, RR: 57 Reply 17, posted (10 months 1 week 5 days 12 hours ago) and read 29261 times:
Quoting sweair (Reply 19):
A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?
1) They are still a new and unproven technology.
2) They run at 400-800°C, which brings up a whole array of thermal containment issues for certification.
3) They would have to crack the fuel for hydrogen and then combine it with oxygen, leaving us to do what with the carbon?
I wont have to be hydrogen, it can be jet fuel or methanol or any other hydrocarbon source for a fuel cell. Airbus and Boeing are both researching fuel cells. One day we could do away with the apu and batteries. Its sadly no option on the 787.
But to be an optimist, maybe this incident will lead to greater efforts to make the fuel cell a viable option for commercial aviation in the future.
DocLightning From United States of America, joined Nov 2005, 17900 posts, RR: 57 Reply 20, posted (10 months 1 week 5 days 10 hours ago) and read 28043 times:
Quoting LN-KGL (Reply 21): Plasma and hydrogen on a plane to me says: This is even more dangerous than Lithium-ion battery - dare I mention STS-51 Challenger.
I think fuel cells on planes are an inevitability. I just am very doubtful that it will be one of the earlier applications. I think we'll see vast batteries of fuel cells powering ships before one flies aboard an airliner.
sankaps From United States of America, joined Jan 2008, 2237 posts, RR: 2 Reply 23, posted (10 months 1 week 5 days 10 hours ago) and read 27491 times:
Quoting PC12Fan (Reply 24): Like they did after two events that could have been catastrophic?? No, the FAA acts as they always have - reactive.
Well, if that is your definition of reactive, then no new airplane or technology would ever fly. There is a "tipping point" at which one must act. Waiting too long would be reactive. Acting too early would just kill all innovation. Acting at the tipping point, before something calamitous happens, is prudent and proactive (in that they don't wait for an actual crash before they act).
pliersinsight From United States of America, joined May 2008, 478 posts, RR: 0 Reply 24, posted (10 months 1 week 5 days 9 hours ago) and read 27435 times:
Quting flyglobal: "And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location)."
Are you taking battery compartment temps or air temp. I'm not so sure the air temperature reaches 100C (212F) in Death Valley. I've never been to India.....
25 tdscanuck: Fortunately for all of us, airplane's aren't designed to Murphy's Law...otherwise they'd never fly. Murphy's Law does get applied to individual compo
26 abba: I think Airbus has (or is in the process) as well - If my memory serves me well, it was to substitute the APU.
27 alfablue: Another comment which barely reflects facts or knowledge. The 787 is (or was) ETOPS certified and those Transatlantic tracks are not fixed. They chan
28 sweair: http://www.technologyreview.com/news...693/fuel-cells-take-to-the-runway/ http://oilprice.com/Latest-Energy-Ne...en-Fuel-Cell-Powered-Aircraft.html Yo
29 tdscanuck: The comment I was replying to specifically referenced severe turbulence. I didn't repeat "severe" because I was typing quickly (shame on me) and was
30 thunderboltdrgn: Actually it did happened two weeks ago when a commuter train crashed into a house. Caused by a chain of events/factors so unlikely that they together
31 PHX787: http://www.japantoday.com/category/n...l-unable-to-find-cause-of-787-fire This is nuts. Wouldn't they be better off with a replacement source of elect
32 Kaiarahi: May I inject a small dose of reality. The probability of a thermal runaway, coupled with severe turbulence that somehow throws a paste electrolyte in
33 AeroWesty: Which stranded pax? Anyone disrupted in the first couple of days were long ago reaccommodated, and those on flights continuing to be cancelled are be
34 packsonflight: Come on, you know better. Every certification requirement, and that includes the special Li ion certification requirement, is issued for the whole ce
35 cornutt: Hmm... I wonder if they have a concern about the external venting. Were that to become blocked early in a battery event, say by melted material, coul
36 tdscanuck: Yes, for those that are stranded. Are there any left? Generally not. Even if that were the policy (and it's not), DOT has zero jurisdiction on what h
37 vivekman2006: OMG No! Nowhere on this planet does the air temperature reach 100C (212F) Not even close! 100C is the temperature at which water boils and is absolut
38 lightsaber: Sadly, I think that is likely. At least for a bit. Besides otherwise mentioned limitations, fuel cells are heavy for the power delivered, have a slow
39 nycdave: Have been fascinated and (sometimes) enlightened by these threads. Just hoping that in this latest iteration we can at least avoid the "it's a politic
40 KELPkid: I just hope that when all is said and done, if the FAA's calls of the sky falling proves to be baseless, then someone makes those heads go rolling
41 tdscanuck: That's certainly a good option...it would be consistent with all the FAA/NTSB comments I can think of so far and explain their concerns. Without seei
42 packsonflight: As I understand this, the special condition say that battery fire should contained and not pose a danger to other system, and this goes for the whole
43 beau222: I tried reading through the entire topic from 1-6 and did not see this questions posted. Does the 748 series use the same type of battery or batteries
44 ComeAndGo: Not in nature but in a Sauna you can go up to 120 deg C. Humidity is zero, though. . . . and I've been in 135F in Palm Springs
45 Aesma: You quote a post that you have not understood at all, apparently. You just made me think of something. You're talking about the venting of the batter
46 cornutt: Interesting point. How much smoke would be generated, and how toxic would it be? Although if the outflow valve was completely blocked, I think the wh
47 JoeCanuck: The FAA approved the containment...and for the most part, the containment did it's job; it prevented the spread of fire, significant damage from fire
