As the majority of the replys in the last thread were off tech/ops nature, please keep this thread for any news/updates on the progress for getting the Dreamliner back flying again. If you wish to discuss the battery issues/fire/APU etc then discuss them in B787 Grounding: Tech/ops Thread Part 2 which can be found here B787 Grounding: Tech/ops Thread Part 2 (by 777ER Mar 9 2013 in Tech Ops)
WARNING: Due to thread 9 going off topic quickly and turning into a 'battle ground', the moderators will be watching this thread frequently and ANY offending/rule breaking posts will be removed. Please respect each others right to have their opinion
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Independent experts view the fail-safe part of Boeing’s proposed 787 Dreamliner fix — a heavy stainless steel box that will contain any heat, flames or flammable vapors from the lithium ion battery — as a solid solution.
But to John Goglia, a former member of the National Transportation Safety Board and now an outspoken critic of the FAA and Boeing, it’s this box that makes Boeing’s solution acceptable.
“No matter what happens to the battery now, it won’t be a problem because it’s contained,” Goglia said. “It’ll probably satisfy the FAA to get the airplane back in the sky.”
Other tests are more severe, including one lab test that involves igniting propane inside the containment box, causing an explosion that increases the pressure to three times what could be expected in the worst-case scenario.
Boeing has already done a successful run-through of this test. A video shows the 1/8th-inch-thick steel walls of the box bulge out in slow motion. But they hold fast and regain their shape.
“It’s easy to calculate the amount of energy in the battery and it’s easy to calculate the amount of energy the box can absorb,” said Janicki. “Mathematically, to know whether it will work is a fairly precise science.”
An aviation-safety engineer, who asked for anonymity because he spoke without the approval of his employer (not Boeing), agreed that the proposed battery fix “looks pretty good.”
Though he’s critical of how the FAA appears to have rubber-stamped Boeing’s original battery design, he said the revised battery system should be approved and certified to fly.
He said the fix, which adds 150 pounds to the weight of the airplane — more than doubling the weight of the two main batteries involved — completely negates the weight savings that had been expected from using lithium ion instead of nickel cadmium batteries.
JAAlbert From United States of America, joined Jan 2006, 1804 posts, RR: 1
Reply 5, posted (3 years 2 months 5 days 14 hours ago) and read 42647 times:
Quoting blrsea (Reply 4): Independent experts view the fail-safe part of Boeing’s proposed 787 Dreamliner fix — a heavy stainless steel box that will contain any heat, flames or flammable vapors from the lithium ion battery — as a solid solution.
So the box will contain any failure - but it doesn't sound like this fix gets to the issue as to why the batteries overheated in the first place, does it? The original batteries from what I read were failing at a high rate -- what is or has been done to correct that problem? I'm sure the airlines don't want to be replacing these batteries every few months.
kanban From United States of America, joined Jan 2008, 4331 posts, RR: 30
Reply 6, posted (3 years 2 months 5 days 13 hours ago) and read 42557 times:
Quoting JAAlbert (Reply 5): The original batteries from what I read were failing at a high rate --
depends on what you call failing.. As I recall of those removed (and called failures by some) 90% were because that had been drawn down to a point where they were locked out for recharging on the plane. the causes were predominately ramps/cleaning crews using battery power instead of ground power.. because a seriously drawn down battery is more unstable than one discharged in normal use, it must be removed to recharge and reset the limiters. There was a breakdown of the other 10% however I don't recall what they were
NAV20 From Australia, joined Nov 2003, 9909 posts, RR: 35
Reply 7, posted (3 years 2 months 5 days 13 hours ago) and read 42490 times:
Quoting JAAlbert (Reply 5): but it doesn't sound like this fix gets to the issue as to why the batteries overheated in the first place, does it? The original batteries from what I read were failing at a high rate -- what is or has been done to correct that problem?
