Having had a good look around said airplane. If it had been a fire in a metal fuselage and left unchecked as in this case it would have seriously compromised the skin.

What are the drivers to return damaged aircraft to service? Loss of revenue, loss of manufacturer prestige, the insurance companies who have to pay out? Higher insurance cost for this type of aircraft? A new aircraft expected to fly on for more than 25 years damaged in its first year of operation? a combination of all these probably.

A tailstrike can damage the lower rear fuselage area. Whatever caused the fire, the structural damage on the crown of the rear fuselage appears similar to that caused by a tailstrike, damaged skin and damage to the structure in the vicinity of the rear pressure bulkhead. Any repair would be accomplished to the manufacturers requirements but there is the chance that a latent failure site could be created. Returned to service the aircraft continues to fly and the repair appears fine only to suffer catastrophic failure much later.

I sincerely hope that history doesn't repeat itself because there has been precedents and I highlight two that anyone can research.

1 - JAL Flt 123 in 1985 747 bulkhead repaired only to fail about 12000 flights later.

2 - China Airlines Flt 611 747 tail section repaired only to fail 22 years later.

All humans that were involved in the repairs on these two aircraft thought they had done a good job, they wouldn't have knowingly built in a latent fault.

A repair could be done to this aircraft, it will be a logistical difficult task given it's location. Eventually the aircraft could be back in service but unless everyone is absolutely convinced history won't repeat itself, this damaged 787 should be taken out of service. The industry should take the financial hit. It costs money but technical development in aviation has never been easy and safety has to be seen to be paramount to maintain passenger confidence.

@gas_path:

Interesting report!

Given the doubts and concerns about performance of epoxy/carbon composite skins in fire, I think it very important that the accident investigation address -- to the extent feasible -- how the damage (and its projected effects, had the fire occurred in flight) would compare to a similar fire scenario on a plane of conventional construction.


*** Links that may be of interest ***

An Airbus presentation from last year on Li battery fire hazards, that identifies the ELT batt as one of the "permanently installed batteries," along with the Airbus approach to mitigating the risks:

http://www.skybrary.aero/bookshelf/books/2078.pdf

A little brochure for a Honeywell transport ELT (I do NOT assume this is the same model as installed on the incident 787 -- just an example for those curious about these kinds of gadget):

http://www51.honeywell.com/aero/comm...06_AFN_ELT.pdf

time-ex:Yes, all these, plus the total cost of the repair (including EW gain, special recurrent inspections, ...) compared to the "as-repaired" market value of the ship, and the alternative market value of parting out the ship for LRUs and major components.

@time-ex:

In both of the B747 disasters cited (thanks for that, by the way -- I was not familiar with the China crash), the repairs were NOT in accordance with repair procedures approved by Boeing, even though in the JAL case the incorrect repair was made by Boeing technicians.

Modern aviation has a long history of really extensive airframe repairs, including components as fundamental as wing carry-through structures. To my knowledge, the safety record of such repairs is fine, when they are performed correctly.

My expectation (God knows, I could be wrong) is that any team conducting a repair on this burnt 787 -- if the ship will indeed be repaired -- will include people who know the heart-breaking history of the JAL crash. It was a massive loss of life that was Boeing's fault, the worst nightmare for most people in the industry, and one not readily forgotten. [Anecdotally, in the mid 90's I was talking with a Boeing-Seattle engineer who referred to the Associated Grocers' B-29 crash from 50 years earlier ... not only before his time, but before he was born.]

If Boeing makes/supervises a repair to the 787, and they aren't truly able to assure the safety of that repair, then what is their understanding of the materials and processes? How could they make an airworthy ship in their own factory, without such understanding? Carbon composites are not magical/mystical materials. People have been making lots of things with them for a long time, breaking those things, and repairing them. It is precisely BECAUSE these materials are so well understood, that the naturally cautious air transport world has by stages introduced them into airframe structures.

time-ex - if you look into it, you'll see that JAL123 was not repaired properly, and failed almost exactly where predicted when they worked out the mistake had been made in hindsight.

still, the fix for the 787 looks far from straightforward - the damage area for the structure will be extensive - far more that what is visible and could well be very complex, and could be a write off.

more worryingly, if the ELT just ignited with no obvious manufacturing defect, then we could be looking at another rather costly AD.

still, on the bright side, the ELT was probably almost brand new, which may mean that there is a hopefully an obvious issue to find.

it is only speculation that the ELT is to blame - too early to assume that I think.

time-ex:
I do not believe either of these incidents support your point, in that in both cases, the aircraft were improperly repaired, contrary to Boeing specifications.

