FAA Grounds 787s
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That way, the bird can sleep without falling off its perch.
Inverse logic at its best. Better to have a few heat plugs blow, rather than not stop at all.
Last edited by mm43; 20th Feb 2013 at 02:12.
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Any replacement battery needs to be capable of braking the airplane to a stop
This generator was normally inactive, but at night it could be brought into contact with the tires and it then generated power for the head and tail lights.
Isn't it possible that for emergency use during the landing run of a 787 the wheels could supply adequate electric power for the brakes, even down to very low speeds?
Such a generator might be built into the wheels, or it could be a separate generator mechanically lowered onto contact with the tires in the same manner (kind of) as on my bike. A little bit like lowering a RAT into the airstream.
In short, a battery is not the only way to power brakes in an emergency, and an alternative source might be more reliable (the power source is always there) without being a fire hazard.
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@picky perkins
Currently,the technology being developed includes a motor inside LG wheel
the concept being "tugless pushback and taxiing" to save fuel.
motor-generators are alreadywell-proven technology on this aircraft and was in commercial use in the 1950's-60's Bond and Messerschmitt 3-wheelers both used SIBA DYNASTART.
What you're proposing is regenerative braking -using the energy to supply the power to apply the brakes to absorb the energy....won't work without a huge Capacitor or another s/b battery.
Much better to use an electro-mechanical system-say reversible servo-motor/leadscrew(worm) and nut arrangement which would leave the brake"pressure" at the point the energy gave out.
Nice idea but fundamentally flawed,i'm afraid.
Currently,the technology being developed includes a motor inside LG wheel
the concept being "tugless pushback and taxiing" to save fuel.
motor-generators are alreadywell-proven technology on this aircraft and was in commercial use in the 1950's-60's Bond and Messerschmitt 3-wheelers both used SIBA DYNASTART.
What you're proposing is regenerative braking -using the energy to supply the power to apply the brakes to absorb the energy....won't work without a huge Capacitor or another s/b battery.
Much better to use an electro-mechanical system-say reversible servo-motor/leadscrew(worm) and nut arrangement which would leave the brake"pressure" at the point the energy gave out.
Nice idea but fundamentally flawed,i'm afraid.
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@CockneySteve
No, what PP proposes is quite feasible. This is an example of energy from braking where the power does not need to be stored even momentarily, but is tapped directly as required. As the wheels spin up within the first second of ground contact, enough power to work the brakes in smart antiskid mode becomes available. They'd need to be mechanically locked on before the ground speed drops to a really low value.
(Not a pilot, but have some knowledge of engineering physics.)
No, what PP proposes is quite feasible. This is an example of energy from braking where the power does not need to be stored even momentarily, but is tapped directly as required. As the wheels spin up within the first second of ground contact, enough power to work the brakes in smart antiskid mode becomes available. They'd need to be mechanically locked on before the ground speed drops to a really low value.
(Not a pilot, but have some knowledge of engineering physics.)
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@ romulus
Interesting consumer attitude!- so you consider it quite normal to buy a "rigorously" tested developed and certified bit of kit and then be expected to shell out cuntinuously on a component that doesn't make even 10% of it's anticipated life and then have to put your massive,costly investment on hold indefinitely.
To think Ralph Nader risked all to protect "mugs" with that outlook!
His book "unsafe at any speed" should be compulsory reading.
Bean counters decided that releasing a defective product would be more cost-effective after paying victim "hush-money" than the ethical and moral way forward, to engineer a safe product.
Areal sense of Deja Vu , here, Sir,It has nothing to do with HINDSIGHT.
A building burnt down during development....there was,IIRC, an on-board "event" during development. The technology's drawbacks are well -known among mainstream users...Boeing/Thates?planesecure between them managed to gain (self) certification on a system which doesn't work.
the 50 currently laid-up are very expensive"field-trial guinea-pigs"
There was a distinct lack of forward-planning by Boeing "suits" for a fallback -position WHEN or if, they got caught with their pants down
As things stand, a lot of people' livelihoods are at stake because of this poor decision-making.
I've no doubt the technology CAN be made to work sucessfully and meet a (downgraded) performance spec'.
monitoring/charging/bus interfaces. that's the problem area.
the intrigueing question is WHY
Fix it or Replace it.
To think Ralph Nader risked all to protect "mugs" with that outlook!
His book "unsafe at any speed" should be compulsory reading.
Bean counters decided that releasing a defective product would be more cost-effective after paying victim "hush-money" than the ethical and moral way forward, to engineer a safe product.
Areal sense of Deja Vu , here, Sir,It has nothing to do with HINDSIGHT.
