Repairing the damage
 

FWIW my guess is that Boeing are looking at 2 repair options for the fuselage.
The first would be to perform a complex bolted repair, I don't believe a bonded repair would be permissable. The repair plate would be (guessing) at least 12 ft by 3 ft, and possibly compound curvature. If EA accepted a non-flush repair then it could be fitted on the outside, a much easier option, but with some drag, and therefore performance, penalty. And it would be visible. If they demanded a flush repair (i.e. non visible), then the plate goes on the inside, and has to accomodate all the other fuselage structure, frames, stringers and whatever, as well as whatever systems are there, much more difficult. This supposes that the only structure damaged is the fuselage. It seems to me the fin (VS) may well also be affected . . .

The other option is to replace the damaged fuselage sections completely. This would appear to be the aft fuselage and tailcone sections, all 75 ft of it. The big advantage would be that all the fire and smoke damaged items would be replaced, with no concerns for repair integrity, future maintenance, inspections, etc. But it would be a massive job indeed, including the need to jig the fuselage, remove and replace the empennage, all the systems, interior fittings, etc. And to add to the problems would be sourcing these sections; I would have thought that all major components like these are already assigned to specific aircraft in build or planned, for some years ahead.

My guess is that the 2nd option is completely unviable financially, but who knows what Boeing are thinking. As someone has already said, the bad PR from writing off an aircraft so early may be too bitter a pill to swallow.

Just my thoughts, with no deep knowledge of Boeing or their aircraft.

Nonsense and 787 is autoclave cured and is , I note again FLAMMABLE.

As most spotters who were at LHR know, this was by no means the only emergency on the go at the time. However, I don't intend to feed the media.

Fenland 787,
I said that self ignition temperature of the Toray 3900-2 resin is 580 degrees F not 540 thereby releasing dreaded FST. This is from Toray, FAA and Boeing, so don't try and spin, it won't work. It is flammable, end of story, and top half of 787 is not insulated via Boeing lobbying of the FAA asi stated a while back.
Defending the indefensible is neither pretty nor useful.

NOT BATTERY RELATED
 

At approximately 1550 hrs UTC on 12 July 2013 a Boeing 787-8 of Ethiopian Airlines, registration
ET-AOP, suffered an event at London Heathrow whilst the aircraft was parked on stand, with no
persons on board. The initial witness and physical evidence shows that this event resulted in
smoke throughout the fuselage and extensive heat damage in the upper portion of the rear
fuselage.
In exercise of his powers the Chief Inspector of the Air Accidents Investigation Branch (AAIB) has
ordered that an investigation into this serious incident be carried out, in accordance with the Civil
Aviation (Investigation of Air Accidents and Incidents) Regulations 1996 and the Standards and
Recommended Practices of Annex 13 of the International Civil Aviation Organisation (ICAO). The
sole objective of the investigation is to determine the causal and contributory factors of this serious
incident, with the intention of preventing a recurrence. It is not the purpose to apportion blame or
liability.
In accordance with these international standards and recommended practices, the National
Transportation Safety Board (NTSB), USA, representing the State of Design and Manufacture, and
the Civil Aviation Authority of Ethiopia, representing the State of Registry and Operator, have been
invited to appoint Accredited Representatives to participate in the investigation, along with
advisors from the Federal Aviation Administration, Boeing Commercial Airplanes and Ethiopian
Airlines. The AAIB has also invited the participation of the EASA (European Aviation Safety
Agency) and the UK CAA (Civil Aviation Authority) as advisors to the investigation.
This team, under the direction of the AAIB, has initiated the technical investigation into the event.
The aircraft is currently located in a hangar at London Heathrow. There has been extensive heat
damage in the upper portion of the rear fuselage, a complex part of the aircraft, and the initial
investigation is likely to take several days. However, it is clear that this heat damage is remote
from the area in which the aircraft main and APU (Auxiliary Power Unit) batteries are located, and,
at this stage, there is no evidence of a direct causal relationship.

http://www.aaib.gov.uk/cms_resources...%20Release.pdf

Repairing the Damage;

Does anyone else remember the Boeing repair scheme for the 707 when they started to turn into bananas?

