Then it is not just a battery problem...........
A design too far perhaps?
I hope not.
Boeing's flagship fleet of 787 Dreamliner aircraft will be grounded for the foreseeable future after a preliminary report from the National Transportation Safety Board (NTSB) said the cause of two battery fires had yet to be found, and that Japanese investigators are similarly baffled. "We have not ruled anything out as a …
I have an old rare photo taken by a guy, while his friends run for their lives, as a Chinook (twin prop) is coming into land on fire.
The rear ramp is down. Flames are blowing out off it's interior like a giant blow torch...
The cock pit is filled with black smoke......
It's about 120 feet up in the air and coming in for a landing and apparently when the blades smash on impact, the pieces can be flung quite a distance.
Hence the guy taking the picture gets the other soldiers in frame as they run for their lives.
It's a really great photograph, of a really, really, bad situation to be in.
I'm an ex-fuel cell guy, but fuel cells and batteries are two sides of the same coin.Li ion battery's that have been through as much testing as these have, if they start thermally running away when put into service, almost always do so due to an interaction between the charge circuit and the battery resulting in the battery being charged/discharged too fast or overcharged. The cure might be as simple as lowering the maximum charge & discharge current density the power conditioning circuitry allows. Whether that is too low to power all of the entertainment systems, well...
I agree, mostly because I find it hard to believe a japanese company like GS Yuasa would make substandard battery cells.
Li-Ion at too low voltage or too high voltage will start producing metallic lithium (highly volatile), or starts dissolving the copper current collectors into the electrolyte. This dissolved copper then becomes metallic again when battery voltage is restored to safe levels, and the copper might have formed thin strands acting as shunts. Current across those can locally heat up the cell sufficiently to set off thermal runaway (iirc the required temperature is slightly above 100C). Think of it as chemically "growing" an ignition wire into the insides...
When having multiple cells, each cell must be individually monitored to stay within prescribed voltage limits. In order to not get the entire pack limited by the lowest voltage cell and highest voltage cell, you need some sort of system that either adds more charge to the lowest cell, or removes power from the highest cell. Removing from the highest cell is the most common practice. Then you need to design this balancing system so that it fails in a safe way. Many electrical vehicle hobbyists have been bitten by this, their electronics have failed and a single battery cell has been drained totally dead. Trying to either charge or discharge that pack will then most likely cause a fire.
The charging system needs feedback from this balancing system, so that the charging system doesn't charge faster than the balancing system can remove charge from the highest cell(s). Without that feedback, there'll be atleast one cell that gets overvolted for a brief period of time. The damage accumulates (you can't just say "oops, but it didnt blow up this time, so it's ok")
Same applies to discharge portion, must cease discharging when the lowest cell reaches lowest permissible voltage. Using the pack voltage for this purpose will lead to problems.
I've seen a surprising amount of highly skilled electrical and electronics engineers that have absolutely no clue about batteries, they would blow up a Li-Ion pack quite quickly with the battery management they'd design. Alot of EEs seem to treat batteries as some sort of black boxes that work as electronic fuel tanks and manage themselves. I guess it makes sense, they're electronics people not chemistry people.. Wouldn't surprise me if the problem can be traced back to the battery management system...
I believe temperatue also plays a role in this. My friendly Li battery expert who provides me with Li batteries for Dive Propulsion Vehicles has charging/load protection to stop the use of the battery when the battery is too cold. Bad stuff happens to Li batteries when they get too cold and once the battery has been frozen, its basically kaput. It is winter in the Northern Hemisphere and I have to ask what temperature cycling is occurring in the belly of an aircraft sitting for extended periods in below freezing conditions while the aircraft is powered down?
"A design too far perhaps?"
Perhaps it's an intrinsic problem with the technology (chemistry). I remember a time a decade or so ago when the operation I was with had to ship these lithium batteries by sea, as they were deemed far too dangerous to even ship by air!
So what happened? Seems to me that this is another instance of where regulators are being forced to compromise safety because of commercial pressures.
BTW, the use of fly-by-wire is the reason for the need for massive backup power—and fly-by-wire is principally an economic consideration. Electronics is my profession so I have a suspicion of electronic systems when used in super-critical environments because of susceptibility to interference, failure etc. The question is why would one substitute a well-understood mechanical system for an electronic one. After all, a mechanical system is one made up of atoms—atoms whose electrons are tightly bound to the nucleus and thus extremely stable. However, in an electronic system electrons are freed from atoms and are subject to the most ephemeral and easily disrupted of all the forces of nature—the electromotive force.
Just recently, in a lecture on the 787 fly-by-wire, I had the chance of putting this question to a group of aviation experts and, after their initial surprise, they essentially agreed that economic considerations were the principal and driving consideration for the change from mechanical controls to electronic fly-by-wire.
I've been a user or raw lithium cells (no protection) since the early days..when fires were very common.
Proper design of chargers, and less flammable chemistry (its the organic electrolyte, nit the 'lithium' that burns) have all but eliminated the risk.
What is strange is that Yuasa hasn't actually seemed to follow these developments.
Or that there hasn't been proper collusion between the charge/discharge protection and the cell types used.
I'd say there's at least a years delay now to redesign and re certify the whole pack/charger/protection block. And possibly retrofit fire equipment.
After all, a mechanical system is one made up of atoms—atoms whose electrons are tightly bound to the nucleus and thus extremely stable. However, in an electronic system electrons are freed from atoms and are subject to the most ephemeral and easily disrupted of all the forces of nature—the electromotive force
Hope you didn't ask the aviation experts about this. Any conductor has free electrons; that's why it's an electrical conductor (and, to a lesser extent, a heat conductor). Mechanical systems tend to be metallic, and so have free electrons. Look up 'conduction band'. And there's nothing "ephemeral and easily disrupted" about electromagnetism ("the electromotive force"). Look around you - everything you see, every natural phenomena, the form of every physical object - if it's not that way because of gravity, or the strong or weak nuclear forces, then it's that way because of electromagnetism.
First, I did mean to say "electromagnetic force", heavens know why I said "electromotive force"—my once lecturers would be horrified (and that error's sometimes a trick exam question).
"Hope you didn't ask the aviation experts about this." Yes, I did actually. I won't bore you with the ins and outs of the discussion except to say that weight/fuel economy is a major/principal reason for fly-by-wire but it's not the only one—another compelling one is that pilots simply like using it (as most of us have become addicted to smartphones). And there's other reasons too.
