LipeGIG
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FAA Grounds B787: Part 14

Sat Mar 23, 2013 2:34 pm

As the previous one become too big, we are opening a new thread for discussions

Link to thread 13 : FAA Grounds B787: Part 13 (by 777ER Mar 9 2013 in Civil Aviation)

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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bellancacf
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RE: FAA Grounds B787: Part 14

Sat Mar 23, 2013 4:50 pm

Did any test flights take place?
 
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7BOEING7
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RE: FAA Grounds B787: Part 14

Sat Mar 23, 2013 6:27 pm

Quoting bellancacf (Reply 1):
Did any test flights take place?

Not yet.
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Sat Mar 23, 2013 9:28 pm

SP-LRC was deiced yesterday but did not fly.

http://www.flickr.com/photos/microvolt/8581796192/in/photostream
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
blrsea
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RE: FAA Grounds B787: Part 14

Sat Mar 23, 2013 11:55 pm

Experts weigh in on Boeing's solution. Looks like external experts are satisfied with Boeing's proposed solution. Also reports on the tests conducted so far.

787 battery fix gets thumbs up from aviation experts

Quote:

...
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
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 1:35 am

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.
 
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kanban
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 1:48 am

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
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 1:58 am

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.
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Stitch
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 2:47 am

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.
 
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lightsaber
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:29 am

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.)

Quoting Stitch (Reply 8):
The maximum discharge level

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.

Lightsaber
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sweair
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 8:05 am

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.
 
NAV20
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 9:54 am

Pretty informative (and up-to-date) press article here:-

http://www.aviationweek.com/Article....l/AW_03_25_2013_p35-561498.xml&p=1
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Francoflier
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 10:01 am

Quoting JAAlbert (Reply 5):
I'm sure the airlines don't want to be replacing these batteries every few months.

Especially now that it has become a lot more complicated to do a battery swap...

Is there any word on whether this will affect ETOPS capability yet?

The safety issue is pretty much taken care of, but the battery reliability issue is still an unknown.
If I understood correctly, these batteries are critical ETOPS items.
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AeroWesty
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 10:13 am

Quoting NAV20 (Reply 11):
Pretty informative (and up-to-date) press article here:-

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.
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scbriml
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 10:53 am

Quoting sweair (Reply 10):
However many here think that this is the final solution

Maybe because Boeing has indicated as much?
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2175301
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 11:16 am

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).

Have a great day,
 
Kaiarahi
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 2:40 pm

Quoting NAV20 (Reply 11):
Pretty informative (and up-to-date) press article here:-

Not so up to date. The full details were actually made public by Boeing 10 days ago.

http://787updates.newairplane.com/Bo...-solution-presentation-English.pdf

[Edited 2013-03-24 07:44:23]
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Stitch
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 3:38 pm

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.
 
Kaiarahi
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 3:46 pm

Quoting Stitch (Reply 17):
Boeing will have to modify the APU system design so that the APU can be started and operated without the APU battery.

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).
Empty vessels make the most noise.
 
AeroWesty
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 3:51 pm

Quoting Kaiarahi (Reply 16):
The full details were actually made public by Boeing 10 days ago.

Drilling additional holes in the fuselage is a new detail not disclosed in the Boeing presentation (at least not blatantly apparent).
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blrsea
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 3:55 pm

How different is it in drilling holes in CFRP fuselage compared to aluminium ones? Will it have any effect on the CFRP strength?
 
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Francoflier
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 3:55 pm

Quoting Stitch (Reply 17):

Thanks!
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Stitch
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:03 pm

Quoting blrsea (Reply 20):
How different is it in drilling holes in CFRP fuselage compared to aluminium ones? Will it have any effect on the CFRP strength?

There are already plenty of holes and ducts in the structure, so that should not be an issue.
 
AeroWesty
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:05 pm

Quoting blrsea (Reply 20):
How different is it in drilling holes in CFRP fuselage compared to aluminium ones?

B787 Grounding: Tech/ops Thread Part 2 (by 777ER Mar 9 2013 in Tech Ops)

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.
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7BOEING7
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:06 pm

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.
 
Kaiarahi
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:29 pm

Quoting AeroWesty (Reply 19):

Drilling additional holes in the fuselage is a new detail not disclosed in the Boeing presentation (at least not blatantly apparent).

Slide 15: "dedicated vent line"

Quoting AeroWesty (Reply 23):
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.

The answer is in TechOps thread one (Tom) - titanium doublers.
Empty vessels make the most noise.
 