A building burnt down during development....there was,IIRC, an on-board "event" during development. The technology's drawbacks are well -known among mainstream users...Boeing/Thates?planesecure between them managed to gain (self) certification on a system which doesn't work.
the 50 currently laid-up are very expensive"field-trial guinea-pigs"
There was a distinct lack of forward-planning by Boeing "suits" for a fallback -position WHEN or if, they got caught with their pants down
As things stand, a lot of people' livelihoods are at stake because of this poor decision-making.
I've no doubt the technology CAN be made to work sucessfully and meet a (downgraded) performance spec'.
monitoring/charging/bus interfaces. that's the problem area.
the intrigueing question is WHY
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They could redesign the brakes so that they are normally fully on and elictric power is only needed to hold them off. Some bird's feet work that way
Not sure that having brakes' locked on' is a good failsafe. Just as hydraulic systems have an accumulator which will provide a set number of braking actions, surely the redundancy here would be to have an 'electrical accumulator' (known as a capacitor) to power the brake actuators when all else fails.
If the capacitor has any spare electrical capacity it could also run a redundant anti-lock system too. :-)
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20 February 2013 13:17:51Boeing Co Said to have found a fix for 787 Dreamliner battery problem - financial press (update)- Fix involves increasing the amount of space between battery cells to prevent overheating. ***Note that on Feb 17th, there were reports that a short-term 787 fix could come this week. The short term solution mentioned comprised a heavy-duty titanium or steel containment box around the battery cells, high-pressure evacuation tubes that, in the event of a battery fire, would vent any gases directly to the outside of the jet. - Source TradeTheNews.com
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Boeing close to fixing Dreamliner battery - source | Reuters
As above, seems an interim fix is close.
As above, seems an interim fix is close.
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Significant news from Japan: Japan probe finds miswiring of battery on Boeing 787 'Dreamliner' | Fox News
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As above, seems an interim fix is close.
If Boeing are saying that they are now physically and thermally separating individual 'cells' as their 'interim fix', then I guess they have already been given the knock back by the FAA on the 'bigger, stronger blue box' idea.
None but a blockhead
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Both strands - the 'more space for better cooling' and 'miswiring' - create yet more questions. How can you go through design, testing, certification and operation without spotting an overheat problem in a lithium battery pack where heat is one of your number one enemies and demands the closest of attention? It's like designing a petrol tank and not bothering to make sure it's vapour-tight. Any basic design problem that is first spotted through its combustion products is more than a basic design problem.
As for miswiring - how many levels of test, inspection and approval did the packs go through?
I hope some competent entity is given the brief to shake the regulatory process as hard as possible and see what drops out. Who that might be, alas, I don't know. If the level of incompetence approaches criminality, and as pax in danger of incineration I'm sympathetic to that view, then I wouldn't be at all sad to see the forces of Laura Norder get their size thirteens through the door.
As for miswiring - how many levels of test, inspection and approval did the packs go through?
I hope some competent entity is given the brief to shake the regulatory process as hard as possible and see what drops out. Who that might be, alas, I don't know. If the level of incompetence approaches criminality, and as pax in danger of incineration I'm sympathetic to that view, then I wouldn't be at all sad to see the forces of Laura Norder get their size thirteens through the door.
EastMids:
Japan probe finds miswiring of Boeing 787 battery
If this is the case (and not a non-tech reporter's mis-stating the problem), its not a battery subsystem problem. Its a Boeing QA problem.
I was there back when the FAA came in following QA and configuration control problems with the 757, 737 and others. It wasn't a pretty sight. I hope Boeing didn't throw out the baby with the bathwater after all the work we put in rescuing Boeing's production certificate. One can find and fix a problem once and be forgiven. Make the same mistake again and people will start wondering if they are really up to the job. The whole self certification and production inspection might have to be revisited, with the solution being FAA inspectors on site signing off each plane.
Japan probe finds miswiring of Boeing 787 battery
If this is the case (and not a non-tech reporter's mis-stating the problem), its not a battery subsystem problem. Its a Boeing QA problem.
I was there back when the FAA came in following QA and configuration control problems with the 757, 737 and others. It wasn't a pretty sight. I hope Boeing didn't throw out the baby with the bathwater after all the work we put in rescuing Boeing's production certificate. One can find and fix a problem once and be forgiven. Make the same mistake again and people will start wondering if they are really up to the job. The whole self certification and production inspection might have to be revisited, with the solution being FAA inspectors on site signing off each plane.
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They could redesign the brakes so that they are normally fully on and elictric power is only needed to hold them off. Some bird's feet work that way - by default they grip any twig the bird perches on and effort is needed to release the grip when they want to fly away. That way, the bird can sleep without falling off its perch.
The brakes on every coach are held on (by springs, for example) and released by the action of a round-train circuit, in early days pneumatic/vacuum, these days electrical. The circuit needs to be complete - and everything else needs to be operating correctly - to release the brakes; if the train separates or something else goes wrong, or the power is cut, the brakes apply. Of course a million implausible runaway-train movies ignore this but that's to be expected ;-).