Right, conductors do have free electrons but also they have 'bound' ones. The reason the table my laptop is resting on remains solid or why one bleeds after having been bashed against a solid plate of conductive steel is because of 'bound' electrons—if you like the electronic structure of matter. I beg to differ with you about the electromagnetic force as it is much weaker than the strong force and operates over a long (theoretically infinite) range subject to the inverse square law. And that's the rub—that the electromagnetic force can induce currents at a distance from the source, apart from being why electrical stuff works, it underpins the reason for the problem of electrical interference. (Signals induced into TV antennae miles from the TV station illustrate the point—here they're wanted but unwanted ones are induced the same way).
Obviously, I'm not opposed to using electronic control systems—after all, that's my profession—but I've seen enough system failures, whether through interference or other electronic faults, to question whether ripping out a perfectly reliable and simple mechanical system only to have it replaced with a complex electronic one is the correct move. Often the answer is 'yes' but the question must be asked. Here's a simplistic illustration of how new problems arise: at present I've an annoying intermittent electronic fault in my car's dashboard and when it fails I lose everything. In older cars that I've owned when the speedometer cable broke, the simpler and less tightly coupled system meant that I still had functioning fuel and temperature gauges.
There's no doubt the electronics/control systems in the 787 are remarkable and a credit to the designers. The keyword here is reliability—key electronics consist of multiple/dual systems that function the same but which are different in design in that they've been designed by different teams/organizations under 'clean-room' conditions.
That said things still go wrong with the best designed electronic systems and sometimes finding glitches, intermittent faults and interference sources—which in the case of aircraft are highly variable as they change their environments—can be incredibly complex, especially in a system as complex as a 787. (Those who've had a PC that has locked up for no apparent reason know the problem.) Moreover, there are other well-publicised instances where electronics, which have replaced critical mechanical (but historically very reliable) systems, that have had electronic failures which have led to serious accidents. For example, it's still unclear why the electronics in the Toyota Prius accelerator failed (anyway, the public is still in the dark).
There's a final reason why I reckon it's important to have fallback in critical systems (here a different technology—mechanical backup), and that's because it's essentially impossible to do a full state analysis (analysing/checking every permutation and combination of operation) on a system as complex as 787. A state analysis on even something as simple as a domestic VCR can fail through its complexity. Here's just one example: I'm aware of a mass-produced VCR with many hundreds of thousands of units in the field where it was eventually found to fail by pressing a certain combination of buttons—but the fault was only found years after it had been released!
Certainly fly-by-wire isn't going to go disappear, but the lesson we should learn is that modern electronic systems are both new (in that we don't have a century or so experience using them), and often they're extremely complex and that sometimes they fail in unpredictable ways—in ways and at times that we least expect.
I wasn't objecting to your use of EMF; I just put it in quotes because I didn't want to repeat it.
The point of my reply was that free electrons are not a problem. They can't be, because metals are full of them, and you have no problem with mechanical systems. But, you do have a problem with electronic systems, precisely because of the free electrons.
Ok, you may have lots of valid reasons for not trusting electronic systems, but "free electrons" should not be one of them. Besides, in this case, it's Chemistry that's the problem, not electronics.
And I was also pointing out that electromagnetism is not "ephemeral and easily disrupted". And, quite apart from anything else, the actual movement of electrons has pretty much nothing to do with the operation of electronics. That's just something they teach kids in school. Electrons crawl through a conductor - I forget precisely how fast, but maybe a cm a second. But signals propagate across PCBs and ICs at close to the speed of light. Electronics is about electric fields, not electron movement.
Airlines prohibit the use of spare batteries in the hold *, so clearly this is a known concern. I would have thought that Boeing would have known about this and taken the correct measures to compensate... but apparently not.
* Of course airlines won't prohibit them completely because they would lose too much business if they outright banned the things. I'm not sure what the logic is of insisting they're in teh cabin rather than the hold. If a battery DOES catch fire i'd prefer if it's NOT in the same space as the passengers. Perhaps because they don't have good fire detection / suppression in teh hold, while in teh cabin it can be dealt with better, whatever the nasty potential effects on the passengers?
Also, what about temperature / pressure? Hold isn't heated so maybe extreme cold can prevent ignition? On the other hand, hold is also not pressurised and could somehow encourage ignition?
with all respect to your experience and knowledge, I think you can agree with me in saying that an electronic system can be just as thoroughly tested and just as predictable as a mechanical system provided sufficient testing is done on it.
Fly-by-wire has a multitude of other advantages apart from the main one of economy; both in civvies and military aircraft. For civvies think of Airbus and its application of normal and alternate laws to protect against load factor excesses, stalls and improve low-speed stability. In military versions fly-by-wire means that the Eurofighter can actually fly. Its design is for an inherently unstable craft that only become "fly-able" with the aid of computers which results in a extremely agile dogfighter.
Now, back to electronics, there are very specialised FMEA standards that apply to aviation and especially more os on electronics. Which is why by modern standards the electronics keeping the Airbuses aloft would be considered positively neolithic.
In summary, I don't see electronics as inherently more dangerous than any other newly introduced innovation and they should be treated as such i.e. with respect and healthy suspicion until they are proven by life.
"Good to see traditional crappy American engineering screwing them over. Roll on Airbus...."
This would be the same airbus that had an engine explode on a brand new Quantus A380 in flight would it? It was only sheer good luck that the shrapnel didn't hit anything vital that prevented 500 people dying that day.
Pot, Kettle, etc?
"The aircraft has an inert gas system in the cargo hold to counter fire, but the FAA decided similar systems weren't necessary for other areas of the aircraft."
So, of course, the airlines assumed that fire can only break out in areas with fire extinguishers. Being at 35,000 feet is a tad inconvenient for those folks stuck in the back end.
Those who forget history, are cursed to relive it.
To my knowledge, Inert gas extinguishers, or anything else, will not help much in a lithium ion battery fire. As they burn they produce their own oxygen. With this kind of fire, you just try to keep anything else from igniting and wait for the fire to burn itself out. Note that it took two hours after the firefighters arrived until the fire was out.
indeed. Class D fires are sometimes not easy things to control (outside a pot of magnesium). inert gas works fine for non oxidising agents but if the reactant can create its own oxidiser and has already generated heat then smothering with fine powder to try and inhibit the oxidiser is about the best you can get. Wicking heat from one cell to another wont work too well for obvious reasons.
The powders are not exactly lung friendly substances either. You dont want the stuff getting into the air recyclers and being pumped to the cattle.
The obvious approach is to swap the Li cells with NiMH (are you still allowed to make NiCads?)
"Inert gas extinguishers, or anything else, will not help much in a lithium ion battery fire."
Whilst I agree with this and have on several occasions in my lab career extinguished burning metal & metal hydride fires using special ternary powder extinguishers and whilst noting that these batteries are worst in having their own oxidant the use of inert gas would at least help to control any collateral fires in the vicinity.
