Ethiopean 787 fire at Heathrow

[207592]

PRESS RELEASE

Date: 13 July 2013
Serious Incident to Boeing 787-8, ET-AOP,

at London Heathrow Airport on 12 July 2013




Date & Time: 12 July 2013 at approx 1550 hrs UTC

Location: London Heathrow Airport

Aircraft Type: Boeing 787-8

Operator: Ethiopian Airlines

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.cfm?file=/Boeing%20787-8%20ET-AOP%20Press%20Release.pdf

As to criticism of the actions of the fire crew, fellow PPRuners, please remember the Heathrow Fire Team are especially trained to deal with aircraft fires and their managers will be under no illusion as to the cost of keeping the airport closed. They will also have studied the causes of past disastrous aircraft fires on the ground. Before the scene of a fire is vacated, the fire team have to sure there is no chance of re-ignition, and until then, they need to be able to deal with the worst case scenario.

[severebluesky]

The extend of the damage in the upper skin area is far beyond the size of the high glossy composite 59 minutes repair brochure under laboratory conditions.
We have here to consider the 1 piece section integral manufacturing process, wide heat damage, spherical shaped surfaces (funny for Ti-repair), the highest loaded fuselage area, ...
For me it looks like a "rear section replacement". Forget about the "metal type repair" out of the sales brochure and face CFRP reality beyond coin size damage.
Mr. Steven F. Udvar-Házy and others will learn a lot in the coming months.

[1a sound asleep]

Seems to me that everybody is very tight lipped about the source of the fire. By now a large number of people would have inspected the plane and it would be obvious where the fire originated, even if they cant ascertain why.

Boeing really need to quickly calm the world concern as a matter of protecting their reputation and the future of the 787.

[atpcliff]

Being a composite fuselage, the 787 fuselage has the potential to be MUCH stronger than the 777 fuselage, and hence more able to withstand higher impact forces...it depends on how they used the carbon fiber in making the 787 fuselage.

As to how well the 787 fuselage compares to the 777 fuselage in fire-resistance, I have no idea.

[m.Berger]

No criticism of the fire crew or procedures here. An unattended aircraft caught fire. I regard that as serious.
I'm glad to see, (as I expected,) that the AAIB will be heading up the investigation. Their report will be both thorough and made available to the public so whatever the truth, we shall be told it. (Anathema to a rumour network, I know but preferable to a
Boeing press statement that would not be trusted by many.)

[londonman]

@ p.j.m - Australia.

You have no idea how comforting it is to have 'armchair-experts', like yourself, ever ready to give profound and insightful comments such as those you have made. I am in shock and awe.

On second thoughts, no, I'm not.

[alisoncc]

If I recollect correctly, the aircraft was being prepped for towing when the fired was noted. It may be pure coincidence but the "Grounding 787's" thread also makes mention of towing being an issue with the battery fire.

The APU Battery supplies the APU Hot Battery Bus ONLY. AFAIK it's job is to start the APU when no other power is available and power the Nav Lights when towing without APU. Thats it.

Just one thing. The towing switch is a selected function, not automatic. Depending on Main Batt charge state, there may only be enough power for a half hour tow.

My understanding of the refined battery system. The min discharge level has been increased. This will shut the battery down at a higher charge, but will mean that it can still be recharged in-situ if normal power is returned to the a/c.

EG A non-APU towing scenario, on bat only. instead of, say, 30 mins of useable power from the bat, one may only have 25 mins. The bat circuit automatically shuts off power and then when the GPU is connected the battery will recharge.

I could be wrong, but this seems the most logical outcome, otherwise we are still going to be changing batteries ad-nauseum due to towing operators not monitoring the bat state.

[Request Orbit]

Regarding the discussion about the fire response. Several pages back, and on other sites on the internet, multiple people have stated there were also fire trucks called out to a separate incident (from memory, a Boeing PIA). So when you're making your expert analysis - seemingly based solely on a picture of a few trucks - do remember that you're probably not privy to everything that was going on at the time.

[alisoncc]

TWT, I am aware of that. Never suggested it had anything to do with the battery per se, but as the cause of the battery malfunction has never been accurately determined, and this fire seems to be when the aircraft is undergoing similar activity, namely towing related, there could be some connection.

[joy ride]

"no evidence of a direct causal relationship"

I fully understand that this needs to be investigated thoroughly and this will take time, but this carefully loose phrase does not reassure me about the entire battery and electrical system.

Add to this the fact that Boeing seems to have declined strong advice to insulate the roof structure, and that the Manchester 787 had electrical faults relating to toilets and galleys all leaves me very uneasy.

The Dreamliner reminds me of the British Advanced Passenger Train, in which every single component was new, radical and unproven. The project ended up seriously behind schedule, massively over-budget, and was then pressed into trial service too soon. It was technically superb, but unreliable and a failure. For the time being this is one Boeing in which I am NOT going.

[Lemain]

1a fast asleep: Seems to me that everybody is very tight lipped about the source of the fire. By now a large number of people would have inspected the plane and it would be obvious where the fire originated, even if they cant ascertain why.

Boeing really need to quickly calm the world concern as a matter of protecting their reputation and the future of the 787.Hear hear! I would only add that the entire aviation industry is harmed in such cases, especially now that there is essentially a global duopoly for the manufacture of advanced passenger jets.

Unfortunately, if you go through every speculation as to cause, in this thread, not one is likely to have a good outcome. A faulty coffee-maker? Yikes....that's arguably the most frightening of all.

[WYOMINGPILOT]

"Quoting Mark Mangooni, Ethiopian Airlines' senior manager in Britain, the Financial Times reported that airline staff had discovered a problem with the aircraft's air conditioning system during a routine inspection and had seen sparks but no flames."

Now I really feel comfortable. The maintenance staff only saw sparks but no flames. The fire may have come from the air-conditioning ducting routed above the galley.

[Stuffy]

Once the public get a negative mind set. It is difficult to recover a positive one.

What happens when the negativity is reinforced by another incident?

I am not convinced by the battery 'fix'. Putting it in a metal box with a venting tube if it should overheat again. Is not a solution.

It may have been the only solution ?

I am sure Boeing will get there in the end?

[cockney steve]

To those who declare this hull to be a writeoff.

Like you, I'm not a Composites expert,however,I do have background knowledge.

Boats/ships have a long history of all-composite construction and remember the medium in which they're immersed ,is somewhat denser than air and a lot more turbulent -hence the vessel is a lot more highly stressed and suffers continual impact-stresses. (waves hitting! )

Manufacturers will always make more sections than they need....why?
Because some will be rejects, others will be required , complete, for repairs.
Rveryone seems to be fixated on "complete section" replacement....it's just not needed...in the case above ,of a reject, the faulty area can be hacked-out and the rest used to supply a part-panel.

There is no technical reason why a repair could not be pieced-in without loss of structural integrity.
The bigger problem, is the repair being TOO STRONG and transferring stresses to other areas not designed to absorb them!
(something that emerged in the development of motor-body crumple-zones.)
All this B/s about"holding up production" and " all sections already assigned to a build"....sheesh!

I wouldn't fly on one either, but it's got nothing to do with the structural integrity of "patched composites" FFS, that's how it's built in the first place!...."Airfix Kit " was nearer the mark than you realise ;)

[Flyer94]

@ManaAdaSystem

Quote:
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...)

So Fritz did not shut down FRA, just one runway? THAT was a smart decision. LHR have shut down several times, even when one or both runways were available.


You know the layout of FRA? Closing rwy 18 for an incident at it's rear end does not necessarily require to close 25L/R. It's a very large distance between the end of rwy 18 and the traffic on 25 L/R. So if they didn't went out of emergency services it was easy to let open the airport.

[blakmax]

Geez, Cockney Steve

Where do I start? Firstly, remember the "Phillips Explorer", the multi-hull vessel that was designed to circumnavigate the world in 80 days and then had a "structural malfunction" in the English Channel just after Lizzie launched her, and then sank in the Atlantic on her maiden voyage? (Shades of the Titanic).

There are vast differences between structures restricted to water travel where weight is not as critical and margins of safety are far more generous and aircraft where margins are much more finely managed. In a marine environment, a bad repair may involve a desperate resort to a dinghy and activation of an EPERB but in aircraft a bad repair may have far more significant ramifications. You have no life raft and you can not swim for long in air.

As for the "air-fix" comment, it is difficult for most people to comprehend that almost every aircraft anywhere has some adhesive bonded structure and in my (extensive) experience in adhesive bond failure forensics there have been an inordinate number of adhesive bond failures to metallic structures, so casting aspersions towards a "plastic" or "bin-liner" structure shows a neanderthalic ignorance of structural materials. There are even more significant deficiencies in bonded metallic structures than there are associated with fibre composites.

Next the "too-strong" comment. In reality, the problem of load transfer is not strength related, it is stiffness related. A compliant-but-strong material (like fibre-glass, high strength but low elastic modulus) will not cause as much load interaction as a stiff-but-weak material such as mild steel (low strength but high elastic modulus). Stiffness causes load redistribution problems, not strength.

[HDRW]

While I'm only a PPL, I do seem to know more about electrics than some posters on here, so I feel I should point out some items: Circuit Breakers and fuses that are away from the device being protected will only respond to an electrical overload - an overheating boiler, oven, whatever, would only have its circuit interrupted by a thermal device on the thing itself, not by an overcuttent breaker in a panel somewhere else. An overheating "heater" draws roughly the same current as one that's working normally, so nothing in the electrical system will "notice" the problem. Any heating device should have thermal overload protection, and if it turns out that something in the galley had been left on and resulted in this fire, then the thermal cutout must have malfunctioned. A friend of mine used to work in a domestic electrical appliance test laboratory, and they test thermal runaway to prove that the cutout will do the job, and also do "special" tests where the thermal cutout is disabled, to find out what happens then. (Anything from melting the element or the wiring to it, so disconnecting the circuit, to exploding and showing plastic everywhere!). I inadvertently tested my own automatic electric kettle recently, by leaving the lid open so the steam-sensor didn't work. Came back later to find damp wallpaper for the top three feet of the walls, and the kettle empty and turned off by its thermal trip. If a £15 kettle does this, £thousands of aircraft galley equipment will (should) too!

[Airsafes]

Whilst watching the news footage of the heat damage to the outer body on the 787 I wondered if anyone knows how lightning strikes are dissipated around the airframe on composite bodies compared to the older alloy airframes?
Plastic doesnt conduct but I would ahve thought the extreme voltage and heat would damage any plastic material?

I found some information on the wiki site about lightning strikes but wondered about its effects on composite material if anyone had any ideas?
Lightning - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Lightning)
Some of its comments.
"As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous. At the present time, aircraft (http://en.wikipedia.org/wiki/Aircraft) are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider (http://en.wikipedia.org/wiki/Glider_(sailplane)) in 1999.[37] (http://en.wikipedia.org/wiki/Lightning#cite_note-37) The standard in force at the time of the crash, Advisory Circular AC 20-53A, was replaced by Advisory Circular AC 20-53B in 2006,[38] (http://en.wikipedia.org/wiki/Lightning#cite_note-38) however it is unclear whether adequate protection against positive lightning was incorporated.[39] (http://en.wikipedia.org/wiki/Lightning#cite_note-39)[40] (http://en.wikipedia.org/wiki/Lightning#cite_note-40)Positive lightning is also now believed to have been responsible for the 1963 in-flight explosion and subsequent crash of Pan Am Flight 214 (http://en.wikipedia.org/wiki/Pan_Am_Flight_214), a Boeing 707 (http://en.wikipedia.org/wiki/Boeing_707).[41] (http://en.wikipedia.org/wiki/Lightning#cite_note-asn-41) Due to the dangers of lightning, aircraft operating in U.S. airspace have been required to have static discharge wicks (http://en.wikipedia.org/wiki/Static_discharger) to reduce the possibility of attracting a lightning strike, as well as to mitigate radio interference due to static buildup through friction with the air, but these measures may be insufficient for positive lightning.[42] (http://en.wikipedia.org/wiki/Lightning#cite_note-42)"

[jolihokistix]

Even the BBC today seems to be tiptoeing around this thing: "Fire-retardant foam was sprayed at the airliner and an area on top of the fuselage in front of the tail appeared to be scorched." :mad:

[aergid]

Oh well may as well put my pennies worth in to mix also:

By looking at the limited quality of the photographs of the damage to this aircraft. a full section replacement will most probably be carried out.
As the Aircraft is manufactured as a complete section by section structure (not panelised) any permanent repair would obviously in my opinion have to the same.
Nobody is debating that this could or could not be an electrical fault causing the fire. If it is an electrical fault then the batteries are related as they are the primary electrical system. We will just have to wait see what the AAIB investigation throws up....

as for the Fire Service. If they had 2 incidents ongoing the OIC would close the Airport as he could not guarantee response times. Also as stated before once the larger tenders were emptied they would have to be topped up again before any decent CAT level could be restored. So bravo to the OIC for taking what would have been a very challenged decision but the I believe to the correct one:ok:

[fenland787]

Even the BBC today seems to be tiptoeing around this thing: "Fire-retardant foam was sprayed at the airliner and an area on top of the fuselage in front of the tail appeared to be scorched." http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/censored.gif

Are they tiptoeing around or are they (unusually) doing what we often complain journalists don't do, ie not speculating and waiting 'till they have some facts?