48 rwessel: If you had H2/O2 powered fuel cells, you'd need enough power to open the valves to the tanks, assuming the tanks were pressurized. You'd also need so
49 AngMoh: Automotive specification for max temperature for components: Cabin mounted components: max operating temp 85 deg C Components mounted in engine bay:
50 Unflug: I don't think that air temperature is relevant in this case, we are talking about limits for car batteries. I am quite sure that the inside of a blac
51 seahawk: Well, I would say the containment worked reasonably in the first incident, but failed in the second. Flammable liquids (or paste) must not escape the
52 flyglobal: To make thinks clear: we talk about a car which stays in the sun in 45°C for lets say 2-3 hs. It heats up quickly above the outside temperature. At
53 rotating14: I was watching the news ticker and saw something close to the link below. Looks like the investigation is shifting from the battery itself and now to
54 XT6Wagon: To me the FAA has been reasonable. The grounding while largely fueled by Media Frenzy, does make cautionary sense until they get a handle on the comm
55 faro: Some new developments from Reuters: http://www.reuters.com/article/2013/...mliner-japan-idUSBRE90R05C20130128 Difficult to see whether this will have
56 seahawk: Please read my post correctly. I said flammable liquids, this does not mean 100% containment. I am fully aware that gases must be able to escape in a
57 RickNRoll: Not if you can provide sufficient expansion for the solids, and an escape valve externally for the gases. The existing container was what you have de
58 PITingres: XT6Wagon's statement stands correct. There is no criteria for containment of liquids, flammable or not. The only criterion that matters is that the l
59 7BOEING7: The forward overboard vent valve while not as large as the aft outflow valve is still large enough that blocking it would be difficult and is not in
60 InsideMan: don't know if this was posted earlier, interesting article.... http://www.huffingtonpost.com/2013/0...ive-japan-eased-saf_n_2564630.html
61 Kaiarahi: Which does make me wonder how they'll react when a consumer device lets go in the cabin with serious damage. Of the 132 incidents documented so far b
62 Stitch: No. I's probably NiCad (747s before the 747-400 use lead acid).
63 mham001: I don't know about others but these batteries only get hot under heavy discharge/charge. The 787 batts don't see that much use by design. I do think
64 PITingres: Well, maybe. Trouble is that as soon as you take the management circuitry out of the box you have cabling and connectors to worry about, and they fai
65 par13del: Article on the BBC, now what. http://www.bbc.co.uk/news/business-21230940
66 rolfen: 7 years to design the battery and they still couldn't get it right?
67 sankaps: Excerpt from the Wall Street Journal today: "Shortly after the Federal Aviation Administration issued safety rules in 2007 for using lithium-ion batte
68 spacecadet: Now they move on to looking at other parts of the electrical system, or to the design of the battery itself. It does not mean they're at a dead end,
69 frmrCapCadet: There are reports coming out that that are clearing various parts and systems from fault, can one of the experts here tell us what this means. To an a
70 asctty: Thank you, my specific post on this was deleted by the moderators. Lithium Ion batteries are used all over complex industry sectors as part of Uninte
71 seahawk: No obvious fault in the 2 major systems, this is not good.
72 SonomaFlyer: The articles seem to rule out the battery and charging system. I am assuming they rule out any material defect in the assembly of the battery? If the
73 rolfen: I don't think any system can be "cleared" in the sense where it can be absolved from any responsibility. Electrical systems are complex and bugs can
74 DocLightning: It is, and if it turns out that the explanation is "statistical aberration," then it will take many hundreds of thousands of event-free flying hours
75 Kaiarahi: Before everyone concludes that 2+2=22, what the NTSB actually said was that it found no obvious anomalies in the undamaged JL battery (i.e. the forwar
76 rheinwaldner: Lipos don't like cold temperatures. They loose a lot of capacity. Thus the real RC nerds heat them to 40°C before flying in Winter. That's for sure
77 ComeAndGo: it already happened, the airlines will ban Li-Ion's from flight. Virgin Atlantic did so a few years ago.
78 Unflug: No more cell phones, cameras, tablets and notebooks in the cabin? That will be kind of hard to enforce.
79 ba319-131: Well, if the batteries have found to be 'clear' for duty, this seems to fall back to the electrical system in general. Given the huge amount of electr
80 scbriml: That was a short-term issue related to two specific brands of laptop - Dell and Apple had a massive battery recall in 2006 after several battery fire
81 ComeAndGo: According to the NTSB slide presentation each battery cell has a Rupture Valve. Where does the electrolyte go to if it escapes through that valve. And
82 tdscanuck: The "exception" is the "extremely remote" stipulation...the FAA didn't require 100% protection, as they do for any single failure, but allow a (very
83 asctty: The point here is that that batteries are OK if the control system works. Who owns the control system? The battery manufacturer specifies safe parame
84 francoflier: The ban concerns checked luggage, freight, anything that is not accessible in flight. Let's not forget that Li-ion batteries have already downed an a
85 7BOEING7: If there is smoke in the fwd equipment area the fwd vent valve opens to clear the smoke overbd. It is a several inch hole in the airplane and it woul
86 asctty: This is locking the door after the horse has bolted in safety terms as it will not prevent the battery overhating in the first place. A very complex
87 michiganatc: Forgive me if this was already talked about, I haven't had a chance to read through the 750+ posts With the 787's all grounded, what airports did Unit