Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
How Will The Ethiopian 787 Be Repaired?  
User currently offlineByrdluvs747 From United States of America, joined Jul 2004, 2341 posts, RR: 1
Posted (12 months 2 days 22 hours ago) and read 25594 times:

From the first time I saw the burn marks on the Ethiopian 787, I wondered how the aircraft will be repaired. With such heat, I imagine that the resin in the CFRP barrels is damaged beyond a simple patching repair. Pressurising the cabin seems to be an issue also. So will Boeing just replace the entire section?

This also raises the question of having to fly a plane to Washington in order to do hull repairs.


The 747: The hands who designed it were guided by god.
109 replies: All unread, showing first 25:
 
User currently offlineBestWestern From Hong Kong, joined Sep 2000, 7062 posts, RR: 57
Reply 1, posted (12 months 2 days 22 hours ago) and read 25604 times:

Simples... replace the coffee pot...



Until we know what the problem is, how can we even think of answering this question. And nobody here knows.



The world is really getting smaller these days
User currently offlineTC957 From UK - England, joined May 2012, 790 posts, RR: 0
Reply 2, posted (12 months 2 days 22 hours ago) and read 25518 times:

Answer is with great difficulty. And I suspect there will be a lot of A-net threads asking the same thing over the coming weeks. We'll just have to be patient and let the investigators do their stuff first and then look out for official press releases. Unless of course, there's an a-netter amongst the investigative team who can update us....
 


User currently offlineByrdluvs747 From United States of America, joined Jul 2004, 2341 posts, RR: 1
Reply 3, posted (12 months 2 days 20 hours ago) and read 25166 times:

Quoting BestWestern (Reply 1):
Until we know what the problem is, how can we even think of answering this question. And nobody here knows.

My question has nothing to do with what caused the fire, but how to repair the resulting damage.

Quoting TC957 (Reply 2):
We'll just have to be patient and let the investigators do their stuff first and then look out for official press releases.

Yes, but the CFRP repair itself has nothing to do with any investigation. The hull is burned, what caused it to burn doesn't change how it will be repaired. Boeing should (I hope to dear god) have already have procedures in place to repair various damage to the 787s skin.



The 747: The hands who designed it were guided by god.
User currently offlineBestWestern From Hong Kong, joined Sep 2000, 7062 posts, RR: 57
Reply 4, posted (12 months 2 days 20 hours ago) and read 25127 times:

Quoting Byrdluvs747 (Reply 3):
My question has nothing to do with what caused the fire, but how to repair the resulting damage.

How do you expect anyone to answer your question without knowing what damage the aircraft has suffered. nobody knows what damage was done in the fire.

Its like asking how do you fix a broken down car without the person you ask knowing whats wrong with it..



The world is really getting smaller these days
User currently offlineEK413 From Australia, joined Nov 2003, 4820 posts, RR: 4
Reply 5, posted (12 months 2 days 20 hours ago) and read 25057 times:

Quoting Byrdluvs747 (Reply 3):
Yes, but the CFRP repair itself has nothing to do with any investigation. The hull is burned, what caused it to burn doesn't change how it will be repaired. Boeing should (I hope to dear god) have already have procedures in place to repair various damage to the 787s skin.

Boeing have procedures in place to repair various damage caused to the B787 skin & these words came from the horses mouth "Boeing" rep during the Dreamliner tour. We shouldn't speculate as many of us have read apparently the aircraft is to be written off just like VH-OQA 'Nancy Bird' was suppose to be written off but she returned to revenue service after under going extensive repairs in SIN.
Lets wait for the final report once the investigation is complete and then I'm sure Boeing will send a team to access the damage and determine if the aircraft is repairable. We know repairs have been done on the B767 http://channel.nationalgeographic.com/channel/videos/boeing-767/ but this is a different kettle of fish.

EK8413

[Edited 2013-07-14 03:13:49]


Good evening, ladies and gentlemen. We are tonight’s entertainment!
User currently offlineDTW2HYD From United States of America, joined Jan 2013, 1679 posts, RR: 2
Reply 6, posted (12 months 2 days 10 hours ago) and read 22320 times:

Two part epoxy, fiberglass cloth and lot of elbow grease.

Or find a spare Aft. Fuselage section in South Carolina.


User currently offlineWingedMigrator From United States of America, joined Oct 2005, 2211 posts, RR: 56
Reply 7, posted (12 months 2 days 10 hours ago) and read 22029 times:

They will just replace the crown panel   

User currently offlineJoePatroni707 From United States of America, joined Dec 2012, 493 posts, RR: 0
Reply 8, posted (12 months 2 days 10 hours ago) and read 21822 times:

The airplane will fall under the "lemon law" and Boeing will give ET a brand new 787!   

User currently offlinenorthwest 777 From United States of America, joined Sep 2000, 224 posts, RR: 0
Reply 9, posted (12 months 2 days 9 hours ago) and read 21454 times:

Quoting BestWestern (Reply 4):
How do you expect anyone to answer your question without knowing what damage the aircraft has suffered. nobody knows what damage was done in the fire.

His question doesn't require knowing what is wrong with the plane, per se. His question clearly asks if there is damage beyond what a simple 'patch' of sorts could fix (and he is clearly referring to the 'hull' itself) HOW would the Boeing need to fix it. Would they have to hack the ass end of the pig or not. I understood what he was asking, and I'm an idiot.

Now relax.


User currently offlinerfields5421 From United States of America, joined Jul 2007, 7503 posts, RR: 32
Reply 10, posted (12 months 2 days 9 hours ago) and read 21403 times:

Quoting EK413 (Reply 5):
the aircraft is to be written off

I would not be surprised to see the aircraft return to service. In fact, I would be greatly surprised to not see it flying again.

Cost would not be a factor.

Boeing and Airbus both need the plane back in the air to demonstrate repairs to the CFRP fuselage are possible after hul damage, and hopefully economic.

Otherwise both the B787 and A350 are doomed, and both companies have bet their future on those aircraft.


User currently offlinenorthwest 777 From United States of America, joined Sep 2000, 224 posts, RR: 0
Reply 11, posted (12 months 2 days 9 hours ago) and read 21336 times:

For what it's worth BestWestern, that post of mine came off as snarky, and I apologize. It wrote differently and more playfully than it reads LOL. By the way, I see both you and I joined the same time, waaaaay back in September of 2000. I don't know about you, but I'm not sure if I should be proud of that, or depressed by that!

User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 12, posted (12 months 2 days 9 hours ago) and read 20903 times:

Quoting rfields5421 (Reply 10):
I would not be surprised to see the aircraft return to service. In fact, I would be greatly surprised to not see it flying again.

Indeed – Boeing's other customers require them to demonstrate the repairability of the new fuselage construction, and Boeing knows it.

There will be no writeoff if it can be helped at all. But it's probably not necessary anyway, unless the heat has crept forward all the way and seriously damaged the crown area across the entire length of the fuselage.

Quoting rfields5421 (Reply 10):
Boeing and Airbus both need the plane back in the air to demonstrate repairs to the CFRP fuselage are possible after hul damage, and hopefully economic.

Otherwise both the B787 and A350 are doomed, and both companies have bet their future on those aircraft.

Not quite – this incident is actually a strong argument for Airbus' construction with separately replaceable segments – in this case on an A350 you'd only have to replace the crown segment(s) if a patch should not be sufficient. In such a case Boeing may have to replace the entire barrel, maybe even the adjacent one as well if its structural strength is compromised enough.

The repair may be many times more expensive on the 787 than it would be on the A350 if a very large patch in this critical area is not feasible. Not great for Boeing. They will move heaven and earth to keep it below that if they can.

And if you were John Leahy, would you really fail to refer to such a 787 barrel replacement (with all the associated much more extensive disassembly / reassembly) in your repairability presentations on the A350?

This incident hands him a great argument on a silver platter.

[Edited 2013-07-14 13:34:52]

User currently offlineWingtips56 From United States of America, joined Dec 2010, 351 posts, RR: 0
Reply 13, posted (12 months 2 days 9 hours ago) and read 20844 times:

Have there been any genuine reports about what the damage is... ie., is is burned through, intact but scorched, interior damage, etc.? Is there damage inside the cabin? The only news items I've seen are the initial ones about the 'blaze' and then the reports that it is not attributed to the batteries, but then 90% of the article goes on and on about the previous battery incidents. Nothing about this one, like the cabin was gutted in the fire, the galley is toast, you can see daylight through the ceiling or it's all melted like the Wicked Witch. It's as if nobody has even gone inside yet.

That said, I can see the validity of the with the original post's question being how much could be done at LHR, assuming it's not flyable as is. Could they do the laminate repairs there or even take the plane apart and replace the barrel section there? If it isn't flyable and does require a section swap out, then I can see it's only fate being to cut it up and haul it away. Can it be taken apart and the sections ferried out on the DreamLifter for repair and reassembly by Boeing at PAE or CHS? I'd hate to see it become the LHR Fire Brigade's new training hull.



Worked for WestAir, Apollo Airways, Desert Pacific, Western, AirCal and American Airlines
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 14, posted (12 months 2 days 9 hours ago) and read 20451 times:

Quoting Wingtips56 (Reply 13):
Have there been any genuine reports about what the damage is... ie., is is burned through, intact but scorched, interior damage, etc.? Is there damage inside the cabin?

Not really as far as I have seen – the earlier "coffe maker" rumour seems to have been a false lead.

Quoting Wingtips56 (Reply 13):
That said, I can see the validity of the with the original post's question being how much could be done at LHR, assuming it's not flyable as is. Could they do the laminate repairs there or even take the plane apart and replace the barrel section there? If it isn't flyable and does require a section swap out, then I can see it's only fate being to cut it up and haul it away.
BA is getting 787s anyway. They'll jump at the chance to train their maintenance at major 787 repairs right on their doorstep, and they'll have the full support of Boeing behind them.

