Dreamliner Grounded.
Thread Starter
Join Date: Dec 2012
Location: USA
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
Dreamliner Grounded.
I guess they thought Lithium Ion batteries were a good choice, .....based on how wonderful Nicads were?
Never failed to amuse at school when guys would argue for Nicads, half a day spent on battery overheat procedures...then when you go to a Lead Acid battery...for a tenth the cost, no inspection and deep cycles... INOP the temp guage, rip out two pages of checklist items. Now it's like car battery...either works or it doesn't.
Boeing must have some rocket scientists working there.
Never failed to amuse at school when guys would argue for Nicads, half a day spent on battery overheat procedures...then when you go to a Lead Acid battery...for a tenth the cost, no inspection and deep cycles... INOP the temp guage, rip out two pages of checklist items. Now it's like car battery...either works or it doesn't.
Boeing must have some rocket scientists working there.
Join Date: Oct 2009
Location: UK
Posts: 1,270
Likes: 0
Received 0 Likes
on
0 Posts
Hi TheRobe,
L1011s had NiCad batteries.
See page 25-6 of MMEL Electrical Power for "condition light" (read battery temperature)
http://www.caa.co.uk/docs/33/srg_acp_l1011_rev1_all.pdf
We never went back to Lead Acid Batteries - the battery charger technology simply improved.
based on how wonderful Nicads were?
half a day spent on battery overheat procedures
http://www.caa.co.uk/docs/33/srg_acp_l1011_rev1_all.pdf
We never went back to Lead Acid Batteries - the battery charger technology simply improved.
Seems to be a control issue
The Yuasa batteries are managed by a Thales control system, allegedly quadruply redundant, which is tasked with monitoring the batteries charging and discharging currents as well as its temperatures.
There are now reports that suggest both aircraft may have had used parts from a bad lot of circuit boards in the battery controller. This seems more plausible to me than two random battery failures.
The real shock imho was the poor containment performance of the design, with fumes vented into the cabin and cockpit as well as ejected battery fluid bathing much of the battery compartment. This was not supposed to happen, fumes were supposed to be vented and fluids contained.
Both the FAA and Boeing should be grateful for this wake-up call and take advantage of the opportunity to do a more jaundiced reappraisal of how well the outsourcing of critical subsystem design and assembly really serves the aircraft buyers and the travelling public.
There are now reports that suggest both aircraft may have had used parts from a bad lot of circuit boards in the battery controller. This seems more plausible to me than two random battery failures.
The real shock imho was the poor containment performance of the design, with fumes vented into the cabin and cockpit as well as ejected battery fluid bathing much of the battery compartment. This was not supposed to happen, fumes were supposed to be vented and fluids contained.
Both the FAA and Boeing should be grateful for this wake-up call and take advantage of the opportunity to do a more jaundiced reappraisal of how well the outsourcing of critical subsystem design and assembly really serves the aircraft buyers and the travelling public.
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
Posts: 3,832
Likes: 0
Received 0 Likes
on
0 Posts
Never failed to amuse at school when guys would argue for Nicads, half a day spent on battery overheat procedures...then when you go to a Lead Acid battery...for a tenth the cost, no inspection and deep cycles... INOP the temp guage, rip out two pages of checklist items. Now it's like car battery...either works or it doesn't.
Previous discussion here Battery - Lead Acid vs. NiCad preferences. [Archive] - PPRuNe Forums
Despite misconceptions, lead acids may have a thermal runaway. Photo of such in a car.
.All battery systems may be driven into thermal runaway if severely overcharged for a prolonged period at high temperatures. The lead acid battery, when driven into thermal runaway, will fail in such a manner that the aircraft is not endangered.
All battery systems in thermal runaway will produce large amounts of hydrogen and oxygen gas which must be vented outboard of the aircraft.
A nickel cadmium battery in an uncontrolled thermal runaway may get so hot that the battery separator melts causing shorts within the cells and the cell containers melt causing ground shorts to the outside stainless steel container. The result of these shorts is that the battery may catch fire, explode, or the resultant arcing may burn holes in the outer stainless steel box and surrounding aircraft structure. For this reason, the nickel cadmium batteries are equipped with temperature sensors and temperature warning systems.