The answer was to fit straps to the outside of the fuselage, usually at the back of the fuselage behind the wing trailing edge. The straps were about ten feet long.

Really bad ones had straps rivetted onto the front roof as well.

I have some photographs somewhere in the attic that I took of a TWA 707-131 that I got into in Denver (?) which had straps front and back. Being a short fuselage 707, it looked horrific but the bucks fizz in first class helped to divert my attention.

This doesn't read as a simple coffee pot left on, or discarded cigarette: AAIB

deggers, I agree: a battery problem - already known - would be the best for Boeing. A new, previously unknown, problem with the Dreamliner, also causing a fire hazard, will develop a nightmare for Boeing.

What happened at LHR is a huge disaster for Boeing and all airlines that operate the B787. A lot of passengers are scared of travelling on a Dreamliner for a long time.

The initial AAIB report mentioned extensive heat damage at the rear of the a/c a complex part of the struture. This is going to take a while to fully evalulate.
I would be very worried about the potential, outcome, How do these plastic beams etc cope with heat stress. The fin & tailplane put a lot of forces into the structure at this point.

@quentinc:

I don't see how you arrived at that surmise ... are you supposing that because damage is extensive, the origin of the fire is not small or simple?

It's in the nature of fire that small and mundane origins (e.g., a cigarette) can lead to vast destruction.

One of the important questions for safety: had the same situation occurred in flight, in what time frame would it be likely for the fire to be detected and (if feasible) suppressed. This won't be answerable, until the origin has been identified.

If the fire likely would have been stopped early in its evolution, then its safety implications would be less worrisome.

Maybe the same in principle, but the layout of the servicing points would seem to reduce the safety of this operation. At the risk of getting rather off topic, it seems that this aspect of 787 ops is significantly non-standard. The 777 has a similar layout to all derivatives of the 737 and also the 767 and 757. The pneumatic connection is close to the fuselage centreline just aft of the leading edge of the wing root. The air cart is parked forward of the wing, on the LHS. I would expect the tug driver has good visibility of the ground staff and I imagine that the flight deck has visibility of the air cart.

For the 787 the aft electrical connection is under the trailing edge of the wing, significantly left of centreline. The power cart is parked behind the wing outboard of the engine.I understand from previous Boeing documents, when there were two aft connectors, that this design was for applying ground power during hangar maintenance. The aft connector is at 2.2m, the forward connector is at 2.7m. The steps can be seen on the photo I posted earlier.

My observations are that apart from being aft of a line drawn behind the tailpipe, instead of mid-engine, the ground staff are basically working in a blind spot. The flight deck may be unable to see if the power cart is clear. At a height of 2.2m, it is possible that steps may be required to remove the cable. the ground staff has to walk behind the main gear to retrieve the cable and steps. In my mind there is a risk of conflict, especially if the ground cart is removed and a worker goes back for the steps. It would require vigilance not to start push-back as soon as the cart is seen to move clear.

I am glad to see that the A350 have not broken with convention and has the air cart forward. I am aware that rear engined types such as B727, MD-90, F100 and the E-jets have the pneumatic below the engines, but still forward of the tailpipes.Hence, my question of do actual airline ops allow the use of this, or do operators accept the longer start time and dispense with the third power source.

The implications of trying to support this with fixed installations is even worse. Seems to be the option of either a ground pit, between the undercarriage track, or the use of a very long cable on an articulated system. Both with the inherent risk of ground damage.I would question if this is covered in AHM 33, Chapter 4 Ground Ops Manual, I only see references to ASU engine starts. Maybe you are right and everyone assumes that the protocol is the same, I see a few holes in alignment .

787 Cabin Crew Uniform

http://i586.photobucket.com/albums/s...ps84fa241b.jpg

At approximately 1550 hrs UTC on 12 July 2013 a Boeing 787-8 of Ethiopian Airlines, registration ET-AOP, suffered an event at London Heathrow

Nearly had an "event" in my pants when I read that description!:ok:

Jack

Indeed - if the aircraft had no-one on board then the fire would not have been detected until it burnt through the outer skin of the fuselage (and with no steps and no airbridge then this is pretty much the only way the fire would have become known about as nobody going on board when it's "ready for towing" could have discovered it as there's no access for them) which means the fire probably had quite some time for the fire to propogate internally prior to discovery.