And Boeing must have designed their repair processes to be feasible at far more sparsely equipped airports than London Heathrow.

Even if they'll have to replace entire barrel sections they'll do that on site. There should be transportable jigs for that purpose either available or designed for implementation. Even british Airbus infrastructure might be usable for some of the work.

Given that the incident happened at all, Heathrow should be close to a best case in terms of location and infrastructure.

[Edited 2013-07-14 13:54:45]

User currently offlineDTWPurserBoy From United States of America, joined Feb 2010, 1499 posts, RR: 7
Reply 15, posted (12 months 2 days 8 hours ago) and read 20082 times:

Quoting Wingtips56 (Reply 13):
Have there been any genuine reports about what the damage is... ie., is is burned through, intact but scorched, interior damage, etc.? Is there damage inside the cabin?

I asked this same question on another thread. With the kind of heat required to damage the exterior, there had to have been considerable damage to the cabin interior from heat, smoke and water. Gutting the airframe will be expensive.

I have seen aircraft that had substantial hull damage away from a major maintenance facility. What was done then was to provide a temporary fix and the aircraft receives a special ferry permit to fly the airplane to the nearest facility capable of performing the work. BA has considerable maintenance facilities at LHR but I am not sure if they know how to repair the composite. I suppose, in theory, Boeing could fly in an entire tail assembly on one of their Belugas but marrying those two sections without the required jigs would be very difficult. IMHO the aircraft will have to be flown to South Carolina for complete repair. I am not sure how you could do a temporary repair and make the plane safe enough for a trans-Atlantic ferry flight, presumably being flown by Boeing pilots.

It will ne interesting in the coming days to see what happens.



Qualified on Concorde/B707/B720/B727/B737/B747/B757/B767/B777/DC-8/DC-9/DC-10/A319/A320/A330/MD-88-90
User currently offlineStitch From United States of America, joined Jul 2005, 30415 posts, RR: 84
Reply 16, posted (12 months 2 days 8 hours ago) and read 19705 times:
Support Airliners.net - become a First Class Member!

Quoting Klaus (Reply 12):
Not quite – this incident is actually a strong argument for Airbus' construction with separately replaceable segments – in this case on an A350 you'd only have to replace the crown segment(s) if a patch should not be sufficient. In such a case Boeing may have to replace the entire barrel, maybe even the adjacent one as well if its structural strength is compromised enough.

If the damage is so extensive as to require a barrel swap, if the plane was an A350 I expect they'd have to pull the two sidewall panels in addition to the crown panel. A barrel swap might also be quicker than a panel (much less a three panel) swap due to the lower number of fasteners needing removal and replacement.

Using panels to improve repairability has always struck me as a red herring. IMO, Airbus went with panels because they are very familiar with the process (in Al) and they wanted to reduce risk. I expect there was some Intellectual Property issues, as well, but even if Airbus could have done the A350 with barrels, they likely would not have.


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 17, posted (12 months 2 days 8 hours ago) and read 19149 times:

Quoting Stitch (Reply 16):
If the damage is so extensive as to require a barrel swap, if the plane was an A350 I expect they'd have to pull the two sidewall panels in addition to the crown panel.

Why? there is no indication for that whatsoever. Heat rises up, and by all indications it is highly plausible that it remained concentrated just in the crown area above the cabin ceiling – the side panels in an A350 would most likely have remained unaffected.

Quoting Stitch (Reply 16):
A barrel swap might also be quicker than a panel (much less a three panel) swap due to the lower number of fasteners needing removal and replacement.

Possible. But the structural re-certification would be at least as strenuous, plus all installations below the crown panel would have to be swapped over or be completely replaced vs. nothing to be done there on the A350 beyond reconnecting just everything actually attached to the crown panel.

Quoting Stitch (Reply 16):
Using panels to improve repairability has always struck me as a red herring. IMO, Airbus went with panels because they are very familiar with the process (in Al) and they wanted to reduce risk. I expect there was some Intellectual Property issues, as well, but even if Airbus could have done the A350 with barrels, they likely would not have.

Do you really think replacing at least the tail section if not possibly even the barrel in front of that as well due to the damaged join would be cheaper, quicker and easier than swapping in one or two new crown panels on an A350?

I have some difficulty believing that.

You may get some cost savings in production (somewhere down the road) and some weight savings from the whole barrel construction, but this incident looks to be close to a worst case regarding repairability compared to the alternative.


User currently offlineEK413 From Australia, joined Nov 2003, 4820 posts, RR: 4
Reply 18, posted (12 months 2 days 8 hours ago) and read 19081 times:

Quoting rfields5421 (Reply 10):
Quoting EK413 (Reply 5):
the aircraft is to be written off

I would not be surprised to see the aircraft return to service. In fact, I would be greatly surprised to not see it flying again

I never said the aircraft is to be written off. Various forums have made the claim & personally I believe the aircraft will be repaired just like QF A380 VH-OQA 'Nancy Bird'.

EK8413



Good evening, ladies and gentlemen. We are tonight’s entertainment!
User currently offlineOllieJolly From United Kingdom, joined Jul 2012, 71 posts, RR: 0
Reply 19, posted (12 months 2 days 7 hours ago) and read 18970 times:

I guess if ET still have the receipt they can just send it back, I guess Boeing wouldn't pay for the postage & packaging but perhaps the airline could make a deal with Royal Mail as it would be some nice publicity for them.


Really though, I wondered this myself when I first saw it, because while it isn't "terminal" looking damage, it certainly looks non-airworthy, however I'm sure that things will already be in motion with regards to how ET will have it fixed, because I highly doubt the aircraft would be written off, especially with it being so new.


User currently offlineStitch From United States of America, joined Jul 2005, 30415 posts, RR: 84
Reply 20, posted (12 months 2 days 7 hours ago) and read 18870 times:
Support Airliners.net - become a First Class Member!

We have yet to confirm that the fuselage was actually opened to the elements. It's been suggested that what people are calling "holes" are actually just paint charring and the structure is still intact. The thickness of the stringers may very well have reduced the thermal transfer to the paint sufficiently to prevent it from being as charred.

[Edited 2013-07-14 16:04:16]

User currently offlineEK413 From Australia, joined Nov 2003, 4820 posts, RR: 4
Reply 21, posted (12 months 2 days 7 hours ago) and read 18838 times:

Quoting OllieJolly (Reply 19):
I highly doubt the aircraft would be written off, especially with it being so new.

New aircraft have been written off in the past.


A340-642(HGW) MSN 0856 [F-WWCJ] [EY]



EK8413

[Edited 2013-07-14 15:11:18]


Good evening, ladies and gentlemen. We are tonight’s entertainment!
User currently offlineViscount724 From Switzerland, joined Oct 2006, 24643 posts, RR: 22
Reply 22, posted (12 months 2 days 7 hours ago) and read 18521 times:

Many aircraft have been repaired and returned to service after far more apparent damage than the ET 787.

A TWA 707-331B had the complete cockpit/nose section destroyed in a terrorist bombing at Damascus, Syria in 1969 after the aircraft was hijacked there on a flight from FCO to TLV. A Boeing team flew in a new nose section and repaired the aircraft and it spent another decade or more in TWA service.

Others that come to mind include the AC (still TCA then) DC-8-54F combi that was seriously damaged in a high speed rejected takeoff at LHR in 1963. It overran the runway by about 2,000 feet. A Douglas team repaired the aircraft over the next several months in a BOAC hangar at LHR.

There was also the JAL DC-8-62 that landed in San Francisco Bay about 2 miles short of the runway in 1968. It was repaired by UA and spent another 30 years or more in service, including many years as a freighter after JAL retired it.

There was also the JAL 747-200 that was blown off a snow-covered taxiway at ANC in 1975 and slid backwards down an embankment. A Boeing team also repaired that aircraft on-site in the open air. I recall at the time Boeing said it was their largest-ever on-site repair job.


User currently offlineBrianDromey From Ireland, joined Dec 2006, 3915 posts, RR: 9
Reply 23, posted (12 months 2 days 7 hours ago) and read 18402 times:

To be fair that EY bird was broken pretty cleany in two, with untold stresses on the fuselage.

Probably the best example of an entire "barrel" or section being replaced is N862RW, which was involved in a runway overrun and had its entire front fuselage replaced in CLE.



Next flights: MAN-ORK-LHR(EI)-MAN(BD); MAN-LHR(BD)-ORK (EI); DUB-ZRH-LAX (LX) LAX-YYZ (AC) YYZ-YHZ-LHR(AC)-DUB(BD)
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5383 posts, RR: 30
Reply 24, posted (12 months 2 days 7 hours ago) and read 18361 times:

CFRP is just a building material...it's not voodoo. It's been used in aerospace for decades and has been repaired since its first ding.

While this may require more extensive repair than many other incidents, bigger repairs aren't impossible repairs. They can splice in stringers and use as much fuse sheet material as required. Splicing composite parts has been done forever.

Worse structural repairs have been done to aluminum aircraft and other composite structures...just not on a 787.

I'm really very surprised at the amount of 'how will Boeing fix/maintain the dreaded CFRP bits' fear mongering that takes place whenever anything brushes up against a 787.

They'll take as much skin, stringer bits, adhesives and fasteners as required to do the job and in the end, nobody will ever be able to tell it was ever injured at all.

The real important question is not, 'how will they fix it?', but 'how did it start?'...that's the worrying bit.



What the...?
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 25, posted (12 months 2 days 7 hours ago) and read 19066 times:

Quoting Stitch (Reply 20):
As such, the actual repair may just be some additional reinforcement patching underneath the affected area and a fresh respray of the area.

Is it really plausible that the structural integrity of the CFRP could have remained intact enough (particularly the resin component) even with the paint charring to black on the outside to allow that, and that in a critical area like this?


