Ethiopean 787 fire at Heathrow
Joined: Oct 2013
Posts: 443
Likes: 0
From: Sweden
A and C
I would opt for this too.
That is why it is so interesting to know why Boeing do what they do. There must be a very well thought out reason for their repair technique - I would love to follow that reasoning!
My preferred option would have been to fit the new section as a plug from the inside as this would be less disruptive to the outside of the aircraft.
That is why it is so interesting to know why Boeing do what they do. There must be a very well thought out reason for their repair technique - I would love to follow that reasoning!
Joined: Mar 2008
Posts: 13
Likes: 0
From: Canada
A and C
Indeed perhaps it will be a combination:
1. A scarfed joint with the patch installed as a plug from the inside, and then
2. The 8 inch wide extra strips placed over the scarfed joint on the inside (glued and/or riveted in place to give extra support to the scarfed joint).
That might be a good combination.
However there might be a lot of interference from structure inside the plane (ribs, etc) to make this more challenging.
Speedbump
Indeed perhaps it will be a combination:
1. A scarfed joint with the patch installed as a plug from the inside, and then
2. The 8 inch wide extra strips placed over the scarfed joint on the inside (glued and/or riveted in place to give extra support to the scarfed joint).
That might be a good combination.
However there might be a lot of interference from structure inside the plane (ribs, etc) to make this more challenging.
Speedbump
Joined: Oct 2013
Posts: 443
Likes: 0
From: Sweden
Re plugs:
I thought the above stated that they are plugging it from the outside. Did I misinterpret the description? "Drop it into the space" etc...
It will cut the patch to the same size and shape and drop it into the space as a plug. The tiny gap around the patch will be filled with paintable sealant that will stretch and compress as the fuselage is pressurized and unpressurized.
Then mechanics will work on the inside, gluing a splice plate to the original skin and to the patch, overlapping both by about 4 inches.
Then mechanics will work on the inside, gluing a splice plate to the original skin and to the patch, overlapping both by about 4 inches.
Joined: Mar 2008
Posts: 13
Likes: 0
From: Canada
I thought the same. But calling the patch a "plug" kind of indicates that it will be installed from the inside to plug the hole (maybe scarfed).
Presumably the Seattle Times reporter is not an expert on composite repair and we should not read too much into the finer details of what he wrote.
And who knows how accurate his source is anyhow.
Speedbump
Presumably the Seattle Times reporter is not an expert on composite repair and we should not read too much into the finer details of what he wrote.
And who knows how accurate his source is anyhow.
Speedbump
Joined: Apr 2008
Posts: 25
Likes: 3
From: London
Joined: Aug 2001
Posts: 865
Likes: 15
From: Greater Aldergrove
Looking forward to hearing how this repair was finally carried out.
I've said it on here before, but I think this is a great story for Boeing and the 787...a fire that would have destroyed a metal frame, and yet this aircraft is being repaired, and will fly again. CFRP is the way ahead, and Boeing will have learnt even more in developing this fix. Well done to all...
I've said it on here before, but I think this is a great story for Boeing and the 787...a fire that would have destroyed a metal frame, and yet this aircraft is being repaired, and will fly again. CFRP is the way ahead, and Boeing will have learnt even more in developing this fix. Well done to all...
Joined: Jan 2008
Posts: 292
Likes: 0
From: UK
I've said it on here before, but I think this is a great story for Boeing and the 787...a fire that would have destroyed a metal frame, and yet this aircraft is being repaired, and will fly again. CFRP is the way ahead, and Boeing will have learnt even more in developing this fix. Well done to all...
Joined: Jul 2007
Posts: 48
Likes: 0
From: United States
metal vs. composite
Lemain.
Well said and I completely concur that it would have been a non-event or very minor repair for a metallic as the ELT battery is very small with little energy and I bet we never find out the repair cost either.
Well said and I completely concur that it would have been a non-event or very minor repair for a metallic as the ELT battery is very small with little energy and I bet we never find out the repair cost either.
Joined: Jan 1999
Posts: 6,209
Likes: 2
From: north of barlu
Amicus
I don't think we have enough data to predict the damage that would have been done to a metal airframe and I would suggest that it would not be the ELT battery that would do the damage but rather the burning of what it sets fire to.
As to the time the repair has taken, it looks to me as if the legal wrangling and getting the logistics sorted has taken longer than fixing the aircraft. I think Boeing have done rather well, after all this is the first major field repair of a large composite airliner being done by a company that is not yet well versed in composite repair techniques and no doubt being hindered by those who know a lot about metal aircraft and very little about composites.
I would very much like to get a look at the repair to see what techniques were used.
As to the time the repair has taken, it looks to me as if the legal wrangling and getting the logistics sorted has taken longer than fixing the aircraft. I think Boeing have done rather well, after all this is the first major field repair of a large composite airliner being done by a company that is not yet well versed in composite repair techniques and no doubt being hindered by those who know a lot about metal aircraft and very little about composites.
I would very much like to get a look at the repair to see what techniques were used.
