ANA 787 makes emergency landing due 'battery fire warning'
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
E S P....
Thanks, I assumed as much. It strikes me that in a very dynamic draw, supply situation, the Generation, load, and "surge" (battery) would have to be balanced in intricate fashion. At times , in load transition, the Battery is passive, merely a conductor, and the relative flow can create temporary overloads, and conversely, wide open draw. My question was meant to attempt to extrapolate a system I became used to, to the current one.
It strikes me that those two batteries are the pinch in a very large pipeline, so I would have expected there to be more than two batteries (each eight cells)...likewise ambient temps would seem to be rather important.
thanks for your response
Thanks, I assumed as much. It strikes me that in a very dynamic draw, supply situation, the Generation, load, and "surge" (battery) would have to be balanced in intricate fashion. At times , in load transition, the Battery is passive, merely a conductor, and the relative flow can create temporary overloads, and conversely, wide open draw. My question was meant to attempt to extrapolate a system I became used to, to the current one.
It strikes me that those two batteries are the pinch in a very large pipeline, so I would have expected there to be more than two batteries (each eight cells)...likewise ambient temps would seem to be rather important.
thanks for your response
Last edited by Lyman; 18th Jan 2013 at 19:11.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Non conventional design with LiIon
Rory166:
The info we have so far points to the second approach. Not the simpler(old) one.
Traditional batteries are used to regulate the voltage on the busses. They are able to tolerate overcharging quite well. In my view best use of Lithium technology would involve having a separate voltage regulation system with the battery waiting in reserve, perhaps connected through a diode, to provide power in the event of a generation shortfall below demand.
The info we have so far points to the second approach. Not the simpler(old) one.
Join Date: Mar 2011
Location: engineer at large
Posts: 1,409
Likes: 0
Received 0 Likes
on
0 Posts
state of the art battery? who wired this up???
Look at that wiring mess on top of the cells....why is there even wiring like that? this looks to me like it was hacked together...
Look at that wiring mess on top of the cells....why is there even wiring like that? this looks to me like it was hacked together...
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Floating voltage
Bear:
See Float voltage
Definition: The voltage at which the battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery.
Is that what you mean by "Float"?
See Float voltage
Definition: The voltage at which the battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery.
Join Date: Jan 2008
Location: uk
Age: 68
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
wiring
Flight
The visible wiring is almost certainly the BMS connection. The heavy current connection between cells would most likely be by bars. I imagine the point you are making is that the BMS wiring would have been better tied to a supporting structure rather than draped over the cells where possibly warm metal might damage the insulation and cause a short. It does appear to be formed into a loom away from the terminals and busbars. One would hope the battery terminals would also have insulated covering. In general things often look more of a mess having caught fire than they did before.
The visible wiring is almost certainly the BMS connection. The heavy current connection between cells would most likely be by bars. I imagine the point you are making is that the BMS wiring would have been better tied to a supporting structure rather than draped over the cells where possibly warm metal might damage the insulation and cause a short. It does appear to be formed into a loom away from the terminals and busbars. One would hope the battery terminals would also have insulated covering. In general things often look more of a mess having caught fire than they did before.
Last edited by Rory166; 18th Jan 2013 at 23:40. Reason: add last line.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
State of the art battery
FPO:
The answer is at your RH picture. The plastic plate melted an the harness resisted the heat.
Look at that wiring mess on top of the cells....why is there even wiring like that?
The answer is at your RH picture. The plastic plate melted an the harness resisted the heat.
Join Date: Nov 2010
Location: USA
Posts: 100
Likes: 0
Received 0 Likes
on
0 Posts
What puzzles me about these battery events is why they happened when they happened? And why now for, apparently, the first time?
FYI, the ANA aircraft (Line number 9, first flight Jan. 9, 2011) and JAL aircraft (line number 84, first flight Dec. 7, 2012) came off the production line almost two years part. Line Number 1 first flight was Dec. 15, 2009.