User currently offlineflylku From United States of America, joined Apr 2006, 797 posts, RR: 0
Reply 26, posted (12 months 2 days 7 hours ago) and read 19057 times:

Sorry, cannot resist, and given what we know this answer is as good as any other: with 500 knot aviation grade duct tape.


...are we there yet?
User currently offlineStitch From United States of America, joined Jul 2005, 30415 posts, RR: 84
Reply 27, posted (12 months 2 days 6 hours ago) and read 19059 times:
Support Airliners.net - become a First Class Member!

Quoting Klaus (Reply 25):
Is it really plausible that the structural integrity of the CFRP could have remained intact enough (particularly the resin component) even with the paint charring to black on the outside to allow that, and that in a critical area like this?

At this point t's no more or less probable than suggestions that the CFRP has been irrevocably and irreparably damaged considering we have no data to work from and are all just wildly speculating.


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 28, posted (12 months 2 days 5 hours ago) and read 18576 times:

Quoting Stitch (Reply 27):
At this point t's no more or less probable than suggestions that the CFRP has been irrevocably and irreparably damaged considering we have no data to work from and are all just wildly speculating.

The external part of the damage is visible – and quite a few properties of materials involved are known. It's not entirely speculation (apart from that being one of the main purposes of this site anyway).


User currently offlineDocLightning From United States of America, joined Nov 2005, 19278 posts, RR: 58
Reply 29, posted (12 months 2 days 5 hours ago) and read 18556 times:

Quoting Stitch (Reply 16):
Using panels to improve repairability has always struck me as a red herring. IMO, Airbus went with panels because they are very familiar with the process (in Al) and they wanted to reduce risk.

Transport is also easier, and smaller autoclaves can be used.

Quoting EK413 (Reply 21):
New aircraft have been written off in the past.

That was an extreme situation with damage to just about every segment of the airframe. The tail was banged up, the wing was damaged, the front end absolutely destroyed. I think the only part of that airframe that was unscathed was the tailfin... there was more damaged plane than undamaged plane. This 787 could have damage to the entire crown from nose to tail and still be cheaper to fix than to replace.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19278 posts, RR: 58
Reply 30, posted (12 months 2 days ago) and read 18363 times:

Quoting Stitch (Reply 16):
Using panels to improve repairability has always struck me as a red herring. IMO, Airbus went with panels because they are very familiar with the process (in Al) and they wanted to reduce risk.

Transport is also easier, and smaller autoclaves can be used.

Quoting EK413 (Reply 21):
New aircraft have been written off in the past.

That was an extreme situation with damage to just about every segment of the airframe and it was among the last A340s to be built. The tail was banged up, the wing was damaged, the front end absolutely destroyed. I think the only part of that airframe that was unscathed was the tailfin... there was more damaged plane than undamaged plane. By contrast, this 787 could have damage to the entire crown from nose to tail and still be cheaper to fix than to replace. There are something like 60-70 frames in operation world-wide and the type has an enormous backlog. Add to that the non-numerical reasons involving the emotional response to writing off a frame so early in the program. It's not a question of will they fix it, but [i]can[/i[ they fix it?


User currently offlineSkydrol From Canada, joined Oct 2003, 957 posts, RR: 10
Reply 31, posted (12 months 1 day 22 hours ago) and read 18328 times:

White spray paint.

This way passengers will never see any burn damage evidence from the departure lounge, prior to boarding this airplane.




LD4



∙ ---{--« ∙ ----{--« ∙ --{-« ∙ ---{--« ∙ --{--« ∙ --{-« ∙ ----{--« ∙
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 32, posted (12 months 1 day 19 hours ago) and read 18266 times:

Quoting Byrdluvs747 (Thread starter):
With such heat, I imagine that the resin in the CFRP barrels is damaged beyond a simple patching repair. Pressurising the cabin seems to be an issue also. So will Boeing just replace the entire section?

The change of composite which are exposed to extreme heat like this called pyrolyzation. It can lead to composite fibers being exposed that are normally within a resin matrix. If this has happened, it will complicate the investigation and repair as these fibers are considered hazardous to human health without the correct protective equipment.

As this event did not occur during operation, it was parked at a remote stand, it could not really be classified as an aircraft accident. Therefore I would suggest it would be given a lower priority for investigation by the AAIB. However it is a new type design, so it may attract some attention as it would be the first composite air frame of its size to suffer a widespread heat source on the inside.

The type of repair that will be performed will in part be a function of what equipment and skills are available in LHR to perform large scale composite repairs, the location and type of damage that exists inside the cabin, and the loads that are seen in the area.

It is possible that the damage transcends a join in the barrel. We need to keep in mind that the fiber placement in the barrel is not unidirectional, it is tailored to suit loads in the area. Typical composite repairs which involve the removal of an area of composite, or a wet layup of new composites over this area may not be effective due to the load path to be preserved, and the possibility of pyrolyzation on underlying layers making the matrix bonds less effective.

In many ways if this was a metallic structure it may be easier to repair, the tail removed (to unstress the area), support the area in a makeshift jig, removed the damaged interior, remove the old skin panels, removed damaged stringers, repair the interior, much like a tail scrape repair is done today. Most of the work we have seen relating to 787 damage tolerance was in relation to ground equipment hitting the air frame, dropping of tools, and drop testing of the fuselage. Larger areas of heat damage are hard to develop a generalized repair for.

Doing a damage tolerance assessment of the repair could well be the hardest part of trying to work out if they should replace, fix, or scrap the air frame.

The interior parts that maybe damage are possible also too large to enter via the normal doors, from a logistics point of view, it might be just as easy to remove the aft pressure bulkhead in order to place new overhead ducts, galley, stringers, frame etc.

We have very little information on the extent of the damage on the inside, we can only guess by the amount of heat needed to cause the paint to change color on the outside. The heat damage may have found easy paths to spread through the aircraft like the air ducts, and may have been accelerated with passenger oxygen system.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineGoldenshield From United States of America, joined Jan 2001, 5961 posts, RR: 14
Reply 33, posted (12 months 1 day 19 hours ago) and read 18248 times:

Well, if the airline can't repair it, send in this guy! He's been repairing composites for years!

http://www.alphazulucomposites.com/



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlinedavidho1985 From Hong Kong, joined Oct 2012, 320 posts, RR: 0
Reply 34, posted (12 months 1 day 15 hours ago) and read 18058 times:
Support Airliners.net - become a First Class Member!

I believe this 787 will be repaired at any cost (even it is much more expensive than replace it with a new one).

With the past incidents, both Boeing and the 787 itself can't afford a brand-new 787 being written-off at this monent.
It will be a huge discaster to them.

Same case as QF's 744 which overrun at Bangkok and their A380.

[Edited 2013-07-15 07:31:30]

User currently offlinenomadd22 From United States of America, joined Feb 2008, 1820 posts, RR: 0
Reply 35, posted (12 months 1 day 14 hours ago) and read 18008 times:

They could always start cutting patches for repairs like this out of LN003.


Andy Goetsch
User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 36, posted (12 months 1 day 11 hours ago) and read 17863 times:

Even though the barrel is one "spunned" unit, the frames are not. It is logical that any large area repair will start at the frame splice.

The barrel skin can be cut and spliced as needed.

My guess is if they are to replace the crown area. They will fab a new crown skin section. They will replace as many frames as needed and bolt on the new crown in a similar way they did the mod with the 737 Wedgetail aircraft.

Repairing a composite crown will be more difficult than repairing an aluminum crown because you will have to have your dimension more closely matched in CFRP than you would with an aluminum panel. The drilling on CFRP would require sharper bits and you will be using bolts instead of rivets.

This is all generalization. We will have to wait and see how this specific situation will be resolved.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineCaptainKramer From United Kingdom, joined Feb 2012, 225 posts, RR: 0
Reply 37, posted (12 months 1 day 9 hours ago) and read 17816 times:

I would be very surprised if the investigation by the AAIB of the Ethiopian B787 incident at LHR is not given the highest priority, given the aircraft's history and the nature of the incidents prior to this latest one.

They don't owe it to Boeing, or the various tiers of Suppliers, or the Airlines that use it, but they do owe it to the Passengers, Pilots and Cabin Crew, who with each passing day of the Aircraft's operation, take on the role of Guinea Pigs.

As regards the question of whether to fix or not to fix, if the will is there, and enough cash, anything is possible. I just wish Boeing would do the same with regards the whole B787 Program, thankfully they have dodged a bullet, so far. It's not too late.

However if the Space Shuttle Program and the first Challenger Accident that NASA failed to draw lessons from to prevent the second Columbia Accident is anything to go by, then I don't hold much hope with Boeing in the short term, as I observe the same culture of "Normalising of the Abnormal" that crept into NASA, creeping into Boeing, specifically regarding the "All Electric B787".

I just hope no Passengers, Pilots and Cabin Crew have to pay the ultimate price, as they have done so many times in the past with other "Technological Revolutions", to find a lasting solution to the B787's ongoing issue's.


User currently offlineA380900 From France, joined Dec 2003, 1097 posts, RR: 1
Reply 38, posted (12 months 1 day 7 hours ago) and read 17755 times:

Quoting Wingtips56 (Reply 13):
It's as if nobody has even gone inside yet.

I'm sure info and pics about this one are a closely guarded secret. I'd be surprised if Boeing opted for the "transparency mode" regarding the 787. Too much transparency could well mean more grounding. And I don't think grounding is part of the equation anymore. I'd be surprised if the 787 got grounded again without fatalities involved. Boeing is all in now. Make or break.

Quoting CaptainKramer (Reply 37):
However if the Space Shuttle Program and the first Challenger Accident that NASA failed to draw lessons from to prevent the second Columbia Accident is anything to go by, then I don't hold much hope with Boeing in the short term, as I observe the same culture of "Normalising of the Abnormal" that crept into NASA, creeping into Boeing, specifically regarding the "All Electric B787".

As I say. The train has left the station. There won't be any more grounding of this plane unless there are fatalities. Let's hope it does not come to that.