That fire, in your link, was caused by a high end entertainment system that had been added well after initial construction.
If I recall, the equipment was connected to a main bus without the benefit of a circuit breaker, something they teach in Basic Electricity 101.
Ended Swissair and the smaller version is called Swiss.
They may be over thinking the cause. It could just be a quality control problem either from the battery manufacturer or the installation at Boeing. The fact that they are having such a hard time pinpointing the cause makes me think the battery fire is part of the symptom and not the source.
It's much too complex and risky a design, in their rush to produce more efficient lighter planes they've thrown away too many tried and tested things.
Electronics are notoriously less reliable than hydraulics. Which is why your brakes on your car aren't electronic.
When I hear "most advanced" I always think it will also be more likely to have quirks or go wrong. Citroens have been very advanced too and it shows in their re-sale price, Xantia's or XMs were a nightmare.
"It's much too complex and risky a design, in their rush to produce more efficient lighter planes they've thrown away too many tried and tested things."
Not really. Most of the aircraft is fine, the only big issue seems to be the battery. That *could* be fixed by switching battery chemistry (albeit at the expense of some weight and some space).
"Electronics are notoriously less reliable than hydraulics. Which is why your brakes on your car aren't electronic."
Not so - hydraulic systems are a pain in the arse. Leaks, etc, are a real nuisance. They're only used because you can get a lot of force through small pipes into small actuators that can provide a lot of shove, where electrical equivalents would be significantly bigger (and probably less reliable). The brakes on your car are most likely controlled by electronics.
"When I hear "most advanced" I always think it will also be more likely to have quirks or go wrong. Citroens have been very advanced too and it shows in their re-sale price, Xantia's or XMs were a nightmare."
Fortunately Citroen aren't in the aviation business.
Agreed, fly by wire has been around since the first Airbus, it is a mature technology.
My car has electric steering, the connection between the steering wheel and steering rack is by wire not by by a mechanical or hydraulic connection. In 6 years never a murmur.
However, the carbon fibre technology is untested, the fuselage or wings might not readily show strike damage, whereas with a normal aluminium construction there would be the warning sign of rippling.
The first of its kind, cars,, aircraft, engines etc usually have teething problems and over the years these get iron out. Unfortunately there usually has to be a disaster before the faults are found.
"I've never heard of a mainstream car with purely electric steering."
Me neither. Electrical servo assisted steering, yes, but never pure electric.
Mercedes Benz do a braking system where there is no direct mechanical / hydraulic link between your foot and the pads (it was used on the McLaren / Mercedes SLR, maybe others too). There was some electronics in the way. Apparently it is very 'odd' to drive, but the car did have tremendous stopping power...
Mercedes Benz do a braking system where there is no direct mechanical / hydraulic link between your foot and the pads (it was used on the McLaren / Mercedes SLR, maybe others too). There was some electronics in the way. Apparently it is very 'odd' to drive, but the car did have tremendous stopping power...
Power assisted brakes are more or less ubiquitous - far more so than power steering or even ABS - but AFAIK all current road cars use some form of mechanical linkage for both brakes and steering. The power assistance only works when the ignition is on - it would rapidly deplete the battery if used outside of that - which means among other things you wouldn't be able o tow a car without the linkage.
This is well understood by the sports car manufacturers in particular who could greatly improve handling by trading camber angle for caster angle in the front suspension geometry. They resist that temptation to a certain exist since increased caster increases the steering wheel resistance - too much and it gets very difficult to drive without the power steering.
Actually the assistance is mechanical/hydraulic too, not electronic. It works from the vacuum of the inlet manifold of the engine, which operates a servo to assist the pedal going down. It does not work "when the ignition is on", only when the engine is running, and has nothing to do with electronics. The reason brakes still work when the engine is off is because the brake pedal is hydraulically attached to the brake calliper, and the servo only assists, it does not actually control the brake calliper as an electronic system does. The same with ABS, it just temporarily overrides the hydraulics but never disconnects the pedal from the brakes.
It used to be the case (not sure if it still is) that the main brakes and the handbrake had to use a different technology to work each. I.e, you couldn't have hydraulic main brakes and hydraulic handbrake. You couldn't have electronic main brakes and electronic handbrake. I'm not sure if there are any secondary/mechanical backups for the controls in a aircraft, but I would sure hope so. Software bugs are a bitch.
> AFAIK all current road cars use some form of mechanical linkage for both brakes and steering
The big hydraulic Citroens don't - there's no master cylinder. You've got a valve off the pressure reservoir to the calipers. It makes for loads of power assist, and some excellent self-balancing and anti-dive characteristics, but you have to cope with a rather "nervy" pedal...
Crikey! I'm not sure I like the idea myself...
Ever looked at how the car industry does 'safety critical' software? Thus far they've sort of dodged the issue. There's the MISRA rule set which enforces sensible source coding standards. But they don't do the whole triplicate systems + trusted voter like an aircraft does.
This approach has mixed blessings. It's cheap - no triplication. It's reasonable - software systems on a car aren't actually doing a job that's massively safety critical. The brakes are primarily hydro-mechanical, electronically modulated but it's still your foot pushing the pads to the disc. The steering has a mechanical linkage, assisted but not controlled by a servo. And so on.
However I've noticed big problems in at least one highly regarded embedded tool chain which has a MISRA check box in the IDE. The library source code is atrocious, very non-MISRA and buggy. Not a very good basis for a safety critical system.
As soon as the car industry starts replacing the primacy of mechanical and hydraulic components with software one has to question whether MISRA alone is enough. Take that Nissan for example; the question of 'did the driver steer the car that way?' now becomes very important indeed. Is there a black box recorder for it? Who is responsible if it goes wrong? Would the driver have to prove the existence of a fault to avoid blame, or would the legal working assumption be that Nissan would have to prove that their system operated correctly?
The legal precedents we have at the moment are based on the assumption that a car doesn't have a mind of its own. That's fair enough if the car is primarily controlled through hydraulic and mechanical systems. But with a drive-by-wire system the car does have a mind of its own; I doubt the legal world will be quick to adjust their assumptions to match.
@Steven Jones - in the UK (and I would assume by extension, the EU) steering systems are one of the last in-car systems *required* to have a mechanical link to the driver.
I'm not sure I'd get into a car which did not have that link, in the same way I'm not sure I'd get into a car (or plane) in which robotics replaced the driver... irrespective of whether the electronics can do a better job of controlling it.
The failure of power steering and brakes on most modern cars is something that, at the very best, will allow you to stop safely.