My guess: If there aren't serious design problems, is that there are defectively manufactured electrical component(s) involved.
FYI, the ANA aircraft (Line number 9, first flight Jan. 9, 2011) and JAL aircraft (line number 84, first flight Dec. 7, 2012) came off the production line almost two years part. Line Number 1 first flight was Dec. 15, 2009.
My guess: If there aren't serious design problems, is that there are defectively manufactured electrical component(s) involved.
Last edited by airman1900; 19th Jan 2013 at 00:43.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Intriguing indeed, i agree
airman1900:
Over voltage as reported can explain very well. But why? And the timing for the apparently same problem is intriguing.
A software issue? We would need more info on the subsystems "around" the batteries.
NTSB at JAL 787 (BOS):
What puzzles me about these battery events is why they happened when they happened? And why now for, apparently, the first time?
Over voltage as reported can explain very well. But why? And the timing for the apparently same problem is intriguing.
A software issue? We would need more info on the subsystems "around" the batteries.
NTSB at JAL 787 (BOS):
Last edited by RR_NDB; 19th Jan 2013 at 01:17. Reason: Include: Software issue? Include Pic
Join Date: Dec 2012
Location: USA
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
You know someone at Boeng that pushed for these batteries is having a long talk with a chairman that just lost $50 million in stock options from this fiasco. 'So why didn't we go with Lead Acid batteries?'
'Well uh, well gee, um...'
'Well uh, well gee, um...'
Join Date: Nov 1999
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
HelderBerg (SAA 747 Combi downing in Indian Ocean)
"Helderberg crash IASA Lithium Fire"
Any aviation journalist who googles that will have a wealth of information on the first large aircraft downing due to Lithium Ion battery fires - so many decades ago now. Boeing stopped offering the "cargo in aft section of pax compartment" 747 Combi after that event. The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. That bulk carriage of Li ion batts in air-freight is now banned by IATA and the FAA. Not sure why a bunch of aircraft-powering Li Ion accumulators with an even higher power density is (perversely) OK, yet a properly packed container of segregated tiny watch/calculator/phone batteries is not.
However anybody who's seen the results of the Dell laptop battery fires would have no doubt that it's an issue best ducked. Thermal runaway that doesn't need oxygen and cannot be suppressed? Bad enough in an isolated cargo hold, but in an avionics compartment or an inaccessible APU location?
It's not as if you can make them jettisonable. A main load center/avionics compartment in a 787 is a slightly different proposition to most other aircraft that aren't so "electrical" in nature. It's the heart of what makes it fly, not just the aircraft avionics. Aircraft control becomes an issue.
The 787 was designed to be a nil hydraulics electrically powered beastie. .... so battery capacity and reliability was quintessential to safety. I'm wondering what dispensations and extra requirements specifications were finagled by Boeing engineers in the design approval process (via sympathetic FAA weenies). Maybe the new FAA administrator started looking into this after the fires started, discovered something and then had no choice but to order a "review". More power to his elbow.
If the Lithium Ion battery fires continue or there's an unexplained loss due to a crew having to quickly monitor off busses in a fire and smoke drill? That will be a nightmare for both Boeing and the FAA. It's got all the potential of a NASA Challenger disaster and a denial of leaky seals being a threat to the Space Shuttle.
But one thing is for certain. Boeing will not be giving up on those Li Ion batteries in the 787. There's no viable alternative with the required power density. And a timely fixing of a new aircraft that's both in service and on the assembly line? Burn that midnight oil you Boeing engineers. Whatever you come up with as a fix better be good.
Any aviation journalist who googles that will have a wealth of information on the first large aircraft downing due to Lithium Ion battery fires - so many decades ago now. Boeing stopped offering the "cargo in aft section of pax compartment" 747 Combi after that event. The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. That bulk carriage of Li ion batts in air-freight is now banned by IATA and the FAA. Not sure why a bunch of aircraft-powering Li Ion accumulators with an even higher power density is (perversely) OK, yet a properly packed container of segregated tiny watch/calculator/phone batteries is not.