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 39, posted (12 months 1 day 4 hours ago) and read 17641 times:

Quoting A380900 (Reply 38):
And I don't think grounding is part of the equation anymore. I'd be surprised if the 787 got grounded again without fatalities involved. Boeing is all in now. Make or break.

You think that the authorities would just let a plausibly dangerous design defect slide now? I think it's rather the opposite: Doing that would directly expose the person and the organisation signing off on such a defect to the full responsibility for any ensuing fatalities.

I'm quite certain that another grounding would only happen after exhaustive examination of all pertinent facts, but I have no doubt that it would be done if necessary, major pain for Boeing or not.

I just don't think that anything we actually know at this point really suggests that to be the likeliest outcome of the ET 787 incident.

But that Boeing staff and management are sweating bullets right now is pretty much a given.


User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 40, posted (12 months 16 hours ago) and read 17417 times:

http://www.bizjournals.com/seattle/n...-known-787-hull-repair-easier.html

Boeing was apparently able to fix a hole punched in the hull of a 787 by a catering truck.


User currently offlineA380900 From France, joined Dec 2003, 1097 posts, RR: 1
Reply 41, posted (12 months 15 hours ago) and read 17324 times:

Quoting Klaus (Reply 39):
You think that the authorities would just let a plausibly dangerous design defect slide now?

In a word: yes. I do not trust the authorities to make the right calls at this point. Put another way: I won't fly on this aircraft in the next few years (if I trusted the authorities, obviously, I would). I think the pressure is too intense.


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 42, posted (12 months 15 hours ago) and read 17309 times:

Personally, I can see your point, but I still don't think that anybody would knowingly sign off on a dangerous defect especially now.

User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 43, posted (12 months 11 hours ago) and read 16835 times:

Quoting LTC8K6 (Reply 40):

Good to hear. Would like more details.

The article mentioned heat cure. But I thought that Boeing say that a bolted repair is still an option with the composite fuselage.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 44, posted (12 months 10 hours ago) and read 16768 times:

Quoting bikerthai (Reply 43):
The article mentioned heat cure. But I thought that Boeing say that a bolted repair is still an option with the composite fuselage.

There's another article on repairing the 787.

http://www.compositesworld.com/artic...-composite-repair-builds-on-basics


User currently offlineJHwk From United States of America, joined Jan 2013, 218 posts, RR: 0
Reply 45, posted (12 months 7 hours ago) and read 16203 times:

It's not that hard to repair the damage. The hard part is to repair it with minimal additional weight. You could add a whole new aluminum frame inside the crown to transfer load around the damaged portions if you wanted to, although it is unlikely you would need to.

In all reality, repair of the damage is likely almost identical to what Airbus would do on a 350. Either way you are taking apart the interior to access the structure, doing ultrasonic or xray imaging of the damage, cutting out whatever needs to be removed, etc.

It is hard for me to believe they would ship in a new tail section. If that is really what it takes to repair it, you have substantial life-cycle issues to deal with...


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 46, posted (12 months 6 hours ago) and read 16126 times:

Quoting JHwk (Reply 45):
In all reality, repair of the damage is likely almost identical to what Airbus would do on a 350.

Unless a local patch was not enough due to size and location – then it would just be a top panel in an A350 contrary to an entire barrel section for the 787. Or two of each if the damage extends across the section join.

Quoting JHwk (Reply 45):
It is hard for me to believe they would ship in a new tail section. If that is really what it takes to repair it, you have substantial life-cycle issues to deal with...

Wouldn't that actually be the best case regarding weight and longevity? It would simply reset the service life of the tail section with zero penalty, wouldn't it?

Contrary to a patch which would increase weight and impose extra inspections for the rest of its service life, which could be shortened simply by the financial consequences if not by structural ones.

[Edited 2013-07-16 16:31:53]

User currently offlineJoeCanuck From Canada, joined Dec 2005, 5383 posts, RR: 30
Reply 47, posted (12 months ago) and read 15725 times:

CFRP is not terribly different than fibreglass. In this case, it probably won't be laid up in place but will be repaired with a CRFP skin patch....of whatever size is required, with the fibers laid up much like the original skin. All of the damage will be cut out and enough to blend the new skin into the old. On the backside, pre formed stringers will be cut to length and spliced in.

To be extra careful, they will probably build up the spices more than they need to and may even use metal fasteners in some places.

This is basically one way composite repairs have been done since there ever was plastic composites. The 'CF' bit of CFRP, is most of the strength and the 'RP' basically holds the fibres in whatever shape is required.

Sailplanes, boats, race cars and other airliners, (the 380 being a very big example), have been using and repairing CRFP, largely without problem.

Why the 787 should suddenly be the fly in the ointment for these materials is far beyond my obviously inadequate powers of perception.

Anything that's obviously burned, they'll cut out and replace. Anything they suspect is burned or compromised in any way, they'll cut out and replace.

I'm curious about their repair techniques because I'm a geek, not because I think it'll be technologically difficult or that tha plane will be unsafe to fly on after being repaired.

ps....I think exactly the same thing for the 350.



What the...?
User currently offlineo0OOO0oChris From Germany, joined May 2012, 17 posts, RR: 0
Reply 48, posted (11 months 4 weeks 1 day 8 hours ago) and read 14955 times:

Sorry if already posted:

Experts ponder how Ethiopian 787 can be repaired


User currently offlineJHwk From United States of America, joined Jan 2013, 218 posts, RR: 0
Reply 49, posted (11 months 4 weeks 1 day 2 hours ago) and read 14709 times:

Quoting Klaus (Reply 46):

The life cycle issues I was referring to are fleet-wide, not this airframe. JoeCanuck did a much better job than I on explaining the process (about how I envision it would happen as well). They might need to add some extra stiffeners into the mix (or engineer the stringers to do the function), but it really isn't that big of a deal.

Airbus would likely never replace a whole panel either; all fasteners would need to be removed, the existing panel removed, and the new panel installed and fixed in place. Why do that when a patch can match the integrity of the installation. Flying in a new barrel section solves nothing for Boeing, unless the whole tail was really damaged.


User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 50, posted (11 months 4 weeks 1 day ago) and read 14723 times:

JAL's 787 cfrp repair experiences:

http://events.aviationweek.com/html/...203_COMPOSITES_HIROKI_FUKUYAMA.pdf


User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 51, posted (11 months 4 weeks 15 hours ago) and read 14422 times:

Quoting LTC8K6 (Reply 50):

Awesome presentation. Wished there was a complete presentation (with audio) available

Lightning strike repair!! Well I guess other than the need to repair, lightning strike isn't much of an issue.

Repairable   

Lightning strike   

Now if only we can check off all these un-forseen issue  

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 52, posted (11 months 4 weeks 9 hours ago) and read 14193 times:

Quoting JHwk (Reply 49):
The life cycle issues I was referring to are fleet-wide, not this airframe.

I still don't see your point.

Quoting JHwk (Reply 49):
Airbus would likely never replace a whole panel either; all fasteners would need to be removed, the existing panel removed, and the new panel installed and fixed in place. Why do that when a patch can match the integrity of the installation. Flying in a new barrel section solves nothing for Boeing, unless the whole tail was really damaged.

That was my whole point all along: When a patch should not be enough (either because it would compromise weight and/or stability too much or because it would be more expensive than a replacement anyway), replacement parts would be the way to go.

This is not a trivial location in terms of airframe strength – if the damage reaches from the barrel join (possibly even farther than that) all the way back to the aft bulkhead, it might become difficult repair and re-certify. This part also has to carry the loads of the stabilizers and the APU, on top of being weakened by the doors.

And that would be where the question of extent and cost of such a part replacement comes in.


User currently offlineStitch From United States of America, joined Jul 2005, 30415 posts, RR: 84
Reply 53, posted (11 months 4 weeks 3 hours ago) and read 14023 times:
Support Airliners.net - become a First Class Member!

The AAIB interim report makes no mention of the fire breaching the hull and Jon Ostrower at the WSJ is reporting the "a person familiar with the investigation says that the fire did not breach the carbon fiber skin of the Dreamliner, likely ruling out the scrapping of the jet.".

So looks like the fire did not penetrate the skin of the plane and those dark spots are charring of the paint, not holes.


User currently onlineStressedOut From United States of America, joined Dec 2008, 78 posts, RR: 0
Reply 54, posted (11 months 4 weeks ago) and read 13984 times:

Quoting LTC8K6 (Reply 50):
JAL's 787 cfrp repair experiences:

http://events.aviationweek.com/html/...203_COMPOSITES_HIROKI_FUKUYAMA.pdf

What a great presentation! It is a classic example of why the post production engineers at Boeing have such great respect for the folks over at JAL and ANA. They have great technical and planning skills. Although very demanding, they are a pleasure to work with as I can attest first hand. The often would end their telex (repair proposal) with "Thank you for your very best effort."  


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16976 posts, RR: 67
Reply 55, posted (11 months 4 weeks ago) and read 13942 times:

Quoting JoeCanuck (Reply 24):
I'm really very surprised at the amount of 'how will Boeing fix/maintain the dreaded CFRP bits' fear mongering that takes place whenever anything brushes up against a 787.

I think people's personal experience of fiberglass, epoxy and so forth colors their impressions of it. CFRP just seems to brittle compared to good old metal.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinePellegrine From United States of America, joined Mar 2007, 2324 posts, RR: 8
Reply 56, posted (11 months 3 weeks 6 days 22 hours ago) and read 13903 times:

Quoting Stitch (Reply 53):

What does it matter!!!? If the laminate were compromised, as it appears to be, it needs to be replaced. We are talking on the order of 50-75 square feet of fuselage, not 6 square inches of lightning or ramp rash damage. Burn through hardly matters if the laminate is compromised or resin is disturbed/melted/burned. Really.



oh boy!!!
User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 57, posted (11 months 3 weeks 6 days 13 hours ago) and read 13754 times:

Quoting Pellegrine (Reply 56):
Burn through hardly matters if the laminate is compromised or resin is disturbed/melted/burned. Really.