AeroWesty
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 4:40 pm

Quoting Kaiarahi (Reply 25):
Slide 15: "dedicated vent line"

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.
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Kaiarahi
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RE: FAA Grounds B787: Part 14

Sun Mar 24, 2013 6:17 pm

Quoting AeroWesty (Reply 27):

Presumably if you repurposed an existing vent, you'd need to cut a new vent for whatever was there before.

Quoting 7BOEING7 (Reply 24):
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.

Perhaps I didn't word my response very clearly. Stitch suggested that the electrical system might eventually need to be modified for ETOPS 180+ so that the APU can be "started and operated" without the APU battery. I was suggesting that "operated" might be enough for some ETOPS requirements (i.e. those where the APU runs the whole time). That would require another source of power for the APU controller, which apparently runs off the APU battery bus.

However, I'm wondering if something Sinnett and/or the NTSB said got misinterpreted. It seems odd to me that there would be redundant ways of starting the APU other than the APU battery, but they're useless without the battery because it alone supplies the APU controller.
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NAV20
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 3:43 am

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 Number 86, an aircraft destined for LOT Polish Airlines. The aircraft is set to undergo a final pre-flight ground test in the afternoon (Pacific time), at Paine Field, Everett on 24th, and if all goes to plan could be cleared for a standard ‘B2’ profile, customer acceptance type flight test on March 25."

http://www.aviationweek.com/Blogs.as...1731f4-1598-4e70-89c5-c0edf1740593
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7BOEING7
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 4:31 am

I'm sure Mr Norris has some good conections at Boeing but I doubt we'll see a customer acceptance flight on ZA272 Monday.
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 8:28 am

I read it as LN86 will fly a customer acceptance flight profile but that doesn't mean it's an acceptance flight.
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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par13del
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 10:30 am

Quoting 7BOEING7 (Reply 29):
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 take the same position as the post below.

Quoting KarelXWB (Reply 30):
I read it as LN86 will fly a customer acceptance flight profile but that doesn't mean it's an acceptance flight.

Just in case, the line from the article is listed below.
"at Paine Field, Everett on 24th, and if all goes to plan could be cleared for a standard ‘B2’ profile, customer acceptance type flight test on March 25."
 
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7BOEING7
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 2:40 pm

Quoting KarelXWB (Reply 30):
I read it as LN86 will fly a customer acceptance flight profile but that doesn't mean it's an acceptance flight.

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 will they fly. And there is no such thing as a "standard 'B2' profile" -- a B-2 is just a cleanup flight for whatever needs fixing after the B-1, it can be 20 minutes long or an hour and 20 minutes long. If he'd said B1 instead of B2 and left the customer part out he would have had a lot more creddibility.
 
hivue
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 3:08 pm

Quoting Kaiarahi (Reply 27):
However, I'm wondering if something Sinnett and/or the NTSB said got misinterpreted.

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 journalists at the Japanese news conference had asked him whether or not Boeing sees this situation as an issue that needs fixing instead of asking stuff like whether Boeing owes the Japanese people an apology, etc.
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 3:36 pm

Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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7BOEING7
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 5:58 pm

Here we go, flight plan filed for LOT ZA272.

http://flightaware.com/live/flight/BOE272
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 6:34 pm

Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 6:40 pm

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.
- Boeing says the LOT 787 will perform a normal flight check profile, that includes electrical system checks.
- After this 787 flight is analysed, certification flight for battery modifications would come within a few days -Boeing.
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 6:53 pm

On the move.

Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 7:02 pm

Rejected takeoff test completed.

Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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7BOEING7
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 7:26 pm

Quoting KarelXWB (Reply 39):
Rejected takeoff test completed.



Actually the RTO (Rejected Take Off) is done at the end of the flight. The test they were doing was to confirm normal operation of the engines at full thrust -- the first time engines are run at full thrust on the airplane -- previous to this full thrust was only done in the test cell at the engine manufacturer. This test was aborted at about 60 or 70 knots -- short of the RTO activation speed. Looks like they are following the B-1 profile done previously on this airplane to the letter.
 
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litz
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 7:40 pm

I think a lot of people are missing that we have two issues at hand :

1) the battery failed
2) the battery containment failed

The first is not necessarily bad; it happens and you replace it.

The second, however, grounded the airplane.

At this point they don't know why #1 happened, but the forensics on #2 were pretty clear.

The new box solves (imho, pretty darned conclusively) #2.