I've had both, and trust me, it was almost impossible to stop or steer the car. The steering reduction simply isn't designed to allow anything short of a human gorilla to actually drive it, nor are the pedal travels on the brakes.
"I've never heard of a mainstream car with purely electric steering. However, there are many with electric power assisted steering. (There are some specialist vehicles with pure fly-by-wire electric steering, but I can't find any cars of that sort - and it strikes me as unwise)."
Unwise, definitely; but SAAB did produce a car with purely electric steering. Can't remember it's name but it was a resolute failure in any case.
Indeed I thought the main reason the brakes and the steering on cars are only ever "electronically assisted" was the very simple design regulation of "fail safe", i.e. if your alternator fails (can happen) and the battery subsequently *completely* discharges (running the cars electronics, head lights, stereo etc) you can still steer and stop because the controls are mechanically linked to the actuators at the wheels (by cable, hydraulics, rack & pinion, whatever).
[the throttle on the other hand these days is often entirely electric, the pedal is just connected to a rheostat or similar]
The reason fly-by-wire is acceptable in aviation and not domestic automobiles is the regulation of maintenance of the vehicles, i.e. cars are maintained by the cheapest grease monkey you can find or not at all.
I've braked and steered with the ignition turned off- the brakes and steering do work, but require more force.
(I was in the outside lane of a motorway, overtaking a lorry. Suddenly the side on nose of a care appeared in front of me; evidently he had joined the motorway and not checked his blindspot, and as a result was being pushed sideways down the motorway- the lorry couldn't avoid it because of me. I had the lorry on my left, the central reservation on my right, and the side-on nose of the car in front of me. Eek.
I had only been driving for a month, and my first thought after [Rising panic] [Brake] was an unfounded "I must draw attention to my car for the benefit of people behind me! [hazard lights]" and must have turned off my ignition whilst fumbling for them.
The brakes and steering felt heavy, which my heightened mind wrongly ascribed to tyre damage- obviously the smoke I saw had come from the pushed car's tyres. I came to a stop on the hard shoulder, 30 yards in front of the lorry and car- nobody was hurt, everyone was in a state of mild shock- after the fire engine turned up I continued my original destination - a pub. )
Fills me with the dear of death....
"My car has electric steering, the connection between the steering wheel and steering rack is by wire not by by a mechanical or hydraulic connection."
So how does the removal of fundamental links like rods and bars and gears and pinions, make it safer.
I mean that electronics are good, but they are not that good....
Me thinks get away from the magic burning batteries and put in "totally reliable" shitty lead acid ones with regenerative caps and vents to the atmosphere..
Personally while there are some benefits to magic batteries, magic wands, velvet gloves and catching fire is not one of them.
Satan - "Arrrrrrrhhhhhh Ha Ha Ha - Electrickery is the Work of the Devil!"
> "It's much too complex and risky a design, in their rush to produce more efficient lighter planes they've thrown away too many tried and tested things."
> Not really. Most of the aircraft is fine, the only big issue seems to be the battery. That *could* be fixed by switching battery chemistry (albeit at the expense of some weight and some space).
That only one thing didn't work doesn't refute the grandparent comment's point. They pushed the boundaries in lots of areas and of course most succeeded, this was a commercial project not a research one but at some point lots of small risks add up. A 1% risk of a battery problem sounds manageable but if there is also a 1% risk of an engine fan blade issue, a wing strength issue and dozens, hundrends or even thousands of other issues then sooner or later you might be talking real possibilities or even probabilities of something going wrong although you don't know which.
You take small risks in 100 different areas of design and lets say 99% succeed, the one that doesn't happens to be the batteries but it could have been something else. The cost will depend on the time to get an airworthy approved solution, lost sales and any damages to the grounded airlines (I've no idea what sort of warranty or SLA a new passenger jet comes with). Until that is known and the aircraft is in service long enough to shake out any other issues including major component lifespans we won't know if the post you responded to was correct that it was "much too complex and risky a design".
"That only one thing didn't work doesn't refute the grandparent comment's point. They pushed the boundaries in lots of areas and of course most succeeded..."
It does. The risk was purely commercial, not technical. The commercial risk was that they'd have to do too much redevelopment to get the aircraft certified and flying and run out of money. By and large the design is OK (apart from the battery), flies, and has the required performance. Once the snagging list has been dealt with it looks like it will be a fine aircraft. In that sense it turns out that it wasn't risky at all.
"A 1% risk of a battery problem sounds manageable but if there is also a 1% risk of an engine fan blade issue, a wing strength issue and dozens, hundreds or even thousands of other issues then sooner or later you might be talking real possibilities or even probabilities of something going wrong although you don't know which."
Only if you ignore them. The point of development testing is to establish that all of those components do indeed meet their specification and are not in fact a risk to the project. You deal with risk in a project by identifying areas of concern and work on them early on. That way you either kill the project before you've wasted a lot of money, change the design or find that the risk didn't materialise. Flight testing is there to make sure that the specifications themselves are correct. Certification testing and inspection is there to make sure that the rules have been followed and that no detrimental technical risks remain.
In the case of the 787's battery it is highly unlikely that any of the companies have taken short cuts in manufacturing or testing (the reputational damage would be immense, and could potentially attract jail time if there were a bad accident). Thus far the NTSB, FAA and everyone else seems baffled as to why the batteries are failing, which suggests that the rules and specs have indeed been followed.
This in turn may suggest that the behaviour of Li-ion cells isn't understood well enough to be able to write a correct specification in the first place. That's no one's fault; the writing of the specification for the battery is something that has rightly involved the companies and also the FAA, EASA, etc. What more could be done?
If the ultimate conclusion of the inquiry is that the spec is wrong then Boeing will have to change battery chemistries, or back off on the specification somewhat (larger, lower power density, greater margins all round). If I were in charge I'd be sorely tempted at this point to change chemistries and accept the weight penalty.
"You deal with risk in a project by identifying areas of concern and work on them early on."
Except when the number of innovations is above a certain level, then the number of possibilities and combinations thereof becomes unmanageable and you respond by identifying 'areas you think might be a concern' and you just don't think about everything else.
If Boeing had done all the design work in house I would be more sanguine but that they outsourced the design work as well seems to have already bitten them in terms of the delays. Who is to say that this is the only way it will bite them post production? Having recently flown long haul on a Dreamliner I feel lucky, I'm not sure I want to feel lucky again.
"Fortunately Citroen aren't in the aviation business."
Not now, but they did make a helicopter: http://ranwhenparked.net/2012/08/13/a-look-at-the-citroen-re-2-a-wankel-powered-helicopter-video/
Leaks can be a bit of a nuisance with the hydraulic systems; I had a somewhat startling moment in my CX GTi Turbo, when I realised the steering was a bit heavy (ie, barely functional; a Diravi with no hydraulic assist is hard to shift). So I applied the brakes, only to realise that they weren't working either, and all I could do was use the gears and the handbrake to slow down and hope that I coasted to a stop before I hit anything.
