FAA Grounds 787s
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Having scanned the report, the reason for the differences of opinion between the NTSB and the FAA become apparent.
Boeing were keen to push the boundaries, hence the 'Electric plane concept' and it's dependence on Li-Ion.
However, this requires the FAA to re-evaluate it's stance on Li-Ion batteries and it consequently introduced new legislation which was designed to prevent the Boston event.
Subtle shift of emphasis away from Boeing and towards the FAA IMO, onus is now on FAA in two respects: firstly, to prove that their legislation was robust enough and secondly, their involvement and analysis on the test data.
On this side of the pond, we'd probably have an independent public inquiry where a senior civil servant chairs an independent team of experts who gather information, analyse said information and present their conclusions.
I assume that the Stateside equivalent would be a congressional inquiry?
Boeing were keen to push the boundaries, hence the 'Electric plane concept' and it's dependence on Li-Ion.
However, this requires the FAA to re-evaluate it's stance on Li-Ion batteries and it consequently introduced new legislation which was designed to prevent the Boston event.
Subtle shift of emphasis away from Boeing and towards the FAA IMO, onus is now on FAA in two respects: firstly, to prove that their legislation was robust enough and secondly, their involvement and analysis on the test data.
On this side of the pond, we'd probably have an independent public inquiry where a senior civil servant chairs an independent team of experts who gather information, analyse said information and present their conclusions.
I assume that the Stateside equivalent would be a congressional inquiry?
Last edited by Momoe; 7th Mar 2013 at 22:09.
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Momoe
Stateside, this is about the best we're gonna get- NTSB is an independent body. Sadly, they can only make recommendations to FAA and Boeing. If this was the subject of a congressional inquiry, it would be a total partisan clusterfcuk.
However, if there were another incident, we could get a coroner's inquest if there were fatalities.
However, if there were another incident, we could get a coroner's inquest if there were fatalities.
Although many are looking at this NTSB report, published today, as new information, I bet there isn't a single item of fact about the event in there that was not known to the Boeing Board of Directors, and the FAA, within 24 hours of the happening. Which makes the Boeing response, of a stronger box being the answer, even more extraordinary. Just how much energy is inside waiting to be released when that, in turn, explodes ?
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poorjohn:
And when the APU shut down, the ventilation to remove the smoke from the burning battery also shut down. In flight this might not have been as serious if the ventilation was also powered by the other generators and pressure difference to the outside. It does argue strongly that Boeing's proposed sealed case and pressure vent is a step in the right direction.
Per the NTSB report, after the APU starts, the APU battery must continue to supply power to the APU control electronics. When the JAL battery failed, the APU shut down.
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FlightPathOBN:
I think that the firefighters may have been intellectually aware of how to contain the fire but gave too much weight to the directive to avoid damage to the equipment in the bay.
Water is the only thing readily available which will both cut off oxygen and cool the battery to prevent re-ignition. The training for flight crew on the other hand emphasizes the importance of water in fighting a Lithium battery fire very strongly. (Urinate on it if you have to...
) Do not try this in the middle of a compartment full of 400+ volt AC!
I would have hoped that the firefighters would have carefully resorted to water much earlier in the incident given that all power had been shut down.
In flight, on the other hand, extinguishing is just not an option:
The fire fighters were not aware of Li nor were able to contain the fire...
in flight..well damn..
in flight..well damn..
Water is the only thing readily available which will both cut off oxygen and cool the battery to prevent re-ignition. The training for flight crew on the other hand emphasizes the importance of water in fighting a Lithium battery fire very strongly. (Urinate on it if you have to...
) Do not try this in the middle of a compartment full of 400+ volt AC!I would have hoped that the firefighters would have carefully resorted to water much earlier in the incident given that all power had been shut down.
In flight, on the other hand, extinguishing is just not an option:
Composite fire liners and a fire door separate the aft E/E from the aft cargo compartment. The aft E/E may be accessed through the aft cargo compartment if the compartment is empty. While the environmental conditions in the E/E are similar to the main passenger cabin above it, the compartment is not accessible from the main passenger deck.
Last edited by inetdog; 8th Mar 2013 at 00:44.
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Battery woes of not so long ago
It is interesting to note the problems that occurred several decades ago when we made the switch from lead acid batteries, now ancient for commercial aerospace applications, to NiCads. The NTSB apparently recorded over a dozen incidents in one year back in the early 1970's. There were alarms sounded, and the same sort of doomsday talk and whinging that is heard today about the lithium-based types in the 787 filled the air back then.
After the teething issues were resolved, NiCads quickly became an industry standard for both private and commercial transport category aircraft. There were no crashes or fatal mishaps.
After the teething issues were resolved, NiCads quickly became an industry standard for both private and commercial transport category aircraft. There were no crashes or fatal mishaps.
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smoke evacuation
From page 34 of the NTSB report, this gem.
I think before the 787 is let loose again, a test flight might be made with the families of some of the executives on board.
During this incident, the supply valves (which are electrically driven) lost electrical power after the APU shut down because the APU was the only source of electrical power being used at the time. As a result, smoke generated by the APU battery could not be effectively redirected outside the cabin and aft E/E bay.
I am sure lots of professionals on this forum will now step forward to explain that this is no problem.I think before the 787 is let loose again, a test flight might be made with the families of some of the executives on board.
