Ethiopean 787 fire at Heathrow
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Whilst I agree the repair can probably replace to original, what I am sure the AAIB is looking at whether this heat damage has weakened the structure before the repair. This aircraft has had numerious electrical fires in the test phase. Composites produce noxious fumes when they burn, this can not be good for pax safety.
Last edited by Walnut; 13th Jul 2013 at 20:14.
Bonded Repair
A and C,
A bonded repair may well match the strength of the parent material, lighter, etc. but such a repair will need the airworthiness authority approval. If they don't approve it then it can't be used, which is why I was guessing they may have to go for a bolted plate repair.
A bonded repair may well match the strength of the parent material, lighter, etc. but such a repair will need the airworthiness authority approval. If they don't approve it then it can't be used, which is why I was guessing they may have to go for a bolted plate repair.
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Presumably everything that has got hot [for some defined value of hot] or [given that the fire wasn't instrumented] can't be proven not to have gotten hot will need to be replaced, simply because its structural properties are no longer a known quantity and it might fail under loads that it previously wouldn't have failed under? So the visibly damaged area will need replacing, but so will all the surrounding areas that were exposed to the fire directly, and the radiated heat of the fire indirectly... given the obvious known properties of hot gases, that could mean a hell of a lot of the top half of the fuselage needing to be replaced, and then there's the rear bulkhead, and the tail fin...
So, how do you patch a plane that has such major and unquantifiable structural damage up to a point where any certifying authority will let you ferry it somewhere for repair, given that for all anybody knows, the tail fin if not the entire back end of the plane could shear off the first time they use the rudder during climb-out from Heathrow and they could end up... improving... Slough High Street?
So, how do you patch a plane that has such major and unquantifiable structural damage up to a point where any certifying authority will let you ferry it somewhere for repair, given that for all anybody knows, the tail fin if not the entire back end of the plane could shear off the first time they use the rudder during climb-out from Heathrow and they could end up... improving... Slough High Street?
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How do you evalute or test a bonded repair?
A & C and any other material specialists....how do you check the workmanship and bond of a bonded repair? With welds, you use various techniques from X-Ray, nuclear, dye penetrant...and the industry is pretty good these days in determining the 'fix'. Same for mechanical repairs, which tend to be over-engineered and can be inspected visually ( Brunel technique). How do you check repairs on these composites?
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If it was a coffee brewer, which I doubt.
It asks more questions than answers.
When I worked for a Hadj airline.
The problem was pilgrims brewing with primus stoves in the isles.
Looking at the photo. The damage looks extensive. Bits hanging down, frames exposed etc.
Wheel the Airfix kit over to BA maintenance, where it will stay for a few months.
The aircraft is not for flying.
It asks more questions than answers.
When I worked for a Hadj airline.
The problem was pilgrims brewing with primus stoves in the isles.
Looking at the photo. The damage looks extensive. Bits hanging down, frames exposed etc.
Wheel the Airfix kit over to BA maintenance, where it will stay for a few months.
The aircraft is not for flying.
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SRMman .....and others !
The damaged section needs cutting back to the undamaged structure, so if in doubt about heat damage the answer is to cut back I till there is no doubt. This should not be seen as frames, stringers and skin but rather as a whole structure, it can all be joined by bonding.
The quality of such a repair can't be inspected after the fact but has to be inspected on a step by step basis during the lay up.
Usually a sample of the resin and carbon cloth or rovings are laid up into a test piece at the same time as the the job is done, this is then tested to destruction in a lab.
The techniques are quite different from metal repair....... In fact it is far closer to the techniques used for the construction and repair of wooden aircraft.
The quality of such a repair can't be inspected after the fact but has to be inspected on a step by step basis during the lay up.
Usually a sample of the resin and carbon cloth or rovings are laid up into a test piece at the same time as the the job is done, this is then tested to destruction in a lab.