As I understand it, JAAlbert, the overheating (just the two incidents so far) is thought to have been caused by 'spreading' short-circuits due to the cells being too close together and uncontained. Boeing and Yuasa have therefore moved the cells further apart, and also added insulation etc. between them.
As far as I know, all previous failures (and I agree that there were a lot of them) occurred on the ground; and the problem was that some batteries could not be recharged 'in situ' and therefore had to be replaced; not a matter of fires etc.. The proposal there appears to be to adjust the appropriate recharging rates and also the levels to which the batteries discharge and recharge; I don't know enough physics fully to understand that, but get the impression that it's mainly a matter of 'calming everything down.' All wiring arrangements etc. have also been reviewed.
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
Stitch From United States of America, joined Jul 2005, 34061 posts, RR: 85
Reply 8, posted (3 years 2 months 5 days 12 hours ago) and read 42212 times:
Quoting JAAlbert (Reply 5): So the box will contain any failure - but it doesn't sound like this fix gets to the issue as to why the batteries overheated in the first place, does it?
No, because why they overheated in the first place isn't known. Rather than keep the fleet grounded until a final cause is determined, this new box will allow any failure to be tolerated in the interim. Once a cause is found, additional remediation will be taken to prevent or reduce the chances of it happening again.
Quoting JAAlbert (Reply 5): The original batteries from what I read were failing at a high rate -- what is or has been done to correct that problem?
The maximum discharge level is being raised to a level that allows the batteries to still be charged aboard the plane if that level is reached.
lightsaber From United States of America, joined Jan 2005, 15653 posts, RR: 100
Reply 9, posted (3 years 2 months 5 days 11 hours ago) and read 41777 times:
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Quoting Stitch (Reply 8): Once a cause is found, additional remediation will be taken to prevent or reduce the chances of it happening again.
To expand, Boeing has also reduced the chance of a battery fire by:
1. Reducing how much the battery may be drained and still recharged on aircraft
2. Reducing how much the battery may be charged (in effect, really cutting back on the number of watt hours that battery may put out)
3. Reducing the battery charge harshness. (I assume by slowing the charge and putting a ramp up or other means into the battery charging profile.)
One of three steps. I know you knew, but I felt your post needed to be expanded upon. Each of the above reduces the chance of a battery fire. The three in combination are belts, suspenders, and an elastic waist in combo.
"They did not know it was impossible, so they did it!" - Mark Twain
sweair From Sweden, joined Nov 2011, 1836 posts, RR: 0
Reply 10, posted (3 years 2 months 5 days 7 hours ago) and read 41031 times:
I hope for the airlines that this will be OK for FAA but not as a final solution. First treat the illness, then develop a remedy, that should be a logical path.
However many here think that this is the final solution, I don´t think even B is satisfied by flying with unknown causes in its batteries. However to redo chemistry and get that tested, accepted and certified would take too long for the airlines to accept. Just do this interim and aim to remake over time and that update should be free of charge to any airline flying the 787. That way it will keep flying and finally have a better cell chemistry in the end.
Quote: New details of the redesigned battery system also reveal why Boeing has remained confident of FAA approval for the fix. The battery enclosure, which is designed to prevent a fire erupting rather than simply containing it, is made of 0.125-in.-thick stainless steel. A 1-in.-dia. titanium vent pipe connects the back of the enclosure to the outer skin of the aircraft where new exit holes—one for each battery—will be cut through the composite skin. The vent pipe is designed to evacuate vaporized electrolytes from the battery should any, or all, of the eight cells in the unit fail. In the event of a cell failure, a small pressure port in the rear of the enclosure is designed to rupture under pressure from the building vapor. The vapor will then exit the aircraft via the vent pipe.
Interesting stuff. Earlier posts here suggested that new holes in the fuselage weren't the best option.