Fortunately, I stopped a few feet short of a parked van.
On a hydraulic Citroen (certainly CX and DS, which I stilll have), there is no mechanical link to the brakes; if the hydraulics fail, you need to hope for the best.
At least on the Citroëns I drove with hydraulics, there was a separate 'high pressure reservoir' for the brakes.
This meant that you still had braking power enough to stop if something happened to the pump.
I've never heard of a system failure that takes out he brakes at the same time as the rest, unless it was the braking system itself that was faulty.
(I've had a few faults; height adjuster on the GS, rotten squid on the CX and BX, worn out column on the BX. Old cars and lots of mileage. Nothing that caused any danger. )
Most Citroëns with Hydraulics have the handbrake working on the front wheels, and it's STRONG!
This is a quote from 'Autocar' in 1978 about the handbrake on the CX
The remarkably effective handbrake operates on the front wheels. It managed an almost unbeatable 0.42g deceleration and easily held the CX Pallas C-Matic on a 1 in 3 slope, from which a restart could be made with contemptuous ease.
I can attest to the GS not being a slouch, either.
In fact, even with a full hydraulics failure, it's possible to DRIVE(slowly) these cars to the workshop for repairs.
(Assuming that you can turn the wheel and the road's not too bumpy)
good old XM. Fearing the the "needs new globes" from the garage. I dont know of any steer by wire cars outside of fork lift trucks though. There are a few that might sound like they do such as ford electro hydraulic steering (which is just PAS with an electric pump in case you stall).
I suppose if you sell a car in multiple markets you could design one for an almost universal cockpit approach if you had drive by wire for ALL the components. Cant say i'd like version 1 though, like most things i'd wait for the service pack....
ABS and EBD control modules assist with only heavy or emergency braking. EBD only works when ESD is turned on. in the event that the ABS control module or sensors fail, you are still able to use the traditional hydraulic braking system. While it is convenient, it is not in complete control of your brakes (IE if the control module board fries you are left floating in a death trap). electronic boards have stricter conditions it needs to operate; temperature, shock, and humidity than hydraulic systems do. this is why they appear more reliable and in most cases are.
as for them being a pain in the arse, i completely agree. but as for them being more reliable and in control of braking in cars i disagree.
No. You're confusing control with actuation. Electronics cannot do what hydraulics does. And most car breaking systems these days are controlled by electronic detection of a loss of traction - a skid.
If this problem is the battery, then it should be relatively easy to solve, although the logic of using a battery capable of sustaining its own combustion is very questionable.
If, as seems more likely, it's the charge and management electronics, then it could be total nightmare.
I genuinely wish you Good Luck, guys.
> Xantia's or XMs were a nightmare.
I don't know about Xantias, but I've had many XMs. They only "nightmare" about them was the dealers...
Many people are scared of working on Citroens, but they're actually pretty easy. The earth connections need redoing on the XM - bloody cheapskates - but that's really not a big deal.
 I used to buy old, high-mileage cars for a song and drive them into the ground. It worked out very much cheaper than trying to keep something serviced...
It certainly is a bit shit.
Boeing would have written a specification for the battery. The manufacturer (Yuasa?) and Boeing would have agreed a test schedule to demonstrate conformance to that spec. The questions will be
Not for Boeing but for all of us. National Geographic had a very interesting program of airplane accidents years ago. As far as I remember the FAA was often accused of being to slack when dealing with accidents and requests to do something about it. The most reluctant where those building the planes and they where also prepared to cheat about it like also those using them.
Hundreds of people lost their life due to this.
If the demands on those who build the planes have increased then that is fine with me. The really ugly problems come later, anyway.
It's a very good sign of the FAA attitude.
The NTSB was created because the FAA used to be in charge of investigating air accidents AND promoting air travel - which led to all their accident reports concluding it was a one-in-a-million act of god that could never happen again.
More recently the FAA have got into trouble for giving US airlines an easy ride on safety violations because it would cost American jobs. Then there was the statement by some US politician that anyone criticising a company as vital to US defense as Boeing was at least a traitor and probably a terrorist.
A fun question to ask:
Who did the inspectors who qualified the 787 work for?
A: The Federal Aviation Authority
B: The National Transportation Safety Board
C: The US Department of Commerce
D: The Boeing Company.
(Hint: http://seattletimes.com/html/boeingaerospace/2009700988_webboeingfaa20.html )
"Who did the inspectors who qualified the 787 work for?"
It's standard in any safety critical industry - and it' the only way to do it.
If the inspectors from the FAA/CAA were directly inspecting the plane - they would have to know more about the design of aircraft in general and the 787 in detail than the Boeing engineers themselves.
Instead the inspectors are checking Boeing's procedures and methodology - just as our ISO auditors do to us.
They don't read through our code with a deep understanding of our business logic - they look at our history of tests, bugs, resolutions, plans etc - and assume we didn't make it all up.
"Who did the inspectors who qualified the 787 work for?"
Hmm, didn't know that! However I don't see that as a major problem. If Boeing took short cuts and aircraft started falling out of the sky they'd be commercially extinct, and people would probably go to jail. You'd have to be really stupid to run that sort of risk just for a few extra dollars profit, and I'm willing to assume that Boeing aren't that stupid. On the other hand there is a reputation to uphold, and being seen to be rigidly and independently inspected is definitely good for one's reputation. It's worth spending a little on reputation maintenance, just to be sure.
Ben Rich (Kelly Johnson's successor at Lockheed's Skunk Works) wrote in his book about how the air force sent in the inspectors to make sure that things were done properly. He said it was a pain in the arse, but that the end result was well worth it and the F117 was a fine aircraft. A lesson there for all of us?
It'a amazing what happens though. Sometime companies are utterly useless when it comes to assessing risk.
You'd have to be really stupid to run that sort of risk just for a few extra dollars profit, and I'm willing to assume that Boeing aren't that stupid.
The fact that Boeing decided to outsource the majority of the work on this plane would cause me to question that statement.
Recently, on this subject (outsourcing the plane's subsystems), I read a commentary that suggested that Boeing outsourced much of the potential profit (on the "Dreamliner") to its subcontractors, while insourcing more of the risk.
With the "Dreamliner", they were now acting as a low value assembler of systems; where previously, they exercised more complete control of aircraft design and construction.
To which I would add: damagement strikes AGAIN!!!!