[SRMman]

Cockney Steve,
You appear to be knowledgeable on the subject, and also dismissive of comments made by others.
You read my post, and therefore will have seen that I suggested Boeing have TWO options; I further discussed the pros and cons of both. Whilst a patch repair may appear to be the best option, it is not necessarily straight forward, and requires a team of design, static and fatigue stress engineers to ensure all aspects (including attracting load) are covered.

I stand by all my previous comments, including what I said about Boeing being very unlikely to have available large fuselage sections to cater for repairs. Time will tell.

[lomapaseo]

If not why not?

Bonding ?

Load Carry?

I'm interested in how the military handles this as well.

Of course I will be surprised if Boeing says it can't

With all the opinions on here maybe the technical answers should be moved to the Technical Questions forum

[DWS]

Its not an issue to be discussed here- and its not an issue PERIOD.
777 have been flying for over a decade with composite tail fin. US Navy planes like A6(E) have had composite wings for over a decade. Airbus has used a composite fin-rudder for nearly two decades. I'm sure all have been hit by lightning at least once in several decades.

techniques include built in ' screen' into layups, sealant caps on fastener penetration of fuel tank areas, plating of tank penetrations for larger parts,, etc etc etc.

Direct damage for strike area is minimal.

Spend UR time on the boeing site for example or on industy sites looking up the magic word ' lightning strikes damage repair etc .

[LookingForAJob]

as for the Fire Service. If they had 2 incidents ongoing the OIC would close the Airport as he could not guarantee response times. Also as stated before once the larger tenders were emptied they would have to be topped up again before any decent CAT level could be restored. So bravo to the OIC for taking what would have been a very challenged decision but the I believe to the correct one this one clearly isn't going away. I made some of this point very early on in this thread but the post got deleted - presumably because it was considered to be deviating from the main topic - but now I have a couple of minutes so I'll try again.

Here is how an airport fire service works in very general terms - what I'm describing is the case for the UK, but there are variations in other countries. An airport decides that it wants to offer itself to particular types and, importantly, sizes of aircraft. Depending upon the size of the largest aircraft that it wants to be able to accommodate, a certain level of fire fighting and rescue facilities are required. These are defined in ICAO Annex 14. Many airports that provide cover or higher categories - bigger - aircraft will actually exceed the minimum requirements for a variety of reasons.

Amongst the other requirements for an airport fire service is to be able to attend an incident anywhere on the airport within a certain period of time. It's important to note that this does not mean every fire vehicle and fireman has to get to the aircraft within that period. Usually what happens is that all the fire vehicles will head out to the incident when called, but a rapid intervention vehicle carrying a senior fire officer will quickly get to the incident and will assess whether some or all of the other vehicles on their way are required.

In the event of a serious incident the external fire services (and indeed hospitals, ambulances and so on) will also be called. In theory the airport fire service is there to provide immediate fire fighting and rescue service with particular expertise for the airport and aircraft environment. As soon as the external services arrive, they start to relieve the airport fire service who are then able to return to their base, replenish their media and in other ways prepare to provide the airport with its published level of fire cover again. During the turnout, as was the case at Heathrow recently, while an incident is being attended by the airport fire service, the level of fire cover available for other movements is reduced, perhaps to zero. In practice, it's likely that any aircraft on the approach or taking off will continue as normal but subsequent movements that require fire cover will quickly be advised of the situation and, we'll need to go somewhere else in accordance with their SOPs.

Those who were astonished, stunned, amazed, indignant and so on, at the picture posted earlier showing lots of fire engines surrounding the ETH aircraft, as was pointed out by another poster earlier, most of the fire vehicles look like they are from external services - as will no doubt be the case for the personnel 'twiddling their thumbs'. A quick glance suggests there are 6 external fire appliances and one or two senior police and fire service personnel cars along with one mobile incident control room (probably part of the airport fire service), two airport appliances, the airport fire boss's car and an airside ops vehicle. All standard fayre after a serious incident at a major airport.

By the way, note that not all aircraft require to have fire cover available. That will not be the case at Heathrow, but there are some situations where movements can continue without fire cover. Unless the runway is blocked, and even that is moot by some interpretations, the airport does not close - it merely cannot provide fire cover.

Return to the situation where the senior fire officer reaches an incident and determines that only a minimum level of response is required and that the majority of the vehicles can return to the station. There's no need to close the airport, it's just that the level of fire cover may be reduced temporarily. At Heathrow this week, it seems highly probable that with two incidents in progress either coincidently or in quick succession, fire cover was reduced to zero.

That the mainstream media cannot distinguish between this situation and the airport being closed may not be surprising. But some supposedly professional aviation people don't know the difference is worrying.

I mentioned early on that sometimes large airport the level of cover is greater than the minimum required in some circumstances. One example is to be able to maintain full, published level of cover for aircraft movements and still to be able to respond to minor incidents or to provide a limited level of cover the public buildings that tend to get put up at an airport. Another situation that is quite common is that of a large airport which requires more than one fire station in order to be able to provide the response required to meet the regulations. For anyone who is interested, there are situations, although not in the UK as far as I am aware, where an airport fire service may leave the airport to attend a fire in nearby areas because the external fire service is far distant - this arises for remote areas where the airport is providing, perhaps, the only access to the area.

This is the general situation. I, of course, would welcome clarification or correction from anyone intimately aware of the current procedures at Heathrow.

[Momoe]

Fire cover is determined by strict parameters, if those parameters can't be met then there is insufficient fire cover.
In the event of insufficient fire cover, it appears that LHR is not open for business, for low fuel state aircraft LTN/STN/SEN and LGW are viable alternatives with minimal additional flight time.

We don't know who calls the shots, whether it's the chief fire officer or higher up, triggered by the insufficient fire cover call from the fire services?

Statistically, the chances of an accident are slim if it remains open, but ATC sorted it out and re-directed aircraft to airports with fire cover without too much drama, maybe those operatives who dispatch without alternatives should rethink their policies rather than Heathrow?

[Passenger 389]

Multiple posters have complained (or expressed bewilderment) that Boeing did not quickly issue a statement regarding the cause of the fire.

One factor may be that Boeing is a publicly traded company. My understanding of United States securities laws is rusty, but my recollection is that publicly traded companies can be sued for making statements that later are alleged to have been false or misleading and thereby impacted the stock market. A small army of American lawyers grew very wealthy by filing many such claims, whether meritorious or not (the cost of defending the claim can be so great that a company pays just to stop the bleeding).

The law governing such claims has changed considerably in recent years, and is now less favorable to claimaints (and their lawyers), yet it surely remains a consideration.

No doubt Boeing's lawyers are carefully reviewing any prospective public statement with that in mind (along with other potential legal issues).

[phil gollin]

Just to note that considering the large number of CCTV cameras which almost certainly covered the incident it is quite amazing that no video footage has surfaced of the discovery and initial fire response.

It would seem that Fleet Street HAS cleaned up its act.

[newvisitor]

As with all internet forums, there has been quite the range of comments, from clearly knowledgeable to the other extreme. I have been in composites research and technology my whole career, since 1980, with both academic and industrial activity. The recurring theme that I find bothersome is the idea that not only does the composites community not know what it is doing, it does not know that it does not know, or is reckless.
So what about the critics in this forum? It is easy to dismiss those who are comfortable to criticize without having the background. In my experience the more knowledgeable you are, the slower you are to offer criticism. More difficult is the question of how to react to amicus. He is clearly a knowledgeable person, an expert in the field, who has strong convictions, which he has offered up previously through the correct channels and yet been rebuffed. Is he right? Is there incompetence in those who have dealt with him? Conspiracy? Management pressure? Or is it that reasonable people have carefully evaluated what he has said and decided that his concerns are too strong? That the risk is not as high as he claims.
Although I claim to be a composites expert, or perhaps because I am, it would take me weeks of work to come up to sufficient speed to offer judgement on amicus’s position. But I know, and have worked with a number of the players mentioned in his manuscript. I know that, in a public forum, even if present, many of those who disagree with amicus have their hands tied – they cannot discuss all the available evidence openly. That is a very unsatisfactory position for readers, but it is the reality of our current system. Generally there is a strong element of truth in what this type of public critic says, and it is taken very seriously behind closed doors. Reviewers work very hard to evaluate the concerns and determine what to do. Typically, but not always, those going public are partially right, because no complex engineering problem is clear-cut, but the balance is off. But the fact that in a public forum we are getting only half the story is very clear.

[jabird]

Just to note that considering the large number of CCTV cameras which almost certainly covered the incident it is quite amazing that no video footage has surfaced of the discovery and initial fire response.

It would seem that Fleet Street HAS cleaned up its act.

Who needs Fleet St when you have UtuBe?



As for the closure issue, I wonder if people are drawing the wrong comparison with what might have happened at AMS, FRA, CDG etc.

No airport would want to operate with anything less than 100% fire cover, and as pointed out above, this is something you have or you don't, no discussion.

Airlines might be operating on slim fuel margins, but again, there should be enough for TOGA or divert to another nearby airport, of which there are many in very close proximity.

The issue is surely one of runway capacity. An hour of diverts from LHR is going to take far longer to get back to normal than a similar situation at almost any other comparable airport, because there are only two available runways. However, I don't think that makes much difference to the arguments about building a third, as that would no doubt be full up soon after opening anyway, and I assume that even in special circumstances like this, the runway isn't going to be long enough to land many heavies.

[Backoffice]

I've seen fire cover requirements refering to ICAO Annex 14 mentioned here.
The actual place to go is Chapter 9.
There you will find the level of fire cover required based on size of aircraft.
This is where Heathrows problem is somewhat obvious.
The amount of water/foam necessary to be available for Cat 6 and above aircraft, which most of LHR's movements are these days (i.e. Widebody's) is about 9 times the requirement for Cat 4/5 typically smaller 737/A319.
So, LHR probably could have stayed open for the smaller aircraft and remained legal for CAA purposes but couldn't meet the higher level required by most of its movements. I can see the headlines now "Newcastle A319 allowed to land while Beiging flight forced to divert", probably easier on ATC to divert everyone than pick and mix.

[parabellum]

Can't believe how anxious people are to rubbish the B787 and how short their memories are!

I remember some years ago arriving at CDG one morning to see a very new A340 sitting in a maintenance bay almost completely burnt out, didn't generate a fraction of the hysteria that the Ethiopian B787 is managing.:(

[TURIN]

If it is an electrical fault then the batteries are related as they are the primary electrical system.

Eh? Primary? :eek::confused:

[Nubian Major]

The requirements are set out in CAP168 chapter 8, not 9, chapt 9 is emergency planning.

If the RFFS cat is declared as 0 it means that, yes the cat could be lowered if appliances, media and personnel are available to respond.

[Backoffice]

"The requirements are set out in CAP168 chapter 8, not 9, chapt 9 is emergency planning."

Agree, the UK interpreted requirements of Annex 14 Chap 9 are in CAP168 Chap 8.
But the whole point is the high level of fire cover required for the type of aircraft operating through LHR in general today.
If they empty one of those big tenders on a small fire that puts the level of fire cover down until it's replenished.
We might all say why haven't they got more tenders, there lies a cost benefit v frequency of incidents arguement.