I'm not sure the fail safe function of this in aviation is entirely as clear cut (eg. if a plane were to land with the brakes stuck on would this cause the landing gear to shear off which may be worse than landing with brakes off - a genuine question, I don't know the answer), but the principle is well founded.
* very long trains - primarily freight - suffer from the problem that a braking 'signal' can take an awfully long time to propagate down the train pneumatically, so the train will 'bunch up' on braking and 'string out' on brake release, meaning careful driving skill is required to avoid damaging the train, but electronic signalling obviously eliminates this these days. I believe unbraked wagons were abandoned even for freight about a century ago, but for that reason I won't be surprised if someone can come up with a counterexample...
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Boeing should solve the problem the was toy manufacturers do when marketing their products ... at the bottom fthe desxription, in the finest print , barely readable without a magnifier...
(Batteries not included, please order separetly)
(Batteries not included, please order separetly)
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UNDERCOVER AGENTS AT WORK?
Was it a Toulouse mole who suggested and pushed the idea of using a glorified laptop battery, as an essential aircrft electrical supply, thereby wrecking Boeings shiny new creation?
Presumably he will be caught and well & truly waterboarded for his efforts.
Anyone know what happened to the carbonfibre delamination of the wing root and internal wingbox on the factory fatigue 787 specimen? Allegedly U-shaped chunks of titanium were grafted in to solve the problem at the wing root!
Maybe 787 is a step too far, stimulated by the radical things being done by the 'bus' makers?
The K I S S principle seems to have been forgotten in design of not only the dirty techie bits, but also of the widgets that the poor evolved Bonobo chimp in the flight deck has to monitor and understand. When the widgets malfunction, said Bonobo has eventually to diagnose and intervene to save the day.
We are seeing many recent accident reports showing the chimp is out of touch with the shiny X-Box360 kit and shows reluctance to throw it away, disconnect A/P & A/T and fly it like the early aircraft on which the chimp learned its trade.
I was horrified to learn that apparently the "bus" has 1 box of electronics to control both nosewheel steering and mainwheel brakes. Presumably done to save a few kilos, easily negated by the arrival of the passenger(s) nowhere near the <80 kilos allowed for in the loadsheet and who we pray will not be sitting beside us in steerage class!
Step forwards management and regulators and take a rollocking for your inaction/inability in addressing these problems!!
Were any old experienced line pilots invited take part in the design phase-a basic qualification for this task should be to have spent say 30+ years flying, submitting and reading Air Safety Reports as a line pilot/trainer. Such a Bonobo chimp will end up with a more cautious and seasoned approach to what's NEEDED by the pilot community, whilst still being aware of the commercial gains due to SOME of the geeks gadgets.
Presumably he will be caught and well & truly waterboarded for his efforts.
Anyone know what happened to the carbonfibre delamination of the wing root and internal wingbox on the factory fatigue 787 specimen? Allegedly U-shaped chunks of titanium were grafted in to solve the problem at the wing root!
Maybe 787 is a step too far, stimulated by the radical things being done by the 'bus' makers?
The K I S S principle seems to have been forgotten in design of not only the dirty techie bits, but also of the widgets that the poor evolved Bonobo chimp in the flight deck has to monitor and understand. When the widgets malfunction, said Bonobo has eventually to diagnose and intervene to save the day.
We are seeing many recent accident reports showing the chimp is out of touch with the shiny X-Box360 kit and shows reluctance to throw it away, disconnect A/P & A/T and fly it like the early aircraft on which the chimp learned its trade.
I was horrified to learn that apparently the "bus" has 1 box of electronics to control both nosewheel steering and mainwheel brakes. Presumably done to save a few kilos, easily negated by the arrival of the passenger(s) nowhere near the <80 kilos allowed for in the loadsheet and who we pray will not be sitting beside us in steerage class!
Step forwards management and regulators and take a rollocking for your inaction/inability in addressing these problems!!
Were any old experienced line pilots invited take part in the design phase-a basic qualification for this task should be to have spent say 30+ years flying, submitting and reading Air Safety Reports as a line pilot/trainer. Such a Bonobo chimp will end up with a more cautious and seasoned approach to what's NEEDED by the pilot community, whilst still being aware of the commercial gains due to SOME of the geeks gadgets.
Last edited by BARKINGMAD; 20th Feb 2013 at 20:35.
Japan’s Transport Safety Board released a report that stated that the battery of the Dreamliner’s auxiliary power unit had been incorrectly connected to the main lithium-ion battery that overheated. It further stated that a protective value would have presented power from the APU from causing any damage.
The Transport Safety Board said in a report that the battery of the aircraft's auxiliary power unit was incorrectly connected to the main battery that overheated, although a protective valve would have prevented power from the APU from doing damage.
That is serious miswiring. I don't buy it.