The lead acid battery in thermal runaway will reach only a relatively moderate internal temperature (approximately 260° F) at which point the water in the electrolyte vaporises and the battery vents steam. As the separator is glass, it is unaffected by this low temperature. The loss of water caused by the venting reduces the conductivity between the battery plates and the battery ceases to accept further charge. The battery slowly cools.
All aircraft I flew professionally only allowed the use of Nicads, no STC being available to allow lead acid, though that has now changed.
http://www.concordebattery.com/otherpdf/finalfaapma.pdf
Last edited by Brian Abraham; 18th Jan 2013 at 03:35.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Battery types
Brian Abraham:
The photo seems a NiCd pack. You may see cells inside and one outside the pack at left.
These batteries gave us "Fault tolerance" and "Graceful degradation". Essential characteristic of a good design.
In general we can say lead acid are less critical.
rudderrudderrat:
Let´s hope for the same in 787. The less damaging scenario.
...Photo of such in a car.
The photo seems a NiCd pack. You may see cells inside and one outside the pack at left.
The lead acid battery, when driven into thermal runaway, will fail in such a manner that the aircraft is not endangered.
In general we can say lead acid are less critical.
rudderrudderrat:
Let´s hope for the same in 787. The less damaging scenario.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Not battery issue? If so, would be the less damaging scenario
etudiant:
A severe malfunction of the battery associated circuitry (charger, etc.) could explain the occurrences. This scenario certainly was not considered in the design. There are limits to redundance, etc.
I hope for the chargers / circuitry malfunction scenario. The "less damaging". If due components (not the design) less worse.
A severe malfunction of the battery associated circuitry (charger, etc.) could explain the occurrences. This scenario certainly was not considered in the design. There are limits to redundance, etc.
I hope for the chargers / circuitry malfunction scenario. The "less damaging". If due components (not the design) less worse.
Thread Starter
Join Date: Dec 2012
Location: USA
Posts: 47
Likes: 0
Received 0 Likes
on
0 Posts
Whatever the case, LION batteries for planes are new technology...so my guess is that they will deep cycle them more often, not try to charge them so hard, go to larger capacity batteries..whatever...always a solution.
Given the hysteria, a lead acid retrofit would be an easy fix until they get the kinks out of the LIONs.
Given the hysteria, a lead acid retrofit would be an easy fix until they get the kinks out of the LIONs.
Last edited by TheRobe; 18th Jan 2013 at 06:41.
Any relevance to the thread?
Photo is of one of TWA's Super Constellations, N7121C, damaged (though later rebuild with a salvaged forward fuselage) when a pressurisation test went wrong at Idlewild in 1959.
Well, anyway, it's a nice picture. I mean, a nice airplane. Er, that is... had been a GREAT aircraft, and the photographer did a neat job. Is it a plain 1049 or a Super G? Have had a soft spot for the Connie since a 749 carried me a quarter of the way round the world in 1955.
The Constellation was THE dreamliner, so Glueball is bang on-topic - pun not intended. (Too many 787 nightmare-threads already.)
The Constellation was THE dreamliner, so Glueball is bang on-topic - pun not intended. (Too many 787 nightmare-threads already.)
I'm reminded of the new London "bendy buses" of a few years ago, now gone, which came from a "world-renowned" German manufacturer.
Shortly after introduction one was completely destroyed by fire. "An absolutely unique incident" said the manufacturers' management.
Then a second was destroyed the same way "the most amazing and unrepeatable coincidence" said the same management.
Then a third one went up in flames as well. And then they were all taken out of service. And then it was discovered the issue had been identified in development, but was suppressed somewhere along the way ........
Shortly after introduction one was completely destroyed by fire. "An absolutely unique incident" said the manufacturers' management.
Then a second was destroyed the same way "the most amazing and unrepeatable coincidence" said the same management.
Then a third one went up in flames as well. And then they were all taken out of service. And then it was discovered the issue had been identified in development, but was suppressed somewhere along the way ........
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Mr O
when the front offside quarter light was open ?