[Etud_lAvia]

@newvisitor:

Thanks for your thoughtful post. I also have read with interest the posts from amicus, who is so obviously worried about the inflammibility of the epoxy resin in the composites make up the skin of the 787 fuselage, and who reports that he was on the losing side in a battle to get the upper part of the fuselage skin lined with thermal insulation.

I also read with interest from the FAA report on flammability properties of these materials that, "Typically, surface combustion needs a high temperature to be sustained, which is usually in excess of 500°C."

In isolation, that the material can burn is an interesting fact suggesting obvious concerns. But it seems to me that more must be taken into account in order to understand the implications of this fact for safety of air transport flights as dynamic systems.

I take as a premise that a powerful fire onboard a pressurized transport at altitude is an extremely dangerous event (whichever materials are used in the airframe), and generally non-survivable unless the fire's duration is limited by fire suppression or exhaustion of fuel/oxidizer.

Though I claim no expertise, I have worked as an engineer in the fire protection industry -- I wonder whether a fire capable of heating a significant area of composite cabin skin to 500+ Celsius for more than a few seconds wouldn't be quite a nasty blaze in its own right. I haven't done any of the analysis necessary to quantify this, which would have to take into account such factors as cooling by conduction to the outer surface.

Wondering about the safety issues of composite skins, brings several questions to mind:

1. Considering the kinds of fires that have been observed or are relatively likely in air transport cabins, how large and sustained would such fires need to be, in order to create the conditions required for sustained burning of the composite skin? For the purpose of discussion, I'll coin the name composite burn-up fires, or CBU fires for short, to refer to cabin fires sufficiently energetic to cause such skin burning.

2. How would conventional aluminium aircraft skins perform under the conditions of CBU fires as defined above?

3. Subtracting the combustion products from the composite skin itself, would the cabin air be able to sustain life in fires meeting the CBU criterion? What would the survivability implications be, regardless of airframe materials?

4. How much toxicity would combustion of the composite resins add to the cabin air, as compared to the toxicity from the CBU fire conditions that would precipitate skin burning?

I get that amicus objects strenuously to the 787's present application of these materials. My questions are about the practical safety implications of this technical vulnerability. In real-world fire scenarios (sadly, smoke/fire incidents on airliners are not so uncommon), what kind of differences in outcomes might be expected, taking the related factors into account?

In a way, we may be thankful for the incident in London, in which noone was hurt. Fire experts will be able to provide some estimates of the power and duration of the fire, offering a practical case of "how bad it got" in order to burn through the skin. Hopefully, the investigation will also address temperatures and toxicity of the cabin atmosphere during the blaze.

I also hope that some assessment can be made of the extent to which the aerostructures were compromised by the damage, and what the structural implications might have been for the plane's ability to land, had such damage occurred in flight.

[Fly3]

The reason that the A340 fire in Paris did not cause the same hysteria is that the cause was quickly identified i.e. the yellow hydraulic electric pump failing to stop after the cargo doors were closed and overheating. Quite different from the B787 problem where the cause still has not been found.

[parabellum]

Quite different from the B787 problem where the cause still has not been found.

So you think the hysteria will die down when the cause of the Ethiopian fire is announced? It has certainly been found but disclosure will be in the hands of the Boeing legal team who will almost certainly have sub-contractor and product liability considerations and don't wish to set themselves up for being sued.

There is a very unhealthy anti Boeing cult developing, nothing short of cancellation of the B787 will satisfy them.

[fflyingdog]

I wouldn't agree entirely on the whole 'anti Boeing' line of thought,but i can understand your point.
I just think people really do want to makes sure or understand that crew/pax will be safe when flying on these aircraft.I personally would like to think that the Boeing engineers had already thought these problems through with regard to fuselage integrity and the survivability of the aircraft to remain intact and airworthy if a fire took place in flight. Not forgetting the pax/crew being able to survive on the rubber jungle and bottles.

[DWS]

I personally would like to think that the Boeing engineers had already thought these problems through with regard to fuselage integrity and the survivability of the aircraft to remain intact and airworthy if a fire took place in flight

As an retired Boeing Engineer I would like to agree with you, but sadly, few such engineers/techs had much to say about such design issues. In the name of cost savings, reduced research, and bucu outsourcing, the majority of those type of decisions were tempered by the faster- cheaper method. Thus we had the fubar non testing of batteries ( driving a nail thru one cell for example ), few system tests of an all up system, etc. NOT that those in charge deliberately looked the other way, but instead the working grunts either bailed out when able, or put self survivablity above pressing an unpopular with top brass questions or issues. Power point rangers rule the roost- thus we had the PR team insist on rollout of an empty shell just to make a nice pr date of 7-8-7.

Consider that the 747 was designed, built, flew, and a new factory was built in less time than the delays on the 787. :sad:

[amicus]

NewVisitor,
.Thank you for your thoughtful and rational comments, they are much appreciated.
I have been working in aerospace engineering since being a young squirt apprenticeship in 1952 at De Havillands. We even had a composites departmen in 1952, well only the superb Mr. Johnston, who I served under for six months and learned copious initial composites knowledge and data from that kind and superb gentleman.
In the early 50's,we employed Redux phenolic bonding extensively on our aircraft including the Sea Vixen and the ill fated Comet 1 for stinger to wing skin bonding as well as for many fuselage components.
I have been working and specializing in the design and analysis of aerospace composites since the mid-60's, so I hope that I know enough to contribute something of merit, from both the engineering and historical aspects of composites in in paricular, the flammability and fire hazards of the 787.
Incidentally, I finished my engineering career consulting concerning composites for three years at Boeing Commercial, so I know pretty well Boeing engineering and BMT. plus Allen Fawcett pretty well as well as many others composites folks at Boeing or now retired.
My point in writing extensively concerning both the flammability and FST hazards of the epoxies on 787 stems from a lot of experience working on FST with NASA, Moffet, Ciba-Geigy, Celanese and several other companies in the early 70's. I I worked for many years getting all FST hazardous epoxies banned for A/C interiors for many years or even decades and the FAA finally passed the no epoxy for interiors in the middle 80's.
Now we are faced with epoxies with FST hazards all over the 787 and the flammability and FST problems inherent therein
I have had many discussions since 2005 with FAA , Boeing, Airbus et al concerning the FST hazard inherent in that A/C,and , I note, trying to work properly through the FAA system. Clearly and undeniably there exists both a flammability and major FST hazard on that A/C calling into question survivable crash flammability and crash hazards.
In summary, I got nowhere, as the FAA always ignored my comments or paid stand bureaucratic lip service with no resulting safety corrections, crash testing or the like, so now we are unfortunately placed as engineers and , I hope,well qualified composites experts, fearing a fatal incident on 787, which could have been and should have been avoided.
Concerning the Ethiopian fire, I again note that the FAA agreed, under strong Boeing pressure, to only have internal burn-through fire insulation on the lower half of the 787.
I protested long and loudly to the FAA concerning the lack of any such insulation on the upper 180 degrees of the fuselage and the LHR fire was in the right place to prove my point, their errors and fortunately with no loss of life, THIS TIME.
I lived through and worked upon the Comet disasters and don't want that experience repeated, but it will be if strong steps and measures are finally and rapidly taken by Boeing, the FAA, EASA and NTSB to correct and remedy the inherent design deficiencies of the 787.
I am neither a Cassandra nor an eccentric, merely a aerospace engineer specializing in design and analysis of composites engineering since the early 60's plus Mr. Johnston's earlier wisdom and training in composites and biffing me around the ears in the early 50's at De Havillands.
And you, Sir, are a breath of sanity and fresh air on this forum as there has been much codswallop written here regarding fires, repairs, and crash-worthiness et al on this board and my Boeing engineering and BMT friends grew to be well attuned to that remark and assessment and remarks concerning codswallop in my three years consulting with them.

[Uncle Fred]

Amicus and Newvisitor

Hats off to both of you. Your rational exchange is what PPrune used to be. Your experience and knowledge, articulately stated, brings the conversation back to an intelligent exchange of ideas and allows the rest of us, without your specific skill set, to listen and learn.

[thesafepassenger]

Amicus...and others. I read your comments with interest.
Interesting to consider the Heathrow fire in the context of the 787 Certification and its Special Conditions for the fuselage. To what extent did the 787 Certification Special Conditions address flammability and survivability then - or was that ('Composite Fuselage ' Special Condition) related only to the physical fuselage structure and its capacity to withstand physical forces in a crash landing.
In the past I have tried to get more detailed information on what the 787 Special Conditions actually mean in practice - especially the ones relating to lithium ion batteries and the fuselage crashworthiness - but without success.

[amicus]

Uncle Fred,
My sincere appreciation and I can only hope that pprune restores itself to its old glory and get rid of the ongoing and wasteful dross and codswallop, so evident of late and in this current thread. I am most grateful yourself and to New Visitor for giving me hope of correction and change.

Thank you, again, Sir,

[NigelOnDraft]

it's not going to be as easy as hitting the TOGA button and taking the shortest route to that nice nearby airport and landing there. All of the normal flows of traffic will be disrupted.Ultimately it comes down to "Command" and awareness.

Any airfield, be it 1, 2 or 3+ RWs could "close" with no notice. Fuel policies allow (but do not require) you to re-arrange your flight to land with "(just) above Reserve" without telling anybody (e.g. ATC) nor having a "Plan B" (Diversion).

I have my "ways" of dealing with such situations, I am sure others have theirs. They vary from informing ATC as soon as possible if a GA will result in either a PAN or Mayday. I suspect (but do not know) that if an aircraft was inside 5NM for LHR, and had clealy notified LHR that "in the event of a GA I will be declaring a Mayday for Fuel", then on Friday they would have been allowed to land.

In the event a short of fuel late GA happens, I will have briefed with my colleague the "bottom" line. This might be 7700 and direct track to 8NM final at XXX, whatever ATC say.

Others may, or may not, disagree. But the other side of the coin - working without thought to minimum fuel policies, and then expecting the normal ATC system to cope with mass diverts and have everybody on the ground with > Reserve, I think is "optimistic" ;)

[davidash]

I have found the discussions on composites extremely interesting. As a lawyer I am currently involved in litigation surrounding the blast effects on laminates so the whole debate is fascinating.
However, as illuminating as the discussion may be, I would avoid flying in a 787 until everyone was satisfied that the aircraft is safe. As things stand, there is a great deal of evidence that suggests the 787 needs more time to work through its teething problems - without passengers on board!
Heaven help Boeing if there was a major accident as a result of some fault - batteries or otherwise.
To use an old adage, they are "playing with fire".

[Capt H Peacock]

I don't think threre's anything particularly anti-Boeing about this.

When ETOPS first came about, the industry set about demonstrating how 2 engined aeroplanes could reliably operate across the wilderness without compromise.

We now have a new aeroplane type that appears to have a predisposition to fire to such an extent that the aircraft could be quickly compromised.

Given its intended market, I believe that is genuine cause for concern.

[NigelOnDraft]

Amicus and Newvisitor

Hats off to both of you. Your rational exchange is what PPrune used to be. Your experience and knowledge, articulately stated, brings the conversation back to an intelligent exchange of ideas and allows the rest of us, without your specific skill set, to listen and learn. You may recall I quizzed amicus early on about the clear knowledge of the 787 and materials ;)

That has led to rather a lot of reading over the weekend of websites / articles, some of which I suspect are authored by amicus. They are not whacky theories, but asking Boeing/FAA probing questions and seemingly not getting the answers.

The articles seem to pre-date the A350 final design, which has now also gone down the composite route, at times apparently against some at Airbus' judgement who might have preferred the A380 "hybrid" route?

As such, I feel better informed and will follow the ET follow up with interest - and maybe cross referred to the 777 SFO accident.

What I am still unclear about is how "different" the A350 is to the 787? 1 difference is "panel" fuselage construction (A350) v Barrel (787) - the panel being simpler and easier to repair i.e. in the ET case, it might require the whole aft fuselage "barrel" replaced if it cannot be patched.

The burn / insulation differences between the 787 Toray 3900-2 and A350 Hexcal M21E materials / construction would also be of interest if anybody can help...