Last edited by edmundronald; 8th Mar 2013 at 00:54.
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Quote:
I also did not specify how much brake pressure would be cranked in. It is a "proportional" system, but a little hard to guess without performance-based feedback.
Land with locked wheels and no anti-skid?
I suspect that's why there was a 
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FlightPathOBN:
But was the cell inside a closed battery compartment with 7 other warm cells at the time? Or even insulated to confine the released energy?
And was the charging system pumping 45 amps in throughout?
The NTSB a month ago established that the fire instead started with an internal short circuit of a single cell in the eight-cell battery.
Boeings pre-certification testing did try to evaluate the effect of an internal short circuit. It chose to do so with a test that punctured a cell with a nail to induce a short circuit.
This test resulted in venting with smoke but no fire, the NTSB reported.
Boeings pre-certification testing did try to evaluate the effect of an internal short circuit. It chose to do so with a test that punctured a cell with a nail to induce a short circuit.
This test resulted in venting with smoke but no fire, the NTSB reported.
And was the charging system pumping 45 amps in throughout?
Last edited by inetdog; 8th Mar 2013 at 00:53.
Paxing All Over The World
From the NTSB report linked earlier:
Well, there's one 'To Do' item.
I think that we can be glad that such a comprehensive document, set in plain language and with real photographs is publically available. I wonder if all countries do this when one of their own is in the frame?
Edmund
Good plan, start a petition. 
The Battery Monitoring Unit main circuit card and sub-circuit card do not contain nonvolatile memory (NVM), and none of the BMU data are recorded on the FDR.
I think that we can be glad that such a comprehensive document, set in plain language and with real photographs is publically available. I wonder if all countries do this when one of their own is in the frame?
Edmund
I think before the 787 is let loose again, a test flight might be made with the families of some of the executives on board.
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I think that we can be glad that such a comprehensive document, set in plain language and with real photographs is publically available. I wonder if all countries do this when one of their own is in the frame?
PAXboy
You should know the answer to this, living, as you do, in the spiritual home of De-Havilland
I wonder if all countries do this when one of their own is in the frame?
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main battery lasted 53 seconds?
I don't understand this from the report
Was the battery switched off on purpose or did was it drained in just the 53 seconds?
1022:00 main battery is discharging
1022:53 main battery power switch is off
1022:53 main battery power switch is off
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So if the brakes are applied to a certain pressure and corresponding braking torque, they will maintain that braking until the actuators are driven in the opposite direction.
What brakes the aircraft (what produces a break torque) is the force compressing the brake disks (and the coefficient of friction). What is defining the force is the ammount of compression by the spindle and the stiffness of the brake disk package. If the brakes are active, they wear and become thinner (just a little bit, of course), but the also get hot, and with the negative thermal expansion of carbon fibre they get even thinner, while the housing from metal expands at the same time. Given the same ammount of deformation (spindle is fixed), the compressing force and hence the brake torque will fade with use. How much strongly depends on specific numbers. So you may lose a significant amount of brake torque if you do not adjust the spindles, which means that without electricity, you will probably end up with less braking power than desired.
which of course still is a simplistic view of the issue...
The fire came to the attention of the ground crew through the smoke permeating the aircraft and the electrics shutting down.
Is there no smoke/fire alarm in the E/E compartment ? Do we have smoke alarms in each readily accessible aircraft toilet, but not in inaccessible compartments full of high energy technical devices ?
Is there no smoke/fire alarm in the E/E compartment ? Do we have smoke alarms in each readily accessible aircraft toilet, but not in inaccessible compartments full of high energy technical devices ?
Does anyone know if the Aft E&E bay is accessible from the cabin, i.e., in flight? From Page 8 of the report:
"This compartment is located aft of the main landing gear and beneath approximately the third set of cabin doors (L3 and R3). The compartment is only accessible from the ground by a door in the aft cargo compartment and a set of doors in the airplane belly."
The second sentence is ambiguous on this point. Is it "only accessible from the ground"? Or "from the ground (only accessible) by a door in the aft cargo compartment and a set of doors in the belly"?
And how about the Forward bay?
"This compartment is located aft of the main landing gear and beneath approximately the third set of cabin doors (L3 and R3). The compartment is only accessible from the ground by a door in the aft cargo compartment and a set of doors in the airplane belly."
The second sentence is ambiguous on this point. Is it "only accessible from the ground"? Or "from the ground (only accessible) by a door in the aft cargo compartment and a set of doors in the belly"?
And how about the Forward bay?
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The NTSB has done a nice writeup.
The APU shutting down when its starting power supply goes down, the smoke evacuation being linked to the equipment on fire, the lack of diagnostic NVRAM are all systems integration issues.
The battery technology is in the end minor and easy to change, give or take the weight of a passenger, but it is to be feared that similar integration issues pervade the rest of the plane's design.
The APU shutting down when its starting power supply goes down, the smoke evacuation being linked to the equipment on fire, the lack of diagnostic NVRAM are all systems integration issues.
The battery technology is in the end minor and easy to change, give or take the weight of a passenger, but it is to be feared that similar integration issues pervade the rest of the plane's design.
But Boeing just won't entertain this. They have come up with all sorts of workarounds to avoid this. If that is their attitude to the prime cause of the fire, what is going to be their approach to the rest of all these issues now unearthed ?
Last edited by WHBM; 8th Mar 2013 at 13:11.