#1 is probably still up in the air; they have changes they suspect will fix it, but aren't sure.

Meanwhile the new box solves #2 and they can get back to flying airplanes.
 
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KarelXWB
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RE: FAA Grounds B787: Part 14

Mon Mar 25, 2013 10:36 pm

"As part of its certification ground tests, Boeing will push a lithium-ion battery on 787 ZA005 to destruction"

http://twitter.com/jonostrower/status/316317161423503360

[Edited 2013-03-25 15:38:47]
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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kanban
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RE: FAA Grounds B787: Part 14

Tue Mar 26, 2013 4:18 am

Quoting litz (Reply 41):
I think a lot of people are missing that we have two issues at hand :

thanks for the clarification that 3500 posts over 14 threads had failed to communicate.
 
davidho1985
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RE: FAA Grounds B787: Part 14

Tue Mar 26, 2013 4:23 am

Quoting KarelXWB (Reply 42):
"As part of its certification ground tests, Boeing will push a lithium-ion battery on 787 ZA005 to destruction"http://twitter.com/jonostrower/status/316317161423503360

Keep on charging the batteries untill they are over-heat and then burn to test the new battery boxes???
 
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bikerthai
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RE: FAA Grounds B787: Part 14

Tue Mar 26, 2013 1:23 pm

Quoting Kaiarahi (Reply 27):
Presumably if you repurposed an existing vent, you'd need to cut a new vent for whatever was there before.

There is two problems with using an existing vent.

One as you mentioned, would require repurposing an exisiting vent. Typically exisiting vents are meant to drain fluid from the bilge or to dump air overboard. I believe these type of vents require special valves that would probably not be compatible with what they are trying to do with the battery vent.

The other problem is that the fluid vent are typically located at the centerline of the aircraft (lowest point in the fuselage. Don't know about the air vent but would assume the same). Who knows how far the battery are from the existing vents? Even if the vent are at the same aiplane station as the battery, the distance from the battery to the vent would probably be more than what you would want for routing a titanium tube. The farther you have to route the tube, the greater chance you have of disturbing existing system routing.

bt
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KarelXWB
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RE: FAA Grounds B787: Part 14

Wed Mar 27, 2013 8:46 pm

Quoting litz (Reply 41):
#1 is probably still up in the air; they have changes they suspect will fix it, but aren't sure.

Few things on this one:

1) As been discussed in one of the first grounding threads, it is very common to replace aircraft parts
2) ANA replaced about 100 to 150 batteries before the fire events, and nobody complained about it
3) It became only a problem when there was a fire, because fire = safety issue
4) So if Boeng can contain the fire then we are back at #2, so that should be enough

[Edited 2013-03-27 13:47:24]
Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
bellancacf
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RE: FAA Grounds B787: Part 14

Wed Mar 27, 2013 11:16 pm

@Karel #46: "ANA replaced 100 - 150 batteries ..."

That _sounds_ like an awful lot of batteries. Is it more than would be replaced on a 767 or 777 over the same time span?

What was going wrong with them? Being replaced when they showed the slightest degradation in capacity? Being swapped out and refurbished (assuming you can refurbish a battery ...)? Something worse: failure of a cell? Short?

I guess what I'm asking is: Is that a smoking gun or not?
 
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Stitch
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RE: FAA Grounds B787: Part 14

Thu Mar 28, 2013 12:37 am

Quoting bellancacf (Reply 47):
What was going wrong with them?

Ground staff were running them down by using them longer than the book called for.



Quoting bellancacf (Reply 47):
I guess what I'm asking is: Is that a smoking gun or not?

Yes, in that it points out 787 ground crew either need better training or better supervision.
 
bellancacf
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RE: FAA Grounds B787: Part 14

Thu Mar 28, 2013 1:57 am

@Stitch #48:

Did this maltreatment do something to the batteries that in some (i.e., 2) cases led to the two notorious incidents? Were maltreated batteries more sensitive to the previously "rough" charging waveform or operation outside of the new, narrower voltage window?

Are B and the airlines currently (no pun intended) speaking to 787 ground crews to keep this maltreatment of the batteries from recurring?

It sounds like the batteries were driven into a corner from which they had no graceful exit -- well, usually graceful, in that they got replaced, but on two occasions pretty dramatic.

I could imagine that ground crew found out that the 787 batteries were so powerful that they could skip supplying external power. Why bother driving the generator buggy across the tarmac when the on-board kit does it all just fine? Something like that?

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