I think the quote (second hand) infers that in order to have a burn through of the CFRP, the fire would have been greater, and underneath damage would be more extensive (thus write-off).

So, if there was no burn through, there is a chance that the damage underneath is more manageable and repair (including replacing of large section of the fuselage panel) is a real possibility.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 58, posted (11 months 3 weeks 6 days 6 hours ago) and read 13618 times:

Quoting bikerthai (Reply 57):
I think the quote (second hand) infers that in order to have a burn through of the CFRP, the fire would have been greater, and underneath damage would be more extensive (thus write-off).

I can't see Ostrower's point either – A large skin area up top is heavily damaged, regardless of burn through or just excessive heat. That distinction alone doesn't say anything about the actual extent of the damaged area.

I would have a hard time believing that the area where the paint had started to peel and char could be salvageable. So it's all about how much more skin area is to be replaced. And if that area is too large or the placement too critical, a section replacement may be in order.

Some damage incurred during the fire fighting (water damage) and cabin smoke contamination probably adds to the equation.

And the cost and feasibility of the ultimately required work will eventually determine whether it would reach write-off level (which still seems unlikely even for the larger repair scenarios).

[Edited 2013-07-19 16:30:34]

User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 59, posted (11 months 3 weeks 6 days 6 hours ago) and read 13634 times:

Quoting bikerthai (Reply 57):
I think the quote (second hand) infers that in order to have a burn through of the CFRP, the fire would have been greater, and underneath damage would be more extensive (thus write-off).

It might also be uninformed comment, a poster on another thread that claimed to be an insurance industry insider claimed it had already been declared a write off.

Quoting bikerthai (Reply 57):
So, if there was no burn through, there is a chance that the damage underneath is more manageable and repair (including replacing of large section of the fuselage panel) is a real possibility.

It will really depend on the amount of pyrolyzation that the structure has suffered. I am not that confident about replacing a large panel vs replacing the barrel. The loads in that area are significant coming from the VTP/HTP. The aircraft's structural vibration modes will change if such a large repairs was made.

Even the L shaped puncture that was repaired on the 787 took a bit more work than a lot of people thought to get repaired, and that was basically a bicycle repair kit job. A large repair like this replacing a large section of panel, you will somehow need to get the fiber placement direction correct, the would need to be exposed in various layers so the patch will line up with the existing fiber placement. Even if all of these things are possible, if it then possible to do such a large large scale repair in a hanger which is not a specialist composite repair facility.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 60, posted (11 months 3 weeks 3 days 15 hours ago) and read 12928 times:

Quoting zeke (Reply 59):
I am not that confident about replacing a large panel vs replacing the barrel.

Replacing a barrel may be faster. Replacing a panel may be cheaper . . . it all becomes a trade.

Quoting zeke (Reply 59):
. A large repair like this replacing a large section of panel, you will somehow need to get the fiber placement direction correct, the would need to be exposed in various layers so the patch will line up with the existing fiber placement.

Typically even if we design using uni-direction material, we often try to replicate a quasi-isotropic material so directly replicating one for one fiber direction may not be needed. For a patch, all the load will probably go through a spicing member anyway, so there goes your fiber orientation continuity.

Your comment on structural vibration mode is probably more important but at the macro level. The fiber direction of the individual plies may not come in to play. The overall stiffness of the skin/string/frame panel or barrel would be more important and is more easily controlled and analyzed at the macro level. (Again assuming that the skin lay-up is near quasi-isotropic condition.)

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 61, posted (11 months 3 weeks 3 days 14 hours ago) and read 12894 times:

Quoting bikerthai (Reply 60):
Replacing a barrel may be faster. Replacing a panel may be cheaper . . . it all becomes a trade.

I think the panel would be more expensive, to design, build, test, and certify. Probably looking at 6 engineers 6 months, just to do the design and analysis, and then to get the regulators approval.

I would think the cost of building a single run of a panel would be more expensive, and building a one off tool to cure it.

From the photos I saw, it looked like the damage only extended over only one barrel section..



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 62, posted (11 months 3 weeks 3 days 13 hours ago) and read 12860 times:

Quoting zeke (Reply 61):
From the photos I saw, it looked like the damage only extended over only one barrel section..

The damage which actually caused enough damage to the outside of the fuselage to make the paint flake and char. But I would be very surprised if that was really 1:1 identical with any structural damage from the inside.


User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 63, posted (11 months 3 weeks 3 days 11 hours ago) and read 12809 times:

Quoting zeke (Reply 61):

I think the panel would be more expensive, to design, build, test, and certify.

You wouldn't have to start from scratch. The basic panel configuration would be similar if not the same as the production barrel at the specific location. You do have to work-out the details at the splice joint.

The tooling question is intriguing though.

The production drum on which the existing barrel is fabricated new panel would be built could (relatively easy) be modified to fabricate the panel. Fiber-place technology do not require a complete barrel to build parts. The aerodynamic surface is controlled by an tool that covers the "barrel drum" during cure which would not need to be modified.

From a availability stand point, you are right. A complete barrel can be pulled from the existing production line without major delays where as a panel splice will require lots more engineering, planning, tooling etc.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlinenomadd22 From United States of America, joined Feb 2008, 1820 posts, RR: 0
Reply 64, posted (11 months 3 weeks 3 days 11 hours ago) and read 12807 times:

I wasn't joking before. The needed section could be cut out of one of the non salable test planes, with only the splice needing engineering.


Andy Goetsch
User currently offlineairtechy From United States of America, joined Dec 2006, 483 posts, RR: 0
Reply 65, posted (11 months 3 weeks 3 days 9 hours ago) and read 12757 times:

Unless you were planning on having to do this on multiple airplanes (heaven forbid!) wouldn't the engineering and tooling cost exceed the cost to just replace the barrel on this one plane? I'm still assuming that the plane will eventually be ferried to a different site for repair.

AT


User currently offlineHAWK21M From India, joined Jan 2001, 31660 posts, RR: 56
Reply 66, posted (11 months 3 weeks 2 days 19 hours ago) and read 12592 times:

Have they concluded what caused the fire.....


Think of the brighter side!
User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 67, posted (11 months 3 weeks 2 days 17 hours ago) and read 12583 times:

Quoting HAWK21M (Reply 66):
Have they concluded what caused the fire.....

I keep seeing "pinched ELT wire" but I don't think that is official.

Nor has it been explained if it means a wire connected to the ELT, or a wire internal to the ELT. There wouldn't be any aircraft power connected to the ELT, but there is wiring for an activation switch and the antenna.

The ELT has an access panel for changing/inspecting the non-rechargeable battery pack.

This is apparently the ELT:

http://www51.honeywell.com/aero/comm...es-documents/RESCU_406_AFN_ELT.pdf

There is apparently a 5 cell pack of these inside:

http://ultralifecorporation.com/download/353/


User currently offlinePygmalion From United States of America, joined Jun 2006, 966 posts, RR: 38
Reply 68, posted (11 months 3 weeks 1 day 11 hours ago) and read 12285 times:

Quoting airtechy (Reply 65):
I'm still assuming that the plane will eventually be ferried to a different site for repair.

Not sure why this keeps coming up. There are lots of good repair stations and hangars at Heathrow where the airplane is. All you need to have to complete most any large repair on any airplane is to be indoors. Jigging up the 787 is no different from jigging up a 767 or a A330. Just because its made of CFRP doesn't change jigging, jacking and shoring.

All you need is a hanger that the 787 will fit in. Even the production lines in Everett and Charleston just have flat floors with movable stands when they build the thing. Hard stand production tooling went out years ago.

And another point. Just because Boeing decided to build barrels in sections, that doesn't mean they can't do repairs using panels. Either cutting a repair panel from an existing barrel or even laid up fresh using a production mandrel. Barrels were a choice not a requirement, the choice of barrel vs panel is not locked in for a repair. Airbus could decide to do a repair at a production break instead of a single panel. Boeing can decide to cut a barrel into panels. Neither choice is all that technically difficult.


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 69, posted (11 months 3 weeks 1 day 5 hours ago) and read 12196 times:

Quoting Pygmalion (Reply 68):
Not sure why this keeps coming up. There are lots of good repair stations and hangars at Heathrow where the airplane is. All you need to have to complete most any large repair on any airplane is to be indoors. Jigging up the 787 is no different from jigging up a 767 or a A330. Just because its made of CFRP doesn't change jigging, jacking and shoring.

BA is a big and experienced Boeing customer and if I'm not mistaken their facilities at Heathrow routinely do all levels of checks on Boeing aircraft already – and they are a fresh 787 operator to boot. Heathrow should pretty much be the best place for this except maybe at the Boeing final assembly line itself.

Quoting Pygmalion (Reply 68):
And another point. Just because Boeing decided to build barrels in sections, that doesn't mean they can't do repairs using panels. Either cutting a repair panel from an existing barrel or even laid up fresh using a production mandrel. Barrels were a choice not a requirement, the choice of barrel vs panel is not locked in for a repair. Airbus could decide to do a repair at a production break instead of a single panel. Boeing can decide to cut a barrel into panels. Neither choice is all that technically difficult.

I don't think that is actually true. There are likely upper limits to the size of a patch before you need to replace the entire part because of stability, weight and/or cost.

The A350 fuselage is designed to be assembled from panels and it has all the associated strucutural considerations needed for that, the 787 one is designed to be assembled from integral barrel sections and lacks the infrastructure for anything else.

You cannot simply reverse fundamental design decisions after the fact just because it would suit you for a specific repair – there is always a price to pay for such design decisions either way, and this price can be slightly higher weight in the case of the A350, but also possibly more expensive repairs in the case of the 787 when the damage exceeds a certain extent.