PS if anybody is interest please see Lonely Scientist (http://www.lonelyscientist.com/) and the 'Impossible Dream' chapters...

[Desert Dawg]

Amicus was vocal on the issue in 2011 when LOT had the unfortunate wheels up landing.

See http://www.pprune.org/rumours-news/467899-polish-lot-767-wheels-up-landing-4.html#post6784032

Edited to say: Amicus was vocal as far back as 2007...!! Search for his enlightening posts ...

[barit1]

A quick question - what UK agency does the official investigation on an event such as this?

The Toulouse A340 runup accident was classified as an industrial accident, not an aviation accident, and thus BEA did not do the final report. Similarly, in the US, it would probably be OSHA and not NTSB doing the official investigation.

[robertbartsch]

Fox News is reporting that investigators have determined that the fire was not electrical related....

Hmmmmmm....

[NigelOnDraft]

A quick question - what UK agency does the official investigation on an event such as this?It does not fall under the AAIB definition of an "Accident" - the definition is less clear as to what is a "Serious Incident".

The AAIB have said: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).and in the 1996 Regs it says:Subject to paragraphs (5) and (6) below, the Chief Inspector may, when he expects to draw air safety lessons from it, carry out, or cause an Inspector to carry out, an investigation into an incident, other than a serious incident, which occurs—
(a)in or over the United Kingdom; or .
(b)otherwise than in or over the United Kingdom to an aircraft registered in the United Kingdom.which gives the AAIB powers to investigate even outside the strict definitions...

[aerolearner]

According to AAIB:
Definition of Accident and Serious Incident

Definition of an Accident

"Accident" means an occurrence associated with the operation of an aircraft which might take place between the time any person boards the aircraft with the intention of flight and such time as all persons have disembarked, in which:
I think the main doubt would be: was there anybody on board with the intention of flight?

On a similar case, the American Airlines B767 uncontained engine failure in Los Angeles on June 2, 2006 (http://www.skybrary.aero/index.php/B762,_Los_Angeles_USA,_2006_(FIRE_GND_AW)), NTSB conducted the investigation, even if there was no intention of flight.

[Lonewolf_50]

A and C
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.
It seems we have come full circle, back to Wilbur and Orville.

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.

Eight figures ranges from about 6% of the cost to just over 60% of the cost of a new bird. ;)

Somebody who once worked for Boeing wrote ...
and bucu outsourcing
I think you mean "beaucoup" (as in "a lot") which is pronounced in American slang (origin I think US military slang, Viet Nam era) to sound like "boo coo" or 'bo coo" ... but maybe it goes back to some Cajun/Coonass slang from Louisiana ...

Or maybe have I missed a new slang term and its origin, yet again. :P

Composite repair: it appears to be a growing field of endeavour as more and more of our airframes, rotary and fixed wing, are made of something other than metal.

[SRMman]

One mustn't forget that composite primary structure on aircraft has been around for a LONG time, e.g. A300-600 with CFRP fin entered service in 1983.

[Etud_lAvia]

@Lonewolf_50:

Eight figures ranges from about 6% of the cost to just over 60% of the cost of a new bird. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif

Correct. Accordingly, EXCEEDING eight figures means costing more than about 60%; and FAR EXCEEDING eight figures means costing a lot more than 60% ;)

Unless repair would require equipment only available at the factory, I would be a bit in awe, to learn that a team with a 100 million dollar budget could find no way to accomplish it.

This is Boeing's chance to demonstrate the repairability of their new construction -- if they fail, their customers (or perhaps, their customers' insurance companies) will have to count the increased financial risk of hull write-off as a factor in the cost of operating such planes.

@robertbartsch:

Leaving to one side the journalistic standards of Fox News ... perhaps the concept of battery-related somehow got mangled into electricity-related? A full pack of dim bulbs...

[A and C]

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.

[Lonewolf_50]

This is Boeing's chance to demonstrate the repairability of their new
construction -- if they fail, their customers (or perhaps, their customers'
insurance companies) will have to count the increased financial risk of hull
write-off as a factor in the cost of operating such planes.
An opportunity to excel. :ok: Let's see how they respond ...

[White Knight]

I remember some years ago arriving at CDG one morning to see a very new A340 sitting in a maintenance bay almost completely burnt out, didn't generate a fraction of the hysteria that the Ethiopian B787 is managing.

Two reasons.

1. The internet and immediate news was not so widespread...............

2. 340s hadn't already had a history of catching fire:{:{................

[Karel_x]

Two reasons.
1. The internet and immediate news was not so widespread...............
2. 340s hadn't already had a history of catching fire................
Maybe third and fourth reasons:
3. Too loud advertising campaign, manipulative name, self-applause. Very nice, good, promising and interesting plane but overweighted with unbalanced ovations, superlatives, glorifying....
4. Increased economy at the expense of safety...?

Sorry for o/t

[SLF3]

Honeywell says participating in Boeing 787 fire investigation | Reuters (http://uk.reuters.com/article/2013/07/15/uk-boeing-dreamliner-honeywell-idUKBRE96E0QF20130715)

[cappt]

Foxnews reports

Reports: Honeywell Part Eyed in 787 Fire Probe
Jul 15, 2013 2:15 PM EDT


Investigators are looking at an emergency locator transmitter built by Honeywell International Inc (NYSE:HON) as the possible cause of a fire on board a Boeing Co (NYSE:BA) Dreamliner in London last week, according to a source familiar with the probe.

The transmitter uses a lithium manganese battery, said the source, who was not authorized to speak on the record.

Honeywell confirmed earlier that it was participating in the UK-led investigation into a fire on a 787 operated by Ethiopian Airlines at Heathrow airport outside London on Friday.

Experts have said lithium-ion batteries likely did not cause Friday's fire, allaying fears about a return of the problem that grounded the Dreamliner for more than three months earlier this year, when one battery caught fire and another overheated.

(Reporting by Andrea Shalal-Esa; Editing by Gerald E. McCormick)

[boguing]

Surely the ELT would not have been turned on?

[NigelOnDraft]

So if a few $Ks of ELT were to just about destroy $00Ms of 787, what do our Aircraft Designer readers have to add?

Should an ELT be shielded? The fuselage about it be shielded? Could an ELT battery really cause this much damage itself... or has it "set light to" the fuselage? What would an Aluminium fuselage do?

Is the 787 ELT pretty "standard"? Or has it been made lighter/riskier as part of the 787 weight shedding programs?

All, of course, in the hypothetical case it is anything to do with the ELT ;)

[ATC Watcher]

Investigators are looking at an emergency locator transmitter.... as the possible cause of the fire '.... according to a source familiar with the probe.
The transmitter uses a lithium manganese battery, said the source,
If this is confirmed and the battery was starting point then it is truly becoming a nightmare, and not only for Boeing and this perticular type.:uhoh:

[Herod]

Amicus. Could you please shed some light on the following. What temperature could one reasonably expect from, say, a laptop catching fire in an overhead locker, and its possibility of reaching a dangerous temperature for the upper fuselage? I ask as a concerned observer, having logged many hours flying, but all in metal aeroplanes.

[henra]

If this is confirmed and the battery was starting point then it is truly becoming a nightmare, and not only for Boeing and this perticular type.:uhoh:

That would be indeed kind of - ooouuuchh.

The ELT being only allowed to be transported by ground, just to be installed in a critical and hardly accesible Location in a 'plastic' aircraft really takes the cake. :}

[Cows getting bigger]

I'm not a believer in coincidence. How many other aircraft could have had a Honeywell ELT let go? What, if anything, is different about this installation?

[gas path]

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.

[time-ex]

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.

[Etud_lAvia]

@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/common/documents/myaerospacecatalog-documents/BA_brochures-documents/RESCU_406_AFN_ELT.pdf

[barit1]

time-ex: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.

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.

[Etud_lAvia]

@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.

[JFZ90]

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.

[Checkerboard 13]

time-ex:
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.

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.

[MurphyWasRight]

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.

[amicus]

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.

[lomapaseo]

amicus

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.

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

[henra]

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


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?

[despegue]

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:

[LASJayhawk]

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:

[MrDK]

I'd fly it tomorrow

[hunbet]

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 !!!

[Machaca]

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


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?

[Machaca]

Honeywell supplies (http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Aircraft_Platforms_documents/Sept_2011/Technologies_Honeywell_Brings_to_the_B787.pdf) quite a variety of items on the 787:

http://i337.photobucket.com/albums/n385/motidog/787Honeywell_zps8b015c84.jpg (http://s337.photobucket.com/user/motidog/media/787Honeywell_zps8b015c84.jpg.html)

[Cool Guys]

I urge the travelling public not to flyon this type of aircraft.


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.

[nomorehelosforme]

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!

[boguing]

Repeat.

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

[RCav8or]

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?

[PPRuNe Towers]

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

Rob

[AtomKraft]

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.

[nitpicker330]

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:

[LASJayhawk]

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.

[olandese_volante]

Lithium Ion batteries have NO business inside any 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.

[Etud_lAvia]

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.

[Etud_lAvia]

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.

[SRMman]

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.

[MPN11]

As a complete non-technical person, I have read the battery discussions with great interest. I drive a Peugeot iOn (https://en.wikipedia.org/wiki/Mitsubishi_i-MiEV) 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 battery has a forced air cooling system to prevent overheating during high charge and discharge rates and consequent damage. There is an integral fan in the battery pack. For rapid charging, the battery pack is additionally cooled with refrigerated air from the cars air conditioning system.

[spannersatcx]

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

[Ex Cargo Clown]

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

[poorjohn]

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.

[Mapleflot]

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

[NorthernKestrel]

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 (http://aerosociety.com/News/Specialst-Papers)

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

[Volume]

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.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.

[Hi_Tech]

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:

[blakmax]

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.

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.

[lomapaseo]

Etud_lAvia

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?


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.

[fflyingdog]

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.

[Hi_Tech]

fflyingdog.
You are right. There are 2 types. One is attached to fuselage forward of the Fin and another inside the cabin as a portable unit, which the Cabin crew can deploy manually also. This unit is the one located in the overhead bins. Both have LI batteries. Both used for several years. Surprising this had to wait for installation B787 to go up in flames in a dramatic way. :ugh:

[SRMman]

Blakmax, spot on!

Repairs, metallic or composite, to commercial aircraft are treated effectively as a modification, and require the same level of approval as the original certification. Repairs that do not meet the same strength standards as the original structure may require an additional maintenance programme, e.g. regular inspections, to assure the repair's continuing integrity.

[MurphyWasRight]

A couple more possibilities on why Honeywell was invitied to join the investigation, beyond the ELT being under suspicion as a primary factor in the fire.

1: If the ELT has non-volatile memory for maintenance purposes the contents might help in creating a time line and conditions of the incident.

2: I took a look at the first few pages of this thread and see no reports on who discovered and reported the fire.
Theres is one qoute re "sparks in AC unit" but with no information on when in the event that was seen.

Begin pure wild speculation, I realize this is unlikely but stranger things have happend:

Is it possible that the fire burned the insulation on the cockpit activation circuit and triggered the ELT?

Did the fire brigade respond to investigate a possible crash?

Even if as is totally likely the above is not the case the ELT may have been triggered so there could be questions on its performance under fire.

[Volume]

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. Gliders do use carbon fibre for wing spars since 1972, and have nothing to to with surfboards. Glider do operate carbon fibre to stress levels even above what large aeroplanes do. The only (and probably most relevant) difference is that gliders are typically clean, while large aeroplanes are contaminated by fuel, oil, hydraulic fluid, deeicers... you name it, they are exposed to it. To do a bondes repair to contaminated structures requires extremely throrough cleaning, otherwise it becomes dangerous. Thats why bolted repair is so popular.

[DWS]

for example
https://commerce.honeywell.com/webapp/wcs/stores/servlet/eSystemDisplay?catalogId=10251&storeId=10651&categoryId=39524&langId=-1

[Jetstream67]

Non rechargeable Lithium batteries will begin to self combust at well below the 500 degree temperatures reported as necessary to burn the airframe.

