B787 repair question
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B787 repair question
Reading about the high tech all composite fuselage of the 787 I can't help wondering how it will be possible to repair the hull after Johnny Groundcrew punctures it with the corner of the honey wagon or whatever.
Anyone enlighten me?
Anyone enlighten me?
Joined: May 2005
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From: Standing at P37
Jo90,
Mate, I've been thinking the same thing myself for quite a while now. It would seem to me that when it comes to the pressurised area of the fuselage, there will be no more quick patch repairs to get you on your way. Carbon, graphite and'or kevlar would generally require lots of heat, vaccuum and time to effect a structural repair. Having said that, one would hope that Boeing have put as much research into the maint/repair of these plastic fantastics as they put into the thought/design/promises of light weight/cost saving.
Not much point having a lightweight/economical aircraft saving you lots of money for a couple of years if the first time the fuselage gets damaged by a catering truck/pushback tug/fuel truck/hangar door etc,etc it stays on the ground for weeks or months waiting for a repair scheme!
Believe me, they all get hit sooner or later- as sure as the sun coming up!
With a "traditional" aluminium skin/structure, the worst hits/holes/dents can be fixed with new metal, rivets and some skilled (or even unskilled) labour in a relatively short time. A big hole in a composite structural area would not be quite so easy in my opinion. Like i said, i'll reserve judgement until manufacturer's start coming up with repair schemes but i wouldn't want to be the first to drive a truck into one!
Mate, I've been thinking the same thing myself for quite a while now. It would seem to me that when it comes to the pressurised area of the fuselage, there will be no more quick patch repairs to get you on your way. Carbon, graphite and'or kevlar would generally require lots of heat, vaccuum and time to effect a structural repair. Having said that, one would hope that Boeing have put as much research into the maint/repair of these plastic fantastics as they put into the thought/design/promises of light weight/cost saving.
Not much point having a lightweight/economical aircraft saving you lots of money for a couple of years if the first time the fuselage gets damaged by a catering truck/pushback tug/fuel truck/hangar door etc,etc it stays on the ground for weeks or months waiting for a repair scheme!
Believe me, they all get hit sooner or later- as sure as the sun coming up!
With a "traditional" aluminium skin/structure, the worst hits/holes/dents can be fixed with new metal, rivets and some skilled (or even unskilled) labour in a relatively short time. A big hole in a composite structural area would not be quite so easy in my opinion. Like i said, i'll reserve judgement until manufacturer's start coming up with repair schemes but i wouldn't want to be the first to drive a truck into one!
Joined: Jun 2001
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From: Boldly going where no split infinitive has gone before..
Do you really think that Boeing would invest billions developing the aircraft, and the airlines would order hundreds of them, if repair-ability hadn't been thought of?
In the first instance, the hull is less prone to damage as it is harder that conventional aluminum structure.
Secondly, a repair regime is part of the package. For a normal type of "ding" such as running a baggage loader into the hull might cause, a patch can be applied that takes 30 minutes to repair and lasts five years.
A major hull damage can be repair on an overnight service and is good until the next full strip down (about equivalent to a "D" check, but at longer intervals.)
Repairablility and therefore avoiding down time is actually one of the (many!) things that is making the 787 a revolution in the industry.
In the first instance, the hull is less prone to damage as it is harder that conventional aluminum structure.
Secondly, a repair regime is part of the package. For a normal type of "ding" such as running a baggage loader into the hull might cause, a patch can be applied that takes 30 minutes to repair and lasts five years.
A major hull damage can be repair on an overnight service and is good until the next full strip down (about equivalent to a "D" check, but at longer intervals.)
Repairablility and therefore avoiding down time is actually one of the (many!) things that is making the 787 a revolution in the industry.
Joined: Oct 1999
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From: UK
But what happens inside the skin?
WizofOz
I am not a composite structures person. But I had an interesting conversation with someone who said he was one, at ORD the other day.
He confirmed what you say - you hit the skin with a 5 pound mallet and you'll break the mallet before you break the skin.
But he also said that while there was no apparent damage inside or outside, when you got to layer 4 or 5 (eg if there are 9 layers) you sometimes see microscopic mechanical changes from some kind of internal refraction which are not seen on the outer layers. Which takes us back to 'how would you know if the aircraft had been damaged if johnny honeycart or ecoli caterers smack the skin and don't report?' Was he talking out of his afterburner?
I am not a composite structures person. But I had an interesting conversation with someone who said he was one, at ORD the other day.
He confirmed what you say - you hit the skin with a 5 pound mallet and you'll break the mallet before you break the skin.