There could be another reason that Honeywell was "invited" (that sure is one invitation that would be hard to decline) to participate in the investigation.

It is possible that the ELT was damaged by fire and the investigators need help in determining if it started/accelerated the fire or more likely was just a casualty.

Having very modest knowledge of fire/arson investigation I know that one of the harder calls can be cause and effect:

Did old house wiring start the fire or did it short as a result of the fire?

In both cases the wire can have similar features including melted "beads" etc.

Unfortunatly it is easier to just say "bad wiring" and stop rather than dig deeper, especially in cases where arson is not suspected.

Nigel and Herod,
Any fire in the upper passenger half or crown of this flammable epoxy FST loaded A/C is a clear and present safety hazard and should be addressed via an emergency AD ordering both grounding and full internal 360 degrees of fuselage insulation. But will it be the NTSB, JAA or EASA forcing our inglorious FAA to comply?
Also cancellation of any or all ETOPs certification might finally get Boeing's attention.
And dumping all Li-ion batteries, be they primary or secondary such as Honeywell's is required.
And note that the Airbus A350 is in the same FST sinking boat.

amicus

Your declaratory statement is without support specifically regarding the word "any"

I do however accept any opinions you may have in this regard as your own even though they are impossible to comply with.

Meanwhile let's see what the official investigators recommend

Even though @amicus is quite committed to getting his message across and obviously has a strong (yet apparently not totally un-founded) opinion on this topic I have to admit that as it is today I would not be really comfortable in a 787 on a North Atlantic Crossing or an ETOPS 210+ across the Pacific.

Just ask yourself: Would you?

I for one refuse to fly on B787.
No fire insulation on the top part of the fuselage:ugh:...

Lithium Ion batteries have NO business inside any aircraft, and especially not connected to any system.:ugh:

I urge the travelling public not to fly on this type of aircraft until these worries have been adressed by eliminating them, not by caging them:ugh:

AFAIK: All the 406 ELT's use lithium batteries, not just Honeywell's. They are also in the ULB's (pinger) The FMS's for memory retention....they are all over the place. But the ELT is the only place I can think of where they are in a plastic box, not metal.

I obviously like the ELT theory, since it was my 1st thought, but I hope MurphyWasRight is on to something, that some other thing heated the ELT to the point of failure. The thought of an AD on every 406 ELT makes me shudder. :sad:

I'd fly it tomorrow

amicus

Why would it make any difference by having insulation when all the occupants of an aircraft that has a 550 degree fire would be incinerated long before the fuselage could burn through.

To all of you who think that having a problem with an elt is a big setback for Boeing, you obviously know nothing about aircraft.

The elt is not connected to the aircraft wiring and the elt in the main cabin would be contained inside a life raft !!!

despegue:
You do realise that on every commercial flight the pax will be bringing aboard dozens to hundreds of Lithium Ion batteries in their mobiles, tablets and laptops?

Honeywell supplies quite a variety of items on the 787:

http://i337.photobucket.com/albums/n...ps8b015c84.jpg

Good; all the more room for me to stretch out. Also less chance of sitting beside some know-it-all getting lectured about something they know nothing about.

JFZ90
 

What are you on about, this thread is a serious issue not a please pay attention pax to our safety demonstration!

By the way I was less than 100 feet from that 787 in a bus going to the BA 0500 flight to Lisbon on Friday morning!

Repeat.

More simply:- why would the ELT have any power when the ac is parked?

As I understand, the ELT is powered by its internal non-rechargeable battery. Since the ELT battery isn't rechargeable, then why would it even have a connection to the aircraft's electrical system?

........ And an interesting location for the ELT in the Honeywell generated diagram a few posts above.

Rob

The topic of how to repair large plastic structures has been raised on here already by me, and replied to by some knowledgeable folk.

This damage would likely be a huge repair on a metal aircraft.

On this CFRP aircraft it will also be a big (or bigger?) job.

I remain worried about the use of CF reinforced plastic in aircraft structures, but hey- I'm not exactly an expert.

Thank goodness it happened while parked.

It's not exactly 'immature' technology in aviation, but could still be quite tricky as a substitute for aluminium main structure.