Repairability (feasibility, time and cost) is one of the factors in the overall design. But manufacturers still make tradeoffs – and in some cases different ones. Boeing will now have to demonstrate how well theirs work in real life.


User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 70, posted (11 months 3 weeks 1 day 2 hours ago) and read 12156 times:

Quoting Pygmalion (Reply 68):
All you need to have to complete most any large repair on any airplane is to be indoors.

Not even that, if you throw enough time and money at it.

Quoting Pygmalion (Reply 68):
Just because its made of CFRP doesn't change jigging, jacking and shoring.

It does however require different people, tools, and processes than a metallic aircraft.

Quoting Pygmalion (Reply 68):
Even the production lines in Everett and Charleston just have flat floors with movable stands when they build the thing.

The "movable stands" are high precision tooling, which normally require a specific floor or rails to work.

Quoting Pygmalion (Reply 68):
Barrels were a choice not a requirement, the choice of barrel vs panel is not locked in for a repair.

When joining composites the esp of this size, it is almost like adding a cargo door to that part of the fuselage. I have never heard of an in-situ scarf repair on such a scale, which then makes it a bolted repair. Bolted repairs are fine up to a point, then you start interfering with the overall load paths in the various layers of tape.

I have never heard of such a large bolted repair on a primary structure either, I would think the SRM would have a size limit on bolted repairs as well.

We have only see the outside from a distance, I remember the DHL 767 N799AX, for the small amount of damage seen on the outside, it had a lot of internal damage.

Quoting Pygmalion (Reply 68):
Boeing can decide to cut a barrel into panels.

If they also decide on how to join them.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 71, posted (11 months 3 weeks 9 hours ago) and read 11938 times:

Quoting LTC8K6 (Reply 67):
I keep seeing "pinched ELT wire" but I don't think that is official.

Nor has it been explained if it means a wire connected to the ELT, or a wire internal to the ELT.

It shall be the internal wires from the 5 cell battery pack that one connect to the internal electronics that got pinched. Most probably that happened ex Honeywell factory when the batteries got refreshed, perhaps as a result of the storage of the frame at Everett. You unscrew the cover, change the battery pack and close the lid with screws, it should have been the last operation where the battery pack wires got pinched meaning the remaining isolation eventually was vibrated through and the battery pack went pooof.....

This could happen in any of these ELTs when the batteries gets refreshed, the link to the 787 would be they spent quite some time in waiting to be delivered.



Non French in France
User currently offlinePygmalion From United States of America, joined Jun 2006, 966 posts, RR: 38
Reply 72, posted (11 months 3 weeks 9 hours ago) and read 11950 times:

Quoting zeke (Reply 70):
The "movable stands" are high precision tooling, which normally require a specific floor or rails to work.

the only "precision tooling" are the wing and center box join tooling and even they don't register off the floor or rails. The tooling aligns to key characteristics and points on the airplane not the floor or the rails. The body tooling is sitting on tires. Its not like it used to be.

Quoting zeke (Reply 70):
Quoting Pygmalion (Reply 68):
Just because its made of CFRP doesn't change jigging, jacking and shoring.


It does however require different people, tools, and processes than a metallic aircraft.



You cradle and shore the airplane to a jigged (nominal assembly position) and go from there.

And actually no its not different people tools or processes. The AOG guys on the 787 are the same AOG guys from the other metal airplane programs. The AOG tools are the same. Sure there are different drill tip shapes and sizes for CFRP etc. but a drill motor is a drill motor. An airplane jack is a jack.

Jigging up an airplane typically uses wing or body cradles and bottle jacks and stands. Nothing really high tech. Those cradles are made of plywood and rubber pads and can be made in a high school shop. Jacking and shoring just consist of stands and bottle jacks and load cells. All off the shelf and are the same as used in metal airplanes for AOG.

The structural analysis methods for CFRP joints are very different from aluminum... that being said, once you understand them, doing a bolted repair is very very similar to any other metal bolted repair.. You drill holes, shim to reduce pull up forces and install fasteners. Area out and bearing bypass loads are more predominate in composites so repair considerations are different.. but doing the repair is very very similar.


User currently offlinePygmalion From United States of America, joined Jun 2006, 966 posts, RR: 38
Reply 73, posted (11 months 3 weeks 9 hours ago) and read 11945 times:

Quoting zeke (Reply 70):
I have never heard of such a large bolted repair on a primary structure either, I would think the SRM would have a size limit on bolted repairs as well.

SRM repairs are airline performed repairs that dont need Boeing coordination or additional Boeing approval. The size limit is only a limit on the pre-approval not the ultimate size. Boeing can approve repairs outside the SRM limits and as the TC holder they actually must approve anything outside the SRM allowances.


User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 74, posted (11 months 3 weeks 8 hours ago) and read 11953 times:

Quoting Pygmalion (Reply 72):
And actually no its not different people tools or processes.

When was the last time the AOG team did a wet lay up or a scarf repair on a metallic aircraft ? Lets not forgot the need for breathing apparatus and special handling of the old parts.

Quoting Pygmalion (Reply 72):
Area out and bearing bypass loads are more predominate in composites so repair considerations are different.. but doing the repair is very very similar.

Not at all, with a metallic aircraft you can look at what was installed there before, buy a new sheet, and basically fasten a new one in place. With a composite repair, it requires a not of design and damage tolerance work done before anything is removed. I have never heard of such a large repair on a primary structure before.

Quoting Pygmalion (Reply 73):
Boeing can approve repairs outside the SRM limits and as the TC holder they actually must approve anything outside the SRM allowances.

Boeing must not only approve the design, the must also perform the design, no one else has the design data. It is VERY expensive, and slow.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 75, posted (11 months 2 weeks 6 days 16 hours ago) and read 11787 times:

Can we all agree that this will not be a scarf and lay-up repair? This will be specially true if the stringer and frames are damaged by the heat.

So if we can agree that this will be a bolted repair, then the approach would be more straight forward.

You still have some challenges like alignment of new parts to old parts etc. And analysis will have to be done.

But as they say, Engineering is cheap . . . the AOG team would be more expensive.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineHAWK21M From India, joined Jan 2001, 31660 posts, RR: 56
Reply 76, posted (11 months 2 weeks 4 days 20 hours ago) and read 11460 times:

Quoting LTC8K6 (Reply 67):
I keep seeing "pinched ELT wire" but I don't think that is official.

Why no cb tripped in this case.



Think of the brighter side!
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 77, posted (11 months 2 weeks 4 days 18 hours ago) and read 11727 times:

Quoting HAWK21M (Reply 76):
Why no cb tripped in this case.

Because the short was apparently directly in the cable coming from the batteries.

And you're missing a question mark, if that was supposed to be a question. Otherwise please disregard my answer.   


User currently offlineStitch From United States of America, joined Jul 2005, 30415 posts, RR: 84
Reply 78, posted (11 months 2 weeks 4 days 7 hours ago) and read 11599 times:
Support Airliners.net - become a First Class Member!

Quoting HAWK21M (Reply 76):
Why no cb tripped in this case(?)

The ELT is not energized by the 787's electrical system, so perhaps there is no circuit-breaker to trip?


User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 79, posted (11 months 2 weeks 4 days 7 hours ago) and read 11575 times:

Quoting Stitch (Reply 78):
The ELT is not energized by the 787's electrical system, so perhaps there is no circuit-breaker to trip?

There may well be some current limitation of some kind, but it would be on the circuit board – behind the cable that's been shorting out apparently.


User currently offlineFinn350 From Finland, joined Jul 2013, 654 posts, RR: 1
Reply 80, posted (11 months 2 weeks 2 days 23 hours ago) and read 11247 times:

Here is a NY Times article that quite nicely summarizes repair options

http://www.nytimes.com/2013/07/30/bu...r-repair-teams.html?pagewanted=all


User currently offlinePygmalion From United States of America, joined Jun 2006, 966 posts, RR: 38
Reply 81, posted (11 months 2 weeks 14 hours ago) and read 10792 times:

Quoting zeke (Reply 74):
When was the last time the AOG team did a wet lay up or a scarf repair on a metallic aircraft ? Lets not forgot the need for breathing apparatus and special handling of the old parts.

The 777 has CFRP floor beams, vertical fin and stabilizer. The AOG folks have been repairing them for years. They do both scarf and bolted repairs. repair of composite structure is not new at all. Even Airbus does it for their vertical fins on the A330.

Special handling? What special handling? Cured CFRP is not exactly plutonium.


User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 82, posted (11 months 2 weeks 11 hours ago) and read 10714 times:

Quoting Pygmalion (Reply 81):

Special handling? What special handling? Cured CFRP is not exactly plutonium.

No, but some places have more stringent OSHA standards than others. And while cured CFRP is relatively safe, burnt and charred CFRP is not as benign. Best just wrap it up in plastic before you do anything with it.

bt



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineAquila3 From Italy, joined Nov 2010, 249 posts, RR: 0
Reply 83, posted (11 months 1 week 6 days 17 hours ago) and read 10479 times:

Quoting Klaus (Reply 79):
Quoting Stitch (Reply 78):
The ELT is not energized by the 787's electrical system, so perhaps there is no circuit-breaker to trip?

There may well be some current limitation of some kind, but it would be on the circuit board – behind the cable that's been shorting out apparently.

Well, I wondered for a while how Honeywell did desisgn this ELT power supply.
You have a battery (primary or not) of the size and energy able to destroy the aircraft, as whe have seen.
I would not believed that if told before, but we all have seen the crude reality.
I wonder if there was not a fuse very up near the battery pole. In this case, pinched battery pack wires would just have blown the fuse.
If the fuse it is correctly dimensioned, that should be enough to avoid any runaway distruction of the cell.
Just to say I am not dreming about , I had in the hands batteries of similar size for instrumentation (non-aero stuff) and there was defenetely a fuse INSIDE the battery pack, before the battery connector.



chi vola vale chi vale vola chi non vola è un vile
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 84, posted (11 months 1 week 6 days 13 hours ago) and read 10378 times:

Quoting Aquila3 (Reply 83):
I wonder if there was not a fuse very up near the battery pole. In this case, pinched battery pack wires would just have blown the fuse.
If the fuse it is correctly dimensioned, that should be enough to avoid any runaway distruction of the cell.