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I believe it is common practice that all the major aerospace companies use their own people to gather the Flight test data required for civil cerification. Normally, the civil certification agency does not get involved in flight testing until the manufacturer has found and fixed any development issues and is ready to seek certification. At the end othe day said data is presented for granting of aircraft certification
All those involved have hold licences issued by the controling authority for that country. eg FAA or CAA
Boeing and many others have been given dispensations on certain saftey requiements, citing past reliability data, (The design and certification concept that fuel tank explosions could be prevented solely by precluding all ignition sources that are regarded as causing the loss of TWA flight 800. or the staggered rectification of the rudder actuator on the 737, rather full grounding (this caused rudder to be locked full stbd or port after correcting from severe turblance & causing the aircraft to roll & nose dive in. and many other instances from other manufacturers)
It appears that commercial pressures are powerful in mitigating saftey.
With the real risk to Boeing that the 787 holds, I know of one avionics bay fire occoured in the prototype, that maybe history is repeating it's self.o
You're both wrong I'm afraid.
The pilot can very well see the deflections and movements of the side-stick on one of the panels (the F/CTL page of the EFIS see also: http://a340gc.iradis.org/gallery/fctl_large.gif )
And don't forget that the pilots have a priority button and can wrest control from their opposite number at any time they wish.
To see a similar occasion when a stick was improperly configured and how a quick witted first officer took over and saved the day. (Google Lufthansa's "Papa-Whiskey" A320-200 incident report)
"I seem to remember Boeing were being total cnuts when Airbus were having problems with their first fly-by-wire plane."
From what I hear things are different in the aero engine business. Apparently there's a tradition of the major players helping each other out when big, disastrous, and difficult to solve problems occur. Sort of along the lines of it being better for all concerned that all aero engines are seen as reliable. Ya-booing the competition just because their engine shafts keep cracking and letting all the hot bits fly out the back isn't going to fill the public with confidence in the industry as a whole.
Airbus are probably being carefully tight-lipped on Boeing's battery problem. They're planning on using Li-ion batteries too, I think...
Boeing have certainly gone very quite on all the statements they made about carbon fiber planes when an American Airlines pilot tried to do a handbrake turn in an Airbus A300 and broke the tail off.
Ironically this is also the only Airbus model that has direct Boeing-style controls that allowed the pilot to break it - rather than a computer that would have stopped him
My question would be is this the "only" LI-ION battery pack on board the plane, because if it isn't, then swapping out for another chemistry could be a lot more awkward.
To me it all seems very strange, because all this stuff gets tested and tested and tested. How come it didn't crop up in the tests?
"To me it all seems very strange, because all this stuff gets tested and tested and tested. How come it didn't crop up in the tests?"
It certainly does get tested time and again. So a follow on question is "is the test the right test?
The following is pure speculation on my part, but this sort of thing happens time and time again.
It's possible that neither Boeing nor their supplier really know what the battery's specification ought to be. They may have re-used the shock, vibe, heat and electrical spec for an older trusted battery type. However, it might be that that old battery design significantly outperformed that public declared spec, and by good fortune alone has survived the test of time. However, any new battery designed exactly to that spec with no margin beyond would not be fit for service in the same conditions.
It would be astonishing if this were actually the case. Boeing are pretty good and careful engineers, and I imagine that the conditions in the electronics bay are actually quite benign. The electrical spec is probably harsher than 'normal', but that would be very easy to measure and quantify.
However we are in a situation where apparently everyone is expressing bafflement as to why the 787 batteries are failing. It could be explained by the spec being wrong in the first place.
I don't think its going to be as simple as that. Caveat - I haven't studied this in detail, but Aeroplane design is rather complicated, and if you're going to rip out the batteries and put in something larger and heavier you're going to have to find somewhere to put something larger and heavier, and then redesign everything that connects to the batteries to cope with the new location, and then deal with all the weight distribution changes and and and... Its not as if you can just remove a couple of passenger seats at the end of the cabinand replace them with a battery compartment and run a couple of heavy duty leads from where the old location was...
Remember, the *brakes* have to work if the engines are stopped, the APU won't come on and all you have left is a Ram Air Turbine that charges at a higher speed than you want to touch down at -- and batteries more depleted every second. If I have this right, that leaves Lithium.
But I could be wrong.
I cant speak to this particular battery but in many aircraft its just a small cooling duct that enters the back of the part from the air conditioning system. They are not always very big. That being said though AC doesnt generally run on the ground and it may just be a small ducted cooling fan which doesnt help a ton if the area is already 35C+
" is it pressurized, "
Generally the whole of the inside of the fuselage is pressurised.
It's very difficult to make a tube where the bit the passengers are in is pressurised but a thin floor away is a cargo hold that isn't. The exception is some planes where you want to open the cargo bay doors in flight - for those special deliveries.
The airlines themselves don't seem to understand this and used to tell you not to put certain items in the checked baggage because they might be damaged by the lack of pressure.
The only difference is that the cargo hold isn't heated (except for the bits you put pets or sleeping crew in)
More likely, as with most other giant project cock ups, to be down to older Gen X "managers".
These are the people with MBAs and a qualification in a soft subject, who took over the management of engineering and development from the older baby boomer and pre-war generation engineers and scientists.
Their main motivation tends to be short-term stock gains to obtain massive bonuses for themselves and their sociopathic C-level bosses at the expense of the longer-term future.
Yeah, well, the reasoned response of any engineer to an MBA is 'shoot on sight'. MBA schools have been turning people out for years who seem to think that if something has a number associated with it, it is both understood and being managed by the said MBA.
Someone who gets an MBA after twenty years' experience in business probably has something to contribute. Someone who tags it on in an extra year straight after a Bachelor's? I'm not convinced. There's a difference between 'taught' education and practical experience.
"There's a difference between 'taught' education and practical experience."
That should be "There's a difference between 'bought' education and practical experience."
There may be some good MBA's out there but the ones I've had experience of seemed to think they'd paid their ticket and they owned the right to manage.
It was the most profound advert for universal free education I've ever had.
"i agree that its kids running things probably"
You really think that all the good stuff in the 787 came from engineers,and all the bad stuff was foisted on them by accountants and kiddy MBA's? Couldn't possibly be that the experienced and highly qualified staff of Boeing know that they are in business to make money, and actually work together, take both engineering and commercial risks to get new stuff off the ground? And that the engineers know full well (without an accountant in their shirt pocket) that there isn't an unlimited budget or time?
Sometimes things work, sometimes they don't, and rarely is it because the pencils have been bent by the accountants. Airbus had a range of issues with the A380, and with the A400M - keep going back and you'll get to the Comet,and I'm sure there were plenty of other civil aviation engineering failures before that.