Don't believe the diagram. It also shows AOA Vane, Pitot probe and TAT probe behind the right wing!! Obviously not all components were depicted in their actual positions. :ok:

RCav8or: I can't testify to the Honeywell 406 ELT. On the Artex they use ships power to flash a light on the flight deck if the ELT is transmitting as a warning to the pilot it is going off.

boguing: The ELT is always powered by it's internal battery. It can be set to transmit by the remote switch on the flight deck, or by impact if the G switch has been activated. (you've crashed or had a really bad landing)

We want the ELT to work, and continue transmitting even if all ships power is lost, so we can find the downed aircraft.

Apart from the fact that most if not all pax will be carrying some type of Lithium Ion battery either in hand luggage or stowed luggage, as other posters have remarked;

There are several different types of LiIon batteries, with different chemistries.

The type most often used in consumer electronics is Lithium Cobalt or LiCo for short. This chemistry packs most performance in terms of energy density per unit volume and weight, but happens to be a bit touchy - as borne out in various incidents with laptop and mobile phone batteries catching fire.

Other chemistries such as Lithium Iron Phosphate (LiFePO4) do not have such a strong tendency to self-destruct in this manner, and in fact Lithium Iron Phosphate is now becoming the preferred solution for automotive and aerospace applications. However, energy density is somewhat inferior to Lithium Cobalt. On the other hand, Lithium Iron Phosphate cells appear to suffer less degradation with time/cycles.

Apparently (and regrettably) the B787's batteries seem to be LiCo rather than LiFePO4. The reasons for this choice are beyond me, but it might be that the choice was made some years ago when the performance penalty of LiFePO4 versus LiCo was more severe than it is now. 5 years is a long time in bleeding edge battery tech.

I notice that on the pprune threads about developing stories, there is quite a bit of grasping at straws based on tidbits from the press, balanced from time to time by reminders to wait until more is known.

Of course, it's possible that the ELT spontaneously erupted into flames, presumably from its battery. I wonder, is there any precedent for that?

But it's also possible that folks investigating the 787 found the ELT with a burned-up battery, and asked Honeywell (quite appropriately) for assistance. This is not enough to say that investigators have concluded, or even deemed it likely, that the ORIGIN of the fire was in the ELT.

If I understand correctly, Li batteries can "flare up" when put in a fire -- in other words, a fire originating elsewhere could perhaps ignite the ELT battery.

It's early days yet, and we have so few facts.

Composite Skin In-Flight Fire Risk Analysis
 

amicus,

I understand that you did your best in trying to convince the FAA etc. to require thermal insulation throughout the inner surface of the 787 fuselage.

To the extent that I understand the logic of FAA rulemaking, they refer to quantitative estimates of risk. For example, how many aircraft expected to be lost per 10,000,000 flight hours, or some such measure. Their reasoning seems to be, that risks below a certain level don't require regulatory intervention (no doubt I'm oversimplifying, but this is the crux).

To your knowledge, did anyone conduct such an analysis, and present risk estimates to the FAA? If so, is any part of that publicly accessible?

As I tried to outline a couple of days ago, fires are Awfully Dangerous to transport planes at altitude, REGARDLESS of material. So the threshold question would be, how much greater is the quantified risk with composite vs. aluminium fuselage skins.

Further, we might attempt to classify in-flight fires inside the fuselage into three levels of severity:

III. Combination of intensity and duration (under reasonable assumptions of crew response) sufficiently small, that the plane is likely to continue to a safe landing, regardless of construction, or top-half insulation of composites.

II. Intermediate-level, in which fire performance (including inflammibility) of skin material is expected to make a difference to the likelihood of saving the plane, and in which top-half insulation of composite skins could also make a difference.

I. Sufficiently great intensity and duration that the plane would be lost, whether of aluminium or composite skin construction, even with top-half insulation of composites.

Fires falling into levels I and III don't make any difference to flight risk -- none whatsoever.

Did anyone analyze the risks associated the level II fires? For example, did anyone attempt to quantify the parameters of fires that are survivable for aluminium skinned aircraft, but non-survivable for composite skinned (with and without top-half insulation)? Did they then look at aviation safety records, to estimate their rate (for example, how many apparent level II fires have occurred in the last 250,000,000 jet airline departures?

If no such analysis was made, that perhaps doomed the efforts to argue the point with the FAA.

Of course, this London fire offers an opportunity to revisit the question. It can only help the case, to support it with a quantitative risk analysis.

A and C

Quote: "Composite airframes have been around for a lot longer than that ! To the best of my knowlage the first composite repair to primary structure was carried out in the UK in 1965."