The techniques are quite different from metal repair....... In fact it is far closer to the techniques used for the construction and repair of wooden aircraft.
Last edited by A and C; 13th Jul 2013 at 21:08.
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re post 166 and autoclave
NO--- an autoclave NOT needed for most composite repair- vacuum bag techniques plus hot air heaters and different type of epoxy material will generally work. However, in this case, the combination of many stringers and possibly aft pressure bulkhead issues and smoke damage may well tip it to a hull loss.
for example ramp rash does not need autoclave for repair even if a few frames are bent.
My background- did work on composites many moons ago on and ALL composite with some Titanium parts aircraft called the B2- and repair issues were well developed then.
for example ramp rash does not need autoclave for repair even if a few frames are bent.
My background- did work on composites many moons ago on and ALL composite with some Titanium parts aircraft called the B2- and repair issues were well developed then.
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re bin liner post
...A/c grade alu ribs...
Most likely ribs seen were either titanium and/or composite. Aluminum and carbon type composites make neat batteries with low emf but great for corrosion, eating away the aluminum.
Most likely ribs seen were either titanium and/or composite. Aluminum and carbon type composites make neat batteries with low emf but great for corrosion, eating away the aluminum.
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re 233 post on repairs
Most common technique with composites is ultrasound. Simplified version of factory techinque where an xyz gantry shoots multiple streams of low pressure water jets on large piece surface, using ultrasound transducer and computer enhancement of ' echo" returns to determine thickness, debonds, internal flaws.
Such as a drafting pencil dropped on surface by accident as a prepreg tape layup machine was laying down plies. Not discovered until after autoclave and trimming of final part ( major wing upper surface as I remember- which was quite thick ) . it was left in place . . .
In some cases- infrared tomagraphy(sp?) can also be used to find void areas when used with hot air guns.
Such as a drafting pencil dropped on surface by accident as a prepreg tape layup machine was laying down plies. Not discovered until after autoclave and trimming of final part ( major wing upper surface as I remember- which was quite thick ) . it was left in place . . .
In some cases- infrared tomagraphy(sp?) can also be used to find void areas when used with hot air guns.
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Interesting to read opinions about repair of the airframe. Some seem quite certain that the ship can't be repaired; those who describe themselves as experienced with composites seem rather more optimistic.
By my math, the ship minus engines costs about $170,000,000.
If repair is feasible, and the cost does not far exceed 8 figures
...
... then it makes financial sense so to do.
So I presume that those who assert the ship is a write-off, are certain that repair is not technically feasible, even on a giant budget. Perhaps because they know it can't be done without the factory tooling, for example?
I shall study with interest any posts in which knowledge and analysis take up more space than flat claims that "x is wrong," "y is bad," or "z is impossible."
By my math, the ship minus engines costs about $170,000,000.
If repair is feasible, and the cost does not far exceed 8 figures
...... then it makes financial sense so to do.
So I presume that those who assert the ship is a write-off, are certain that repair is not technically feasible, even on a giant budget. Perhaps because they know it can't be done without the factory tooling, for example?
I shall study with interest any posts in which knowledge and analysis take up more space than flat claims that "x is wrong," "y is bad," or "z is impossible."
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Seems some on here think the response by the airport fire service was overkill, not by any means, internal fires can quickly spread so rapid intervention is essential, add to that composites involved in fire, not good for anyone that inhales the released fibres.
@aeromech3
Good point about a/c knowledge but ask an engineer to allow the fire service to practice using their ladders to open doors/hatches and the answer is usually no
@aeromech3
Good point about a/c knowledge but ask an engineer to allow the fire service to practice using their ladders to open doors/hatches and the answer is usually no
Nothing physical would have stopped units standing by at the 787 fire from redeploying somewhere else. I suspect (and hope) there was more to the decision to shut down air operations than simply counting the trucks left in the barns.
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A bit more about composite repair
sort of covers the composite -front
In-situ composite repair builds on basics : CompositesWorld
My point is there are many ways to repair and inspect major- minor damage.