However anybody who's seen the results of the Dell laptop battery fires would have no doubt that it's an issue best ducked. Thermal runaway that doesn't need oxygen and cannot be suppressed? Bad enough in an isolated cargo hold, but in an avionics compartment or an inaccessible APU location?
It's not as if you can make them jettisonable. A main load center/avionics compartment in a 787 is a slightly different proposition to most other aircraft that aren't so "electrical" in nature. It's the heart of what makes it fly, not just the aircraft avionics. Aircraft control becomes an issue.
The 787 was designed to be a nil hydraulics electrically powered beastie. .... so battery capacity and reliability was quintessential to safety. I'm wondering what dispensations and extra requirements specifications were finagled by Boeing engineers in the design approval process (via sympathetic FAA weenies). Maybe the new FAA administrator started looking into this after the fires started, discovered something and then had no choice but to order a "review". More power to his elbow.
If the Lithium Ion battery fires continue or there's an unexplained loss due to a crew having to quickly monitor off busses in a fire and smoke drill? That will be a nightmare for both Boeing and the FAA. It's got all the potential of a NASA Challenger disaster and a denial of leaky seals being a threat to the Space Shuttle.
But one thing is for certain. Boeing will not be giving up on those Li Ion batteries in the 787. There's no viable alternative with the required power density. And a timely fixing of a new aircraft that's both in service and on the assembly line? Burn that midnight oil you Boeing engineers. Whatever you come up with as a fix better be good.
Join Date: Feb 2007
Location: Melbourne
Age: 57
Posts: 628
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by unctuous
Any aviation journalist who googles that will have a wealth of information on the first large aircraft downing due to Lithium Ion battery fires - so many decades ago now. Boeing stopped offering the "cargo in aft section of pax compartment" 747 Combi after that event. The Helderberg event coincided with the bulk carriage of Li Ion watch batteries that happened inreasingly - just as digital watches and pocket calculators were becoming the norm. That bulk carriage of Li ion batts in air-freight is now banned by IATA and the FAA. Not sure why a bunch of aircraft-powering Li Ion accumulators with an even higher power density is (perversely) OK, yet a properly packed container of segregated tiny watch/calculator/phone batteries is not.
Boeing and the OEMs will have done their work and believe that they have properly tested this newer technology and that it is safe for aviation specific applications. That's progress. The watch batteries will not have had any such testing done, why would you spend a bucketload of cash for such an incidental part of a spec when you can just use sea freight?
Lithium ion batteries in aircraft will almost certainly become the norm, but the issues need sorting out first. As a new aircraft the 787 doesn't have the luxury of using tried and tested technology, if you did that you'd effectively get a 777, and as good an aircraft as that is the 787 is far better once the bugs are ironed out.
Join Date: Jan 2008
Location: uk
Age: 68
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Battery Rupture Plate
Having now had the opportunity to view the manufacturers outline spec sheet for the Yuasa Li-Co cells I see the rupture plate is apparently in the side of the battery rather than on top as conventional. This might give the opportunity to place a vent path from this rupture plate to the outside rather than have the emitted chemicals destroy the rest of the contents of the battery case as seems to have happened in the pictures shown on this thread. Clearly the designers of the battery box were confident that the 4 battery management systems (2 in box 2 outside) would ensure that a cell never did rupture.
The requirement for maturity and Aeropspace certification may in this case have been counterproductive in that an older less safe battery chemistry is used in preference to a newer fundamentally safer chemistry.
Does anyone know the pressurisation status of the electronics compartment where the battery is housed. I am slightly mystified as to how the chemicals were vented overboard in one instance and smelled in cockpit and passenger compartment in another.
The requirement for maturity and Aeropspace certification may in this case have been counterproductive in that an older less safe battery chemistry is used in preference to a newer fundamentally safer chemistry.