2175301 From United States of America, joined May 2007, 1404 posts, RR: 0
Reply 15, posted (3 years 2 months 5 days 4 hours ago) and read 40197 times:
Quoting scbriml (Reply 14): Quoting sweair (Reply 10):
However many here think that this is the final solution
Maybe because Boeing has indicated as much?
Actually, I believe that Boeing will change to Titanium boxes in the future instead of 1/8" SS before they change the battery chemistry.
That would probably allow a wight reduction in the box by at least 1/2.
For now (and as an immediate fix), SS was readily available in sufficient quantities and is very easily fabricated. Titanium needs to have better scheduling of material availability (especially certain alloys) and can have fabrication challenges that take some time to perfect the best way.
Note that Boeing used Titanium tubing for the vent pipe which I believes provides a clue to how important weight is. Such tubing in several alloys is readily available. So is SS tubing - which would work as well (but weighs more).
Stitch From United States of America, joined Jul 2005, 34061 posts, RR: 85
Reply 17, posted (3 years 2 months 5 days ago) and read 38985 times:
Quoting francoflier (Reply 12): Is there any word on whether this will affect ETOPS capability yet?
ETOPS-180 should be unaffected by these issues since you can depart with an inoperative APU battery and/or an inoperative APU. So regardless of the failure rate of the APU batteries, the 787 should still meet the requirements for ETOPS-180 operation.
The 787 has yet to be certified for ETOPS-240 or ETOPS-330. In order to attain such certification, either the failure rate of the APU battery will have to be at or below whatever the requirements is or Boeing will have to modify the APU system design so that the APU can be started and operated without the APU battery.
Quote: For a hole in the 787, even if you use the sharpest cutting tool, you will always expect cracks and micro delamination at the cut edges. Sealing will prevent moisture from getting into the crack (and freeze causing additional delamination). However, most likely they will put some sort of bolted and/or bonded doubler around the cutout so any crack growth would be arrested by the bolt clamp-up.
7BOEING7 From United States of America, joined Oct 2012, 2303 posts, RR: 14
Reply 24, posted (3 years 2 months 4 days 23 hours ago) and read 38843 times:
Quoting Kaiarahi (Reply 18): Or perhaps just operated - I haven't looked at ETOPS requirements for a while, but I believe there are some MEL configurations that require continuous APU operation (i.e. started on the ground).
That is true, however, I believe it was stated in a previous thread (somewhere) that Mike Sinnett indicated loss of the APU battery would cause the APU to shut down, so that appearss not to be an option.
: Slide 15: "dedicated vent line" The answer is in TechOps thread one (Tom) - titanium doublers.
: Yes, I saw that, but to me, as a layman, it doesn't say whether that's a new hole or repurposing what already exists.
: Presumably if you repurposed an existing vent, you'd need to cut a new vent for whatever was there before. Perhaps I didn't word my response very cle
: Looks like some 'hard news' about the flight test at last:- "Boeing is on the verge of flight testing the modified 787 battery system changes on Line
: I'm sure Mr Norris has some good conections at Boeing but I doubt we'll see a customer acceptance flight on ZA272 Monday.
: I read it as LN86 will fly a customer acceptance flight profile but that doesn't mean it's an acceptance flight.
: I take the same position as the post below. Just in case, the line from the article is listed below. "at Paine Field, Everett on 24th, and if all goe
: It's only a customer acceptance profile if the the customer is on board. Some follow the Boeing B-1 profile some don't, so which customer profile wil
: What Sinnett said and the NTSB wrote was pretty darn clear, so "misstated," perhaps, but not "misinterpreted." It would have been nice if one the jou
: ZA272 is starting its engines. http://twitter.com/mattcawby/status/316211212348170241
: Here we go, flight plan filed for LOT ZA272. http://flightaware.com/live/flight/BOE272
: Live stream here: http://www.kirotv.com/s/news/live-event/
: More info: - This will be the first of at least two test flights. This one for Boeing...basically a functional check. Then the one for the FAA. - Boei