It could be hard to decide is a burnt ELT was the primary or a secondary source of combustion . . which may be why there is a bit of a delay


Primary Lithium Cells (Non rechargeable)
　
•Capable of self-ignition (thermal runaway)
•May worsen an independent controllable fire event •Violent release of a flammable electrolyte mixed with molten lithium metal (large pressure pulse)

[JFZ90]

Is the ELT in the fin integrated with the aerial through the fuselage? I had assumed that it was. I guess there are ELTs in liferafts too (1 each?) - how many are there on a 787?

[Jetstream67]

A remotely positioned test switch activates them momentarily to confirm RF output level and antenna operation but generally sends a different signal to an accident signal

To a previous poster : The antenna is generally a flush insulated slot section type cut and bolted into a metal (i.e. RF blocking) airframe . . the same may still be true of composite airframes as they have quite a lot of metal mesh included in them to address lightening strike issues and that might reduce signal strength

[amicus]

Etud Iavia,
There has been three fires in 787 fuselage to date with burn-through in two. This is in less than two years of flying and low flying hours, no risk analysis or fancy statistical stuff needed, 'Just the facts.Ma'am, just the facts" as Jack Webb said. Its obvious and clear that a major safety hazard exists on uninsulated (upper180 degrees including the cabin) and possibly on insulated fuselage (lower 180 degrees) and we don't need strawmen categories either.
Isn't it just an obvious, proven and clear safety hazard?

[kwh]

And, a further correction, the self ignition temperature of Toray 3900-2 epoxy is a mere and flammable 580 degrees F

Wait, so... if anything in contact with the skin of the upper fuselage heats to 300 degrees centigrade (like maybe an overloaded electrical cable run or the aformentioned battery?) the fuselage skin catches fire, and that fire is self sustaining? And if this were to happen in flight for some reason, would the airflow over the fuselage act like a blacksmith's bellows and turn the top rear of the plane into a giant roman candle within a few seconds until the charred remnants disintegrated in flight, showering burning confetti and smoking corpses over a vast area?

Or has somebody tested this and proved that it definitely won't happen like that and that the fire hazard is only relevant in a post crash scenario?

[olasek]

I read somewhere else that actually it would be much better to be in a carbon fibre aircraft than in aluminium one with this sort of ELT battery fire. First of all fire in NOT self-sustaining, carbon fuselage tends to char and therefore blocks further propagation of fire but aluminium loses its tensile strength with temperature much faster, by 500 deg, it lost most of its strength.

[daikilo]

Noted. Toray with epoxy 580deg F. That is surprisingly low. If this is correct, I may have some questions.

[Juliet Sierra Papa]

Amicus,
I think you may be confusing "Flash point" with "Ignition point". Material will ignite at flash point of approx 200C/392F with external influence. Ignition point, will self ignite at 516C/961F if local conditions prevail.

I do however stand to be corrected :ok:

[amicus]

JSP,
Please stand by to be corrected, JSP, please.The 580 degree F is definately the self ignition point, not the flash point, so my original contention stands.
And with some of contributors seeking to defend the indefensible, I note that I am NOT, repeat NOt discussing the CF itself, but am discussing the epoxy FST hazard of the composite.
And to those who so foolishly claim that CFRP "merely chars", they ignore that, prior to charring, the epoxy has already caught fire, releasing copious doses of smoke, cyanide, carbon monoxides and a lot of other FST toxic chemicals which immediately incapacitates or kills both pax and crew.
A simple point to those simple people; "Why have epoxy based composites been banned by the FAA and all other regulatory agencies for aircraft interiors for the past 25 years, having been ordered to be replaced phenolics and various thermoplastics? further to those same folks, go read the PiperAlpha offshore fire reportand subsequent mandating replacement of all epoxy based composites by phenolics. We are talking public safety and lives here, for goodness sake.
Further, to such folks, I would note for the last time that the compressive and ILSS composite values are shot, useless, finished and structurally useless by around 360 degrees F or so (in fact Boeing's engineers worry mightily if temperatures on commercial A/C composites exceed 180- 200 degrees).
From a structural safety aspect you only need to reach 330-350 degrees F for the critical strength properties to be shot and kaput and good bye pax and crew.
Equally, aluminum properties of aerospace alloys grade are pretty well shot at 400 degrees F, however a aluminum alloys have the decency to recover if temperatures decrease and not self ignite until 1960 degrees F or so, this is in strong contrast to the self ignition point of a mere self ignition of 580 degrees F for CFRP. In addition, aluminum is a far, far better conductor than CFRP, hence the local peak temperature is agenerlly far lower in contrast to CFRP which is a thermal insulator, not a conductor as is aluminum, this is a critical difference.
Finally, if composites have exceeded their cure temperature by 20 degrees or so, they do not recover their structural properties as aluminum alloys do, a critical aspect from fire-fighting inside the A/C and flight survival .
I hope that this short lecture from a composites engineer helps a mite and that I do not in future have to say Codswallop so often.

[kwh]

So, Amicus, if there is a point heat source (like say an electrical short or a spontaneous ELT battery fire) that applies 581F to the inside top of the fuselage just ahead of the tail fin, what are you suggesting happens?

1. Toxic smoke & fumes from hot resin start to fill the cabin? OK, so presumably there's a procedure for that...

2. The structure around the point heat source is compromised... OK, not great, going to cost a fortune to fix in due course, but one small patch of structural weakness does not translate to a crash...

3. Will the skin of the aircraft actually catch fire? Will it burn, will it self-sustain in a 200mph wind blast? Can somebody say with the confidence born of having evidence, that it won't happen?

[amicus]

Hi kwh,
There are no procedures other than fire-fighting, but alas, no hazmat, full face masks and oxygen available for the crew for fighting internal FST epoxy generated composite fires as, such FST hazardous and flammable epoxies for interiors were banned by a once useful FAA back in the mid-80's. I had worked on FST since early 70's and it took that long for FAA to issue an epoxy banning edict.
In the interim there were FST fatalities, for example the Airtours 737 as Manchester plus a number of others such as Swissair 111 over Canada, which sadly crashed with all killed, it was an MD-11. I refer you to British AAIB for their reports, there were plenty of others in various countries. Most recently I worked as an expert witness concerning the UPS Dubai crash, a 747-400F. There were others in freight area as regs are either very loose of non existent.
Hope that this helps,

[amicus]

KWH,
You are way and unacceptably off in item 2, kwh, the Ethiopian fire would most certainly have caused a fatal crash for all on board if it occurred in flight. So "Not Great" is an unrealistic conclusion to draw and I am being very charitable.
Re item 3, I see no reason why fire would not burn in flight and I refer you to the Swissair MD-11 for your review.

[Machaca]

amicus,
Codswallop


amicus: the self ignition temperature of Toray 3900-2 epoxy is a mere and flammable 580 degrees F

However, in your paper (http://seattletimes.nwsource.com/ABPub/2010/06/26/2012218081.pdf) you state:

"I do not know the specific auto ignition temperature for Toray 3900 series epoxies..."

Have you since tested a cured, fuselage equivalent thickness panel of T800/3900-2 and confirmed your speculation? Please share!

[DozyWannabe]

for example the Airtours 737 as Manchester

That aircraft had an aluminium fuselage that suffered complete structural failure aft of the rear spar. The deaths were by and large due to smoke inhalation from a variety of materials, chiefly the synthetic foam in the seats.

plus a number of others such as Swissair 111 over Canada, which sadly crashed with all killed, it was an MD-11.

The fuel in that case turned out to be the insulation, which turned out to be far more flammable than the FAA's tests indicated. Also, that aircraft hit the water intact - it was the damage to avionics and flight control connections that proved insurmountable.

[tdracer]

One things for sure the 'silence is deafening'from Boeings PR department.

Boeing never publicly comments during on-going investigations - none of the manufactures do. They are effectively under a gag order from the investigating authority.

They'll release general PR stuff like "Boeing is assisting XYZ in their investigation of this incident", but never statements about what caused the event. That's the job of the investigating authority.

[J.O.]

Also, that aircraft hit the water intact - it was the damage to avionics and flight control connections that proved insurmountable.

It's been a long time but I believe the TSB report also stated that there was a strong likelihood that the loss of control may have been due to crew incapacitation because they were exposed to extreme heat and noxious fumes. Cockpit ceiling panels were exposed to heat in excess of 1400 degrees C and there was evidence of molten metal falling from those panels.

[kwh]

So contrary to my optimistic earlier assessment, in the event that it is found that the Ethiopian 787 fire was caused by a spontaneous ELT battery meltdown, had the same incident occurred in flight, one would expect:

1. Numerous passengers and cabin crew to die of asphyxia and/or cyanide poisoning, although flight crew possibly protected by crew oxygen.

2. They will need to try to get on the ground in single digit minutes because otherwise there will be catastrophic structural failure driven by merely heat, e.g. the tail will fall off...

3. But thery won't make it because the skin itself will burn like a firework in the airflow round the plane..

[DozyWannabe]

It's been a long time but I believe...

Sure. The point I was trying to make was that in both of the cases he was citing, the presence of the material he considers such a risk played a relatively minor role.

[olasek]

had the same incident occurred in flight, one would expect:
Yeah, probably the end result would not have been far from what would have happened if this was an aluminium plane. Since the said identical ELT is installed on many other conventional aircraft I bet that if ultimately there is any regulatory action - it will affect all aircraft who carry this antenna/battery regardless of the type of the material the fuselage was made from.

[amicus]

DozyWannabe,
Obviously, and that is why back in the 70's I was working on design andtesting of CF fire blockers with Celanese for all A/C seats. They were not fitted to Airtours 737 seats due to very slow regulatory pace at FAA. and aluminum fuselage had zero influence re Airtours fatalities.
I was discussing banning of epoxies from A/C interiors and kindly check and read all Piper Alpha fire reports too, a steel structure with epoxy components and subsequent edicts concerning substituting phenolics for epoxies on offshore oil platforms in North Sea.

[jolihokistix]

Re ELT battery life in general.

I have understood the oft-repeated 'non-rechargeable' nature of the battery, but what is the ELT useful battery limit and what happens when these reach the end of their battery life? Presumably they are swapped out on a regular basis, say once every five years (?), but are they easy to swap out? Does anyone know?

[LASJayhawk]

The 121.6/243 elt's were a 2 year replacement for the most part. The 406's are usually 7 years (not sure on the Honeywell) The longer life is do to the switch to lithium batteries.

Changing the battery pack itself only takes a few minutes, most of the time involved is removing the elt, testing, and reinstalling and doing a functional test in the aircraft.

[Sevarg]

In my time time-ex ELT batteries were used to power the 'hanger radio' until flat and then treated as toxic waste. Never saw one do anything other than power the radio for a long time.

[tilnextime]

I am wondering too, if LHR should have been shut for so long. I understand the immediate concerns of supervisors dealing directly with incident(s) but what about the wider operational issues? Are decision makers aware of many operators fuel policy, such as dispensing with alternates? If any diversions involved Pan/Mayday calls, it means that the closure decision generated emergencies in its own right. To have large numbers of aircraft with low fuel states diverting is a serious matter in itself.

Strange as it may seem, most airports have what we, in Army Aviation, called a "Pre-Accident Plan" that carefully scripts the response to emergency situations. In developing the plan for the two airfields I was fortunate to command, these very items were addressed, as the directives for a Pre-Accident Plan required it. Each player in the response plan is given specific duties and responsibilities, and rehearsals and dry runs are held to keep the players current. At one of those two airfields (actually a very busy heliport with a typical population of 80 to 120 aircraft tenant on the field), our plan was coordinated with the nearby commercial airport (3.1 miles away) and the National Guard F-4 squadron there, local civilian fire departments, hospitals, ambulance services and ATC.

BTW, part of that Pre-Accident Plan was a direct link between our Range Control Office and civilian ATC to provide for shutting down all artillery firing to enable the massive restricted area to be released to civilian ATC as available airspace to make handling an emergency a bit easier.