I predict that once they pull ALL of the LiON batteries out of service (along with their histories stored in NVRAM), they'll figure it out pretty quickly. With two out of a hundred batteries having gone up in smoke already, I'll venture a guess that there are a few others out there with internal damage, but not to the point of runaway yet. And that damage will be easier to spot if its not in the middle of some melted goo.
The problem is: How to get the used batteries back to the NTSB lab. Show of hands for any cargo carriers willing to load one of these into their hold. Better to put them on a slow boat from China (Japan?).
Boeing like any other corporation isn't adverse to outsourcing however the reason that the parts for the 787 are so widely sourced is that so many non-US companies and governments want skin in the aeronautics game and it would be safe to assume that those countries would be buying fewer 787s if their interests weren't gratified.
In this case, the battery is Japanese-made but subcontracted by the French firm Thales who's responsible for the broader electrical system. I believe the battery's electronic control logic is by a US firm Securaplane which is a subsidiary of the British engineering firm Meggitt.
The wide sourcing was a logistical nightmare and bore much of the responsibility for delays in the plane's delivery. Boeing eventually take some key parts of the work back in-house.
"The wide sourcing was a logistical nightmare and bore much of the responsibility for delays in the plane's delivery. Boeing eventually take some key parts of the work back in-house."
Publicly this is received wisdom, and focuses on the failures. But the A380 was similarly late and similarly over budget despite being relatively traditionally sourced. I would guess that there's plenty of things that have actually worked really well, and Boeing may have learnt lessons that will help it in future. I'd be very surprised if the lesson was "make everything, buy nothing", and would guess that the lesson is more about keeping on top of sub contractor performance, not subbing work that is too complex, and proper sharing of risk and return.
Batteries are GS Yuasa (Japan) integrated by Thales (France) supplying the power conditioning electronics.
Airbus is hoping it is the batteries that are the cause of 787 problems-- (Airbus is using [planning to use] Saft for the A350, Eads would never use Japanese batteries if there were a Euro supplier now would they? No more than Boeing would use a Euro battery supplier when most of Japan flies Boeing... scratchy scratchy). If it turns out to be partly the electronics, well, Thales of France supplies both Airbus and Boeing... although Airbus isn't flying yet with decent size LiIon so they might have dodged a bullet in this case. Otherwise those A350s would end up grounded too. Trailing the market has its advantages.
If you look at the content of semi-equivalent modern Boeing/Airbus aircraft (which means the 787 and the A350), you'll find that there's no obvious nationalism going on, because the customer of those aircraft are the not at all nationalistic (should Airbus ignore their huge US order book? Should Boeing ignore their European customer base?)
There are some very strange things in the world of commercial aerospace: for example, I believe that the main gear for the US 787 is manufactured in France, while that of the Franco/German A350 is from the US... part of the issue is capacity: if company X got the business for one type, then company Y may be better placed for the next simply because of the workload. So if Boeing awarded the business to a French company, then Airbus may discover that the best supplier happens to be someone in Boeing's back yard...
In aerospace what you are discussing is called offsetting. All major aircraft manufacturers do it, they have to in order to sell planes.
If the manufacturer won't let, say Japan, build a major component/system they will order their planes from the competitor. Offsets and country of origin financing are what really make big aircraft deals, not technology.
There is no question of national interests interfering in a commercial Airline's business !
It just happens that no US airline, in receipt of lots of US government aid, chooses to fly Airbus.
And there was no link between BA choosing to buy some Airbusses and getting more landing slots in CDG.
The main reason for Airbus building the A380 is to stop airlines having to buy Boeing if they need a 400+ seat plane.
What is the weight of the older battery arrangement?
As for the savings Boeing is highlighting, is that over a flight or per aircraft lifetime?
Considering how much junk and extra luggage passengers can still get onboard, I wonder how much difference it is in using the new batteries.
This is a worrying tale which pours fuel on the fire and would have one asking serious questions of Boeing and the FAA ...... http://seattletimes.com/html/businesstechnology/2020199686_787batterysafetyxml.html
Good link - horrifying but interesting. To summarise, Boeing expect a certain proportion of the LiON batteries to catch fire and got approval from the FAA for a system that lets the fire burn itself out and vents the smoke out of the aircraft. They hope that the heat will not damage adjacent subsystems. Most pilots think this is insane - I agree.
it's the loss of power to whatever it feeds in an inflight emergency that would scare me. I cannot see any situation where a loss of one out of two batteries whilst on a long flight makes any sense in safety.
Can you imagine the pilot announcing "sorry about the smell, one of our two emergency batteries just caught fire and melted all over the electronics", on a flight crossing the Atlantic when they are halfway across.
As a longtime and high mileage Xantia owner (4 to be precise); can I say they proved far more reliable than that paragon of German engineering & reliablity ; the VW Golf. My C5 and X-Picasso are similarly trouble free - I cannot believe that I have been SO lucky
Half of the resale price bit is due to Peugeot/Citroen discounting new prices so much.
Brits also never liked the hydropneumatic suspension (best bit ever and around since late '50s). Odd when it seems good enough for Rolls-Royce (most of which is Citroen parts..)
"One of these events alone is serious; two of them in close proximity, especially in an airplane model with only about 100,000 flight hours, underscores the importance of getting to the root cause of these incidents."
So, 100,000 'flight hours' - I'm no expert so pardon my ignorance, but I will assume these hours mean time in the air. 100,000 flight hours would equate to almost 11 and a half YEARS in the air...
According to Wikipedia, the 787 was first unveiled on July the 8th, 2007.
No wonder the batteries got hot an exploded, perhaps the flux capacitor was drawing too much current, with the time travel and whatnot....?!
It's a tricky proposition to extinguish a battery fire. Water may just accelerate the fire and inert gas would not necessarily stop the battery from burning (but might stop the fire from spreading). In chemistry labs, we'd have buckets of sand to suppress such difficult-to-extinguish fires, but that's a weighty proposition which won't save the battery. Maybe defective batteries should be ejected from the plane, backup batteries could ensure critical flight functions. But the FAA might not like such a solution.
"Maybe defective batteries should be ejected from the plane..."
This has an added benefit - the ensuing explosion would provide a way out should the plane be struggling to escape the gravity well of a singularity spawned by the collision of two spaceships from the future.
.. Maybe defective batteries should be ejected from the plane, backup batteries could ensure critical flight functions. But the FAA might not like such a solution...
The people on the ground below won't be too happy, either...
Particularly if a British plane drops one over Dresden....
It looks like I'm watching planes take a leap(?) forward with modern tech and I for one welcome our gigantic flying overlords - amazing. Considering all the experience, approvals and safety etc I'd guess the people involved are trying to minimize the chances of anybody dying because they fucked up! Also - If Yuasa can't sort battery problem nobody can!