Joined: Feb 2005
Posts: 4,581
Likes: 0
From: flyover country USA
Would not a metal frame have dissipated more energy resulting in a lower temperature, when the ELT battery failed?
Conversely, carbon composites are better thermal insulators, and contain the heat as seen in this 787.
Joined: Jul 2007
Posts: 48
Likes: 0
From: United States
787
A and C,
As the auto ignition temperature of the Toray 3900-2 epoxy as used on the 787 is a mere 580 degrees F per FAA tests and the autoignition temperature of aluminum alloys is around 2000 degrees F plus CFRP being and good insulator and aluminum an excellent conductor, I think that we can predict and state with full confidence that the damage of an ELT short and fire would be a whole lot less for metallics and we already have proof of small fires in 787 CFRP sitting at Heathrow.
As the auto ignition temperature of the Toray 3900-2 epoxy as used on the 787 is a mere 580 degrees F per FAA tests and the autoignition temperature of aluminum alloys is around 2000 degrees F plus CFRP being and good insulator and aluminum an excellent conductor, I think that we can predict and state with full confidence that the damage of an ELT short and fire would be a whole lot less for metallics and we already have proof of small fires in 787 CFRP sitting at Heathrow.
Joined: Dec 2013
Posts: 261
Likes: 0
From: Paso Robles
I think that we can predict and state with full confidence that the damage of an ELT short and fire would be a whole lot less for metallics
Joined: Oct 2002
Aviation Qualifications: PPL
Posts: 8,208
Likes: 351
From: London UK
As to the time the repair has taken, it looks to me as if the legal wrangling and getting the logistics sorted has taken longer than fixing the aircraft. I think Boeing have done rather well, after all this is the first major field repair of a large composite airliner being done by a company that is not yet well versed in composite repair techniques and no doubt being hindered by those who know a lot about metal aircraft and very little about composites.
Which is correct ?
Joined: Oct 2013
Posts: 443
Likes: 0
From: Sweden
WHBM
Military chain of commands is so much shorter (ok, generally speaking...) so it's more "fix this YESTERDAY and that's an order!" (ok, overemphazising on purpose).
Civil aviation has all kinds of "red tape" running all across the world and with an Ethiopian plane on a UK tarmac with a US built airframe, insured by Someone and on top of that a major PR stunt for Boeing, of course it takes time no matter how well prepared the engineers might be.
Once the work started it seems they did pretty well - remember we don't know how extensive it was on the inside. I do believe that composite materials are pretty well understood IF Boeing chooses to use the military knowledge people in the civilian process. I am not at all familiar with Boeing's corporate structure but there are occasions where military and civilian engineers are completely separate within the same company (you know, secret stuff, classified stuff, not allowed to share because of the safety of the nation etc), leading to peculiar gaps in information exchange. This will of course hamper the development of products, mainly on the civilian side because that side is the one that really has to consider price tags.
Now, as for how they actually fixed it, I am a curious beast. Any gossip, loose rumours, uneducated guesses, anything besides the post in Seattle Times? ;-D
Military chain of commands is so much shorter (ok, generally speaking...) so it's more "fix this YESTERDAY and that's an order!" (ok, overemphazising on purpose).
Civil aviation has all kinds of "red tape" running all across the world and with an Ethiopian plane on a UK tarmac with a US built airframe, insured by Someone and on top of that a major PR stunt for Boeing, of course it takes time no matter how well prepared the engineers might be.
Once the work started it seems they did pretty well - remember we don't know how extensive it was on the inside. I do believe that composite materials are pretty well understood IF Boeing chooses to use the military knowledge people in the civilian process. I am not at all familiar with Boeing's corporate structure but there are occasions where military and civilian engineers are completely separate within the same company (you know, secret stuff, classified stuff, not allowed to share because of the safety of the nation etc), leading to peculiar gaps in information exchange. This will of course hamper the development of products, mainly on the civilian side because that side is the one that really has to consider price tags.
Now, as for how they actually fixed it, I am a curious beast. Any gossip, loose rumours, uneducated guesses, anything besides the post in Seattle Times? ;-D
Joined: Dec 2013
Posts: 261
Likes: 0
From: Paso Robles
and the repair itself; wishful thinking perhaps!
Aviation Week And Space Technology had recently (just about 2 weeks ago) an article on the subject, they said that repair method was 'confidential', and if this very influential and otherwise extremely well informed weekly doesn't know there is a fat chance someone on this forum will ...
Joined: Jan 2008
Posts: 1,191
Likes: 0
From: lancs.UK
if this very influential and otherwise extremely well informed weekly doesn't know there is a fat chance someone on this forum will ...
You think it's highly unlikely that a PPruner will know somebody who worked on the repair and wheedle some info?
IT ISN'T A STATE SECRET....Maybe a confidential industrial one, but as with virtually all industrial secrets, it will eventually out.
Also, some of those involved are likely to set up their own Composite repair business in this niche market where they'd be able to virtually name their own price.
let's sit and wait....who knows, Boeing may, just may want to trumpet their success!