I am quite confident that when the fire brigade at LHR was launched, it involved a hell of a lot more agencies than one would initially imagine, executing a well thought out, pre-determined plan that addressed virtually all the contingencies being worried about here. There really are intelligent life forms out there beyond the wing tips. :)

[Finn47]

At least for this recent Honeywell ELT model, the specs say:

- battery service life 10 years
- battery replacement without removing transmitter unit from aircraft

.. so changing the battery should not be too hard?

http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/BA_brochures-documents/RESCU_406_AFN_ELT.pdf

[Ian W]

I am wondering too, if LHR should have been shut for so long. I understand the immediate concerns of supervisors dealing directly with incident(s) but what about the wider operational issues? Are decision makers aware of many operators fuel policy, such as dispensing with alternates? If any diversions involved Pan/Mayday calls, it means that the closure decision generated emergencies in its own right. To have large numbers of aircraft with low fuel states diverting is a serious matter in itself.

There is a legally defined number of fire and other emergency vehicles that are required to be available for operation of Heathrow. Obviously, they have only enough to deal with one incident, in this case a localized fire on an empty aircraft, or they would have continued flying. This is a cause for concern as there is an obvious possibility (probability) that two incidents could occur at the same time or there could be a really major accident- and Heathrow is demonstrably unable to cope.

[MurphyWasRight]

http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/icons/laugh.gif


Quote:
I am wondering too, if LHR should have been shut for so long. I understand the immediate concerns of supervisors dealing directly with incident(s) but what about the wider operational issues? Are decision makers aware of many operators fuel policy, such as dispensing with alternates? If any diversions involved Pan/Mayday calls, it means that the closure decision generated emergencies in its own right. To have large numbers of aircraft with low fuel states diverting is a serious matter in itself.

Strange as it may seem, most airports have what we, in Army Aviation, called a "Pre-Accident Plan" that carefully scripts the response to emergency situations.


I think an important point in all of this is whether one would prefer that a well thought out and documented plan (that all affected parties understand) be followed or that "common sense" and "everyone knows that" based actions prevail.

Emergencies can pretty much be counted on to have chaos and confusion, having a plan -and- sticking to it is the best way to minimize the risks including responders working at cross purposes.

If problems or ideas for better response are found in a post incident review then the plan can be updated for -next time- with all changes reviewed by affected parties.

[BOAC]

I agree, Ian W - it is concerning. Perhaps "787" and "fire" have a ?temporary? extra weighting in the contingency plan:hmm: (http://www.pprune.org/jet-blast/518987-lhr-r-t.html.) As far as I can see, reducing to single runway landings only, and letting the Airfix kit burn out if need be (since it was empty and on a remote stand) would have been a more acceptable solution.

A salutary lesson to those enthused by the "2 runways, nice day, no div" mantra beloved by EASA and accountants to do what NoD does and I did and have 'something up your sleeve'?

[Una Due Tfc]

I thought the fire crews were also responding to an incident on a PIA 777 on stand too, and so had inadequate cover due to 2 simultaneous situations to keep the runways open?

[Ian W]

I thought the fire crews were also responding to an incident on a PIA 777 on stand too, and so had inadequate cover due to 2 simultaneous situations to keep the runways open?

I agree that it is inadequate cover. Or possibly over-reaction to the incidents rather than keep something back for operations to continue.

[Una Due Tfc]

So you think they should be able to respond to to 3 worst case scenarios simultaneously? Because all fires are treated equally. I'm sure we all know how quickly a fire on board an aircraft full of fuel can escalate, especially when you add in hazardous materials like Lithium and Carbon Fibre

I think you MAY have a point. I assume each fire station in LHR is responsible for 1 runway and the gates/terminals/hangars are assigned to whichever station is closest?

When was the last time LHR had 2 fires at the same time? I also wonder how long it takes to turn around the airport fire vehicles after they have discharged their foam and get them ready to roll again

[tilnextime]

Una Due tfc

When was the last time LHR had 2 fires at the same time? I also wonder how long it takes to turn around the airport fire vehicles after they have discharged their foam and get them ready to roll again

The bold, italic is one of the very concerns a Pre-Accident Plan takes into account. An empty foam unit is of very little value to fire fighting efforts.;)

If every vehicle is committed (or enough of them that the remaining would be insufficient to handle another response), you close operations until you can restore the appropriate level of operational equipment available for immediate response.

[BOAC]

I suspect the 787 is causing a re-write of contingency plans around the globe.

[Una Due Tfc]

Thanks for that

I think all aircraft fires should be treated equal ie as if she is burning nose to tail. If the Ethiopian had been left to burn an awful lot of nasty/cancerous material would have been released in a residential area. Not nice. Also we may never have been able to find out what caused it in the first place.

The fire crews were correct to close the airport IMO with the resources they had. There may be an argument now to give them more resources so as to keep at least 1 runway open during 2 fire incidents

[Nemrytter]

Just out of interest: What was the PIA incident that was ongoing at the same time?

[BOAC]

There may be an argument now to give them more resources so as to keep at least 1 runway open during 2 fire incidents - anyone able to post the assets at LHR? Was extinguishant discharged at the PIA incident?

[JW411]

So what happens to those aircraft who have creatively "committed to Heathrow" due to a shortage of fuel (on the basis that Heathrow has two runways and the weather is reasonable) when both runways suddenly shut?

Do they land at Heathrow without fire cover or do they now demand priority over everyone else who is diverting at the same time?

I would not like to be in that situation.

You could end up in deep sh*t just because a coffee cup or an ELT has caught fire in a Boeing 787 on a remote stand at Heathrow.

[funfly]

I had a lovely glass fibre aircraft once...



http://www.funfly.co.uk/images/KISS.jpg

FF

[JW411]

Well, the rudder looks OK!

[tilnextime]

So what happens to those aircraft who have creatively "committed to Heathrow" due to a shortage of fuel (on the basis that Heathrow has two runways and the weather is reasonable) when both runways suddenly shut?

Do they land at Heathrow without fire cover or do they now demand priority over everyone else who is diverting at the same time?

That's what the Pre-Accident Plan sets into motion - ATC knows the given airport is closed to traffic and executes the established plan to divert flights to nearby (and there are several in the London area) airports. It's the controllers' job to sort out fuel issues. If a pilot failed to adequately plan his fuel, or if winds were greater than forecast, ATC will assist as necessary. In fact, ATC will begin diverting aircraft long before they are "committed" to make room for those that are already committed.

Again, there are sentient life forms in abundance beyond the wing tips, no less the cockpit.

[BOAC]

JW - I guess the "intelligent life forms out there beyond the wing tips." would have allowed the 2/3 short final traffic to land and thrown the rest off on Maydays.

[JW411]

My guess also.

I am eternally grateful that I always worked for an employer who always allowed me to carry a sensible amount of fuel.

[Lonewolf_50]

I am eternally grateful that I always worked for an employer who always allowed me to carry a sensible amount of fuel.
As bean counters (try to) micromanage that more in the future (and why should anyone believe otherwise, given trends to date?) one can see the misgivings in your post manifest themselves into some difficult realities for more than a few flight deck crews. :suspect:

One's best self defense is to stay well ahead of the aircraft and the flight/mission so that when these things crop up, there is an out.

Best wishes to all on that score. The "interesting times" are arriving sooner and sooner. :cool:

[Look_Up]

Just out of interest: What was the PIA incident that was ongoing at the same time?
I was a passenger on an Iberia/Vueling flight that had pushed back at around 1630. Before taxying, at about 1640 the captain shut down the engines and announced we were delayed by an aircraft that had just landed and had one (or was it two) burst tyres ahead of us. I presume this was the PIA incident. We were delayed by about 80 minutes in total when the 787 incident came on top of that and we saw the aircraft in question on taxi for takeoff.

[speedtapeking]

Sure this thread is titled "Ethiopian 787 fire" can we keep it to that? I really don't care what people think over whether the place should of been kept open or closed, I just want to find out about the fire on said aircraft not the ins and outs of what the airport did !

[RodH]

It seems to be taking a very long time to find out the root cause of this fire.
Six days seems to be unusually long and If past history of aircraft fires is anything to judge by it seems to normally only take a few days to find out the cause.
Given the past history of the B787 one would think an answer would be forthcoming ASAP.

[RCav8or]

The latest news says that the AAIB will issue a preliminary report in the next couple of days. Until then Boeing can say very little, except that the the LiOn batteries are in no way involved, which was pretty obvious from the beginning.
An interesting side note was Honeywell's willingness to remove the ELT's, if they are asked to. Can a commercial aircraft legally operate without an ELT?

[LASJayhawk]

"Story" on possible removing of the ELT's

Honeywell says would remove 787 beacons if asked as fire probed (http://news.yahoo.com/honeywell-says-remove-787s-beacons-193923219.html)

[archae86]

A newish Wall Street Journal online story which leads with the assertion that an AAIB interim report is expected soon goes into some ELT detail--including a strong suggestion that someone thinks a possible ELT role in the cause likely enough to consider a possible recommendation for temporary removal of them from 787s.

Regarding the legalities of ELT-free operation, the WSJ article asserts that while they are required on planes to be used for passenger flights in the US, it is allowed to continue operation with them inoperative for as long a 90(!) days before replacement or repair, and further asserts that no case of ELT actually being useful in a large airliner incident has been recorded in the last couple of decades. It asserts that European rules are similar to the US rules.

Lastly, and not in the WSJ article, I learned that this ELT battery is far larger than I might have thought. I've lost the reference, but believe that for this Honeywell model the battery weight was given as a bit over six pounds. If true, that is plenty of energy to serve as a major ignition source if something goes seriously wrong.

[edit: another poster has cast very serious doubt on this battery weight claim. I know I saw it written, but it surprised me. Most likely it was false--possibly by misconstruing the entire ELT weight as being the battery weight]

[LASJayhawk]

The ELT + Battery is 6.6 Lbs.

A wag would be about 2 Lbs for the battery itself.

ETA: on an Artex C-406 the battery pack is about 1 Lb, and the whole thing, ELT + Tray + Battery is 4 Lbs 11 oz.

[ironbutt57]

Many aircraft have portable ELT's vs "installed" ones...

[Buster the Bear]

Having just experienced the Dream Maker and the Thomson Premier Club product to Orlando, all I can say as a passenger is WOW!

My vacuum is noisier than a full load departure compared from the forward cabin and the pressurisation meant that after a nine hour flight we arrived amazingly refreshed!

For me, this aeroplane is frankly brilliant. No smoke, no fires and no drama! Loved the HUD for the crew!

Thomson have it 100% commercially aligned with the market. Premium it certainly is!

[LeadSled]

ELTs, whether fixed or portable (and most “fixed” ELT can, if accessible, be un-clipped and used as a portable) which conform to TSO C-126, can and most do have an inbuilt GPS chip.
It will be a very interesting situation if the fire was cause by a fixed ELT.
Extensive Australian research has shown that fixed ELT are an expensive waste of money, as the failure rate in service (failure to broadcast a signal after an accident, or broadcasting a signal when they shouldn’t) is worse than 90%, and 100% in water.
If this fire is caused by the the ELT, the answer is to get rid of them, and rely on the portables contained in or adjacent to the slide-rafts, the type shown in the illustration.
The “mandatory” fitting of fixed ELTs resulted from political pressure in the US, after a well known politician was killed in Alaska. No cost/benefit analysis was ever carried out.
ICAO picked up the FAA rule, again without detailed consideration.
The Australian research could find no case where a fixed ELT in an airline aircraft had worked after an accident, including accidents where the tail of the aircraft was substantially intact.


Folks,
The above is a reader comment from the Australian blog, "Plane Talking", run by Ben Sandilands, a well known and highly respected transport journalist.
Australian aviation regulations are generally consistent with these finding.
After the Australian rules (dropping mandatory fixed ELT) were put in place in about 1997, a five year post implementation review was carried out by CASA Australia, and the ongoing failure rates of fixed ELT was confirmed, as was the very low failure rates of portables in survivable accidents.
All in all, fixed ELT have proved to be a very expensive waste of money --- and all brought about by a knee-jerk political reaction to a single GA accident in Alaska.

PS: As to what FAA require in US airspace, I would suggest some who have made definitive statements might re-consider.
For any foreign carrier on a FAR 129 Certificate/Operations Specification, it is all in the detail, and unless there has been a major change in recent times, quite a number of foreign carriers, who normally only carry a number of portables, usually attached to the slide-rafts, have not had to fit useless fixed ELT to operate in US airspace.