Who did the inspectors who qualified the 787 work for?
A: Some board that regulates air travel and does not seem to be very good at it
B: Some board that regulates air safety and that urban legend says is successful at doing so (more successful than commercial pressure and advances in technology, that is)
C: An even worse paper-shunting board that no-one knows what it does, really
D: An organization that is actually involved in building and designing aircraft
I don't know why people deplore that the answer is actually D.
A great Air Crash Investigation/Mayday episode when they find out what's wrong with it.
I think because the press have been alerted and have gone in to panic mode regarding the frequency of these events (the Daily Mail will be proud of it) they have had to ground the planes. Nothing more.
" Initial tests at a facility in Arizona show no problems, while Japanese investigators report that their APU circuit boards are too badly burnt to provide meaningful data at this time."
Hopefully the entire facility will not burn to the ground --again-- when testing becomes spontaneously and spectacularly exothermic, as happened earlier in the 787 program. That would slow down the investigation.
"The preliminary findings from the NTSB on the Boston fire report that the plane engineers noticed smoke and flames coming from the auxiliary power unit located under wings"
No. According to the NTSB preliminary report, a "mechanic noted flames coming from APU battery in aft electronics bay".
The aft electronics bay, which holds the battery in question (presumably used to start the APU), is indeed located more or less under the wings, slightly to the rear. The APU on the other hand is at the very end of the plane, as with most other planes (ATR72s being a notable exception, in that the right prop can be disengaged from the engine and the latter used as an APU). The APU is inside the tail cone. That hole that you'll see at the rear of your next plane, that's the APU exhaust.
I know a journo does not need to know this, but it's the second article where the same mistake has been made, and it is annoying and distracting.
I would have sent a correction using the link, but I don't like the mailto: URI. Why not just provide a form?
I would have sent a correction using the link, but I don't like the mailto: URI.
You know, I often wonder about people whose technology peccadilloes result in their foregoing functionality that would let them do something they want to do: "I could have just clicked on the link and sent an email. But I didn't because I think it's wrong. And now I've taken a bunch of my time to complain about it too. You're welcome. Good day, sir!
Lithium-ion batteries have always had fire issues. Find the problem and fix it. It's not like every 787 is having these fires. There has already been speculation that the charging circuit is the issue but this remains to be proven. Internal short-circuits on lithium-ion batteries is nothing new and the cause of past fires in laptops and other devices.
... then the investigation will find nothing, the planes will be cleared to fly again, and then crashes will start occurring, probably over water.
After a heroic recovery of the remains of a Dreamliner from 7 miles down in the Pacific, they will recreate the accident and discover something completely new about battery technology. But by then Airbus will have taken over their markets....
Here we are with a problem that is sufficiently arcane to have, so far, puzzled some of the world's top engineers in their fields, all of them with all available details of how the systems are set up and what's been found out to date. And here we have a whole bunch of commentards who know exactly what the problem is and how to fix it, based on the press reports. Makes you believe in crowd sourcing and wikipedia doesn't it...
I've noticed similar situations with issues involving CPU design, high energy physics, automobile manufacturing, and any number of other fields known for rigorous training requirements and the need for highly experienced people.
It certainly is remarkable that the science and technology world hasn't seized on the clear advantages to be had by hiring from the pool of preternaturally talented Reg commenters; if I were offered a pool of people who would offer nearly instant and free solutions to the world's greatest manufacturing, technology, and science issues, in exchange only for their right to a feeling of smug superiority - why, I'd jump on the opportunity in an instant.
Perhaps one day the world will wise up.
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..you see the battery is built by the Japanese, the chargers by the yanks and the whole thing is integrated by the French. So the Japanese bit will work and be built using SI measurements, the yank bit will be built of bailiing wire using US gallons or god-clods or something measurements and the French went for lunch then chucked the integration together before nipping off to integrate with their mistresses. All I know is that my feet swell up when I take a flight....I wonder if batteries do the same???
The technological choices Boeing took for the 787 were made by the Marketing Department, not by the technical engineers. Best proof is the use of composite materials, touted like marvels that would lead to a lighter aircraft. Marketing department just forgot that aluminium has not only a mechanical function but electrical functions too, making the plane a Faraday cage and providing electrical grounding. The result is engineers had to add a lot of metal to the carbon-based composites, making the 787 between 6 to 11 tons too heavy compared to expectations (cf for instance http://articles.economictimes.indiatimes.com/2012-08-09/news/33118779_1_b-787s-air-india-250-seater-aircraft). Nonetheless, Boeing' marketing dept. continues to claim 787 is lighter because of the use of composite materials.... BS.
Whilst that might or might not be true you aren't supplying any evidence. Just because they've had to build in extra metal alongside the carbon structure it doesn't mean that the resulting structure is heavier than an all metal structure would have been. If you'd hoped to save 10 tons, and you have to put 5 tones of time in then you are still up 5 tons. I think you'll find it not unusual for initial weight estimates to be optimistic. They are, after all, for salesmen to use.
Its not the first time composites have been used in civil aircraft. They have progressively used more and more composite parts for things like wings. They weave conductive threads into the composite to solve problems like lightning strikes. What is new is that this is the first time that they have been used for the fuselage.
The Boeing engineers came up with a bunch of targets to hit before they started on the project. Those targets will have been agreed with Marketing, who have to sell the damned thing, but the engineers wouldn't have agreed to anything that they didn't think they could do. As it happens they came in under their weight target, so they didn't have to use Lithium Ion cells,
particularly to those who are evidently woefully misled on the fundamentals of automobile and aircraft operation. Hell, there are quite a few who can't even spell simple four-letter words.
However, I am unable to make any contribution, as the forum software does not allow me to reply to any of the comments to which I wish to respond.
I bet the loneliest job on the planet right now is that of Battery Power Systems Engineer at Boeing. I imagine the CEO of Boeing is not in a happy place right now, and CEOs under stress tend not to look kindly upon engineers who honestly say, "I do not know what the cause is, I am still researching."
Keep up the search, buddy. I'll raise my glass, one engineer to another.
its heat transfer.. the housing is metal and not toughened plastic or any other low conductive heat material in this http://regmedia.co.uk/2013/01/25/battery_short_circuit.jpg
the batteries charge up when the plane is in use no doubt, without a fully control charged, the blown battery could be running at 140c +
"The lithium ion batteries installed on the Boeing 787 are inherently unsafe, says Elon Musk, founder of SpaceX and owner of electric car maker Tesla."
Enough about this, Boeing will no doubt fix the problem eventually.
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