But he also said that while there was no apparent damage inside or outside, when you got to layer 4 or 5 (eg if there are 9 layers) you sometimes see microscopic mechanical changes from some kind of internal refraction which are not seen on the outer layers. Which takes us back to 'how would you know if the aircraft had been damaged if johnny honeycart or ecoli caterers smack the skin and don't report?' Was he talking out of his afterburner?
Joined: Oct 2002
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From: Northport, NW England
PinkMan,
I'm no expert here but I remember asking the same thing. I was told, anectdotally, that the 787 was supposed to be having a "web" of electric magic filaments embedded in the layers which apparently will highlight any subcutaneous fractures or potential damage to an onboard system - most likely not accessible to the crew - hardly good for crew morale!
These would be in addition to any conductive elements re: lightning strike.
I'm no expert here but I remember asking the same thing. I was told, anectdotally, that the 787 was supposed to be having a "web" of electric magic filaments embedded in the layers which apparently will highlight any subcutaneous fractures or potential damage to an onboard system - most likely not accessible to the crew - hardly good for crew morale!
These would be in addition to any conductive elements re: lightning strike.
Joined: Feb 2005
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From: flyover country USA
The straightforward systems approach would be to resign the honeywagon and his cousins to fail before the aeroplane does. Rather cheaper to fix it than Mr. Boeing's $multimillion flying machine.
(Strange thought: every time Boeing or Airbus sells a carbon-composite aircraft, can they also sell carbon offset credits?)
(Strange thought: every time Boeing or Airbus sells a carbon-composite aircraft, can they also sell carbon offset credits?)
Joined: Dec 2001
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From: what U.S. calls ´old Europe´
Skilled glider repair shops do composite repair for over 40 years now, and they really do repair everything, up to a wing completely broken at the root. Doing your first loop in such an aircraft after finishing the repair is a little scary though...
In 10 years time it will be as comon to repair a plastic phantastic as it is to repair a tin can today. But I do not want to be the first operator to dent the Dreamliner...
In 10 years time it will be as comon to repair a plastic phantastic as it is to repair a tin can today. But I do not want to be the first operator to dent the Dreamliner...
Joined: Jul 2007
Posts: 186
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From: UK
Titanium repair patches with hi-lok fasteners.
Problem like your bumper of your car is what happens when the impact damage spring backs leaving no evidence of damage but defects behind.
Im sure mr boeing has thought of that though.
Problem like your bumper of your car is what happens when the impact damage spring backs leaving no evidence of damage but defects behind.
Im sure mr boeing has thought of that though.
Joined: Mar 2002
Posts: 4,569
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From: Florida
Problem like your bumper of your car is what happens when the impact damage spring backs leaving no evidence of damage but defects behind.
Im sure mr boeing has thought of that though.
Im sure mr boeing has thought of that though.
When they more closely examined the spinner they found that the fiberglass shell was cracked and full of blood spatters. It seems that the bird had caved in the spinner upong impact, cracked it and slipped inside as a blob before being centrifuged inside the face of the fan disk. The spinner than simply sprung back and closed up the crack.
Joined: Jan 2012
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From: Holding at DESDI
Actually, Boeing has already been thru this several times with different press releases, describing the process.
A 'bang' or contact with a foreign object that cannot be detected by a GVI is not a concern.
For minor damages detected by a GVI, an adhesive patch repair that takes a maximum of 1 hour to cure will see the airplane thru until the next C-chk.
At the next C-chk, or for major damages, a permanent repair scheme (similar to a traditional composite repair) has to be executed that takes about 24 hours, and is good for the life of the aircraft.
I'm just being lazy by not posting references, but anyone with access to the 787 SRM will be able to give references.
A 'bang' or contact with a foreign object that cannot be detected by a GVI is not a concern.
For minor damages detected by a GVI, an adhesive patch repair that takes a maximum of 1 hour to cure will see the airplane thru until the next C-chk.
At the next C-chk, or for major damages, a permanent repair scheme (similar to a traditional composite repair) has to be executed that takes about 24 hours, and is good for the life of the aircraft.
I'm just being lazy by not posting references, but anyone with access to the 787 SRM will be able to give references.
Joined: Feb 2002
Aviation Qualifications: AME
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From: UK
At least one 787 operator has had a major attack of ramp rash this year. The catering truck punctured the fuselage below the aft door. An "L" shaped cutout repair was required. A specialist team from Boeing took considerably more time than 24hrs to complete.
Last edited by TURIN; 14th July 2013 at 22:49.