Probably. But if you actually thought that far, you'd first eliminate the pinchable cable in the first place.

Sloppy design enabling sloppy maintenance to result in destruction appears to be the crucial shortcoming here.

By the way: Designing a fuse into the battery pack doesn't just reduce risks, since it adds its own complexity and additional defect scenarios, so you need to weigh your design options carefully – but a pinchable battery cable is a hair-raising design mistake and it would still be in a ground-based device (houses can burn down at least as easily as airplanes).


User currently offlinebikerthai From United States of America, joined Apr 2010, 2056 posts, RR: 4
Reply 85, posted (11 months 1 week 6 days 12 hours ago) and read 10389 times:

Quoting Klaus (Reply 84):
but a pinchable battery cable is a hair-raising design mistake

  This is an easy thing to do now-a-day with CAD design and in-experienced designers. You model the the wire to route just so on the computer and don't realize that the wire can re-position so many different ways. This is why they pay us old farts a little more, we've been there and done that and remembered not to do it again.   

bt

P.S. Or at least until our memories fail us.

[Edited 2013-08-02 10:52:30]


Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 86, posted (11 months 1 week 6 days 12 hours ago) and read 10377 times:

Quoting bikerthai (Reply 85):
This is an easy thing to do now-a-day with CAD design and in-experienced designers. You model the the wire to route just so on the computer and don't realize that the wire can re-position so many different ways. This is why they pay us old farts a little more, we've been there and done that and remembered not to do it again.

Indeed – but especially you learn how to avoid components which may become a risk, even if that can be tricky. The primary mistake here appears to be that whoever designed the battery attachment severely underestimated what can (and ultimately will!) go wrong when people have to manually fiddle with it in the field. And particularly with a relatively dangerous component such as a battery that should be avoided as far as possible.

It is hard to make everything "fool proof", but one should make a major effort to make products at least as "stress/negligence proof" as possible.

Quoting bikerthai (Reply 85):
P.S. Or at least until our memories fail us.

Yeah, at some point one may relapse eventually...   


User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 87, posted (11 months 1 week 4 days 2 hours ago) and read 9999 times:

Quoting HAWK21M (Reply 76):
Why no cb tripped in this case.

There are versions of the batteries used in the ELT that have such protection built in, apparently. They can have PTC resettable fuses if you order them that way. The ones used apparently do not have the fuses. U10013 is apparently used in the ELT in a 5 cell pack.

http://ultralifecorporation.com/be-m...oducts/cylindrical/U10013-CR34610/

The PTC fuses are interesting, but apparently not ideal for this application.

https://en.wikipedia.org/wiki/Resettable_fuse

[Edited 2013-08-04 20:36:00]

User currently offlineAquila3 From Italy, joined Nov 2010, 249 posts, RR: 0
Reply 88, posted (11 months 1 week 3 days 17 hours ago) and read 9980 times:

Quoting LTC8K6 (Reply 87):
The PTC fuses are interesting, but apparently not ideal for this application.

I have no doubts tha you are more informed than me on the subject at hand, but I would like to know why you say so.
This ony for my cultural enrichment, no second scope.

I have myself designed several systems using PTC fuses, and I never had a problem. I particularly see no problem to use them as a "main" fuse, when the required intervention time is no so stringent. That fuse would not protect the system or part of it from being damaged, but would protect what it is around from a catastrophic failure (fire or so). The trick is of course to dimension them correctly. I might add that newer poly fuses , with the addition of only a third pin offer enhanced protection with the introduction of a Zener diode in parallel. That adds a simple and effective protection against reversed polarity and overvoltages.
I can see some problems with PTC if the system uses very high currents (relative to the power source) for very short periods. That might be well the case of an ELT. In such case a PTC fuse "might" be inefficient, in the sense that a considerable amount of power can be lost on the fuse itself, due to its higher resistance compared to classic fuses.
But , again, I suspect that the ones integrated inside the battery would be well calibrated to the battery itself.

Quoting Klaus (Reply 84):
By the way: Designing a fuse into the battery pack doesn't just reduce risks, since it adds its own complexity and additional defect scenarios, so you need to weigh your design options carefully – but a pinchable battery cable is a hair-raising design mistake and it would still be in a ground-based device

Well, here the old designer in me somehow disagrees. I am not trying to upset you, just to say a technical opinion.
Basically:
1) My idea is that anything that has a so considerable source of energy MUST have overcurrent protection, that would often be a fuse. Then, in the case of a battery, the main fuse MUST be as up as possible on the current path, just to avoid at best any possible catastrophic event.
2)
About the pinched wires, I must say that cables and connectors are very often overlooked, but are the the most common sources of problems. Add that they are sometimes during the service life of the system manipulated and you add so many variables in them that it is really difficult (or too expensive, but in Aero this seems to be less a problem) to design a solution that is enough "fool proof". I have seen my rate of brocken or shorted wires, misplugged connectors, bent pins, oxidated or contaminated receptacles, believe me. So the effort to design a wiring that cannot be pinched (or misconnected, or bent, or shorted, or....) can be bigger than what you might think. And again, you still have to go thru 1) because the system itself can in may cases have afailure mode that generates a potentially destructive overcurrent.

So, in conclusion why not a main fuse (IF THT IS THE CASE) is still really beyond me.



chi vola vale chi vale vola chi non vola è un vile
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 89, posted (11 months 1 week 3 days 16 hours ago) and read 9981 times:

Quoting Aquila3 (Reply 88):
Well, here the old designer in me somehow disagrees. I am not trying to upset you, just to say a technical opinion.

I don't see the disagreement, actually. I think we're pretty much on the same page overall.


User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 90, posted (11 months 1 week 3 days 1 hour ago) and read 9686 times:

Quoting Aquila3 (Reply 88):
I have no doubts tha you are more informed than me on the subject at hand, but I would like to know why you say so.
This ony for my cultural enrichment, no second scope.

I had never heard of PTC fuses/devices before looking up the ELT battery and reading the Wiki info.

The Wiki article gives a couple of conditions that may apply to the ELT.

Quote:
Since a PPTC device has an inherently higher resistance than a metallic fuse or circuit breaker at ambient temperature, it may be difficult or impossible to use in circuits that cannot tolerate significant reductions in operating voltage, forcing the engineer to choose the latter in a design.

In case of potted (hard resin or even soft silicone-based) assemblies, manufacturers recommend leaving an open space around the device, to allow expansion. This can be achieved by placing a small box over the PPTC before pouring.


User currently offlineBaconButty From United Kingdom, joined Aug 2013, 179 posts, RR: 0
Reply 91, posted (11 months 5 days 6 hours ago) and read 9065 times:

This article confirms that the ELT had a current limiter that should have prevented the short circuit causing a fire - if indeed it did. http://seattletimes.com/html/busines...gy/2021528093_honeywelleltxml.html

What I don't get its why they need the 5 cells anyway. Marine epirb's that do a similar job will typically have 3 D size 60ish watt hour batteries. With similar operating temperatures they will last 48 hours (vs 50) don't transmit on 243mhz (only 121.5 for homing) and are replaced after 5 years, vs 10, so less self discharge to account for. None of these seems a big issue to be honest, and if you could get a 40% reduction in batteries in the two fixed elt's that would reduce the risk of catastrophic damage from them, and save a few grams in the process.



You could do with some brown sauce on that.
User currently offlinetheducks From Canada, joined Jul 2009, 32 posts, RR: 0
Reply 92, posted (11 months 5 days 1 hour ago) and read 8123 times:

Quoting zeke (Reply 70):
I have never heard of such a large bolted repair on a primary structure either, I would think the SRM would have a size limit on bolted repairs as well.

QANTAS's VH-OJH repair was essentially a replacement of the front of a 747, performed with limited facilities in Thailand. There's a slide-deck going around of pictures of how it was done - pretty impressive.


User currently onlineKELPkid From United States of America, joined Nov 2005, 6339 posts, RR: 3
Reply 93, posted (11 months 4 days 23 hours ago) and read 7997 times:

Quoting BaconButty (Reply 91):
This article confirms that the ELT had a current limiter that should have prevented the short circuit causing a fire - if indeed it did. http://seattletimes.com/html/busines...gy/2021528093_honeywelleltxml.html

Murphy's law of electricity: A $5000 circuit will selflessly sacrifice itself in an effort to save a 5 cent fuse  

Fuses don't always work, and sometimes when they blow, the damage has already been done.

A well known manufacturer of (household) electrical circuit breaker panels here in the USA (Federal Pacific) was put out of business because it was shown that, after a circuit breaker or two had tripped, any subsequent breaker trips could catch the entire panel on fire, and quite a few house fires were attributed to their electrical panels. It was later shown that the panel designers did not take into account that the overcurrent which caused the breaker trip in the first place started to melt and deform the bus bar where the bus bar and the circuit breaker interfaced. Subsequent circuit breaker trips would damage the bus bar in that area further.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 94, posted (11 months 3 days 22 hours ago) and read 7610 times:

The short could have been before the current limiter, bypassing it.

User currently offlineBaconButty From United Kingdom, joined Aug 2013, 179 posts, RR: 0
Reply 95, posted (11 months 3 days 21 hours ago) and read 7596 times:

Quoting LTC8K6 (Reply 94):

The short could have been before the current limiter, bypassing it.