[olasek]

It seems to be taking a very long time to find out the root cause of this fire. Six days seems to be unusually long and
Fire/incendiary investigations often can be the toughest to crack specially if one looks for a 'root cause'. Six days is absolutely nothing. I would argue that a 'root cause' of TWA800 fire/explosion was never found - only the best theory was adopted after years of futile attempts trying to reproduce events. Did they ever find root cause of the 787 batteries fires/failures - NO. I wouldn't be surprised if the preliminary report in this case will offer temporary recommendations and investigation will continue.

[Pittsextra]

At what point does co-incidence in tandem with the lack of understanding with the prior electrical issues fail to provide comfort for the FAA/CAA/EASA?

[mbriscoe]

So you think they should be able to respond to to 3 worst case scenarios simultaneously? Because all fires are treated equally. I'm sure we all know how quickly a fire on board an aircraft full of fuel can escalate, especially when you add in hazardous materials like Lithium and Carbon Fibre

I think you MAY have a point. I assume each fire station in LHR is responsible for 1 runway and the gates/terminals/hangars are assigned to whichever station is closest?

When was the last time LHR had 2 fires at the same time? I also wonder how long it takes to turn around the airport fire vehicles after they have discharged their foam and get them ready to roll again

If the fire cover was increased to be able to handle three, four ... incidents then apart from the huge increase in costs then I can imagine the comments in the media if there was a serious incident involving loss of life and there was a whole fleet of fire appliances sitting in the fire station. They would probably ask why the airport had not been closed to make them available.

Rather than each fire station being responsible for a different runway, I wonder if there are two separate ones to protect against a worse case scenario where an aircraft hit the fire station and disabled the whole fleet?

They might not often have two serious fires simultaneously but they have to allow for training where one fleet of the fire appliances might be involved in training with a dummy fire so could have emptied their tanks of at least the water.

[Hockham Admiral]

HMFC, JW? ;)

[Saint-Ex]

Slightly off the subject but, according to the Daily Mail, I see the 787 holds up to 800 passengers!

[Volume]

Fire/incendiary investigations often can be the toughest to crack specially if one looks for a 'root cause'. Six days is absolutely nothing. I fully agree if the aircraft lies scattered in million pieces on the ocean floor. But if it sits in one piece on the ramp with localized fire damage and fully accessible, I would expect a more informative press release by now.

[JW411]

Hockham Admiral:

HMFC; yes (and all of the seven airlines that I susequently flew for).

[lomapaseo]

But if it sits in one piece on the ramp with localized fire damage and fully accessible, I would expect a more informative press release by now.

Localized damage :confused:

Then why do we have so many posters suggesting that it's unrepairable ?

I wonder where the coffee pot problem came from then?

certainly by now if it were localized PPrune posters would have already solved it.

[Pittsextra]

Boeing 787 Probe Spurs Honeywell Beacon Shutdown, Lithium Checks
By Robert Wall


July 18 (Bloomberg) -- U.K. authorities probing last week’s fire on a Boeing Co. 787 at Heathrow airport said a Honeywell International Inc. beacon installed close to the site of the blaze should be deactivated on all other Dreamliners.
Britain’s Air Accidents Investigation Branch said in a special bulletin that the U.S. Federal Aviation Administration should also lead a safety review into lithium battery-powered transmitters on other aircraft models.
Shutting off the Emergency Locator Transmitter system on the Boeing jet is a precautionary measure “until appropriate airworthiness actions can be completed,” the AAIB said.
The July 12 incident on a Ethiopian Airlines Enterprise Dreamliner was the most-serious setback for Boeing’s marquee jet since regulators ordered the global 787 fleet idled for three months following fires linked to lithium-ion batteries. The AAIB hasn’t called for a grounding following the Heathrow event.
“Had this event occurred in flight it could pose a significant concern and raise challenges for the cabin crew in tackling the resulting fire,” the AAIB said today. “The ELT has shown some indications of disruption to the battery cell.”
Overheating of emergency transmitters “is extremely rare” and last week’s incident was the first affecting the Honeywell system, the safety body said.
Smoke Spotted
The AAIB probe, which included Boeing, the airline, and U.S. safety representatives, was broadened to include Honeywell after the beacon made by the Morris Township, New Jersey-based company was isolated as a potential cause of the fire.
The ELTs rely on chemical batteries made of lithium-manganese dioxide to power the beacon even if the plane’s electrical system fails.
Air traffic control personnel spotted smoke coming from the Ethiopian jet, parked and not under power, at 4:34 p.m. local time, with emergency personnel arriving a minute later to extinguish the fire, according to today’s bulletin.
Fire fighters using breathing equipment entered the plane and initially failed to suppress the blaze using Halon devices. They then removed ceiling panels and applied water.
The plane suffered “extensive heat damage” in the rear, including to its composite-plastic fuselage, the AAIB said. The ELT is the only aircraft system in the area, it said. Flight crew had not reported any technical problems with the plane.
Other Dreamliner users from ANA Holdings Inc., the first to operate the jet, to United Airlines, the world’s largest carrier, have maintained 787 services. Ethiopian Airlines has also continued to operate its three other planes.
Boeing had delivered 66 Dreamliners to 11 airlines and a leasing company through June. The Chicago-based planemaker has booked 930 firm orders for the jet, which has a list price of $206.8 million in its cheapest version.

[Pittsextra]

Air Accidents Investigation: S5/2013 - Boeing 787, ET-AOP (http://www.aaib.gov.uk/publications/special_bulletins/s5_2013___boeing_787__et_aop.cfm)

[DarrenWheeler]

AAIB bulletin has now been released.

Air Accidents Investigation: S5/2013 - Boeing 787, ET-AOP (http://www.aaib.gov.uk/publications/special_bulletins/s5_2013___boeing_787__et_aop.cfm)

"A fire event occurred on a parked, unoccupied and electrically un-powered Boeing 787 aircraft at London Heathrow Airport. Subsequent examination of the fire-affected area has focussed on the Emergency Locator Transmitter (ELT). Two Safety Recommendations have been made."

[tubby linton]

The alarming thing for me , and it is stated on the final page of the AAIB's reort is that if the ELT battery is at fault there remains the possibility that this failure could have occurred in flight in a fuselage zone with restricted access and no local fire surpression or detection.

[MurphyWasRight]

Interesting bit from the report (often what is chosen to include in a preliminary report can be revealing):

The ground handling agent accordingly turned
off ground power at the stand’s control box but left the
power umbilical cables attached. The engineer visually
confirmed on the flight deck that ground power was no
longer available.


Given prior "sneak paths" in the electrical system one wonders if having the cable connected but unpowered resulted in an unforseen circuit.

I have no idea exactly what turning off the power at the stand does, all conductors disconnected, all grounded or some other configuration.

Does sound liket the ELT is involved though, of course there is still the chicken and egg question. (Which came first)

Think about that long enough and you end up with a chicken ommellete...

[Ian W]

In view of LeadSled's earlier post about Australian findings on ELTs, the permanent removal of fixed ELTs would appear to be the most appropriate action.

[DarrenWheeler]

The report also says there over 6000 of this version of ELT's out there fitted to a variety of aircraft, with this being the only significant thermal event.

Is this just a case of bad luck of a faulty unit being fitted to a 787?

[EEngr]

What is the service history of the Honeywell unit? Any other experience with these things bursting into flames?

On a related note: What sort of connections does the ELT have with the aircraft power system? There is a flight deck test switch plus activation annunciation. Is this powered from the aircraft DC system? Any chance that it was connected to a 32 Vdc buss (most other applications are likely to be 28 Vdc).

[Self Loading Freight]

Another case where -- assuming that the initial findings are correct - it's not clear whether the underlying fault was in the battery or the circuitry to which it was connected. Is anyone familiar enough with the ELT circuit to know whether the battery is fused?

High energy battery circuits are supposed to have some form of thermal or electrical cut-out that trips before enough energy has been delivered to start a fire. So, once again, there are two failures to explain: whatever it was that caused the bake-off, and whatever it was that was supposed to stop that happening but didn't.

Interesting that the recommendation to remove the ELT was restricted to 787 carriers. If this is a common part across types, is this an indication that the 787 is uniquely vulnerable?

[Pittsextra]

What is the service history of the Honeywell unit? Any other experience with these things bursting into flames?



The AAIB report says there are 6000 units in a variety of aircraft and to date this is the only thermal event.

[fenland787]

From the BBC "The AAIB said the problem might not be confined to the 787 and recommended that regulators conduct a safety review of similar components in other aircraft."

Does anyone know if there a reason they would have to say that (rather that "turn them all off now") for types other than the one they are investigating? I can't think of one unless they suspect some 'unfortunate' interaction between an ELT battery issue and the 787 systems that wouldn't affect other aircraft types?

[MurphyWasRight]

Does anyone know if there a reason they would have to say that (rather that "turn them all off now") for types other than the one they are investigating? I can't think of one unless they suspect some 'unfortunate' interaction between an ELT battery issue and the 787 systems that wouldn't affect other aircraft types?


For 787 case it is already clear that "bad things" can happen if the ELT gets hot.

For others types it is an open question if the same scale event would have breached the hull. Still not something that one would want in flight though.

Also on protection of battery by fuse, from the spec sheet the unit is rated at 5W at 406Mhz, plus lesser at the lower frequencies.
This translates to expected power in use in the 8 to 12 watt range, plenty to get a wire hot enough to cause trouble.
Could be higher, 8 watts would actually be very impressive effeciency figure.

[LASJayhawk]

Only way to make the ELT inert is to pull the battery pack out.

Artex uses ship power for the light in the cockpit, not sure about Honeywell.

There should be no direct, or even indirect, path between the ship power and the ELT battery pack.

Looking at an Artex pack, I can see a potential failure mode that would short a cell out. I have no reason to think Honeywell's execution of a battery pack would be much different.

If I'm thinking what the AAIB is thinking, were all gonna be pulling ELT's out of everything.

ETA: Self Loading Freight. on the Artex battery pack, it goes straight two 2 fuses in the pack itself.

[Lonewolf_50]

Maybe the Aussies have it right (http://www.pprune.org/rumours-news/518971-ethiopean-787-fire-heathrow-22.html#post7946924), and the requirements were not well substantiated in the first place, particularly for long haul airliners who tend to fly under radar control or under well established flight routes.

The GA event presented as the trigger hardly fits the "we know where it is or will be" model of an airline flight. I can see how an ELT is a good idea when you fly in out of the way areas, or typically in uncontrolled airspace.

I'd be interested to hear what people in the SAR community, civil and military, think about ELT's as an aid to their making first contact with a downed aircraft.

[Speed of Sound]

Power-wise, this unit is completely self-contained, self-testing and with a ten year battery life.

The only electrical integration with the aircraft's systems would seem to be this connection to a flight deck 'test switch'.

Are all Honeywell ELTs connected to the flight deck or just those fitted to the 787?

I am struggling to see how a low voltage/data connection can cause a fire, even when incorrectly connected. And the unit itself in a quiescent state is unlikely to draw more than a few milliamps from the onboard battery, not unlike an electric clock battery which can tick for several years on a single AA 1.5 volt cell.

I can only imagine that if the beacon is the cause of the fire, it somehow suffered some mechanical damage either inflight or during manufacture and installation.

[LASJayhawk]

The requirement for a remote switch in the cockpit on all new installations has been around in the US for 10+ years. All aircraft all installations.

[MLHeliwrench]

It is self contained and there to help SAR teams get to you in the event of a crash. Of course you are right in that most all commercial operators have satellite tracking regardless of control zone type. What if aircraft power is lost suddenly or standard communication equipment fails? Or what about a sudden event where the crew could not get out a distress call?

Modern 406 ELTs transmit exact position for an extended period of time. Very useful if one ever had to ditch and was floating around in the sea. Also useful regardless because the ELT will outlast any other electrical communications after an event.

Bottom line: one faulty ELT is hardly cause to discuss getting rid of them all together on scheduled airliners.

[Lonewolf_50]

I wonder if Boeing EE's are tracing the route of electrons from the ground power receptacle throughout the aircraft to see how current could leak into the ELT circuit. Let us suppose that they find something that allows a stray voltage to wander here or there. Hmmm.