I simply gave the A300-600 fin as an EXAMPLE of a large carbon composite structural component that has been in service for a long time. I'd be interested to know what your example is in 1965.

As a complete non-technical person, I have read the battery discussions with great interest. I drive a Peugeot iOn and sit on top of the 16-kilowatt-hour (58 MJ) lithium-ion battery pack, which consists of 88 cells placed under the base floor. (Scroll down that link a bit for the section on "Battery").

I'm very conscious of the assorted cooling fans and shutters that operate when charging, and when first driving off.

The emergency transmitter is powered by a non-rechargeable lithium-manganese battery.

LiMn is very stable, LiCo will self-ignite and is bloody hard to put out

Etud_lAvia

As I noted much earlier in a 787-battery thread, the FAA commissioned a university study of fire danger re the 787 fuselage material; said study concluded that it was perfectly (-enough) safe. Sorry I'm not in a position to regurgiate the information at the moment, being on travel and on a satellite link.

FST testing of fuselage material is one thing. What about the adhesive/bonding material(s)?

Useful background reading...

An updated learned Paper from RAeS Flight Operations Group on 'Smoke, Fire and Fumes in Transport Aircraft' -(1st download in list)

Royal Aeronautical Society | Specialist Papers

with new stuff on Lithium-ion and composites...

Composite gliders are around since the mid 50s and composite repair to primary structure are common business since the 60s. There are companies around that repair CFRP wings completely broken in several pieces for 25 years, and there is up to now no airframe loss attributed to a faulty repair. Did it myself, and the first time you do aerobatics in a glider where once the wing was in pueces is a bit on an interesting moment. Composite repair technology is known and field proven for decades.

LI Fire
 

Hard to believe that a small LI battery can cause this type of damage. It is possible this battery was smoldering for some time as the aircraft was unattended for several hours. Still this gives us an idea the heat generated by these LI batteries when they go off. Think about the heat from the larger LI Cobalt battery, which is considered the most volatile of all the LI batteries. This calls into question the choice of LI battery for the Main and APU location. This problem will not go away. Every time B787 meets with an incident, the question will pop 'Is it that battery again?'. This is unfortunate.

The choice of composite materials would not have changed the out come here. Aluminum also can melt in a fire situation. Only difference could be metal conduct heat faster, so fire may not make a burn through easily. This damage occurred mainly due to the unattended nature of the aircraft on ground. If this incident had taken place in flight, the fire would be detected quickly and extinguished. ELTs are located inside the overhead storage bin and easily removed. These bins have blankets and pillows stored on most aircraft. May be they contributed to propagate the initial combustion. ELTs are in use on all modern aircraft, and cannot remember having a previous fire incident on this item. Correct me if I am wrong. :uhoh:

A word of caution
 

There is a significant difference between glider (and surfboard) repairs involving fibre-glass materials and that is the elastic modulus of carbon is much higher. Because of the higher stiffness, load transfer through adhesive bonds is much more demanding. For low modulus fibre glass, load transfer is much more gradual and so reliance on just the repair resin system is appropriate. In carbon fibre repairs, the demands of the high stiffness caused by the higher modulus are such that the brittle nature of resin systems virtually demands that the joint is formed by a more ductile system such as an adhesive.

So it does not necessarily mean that "sufboard" repair technology is as appropriate for carbon structures.

Be careful in assuming that just because it is a fibre composite that old technology repairs can provide the same level of structural integrity.

Etud_lAvia

Risk analysis only make sense when you have data to go by and a risk vs cost basis only is done when you are updating a current rule. This of course assumes that the current rules provided adequate protection when implemented years ago but new lessons have now been learned.

If there is something novel in the implementation of a current rule leaving questions about adequacy then it's time for a special condition ruling.

It's between the applicant and the regulator to decide on the adequacy of the product to meet what's on the books (how it's met is necessarily, competitively private).

I'm not sure at this time that the current rule is not adequate, nor if something new has been learned. I still await the investigators findings before I accept a "I told you so" claim.

Our aircraft have two ELTs one situated in flight deck as a portable unit ,the other above the ceiling panels (just forward of the fin),the ELT is attached to the airframe, for locating the aircraft if lost etc.This unit would be almost impossible to locate in flight let alone realise the unit was on fire and take appropriate actions.Its hard enough to get to when doing a simple 'ping' test for maintenance purposes.One things for sure the 'silence is deafening'from Boeings PR department.