Does anyone know the pressurisation status of the electronics compartment where the battery is housed. I am slightly mystified as to how the chemicals were vented overboard in one instance and smelled in cockpit and passenger compartment in another.
Join Date: Jan 2008
Location: uk
Age: 68
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
2 batteries
Mailinator
The two batteries are for different functions apparently. One as the APU power source and one as a backup for the electronics. So the battery backup has 4 monitoring systems but no backup for itself. Once the backup battery failed there would have been no backup in the event of a power failure. Does the dreamliner have a drop down aero generator anyone?
The two batteries are for different functions apparently. One as the APU power source and one as a backup for the electronics. So the battery backup has 4 monitoring systems but no backup for itself. Once the backup battery failed there would have been no backup in the event of a power failure. Does the dreamliner have a drop down aero generator anyone?
But one thing is for certain. Boeing will not be giving up on those Li Ion batteries in the 787. There's no viable alternative with the required power density.
Join Date: Apr 2005
Location: Stockholm Sweden
Age: 74
Posts: 569
Likes: 0
Received 0 Likes
on
0 Posts
Does anyone know the pressurisation status of the electronics compartment where the battery is housed. I am slightly mystified as to how the chemicals were vented overboard in one instance and smelled in cockpit and passenger compartment in another
Although there is positive airflow in flight from the cabin to the underfloor it is amazing how crew regularly smell things happening downstairs, even though the airflow is in the other direction.
Join Date: Aug 2007
Location: London, New York, Paris, Moscow.
Posts: 3,632
Likes: 0
Received 0 Likes
on
0 Posts
From what I can read on the 'net the aft EE bay is the main Electrical distributor point as the 4 main starter/generators and 2 apu generators feed in there.
IF the above picture shows the RAT in it's production location then worryingly does it point to the emergency power distribution system being located in the aft EE bay as well.........all the eggs in one basket?
Airbus have a philosophy of physical separation of primary/secondary and emergency power supply systems with, naturally, a weight penalty.
IF the above picture shows the RAT in it's production location then worryingly does it point to the emergency power distribution system being located in the aft EE bay as well.........all the eggs in one basket?
Airbus have a philosophy of physical separation of primary/secondary and emergency power supply systems with, naturally, a weight penalty.
Join Date: Jul 2007
Location: Germany
Posts: 556
Likes: 0
Received 0 Likes
on
0 Posts
787 smoke venting from E/E bays
As written in a previous post, the reason why it was possible to vent the smoke in cruise, but not on the ground is simple.
Venting is done by an overboard venturi, which only works during flight (it is only used in cases of failure, normal E/E cooling is accomplished using electric fans). On the ground, as in the Boston case, this type of venting cannot work, so smoke was able to enter the cabin.
Glad rag,
The RAT sits under the wings, but feeds into the main circuits in the forward E/E bay.
Venting is done by an overboard venturi, which only works during flight (it is only used in cases of failure, normal E/E cooling is accomplished using electric fans). On the ground, as in the Boston case, this type of venting cannot work, so smoke was able to enter the cabin.
Glad rag,
The RAT sits under the wings, but feeds into the main circuits in the forward E/E bay.
Last edited by bsieker; 19th Jan 2013 at 09:47.
IF the above picture shows the RAT in it's production location
Here's a clearer photo that shows it deployed:
Unctuous.
Where did you get the idea that the 787 is a "nil hydraulics" aircraft. The only system that is electric instead of the usual hydraulic is the brakes.
Flt ctls, l/gear ops are still hydraulic.
The engines still have directly driven hydraulic pumps on the gear boxes.
Where did you get the idea that the 787 is a "nil hydraulics" aircraft. The only system that is electric instead of the usual hydraulic is the brakes.
Flt ctls, l/gear ops are still hydraulic.
The engines still have directly driven hydraulic pumps on the gear boxes.