However- the damage shown so far at Heathrow may well be above reasonable limits- cost- etc.- includinjg electrical- smoke damage - time- cost via insurance and no doubt a few hundred other issues not touched on here
787 and other composite model airplanes with major composite structure have been around for quite a while.
It is NOT like fixing your fiberglass corvette of the 60's and 70's, nor is the old story about epoxy fumes- lighting strikes- etc really applicable.
Hope this tamps down at least Some of the flip flapping
In-situ composite repair builds on basics : CompositesWorld
My point is there are many ways to repair and inspect major- minor damage.
However- the damage shown so far at Heathrow may well be above reasonable limits- cost- etc.- includinjg electrical- smoke damage - time- cost via insurance and no doubt a few hundred other issues not touched on here
787 and other composite model airplanes with major composite structure have been around for quite a while.
It is NOT like fixing your fiberglass corvette of the 60's and 70's, nor is the old story about epoxy fumes- lighting strikes- etc really applicable.
Hope this tamps down at least Some of the flip flapping
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The airport fire manager in charge is acutely aware of the implications of declaring a category 0 rffs (or any other lower category than that promulgated ) to atc and the impact on the business and will at the earliest opportunity restore the airfield category.
As mentioned earlier, any firefighters that were fighting the fire internally would probably need decontaminated due to the risk of composite fibres contaminating their fire kit and ba, this all takes time.
As mentioned earlier, any firefighters that were fighting the fire internally would probably need decontaminated due to the risk of composite fibres contaminating their fire kit and ba, this all takes time.
Last edited by Nubian Major; 14th Jul 2013 at 01:58.
I simply am left speechless. Reading of the Asiana accident and now the Ethiopian incident I have noticed some rather backhanded remarks concerning the fire services and the decisions made by airport authorities. To me it simply beggars belief.
I realize that one cannot get on his high horse and exlude those posters who are not operators/maintainers/controllers etc., but for those who have spent more than 18 seconds on an airport ramp (or looking down at one from the tower cab) will realize that if there is a fire as there was at LHR then I certainly expect a full, even overkill, response from the fire brigade.
Fuel lines, other aircraft, service vehicles, fuel farms, terminals etc. are all within flames reach. Best shut the operation down and unwind it when safe.
At least four times in my flying career I have had to "roll the trucks." Two of these times there was actual smoke in the cockpit (once closing down runway 18 in FRA much to the delight of the gents behind us...) All four of those times the brigade was on the spot as fast as possible--much to my eternal gratitude. Had they sent one truck too many? I cannot remember but if so good. For had things turned for the worse they would have needed them plus backup.
I have always appreciated the give and take of PPrune--one only need to look at the ongoing discussion regarding the repair of composites--but for some reason this really stuck in my craw. LHR emergency response proved its merit a hundred times over during the BA 38 accident--I will trust them implicitly to roll what equipment they think is necessary to deal with the problem at hand.
I have also been on a ramp when a fuel truck exploded--fortunately with no loss of life. Want to know what all that fuel does as it spreads all over--I will leave it to the fire crew to answer that but I will give you a hint as to why with multiple emergencies going that LHR ops shut the airport down. A very wise move IMHO.
I realize that one cannot get on his high horse and exlude those posters who are not operators/maintainers/controllers etc., but for those who have spent more than 18 seconds on an airport ramp (or looking down at one from the tower cab) will realize that if there is a fire as there was at LHR then I certainly expect a full, even overkill, response from the fire brigade.
Fuel lines, other aircraft, service vehicles, fuel farms, terminals etc. are all within flames reach. Best shut the operation down and unwind it when safe.
At least four times in my flying career I have had to "roll the trucks." Two of these times there was actual smoke in the cockpit (once closing down runway 18 in FRA much to the delight of the gents behind us...) All four of those times the brigade was on the spot as fast as possible--much to my eternal gratitude. Had they sent one truck too many? I cannot remember but if so good. For had things turned for the worse they would have needed them plus backup.