After all it takes almost no time at all for a fire to propogate and develop


Note in that video the fire is ignited at 00:40. By 1.10 (30s after ignition) the bed and table are already well ablaze (you can see the fire on the underside of the bed) and that by 1.25 (45s after ignition) the room has already reached flashover.

If anything, in this situation, the low burn temp of the Composites and lack of fire insulation has saved the aircraft from more extensive damage as it caused the fire to become visible much sooner (and therefore with less internal damage) whereas a metal skin with insulation would have contained the fire leading to much more extensive internal damage prior to the fire becoming externally visible.

JW411 Boeing Teams became expert at replacing whole skin sections down route with pre planned kits.
But I am sure with this B787 damage, a temp reinforcing for ferry flight and the aft fuselage section will be de-mated at the Production joint, providing it is forward of the damage and replaced.
One issue, will there be a heap of in-line crimps or are there suitable disconnect points in the precious wiring looms.
When I 1st heard about the manufacturing technique for the B787, I ventured one of my 'line' nightmares: when a fork lift driver misses the cargo door and forks the fuselage;
sure Boeing have also thought through similar scenarios.
Lets hope so!

@Burnie5204: I wonder if PR have the nuts to spin it that it's better to fly in aircraft that a fire burns big holes in - so everyone's alerted that there is a fire - than in an ally fuselage a/c aboard which the fire would stay inside far longer*

(*where the extinguishers are kept).

I suppose if they had the balls they would try to argue that fires wouldn't have time to develop onboard - mid-air when cabin crews have access to extinguishers and are able to enact immediate action drills.

They'd have to have serious balls though.


As I said though - it may have helped in this specific situation making the difference between a repair job to the rear end and a hull loss

Practically thinking, it would never have happened in flight.
A flight attendant would just have said... 'OOH the Coffee boiler has been left switched on, anyone for a coffee?'

And if it was not the coffee brewer, but another cause? In any case, frightening.

What impact on range
 

Hi JW411, sadly I suspect that they were left off to save weight.The very reason for distributing the electrical system, is to reduce the heavy cables fanning out from a central point. I guess it would also not be too convenient for the flight crew to be digging around in the aft cabin ceiling, during flight, to reset a few breakers.

HI Tech
 

Your statement that bonded repairs are only good shows that you are not aquanted with modern composite structural repair, using the correct techniques a bonded repair can match the strength of the original structure. ( we have never had a repair test piece fail and most are 2-3% stronger that the average new test piece) these are for primary structure items such as spar booms.

SRMman while I disagree with you about the use of bonding in that I am of the opinion that with the correct techniques a bonded repair would be lighter, replicate the aerodynamic shape of the original aircraft and. Be as strong as the original aircraft.

Unfortunatly Boeing have demonstrated ( just like Cirrus at the start ) that they don't understand the best composite repair techniques and revert to a metalcentric state of mine when it comes to fixing things...........so Unfortunatly I think you will be correct in that Boeing will end up making a poor, heavy and un aerodynamic repair, and wreck the advantages the composite construction simply because they can't break away from their metal bashing past, so you will probably be correct about the type of repair we will see.

It is clear it wasn't a coffee maker.

Boeing would go PR-RAMPAGE if was the case :D

In the first 24hours you know the reason for the fire.

They are pretty silent though... after that 7% drop on friday...

Is it possible to bond 6-8 damaged frames to 8-9 stringers and then skin it?
This a very serious burn and we haven't even seen the interior yet.

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.

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.

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?

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?

I know an aerospace composites guru - I'll point him at this thread...

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.

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.

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.

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.

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.

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 :eek: ...

... 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."

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

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.

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

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.

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.

because having 60-80 firemen and 12 firetrucks standing around twiddling their thumbs, where the fire had been extinguished (probably by the first truck on the scene) and the aircraft was in a remote parking area, had no one onboard for the last 8 hours, is a good use of firemen and an extremely busy airport.