Not if it was the "pinched wires" that caused the short. The polyswitch is usually located right by the batteries - sometimes heat shrinked in the pack. It would seem to be confirmed by the Honeywell spokesman in the referenced article, anyway.
By the way, I'm not trying to troll here, I've been following the various discussions and I know it's a touchy subject. In any case, the presence of the PPTC should (if it works) protect against external antenna/control wiring going live as much as the internal pinched wires. The AAIB report should be interesting!



You could do with some brown sauce on that.
User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 96, posted (11 months 3 days 17 hours ago) and read 7521 times:

My research actually indicated that the ELT used the battery cells without the built in PTC device, suggesting that the protection device is part of the ELT or the assembled cell pack.

Ultralife makes versions of the cells with and without PTC devices.

I think the PTC device is either in the ELT itself, or was added to the pack when the pack was assembled, because I don't think they use the cells with the built in PTC.

Unless we are certain about the PTC, then we can't say for sure that it couldn't have been bypassed by the short.


User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 97, posted (11 months 3 days 17 hours ago) and read 7522 times:

Why is a carpet fiber company manufacturing ELT's for Honeywell?

User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 98, posted (11 months 3 days 17 hours ago) and read 7511 times:

It's also possible that the battery pack was replaced with a pack that was "equivalent", but not quite, with respect to overcurrent protection.

User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 99, posted (11 months 3 days 16 hours ago) and read 7523 times:

http://www.mcssl.com/content/173388/HONEYWELL_SPARES/1096801-1.JPG

Pack looks like that one with the pull tabs and the connector. Looks difficult to pinch that wiring when replacing the pack.

There is a lot of technical info on the ELT here including electrical diagrams and battery replacement info.

http://amis2000.aerolineas.com.ar/COMPONENTES/1152682-2.pdf


User currently offlineBaconButty From United Kingdom, joined Aug 2013, 179 posts, RR: 0
Reply 100, posted (11 months 3 days 16 hours ago) and read 7495 times:

Quoting LTC8K6 (Reply 96):
Unless we are certain about the PTC, then we can't say for sure that it couldn't have been bypassed by the short.

I was going on the statements by the Honeywell spokesman, paraphrased by the Seattle Times:

Quote:
Honeywell spokesman Steve Brecken said Friday that the ELT contained a current limiter that should have stopped any surge of current caused by a short.

Granted, the fact he wasn't quoted directly leaves a bit of wiggle room, but assuming the reporter has got the gist, it points to the current limiter being in the pack, something you see on Marine epirbs. You couldn't say that with any level of confidence otherwise. Interesting to see a photo of the pack - I imagined it looking more like this www.saftbatteries.com/force_download/3_M20.pdf - but 5 cell - you could easily see how you might pinch the wires there.



You could do with some brown sauce on that.
User currently offlineLTC8K6 From United States of America, joined Jun 2009, 1174 posts, RR: 0
Reply 101, posted (11 months 3 days 15 hours ago) and read 7478 times:

If you look through the pdf manual, at the illustration for replacing the pack, it looks difficult to pinch the wires between the cover and the case.

It certainly could be done, of course.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19278 posts, RR: 58
Reply 102, posted (11 months 3 days 9 hours ago) and read 7539 times:

Quoting Klaus (Reply 84):
Sloppy design enabling sloppy maintenance to result in destruction appears to be the crucial shortcoming here.

This mystifies me, too. There are hundreds (thousands?) of consumer electronic devices powered by Li-ion batteries that are user-replaceable. You pop off a panel, slide out the old battery, slide in the new one, and pop the panel back on. No wires to pinch. This basic design has been applied to a wide range of products including ones designed to handle extreme environments (like deep-sea underwater cameras) to those to which the safety of life or limb is trusted (like portable ventilators or portable IV drip pumps).

So why would the ELT require wires to be connected? Why not just have a "drop/slide-in" design?


User currently offlinePellegrine From United States of America, joined Mar 2007, 2324 posts, RR: 8
Reply 103, posted (10 months 3 weeks 3 days 19 hours ago) and read 6548 times:

Does anyone have any real updates to this? There seems like a firewall      between any real updates or disclosure.


oh boy!!!
User currently offlineaviatorcraig From United Kingdom, joined Mar 2010, 200 posts, RR: 0
Reply 104, posted (10 months 3 weeks 2 days 12 hours ago) and read 6169 times:

Does anyone know where this airframe currently is? Shortly after the fire when the initial investigation by the AAIB was being undertaken, it could be seen in a hanger across the threshold of 27R from the Northern Perimeter Road but has since gone from there. I work nights at LHR and have failed to find its location in the maintenance area.

Is work going on currently to return the aircraft to service or is it sat idle whilst decisions about its repair are taken? Also, I would guess that repairs would be undertaken by a Boeing team using BA's facilities but could possibly use Virgin's hangar instead (does United have a big enough hangar on the South side?).

What are the chances of the aircraft being "patched up" and ferried back to Boeing for the repair proper?

Sorry for the list of questions but I am intrigued that news of the repair of the airframe has dried up with most posts concentrating on the ELT issues.

Thanks,

Craig



707 727 Caravelle Comet Concorde Dash-7 DC-9 DC-10 One-Eleven Trident Tristar Tu-134 VC-10 Viscount plus boring stuff!
User currently onlineKELPkid From United States of America, joined Nov 2005, 6339 posts, RR: 3
Reply 105, posted (10 months 3 weeks 1 day 9 hours ago) and read 5890 times:

Quoting aviatorcraig (Reply 106):
Does anyone know where this airframe currently is?

LHR would be a pretty educated guess....   

But as you know, airports are big places. ET is also a very secretive airline, and I don't think they would appreciate clueing in the aviation community in on the repairs of ET-AOP. We just might have to wait until its done to get the whole story...



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlinercair1 From United States of America, joined Oct 2009, 1301 posts, RR: 52
Reply 106, posted (10 months 3 weeks 1 day 7 hours ago) and read 5846 times:
AIRLINERS.NET CREW
CUSTOMER SERVICE & SUPPORT

Quoting JoeCanuck (Reply 24):

CFRP is just a building material...it's not voodoo.

  

Quoting JoeCanuck (Reply 24):
The real important question is not, 'how will they fix it?', but 'how did it start?'...that's the worrying bit.

On   

Quoting Klaus (Reply 42):

Personally, I can see your point, but I still don't think that anybody would knowingly sign off on a dangerous defect especially now.

Agreed - complacency versus conspiracy and negligence.

Quoting Klaus (Reply 58):
I can't see Ostrower's point either – A large skin area up top is heavily damaged, regardless of burn through or just excessive heat. That distinction alone doesn't say anything about the actual extent of the damaged area.

I do - see the point. It goes to trying to infer the amount of damage from a severe lack of information. In other words - if it burned through there is more damage - and probably a larger damaged area - than if not.

Quoting HAWK21M (Reply 66):

Have they concluded what caused the fire....

No. They have indicated that the fire was in the vicinity of the ELT. They have found evidence of pinched wire in the ELT and, I think, in some others (not sure about that last item).

Quoting LTC8K6 (Reply 67):
or a wire internal to the ELT.

Internal.

Quoting zeke (Reply 70):
It does however require different people, tools, and processes than a metallic aircraft.

So - fly-em-in.

Quoting HAWK21M (Reply 76):
Why no cb tripped in this case

No cb to trip.

Quoting Pellegrine (Reply 103):

Does anyone have any real updates to this

Somebody does.
But nobody here does.   



rcair1
User currently offlineKlaus From Germany, joined exactly 13 years ago today! , 21386 posts, RR: 54
Reply 107, posted (10 months 3 weeks 9 hours ago) and read 5565 times:

Quoting rcair1 (Reply 106):
Quoting Pellegrine (Reply 103):

Does anyone have any real updates to this

Somebody does.
But nobody here does.

At least nobody here who knows something is actually talking...!   


User currently offlinePellegrine From United States of America, joined Mar 2007, 2324 posts, RR: 8
Reply 108, posted (10 months 2 weeks 3 days 14 hours ago) and read 4639 times:

Quoting Klaus (Reply 107):
Quoting rcair1 (Reply 106):
Quoting Pellegrine (Reply 103):

Does anyone have any real updates to this

Somebody does.
But nobody here does.

At least nobody here who knows something is actually talking...!   

Maybe by year's end, or next spring we will find out. I don't think we'll know until after the a/c is back in service.



oh boy!!!
User currently offlinebristolflyer From United Kingdom, joined May 2004, 2288 posts, RR: 0
Reply 109, posted (10 months 2 weeks 3 days 3 hours ago) and read 4468 times:

Quoting Pellegrine (Reply 108):
Maybe by year's end, or next spring we will find out.

How much is parking costing them in the meantime? And who pays for this - insurance?



Fortune favours the brave
Top Of Page
Forum Index

Reply To This Topic How Will The Ethiopian 787 Be Repaired?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Will The 787/350 Be The Only CF Airplanes posted Wed Sep 26 2007 18:21:57 by Revo1059
Will The 787 And A350 Make The A380 Look Out Dated posted Mon Feb 22 2010 20:48:48 by 747400sp
What Approach Will The A380 Be Taking Into BHD? posted Sat Sep 5 2009 03:46:29 by Loughrey1
Will The B787 Be Flight Certified In 9 Months? posted Sat Feb 7 2009 15:04:12 by Keesje
What Will The Next Cessna Piston Be? posted Sat Nov 5 2005 12:25:11 by KBFIspotter
How Will Or How Did The A380 Handle Certification? posted Mon Jan 24 2005 20:34:23 by JumboJim747
When Will The A3XX Be Finished? posted Fri Nov 3 2000 15:18:13 by MD11man
Pilot Review: Flying The Boeing 787 posted Thu Dec 13 2012 11:05:33 by LAXintl
Cones On The Wings: 787 posted Wed Nov 14 2012 00:06:41 by dlramp4life
How Safe The Sky Is.. posted Tue Aug 14 2012 12:42:00 by ymincrement

Sponsor Message:
Printer friendly format