I have always appreciated the give and take of PPrune--one only need to look at the ongoing discussion regarding the repair of composites--but for some reason this really stuck in my craw. LHR emergency response proved its merit a hundred times over during the BA 38 accident--I will trust them implicitly to roll what equipment they think is necessary to deal with the problem at hand.
I have also been on a ramp when a fuel truck exploded--fortunately with no loss of life. Want to know what all that fuel does as it spreads all over--I will leave it to the fire crew to answer that but I will give you a hint as to why with multiple emergencies going that LHR ops shut the airport down. A very wise move IMHO.
Last edited by Uncle Fred; 14th Jul 2013 at 02:12.
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Personally I think the airport authorities acted correctly in closing the airport. If most units had been called out to two suspect fires, they had no option but to stop all aircraft movements.
Last edited by p.j.m; 14th Jul 2013 at 02:57.
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Perhaps a new thread on "Emergency Response" would be appropriate. I'm tiered of hearing the whining about this when what I want to know about is what caused the fire.
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I tend to agree with grumpy.
As to the aircraft - I will await the results of the investigation into the incident with interest. I have confidence that the AAIB will conduct a thorough investigation and present the outcome clearly. I also hope that a clear cause can be found and that subsequent events can be fully identified. Like many other aviation professionals, I have some possible event scenarios in mind that may have been involved. Some may be right, some will not be. Informed 'rumour' such as one might find on this site is interesting but it's not my areas of expertise and I have nothing of substance to add to the discussion - so I read and think about the points raised whilst I await the investigation report.
On the topic of CFR/RFFS response, I do have some expertise and it is frightening to read some of the drivel here, especially from those who purport to have knowledge of the subject.
In response to Chu Chu (and I recognise he/she claims no particular knowledge), whilst you are quite correct that if there is no possibility of the Ethiopian aircraft re-igniting nothing physical would have stopped units standing by at the 787 fire from redeploying somewhere else. But without replenishing water and foam concentrate supplies (along with anything other media and equipment that might have been used), the immediate response capability would be so severely limited as to make the presence of the vehicles almost irrelevant. If hoses had been run out to hydrants for the first event, repacking them will take time and tenders without water/extinguishing media and without hoses to draw additional water are of even less value.
CFR/RFFS cover requirements involves many complexities and there are many sources of relevant information. Maybe it would be a good idea for some posters to look for some of it before spouting misleading rubbish.
As to the aircraft - I will await the results of the investigation into the incident with interest. I have confidence that the AAIB will conduct a thorough investigation and present the outcome clearly. I also hope that a clear cause can be found and that subsequent events can be fully identified. Like many other aviation professionals, I have some possible event scenarios in mind that may have been involved. Some may be right, some will not be. Informed 'rumour' such as one might find on this site is interesting but it's not my areas of expertise and I have nothing of substance to add to the discussion - so I read and think about the points raised whilst I await the investigation report.
On the topic of CFR/RFFS response, I do have some expertise and it is frightening to read some of the drivel here, especially from those who purport to have knowledge of the subject.
In response to Chu Chu (and I recognise he/she claims no particular knowledge), whilst you are quite correct that if there is no possibility of the Ethiopian aircraft re-igniting nothing physical would have stopped units standing by at the 787 fire from redeploying somewhere else. But without replenishing water and foam concentrate supplies (along with anything other media and equipment that might have been used), the immediate response capability would be so severely limited as to make the presence of the vehicles almost irrelevant. If hoses had been run out to hydrants for the first event, repacking them will take time and tenders without water/extinguishing media and without hoses to draw additional water are of even less value.
CFR/RFFS cover requirements involves many complexities and there are many sources of relevant information. Maybe it would be a good idea for some posters to look for some of it before spouting misleading rubbish.