Other than putting all ELT's in the bin, as some Aussies seem to suggest, maybe one could return the ELT to the condition of entirely isolated from all of the aircraft elecrical systems. This would lead to a pre flight test where a CC or maintenance crew accesses the ELT test switch, and either confirms the light or the flight deck crew are listening up on the ELT's freq and confirm via intercom good test or bad.

Yes, it's a crew coordination drill, but you don't need an ELT unless you are intending to fly in the first place. You always fly as a crew. It may also be in the too hard category, in terms of getting access to a test switch from inside the cabin.

Just thinking aloud here ...

[Speed of Sound]

Suggesting that these things are switched off rather than removed, suggests that there may be a problem with their operation rather than their manufacture or installation.

Can they know that by now? :confused:

[MurphyWasRight]

SOS:
I can only imagine that if the beacon is the cause of the fire, it somehow suffered some mechanical damage either inflight or during manufacture and installation.


This could point to environment as well, is the 787 ELT subject to deeper temperature cycles due to it's location compared to other aircraft?

The larger the temperature swing the more mechanical stress there is.

Wonder how hot the unit gets when parked in the sun in Africa?

[HeavyMetallist]

Suggesting that these things are switched off rather than removed, suggests that there may be a problem with their operation rather than their manufacture or installation.
The Bulletin doesn't recommend just turning the unit off, it recommends making it inert. Big difference.

[DWS]

http://www.aaib.gov.uk/cms_resources.cfm?file=/S5-2013%20ET-AOP.pdf

[Speed of Sound]

My reading of the AAIB safety recommendations is that it is only the fixed ELT that is required to be switched off and NOT the portable devices or those attached to life rafts.

Could that be because they are different units or because they are not located in close proximity to a composite structure and are difficult to access in flight?

I take some poster's points about a crew in flight having a time advantage over the ground firefighting crews when tackling the fire. But reading about the firefighting efforts in the report, I doubt it would be easy for crew members to do this in flight given that the firefighters had to hack away at ceiling panels to tackle the fire with water after failing to control it with halon extinguishers.

This could have been extremely nasty! :(

[fenland787]

I wonder if Boeing EE's are tracing the route of electrons from the ground power receptacle throughout the aircraft to see how current could leak into the ELT circuit. Let us suppose that they find something that allows a stray voltage to wander here or there. Hmmm.
I bet they are! I'm not familiar with this kit but, given I understand it is not powered from any aircraft bus, I would have expected any external control wires to be galvanically isolated from the ELT electronics via an opto or something, so there should be no possibility of any sneak back-feeds, but you never know, I have had someone tell me in the past "I don't need to isolation from the system, it's battery powered". Only true if the number of wires connected is equal to or less than one I think!

I presume it has an external antenna? I hope nobody did a bad thing with antenna grounding.

[BOAC]

Don't forget in all this that 'in flight' would probably result in depressurisation of the aircraft making life a lot harder!

[Speed of Sound]

The Bulletin doesn't recommend just turning the unit off, it recommends making it inert. Big difference.

To make it truly inert would require it to be disconnected from any other aircraft systems and the battery to be removed. As access is the problem with this device, wouldn't it be easier to remove it altogether once it was 'exposed'?

[pax2908]

Pitts #452, the version of the report I have downloaded interestingly states "the only _significant_ thermal event".

[LASJayhawk]

Murphy, on smaller aircraft (think King Air, small jet) they are usually aft of the pressure bulkhead in the tail. On larger aircraft (think G-IV and up) they are usually inside the pressure vessel, to prevent cold soak problems on long flights.

[EGLD]

Having just experienced the Dream Maker and the Thomson Premier Club product to Orlando, all I can say as a passenger is WOW!

My vacuum is noisier than a full load departure compared from the forward cabin and the pressurisation meant that after a nine hour flight we arrived amazingly refreshed!

For me, this aeroplane is frankly brilliant. No smoke, no fires and no drama! Loved the HUD for the crew!

Thomson have it 100% commercially aligned with the market. Premium it certainly is!

Living very close to the threshold of EGLL as I do, I can vouch for the volume from the outside as well.

The 787 and the A380 are remarkably quieter than the aircraft they are replacing.

[ECAM_Actions]

Ban Lithium-anything batteries from ANY airborne system!!!!

AAIB recommends review of all lithium-powered ELTs after 787 fire | Reuters (http://www.reuters.com/article/2013/07/18/boeing-dreamliner-idUSL6N0FO3EP20130718)

[Speed of Sound]

Ban Lithium-anything batteries from ANY airborne system!!!!

Lithium-Manganese Dioxide (LiMnO2) batteries are actually at the lower energy/greater safety end of the Li-Ion scale. If these are now catching fire without an external ignition source, it's not good. :eek:

[phil gollin]

The guilt or innocence of the ELT will become clear in due course.

Of more concern are the problems that the firefighter(s) had in getting to the fire and extinguishing it.

Also, the lack of detail of the damage is interesting (I still await the videos of the fire and the close-up photos).

[glad rag]

When we installed the ELT on the '380 the most "difficult" part was wrapping the antenna feeds with fireproof material to ensure that the installation as a "whole " met regulation re-fire/heat resistance.

It seems a somewhat moot point that there is no airframe insulation in that self same area of the 787 by design....:\

[fenland787]

If these are now catching fire without an external ignition source, it's not goodTrue, but we don't know that to be the case yet, as Lonewolf_50 pointed out, folks will be looking for possible sneak circuits that could have caused the problem. If I have correctly identified the ELT on Honeywell's site there are a number of remote connections available so, although it should be unlikely, perhaps there is a back-feed from the airplane system that caused the issue? It is very bad luck for Boeing that with over 3000 of these ELTs out there, the very first one to combust was one of the 50 or so in a 787!

Edit to add link:

http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/BA_brochures-documents/RESCU_406_AFN_ELT.pdf

[tilnextime]

Also, the lack of detail of the damage is interesting

Don't know how the AAIB does investigations, but if the damage did not shed light on causative factors, a detailed evaluation of the damage was not always a required part of the investigation when I was doing them for the US Army. The technical investigation is for prevention purposes - identify causes that can be avoided.

[olasek]

fully agree if the aircraft lies scattered in million pieces on the ocean floor. But if it sits in one piece on the ramp with localized fire damage and fully accessible, I would expect a more informative press release by now.
Yeah, therefore we may get something concrete in months rather than years...

[Speed of Sound]

In layman's terms, is this another battery problem with the B787? Duh....

Only if it was actually the battery, and the incident was directly related to its location, installation, use, integration with other systems, and maintenance.

If not, as someone has already pointed out, it is just sheer bad luck!

This was a serious incident but in fairness to Boeing, if it had occurred on any other model it would have drawn nowhere near the amount of comment and speculation that it has. :*

[daikilo]

In my mind there are 3 key elements in the AAIB report:
1) There are no other aircraft systems in this vicinity which, with the aircraft unpowered, contain stored energy capable of initiating a fire in the area of heat damage
2) It is not clear however whether the combustion in the area of the ELT was initiated by the relase of energy in the batteries or by an external machanism such as an electrical short
3) In the case of a short, the same batteries could provide the energy for an ingnition and suffer damage in a subsequent fire

My interpretation of these words is that the ELT is a suspect but is far from being confirmed as the guilty party. In simple terms, the guy was there, he had a gun, but we can't find any bullets.

[Zeflo27]

Scuffers & Speedo


UK Board: Remove Honeywell Beacons After 787 Fire - ABC News (http://abcnews.go.com/Business/uk-board-remove-honeywell-beacons-787-fire/story?id=19699480)

[Herod]

In all this, how about a vote of thanks to the ATC controller who first spotted it. Well done!!:ok:

[1a sound asleep]

1. ELT source of fire BUT no determination why it ignited
2. No reaction from Boeing apart from an acknowledgment
3. No FAA response

[RetiredF4]

How about moisture being the cause for a short?
In between lines it was a possible cause for the ANA event. The fix with the firebox talks about improved insulation also against humidity.
Does the no metal hull behave differently concerning condensation and causes humidity at places not expected?

[ATC Watcher]

If I read the text correctly, this model of ELT has to be removed from 787s immediately ?
Since ELTs are mandatory for any large aircraft, does Boeing has a substitute certified model avail immediately to retrofit all current 787s flying ? just a question.

[daikilo]

Incorrect, as I understand, it may have to be deactivated on all aircraft on which it is fitted in an equivalent location.

[Jetstream67]

There have been several previous examples of primary (non rechargeable) lithium batteries catching fire without any obvious provocation on aircraft and elsewhere ( a couple in torches IIRC).

I am not convinced by the statements on grounding and 'short circuits' etc. It is perfectly easy to provide both Thermal and Overcurrent protection to protect the Cells and therefore the system from excessive current being drawn and I am quite sure any decent designer would have done just this. Unfortunately neither protection helps if the cell structure breaks down internally and generates its own fire hazard, at that point containment or ejection are the best bets.

[olasek]

ELT source of fire
This is not certain.
I would stick with points presented by daikilo in post #480. Going beyond that is over-interpretation.

[MurphyWasRight]

RetiredF4 How about moisture being the cause for a short?
In between lines it was a possible cause for the ANA event. The fix with the firebox talks about improved insulation also against humidity.
Does the no metal hull behave differently concerning condensation and causes humidity at places not expected?


To expand that a bit since there now appears to be battery related incidents with 2 very different batteries, one of which (ELT) has a significant problem free service history the question can be what is different about the 787 compared to prior design.

A couple of obviouse ones with comments.

Significantly higher "electrical content"
Certainly a factor in the main battery issues but hard to see why this would affect the ELT.

Composite construction:
Possible thermal environment changes, hotter baking in the sun etc.

Non conductive, requires explicit ground (return) paths, improperly sized/damaged these could induce unexpected voltages.
Possibly worse ESD environment.

Different cosmic ray shielding properties?
Particles that would have been blocked by metal may pass through. (Bit of a reach, pure conjecture on this one...)

Outsourcing:
Again possibly a factor in main batteries but the ELT is (so far) problem free on other types.

[Jetstream67]

Humidity (pure water) is not a great conductor of electricity and all the short circuit discussions assume they designed an ELT battery system without a Thermal or Overcurrent fuse . .

[MurphyWasRight]

Jetstream67:

Humidity (pure water) is not a great conductor of electricity and all the short circuit discussions assume they designed an ELT battery system without a Thermal or Overcurrent fuse . .

True but mix in a small amount a lot of things and it does conduct well enough to kill you.

An overcurrent fuse by itself would not prevent the battery from heating a low resistance (not dead short) path.
For operation it has to provide 10W or so, plenty to get a small area very hot.

[fenland787]

An overcurrent fuse by itself would not prevent the battery from heating a low resistance (not dead short) pathTrue, also it provides no protection if something was trying to 'charge' a non-rechargable cell but I really can't believe Honeywell won't have thought of that and ensured that even if volts were applied where they shouldn't be, no reverse current can reach the battery. If it is the first ever 'spontaneous combustion' of this ELT Boeing must be thinking someone hates them or the planets are very badly aligned right now, some reports say over 6000 of this type are out there!

[Speed of Sound]

The more I think of it, the more convinced I am that this request is to do with the ELT's location and proximity to the composite as much as anything else. After all, these things are flying all over the world, every day without trouble.

As I said before, if this had gone up in smoke while airborne, even if it had been spotted straight away I'm not sure how much the cabin crew could do to mitigate the situation before they faced serious problems with both toxic fumes and structural integrity.

What instructions have CC been given with regard to fighting fires that may involve composites?

The LHR fire service were wearing fireproof suits, safety headgear and breathing apparatus and so were able to remain in the area while they pulled down the ceiling to get access to the fire. In flight, there would be a limited amount of firefighting time available before those in the rear of the aircraft would have to be evacuated forward while the flight crew tried to get it on the ground as soon as possible.

[topgas]

Pardon me if this is a silly question, but what activates the ELT? Is it triggered by a loss of ship power, in which case could it be activated if the main battery voltage dropped?

[Speed of Sound]

but what activates the ELT?

A 'G' switch.

[Chu Chu]

I guess the irony is so obvious it's gone unsaid, but it looks like the ELT here "located" the emergency all right.

[Speed of Sound]

Only true if the number of wires connected is equal to or less than one I think!

Looks like there are four wires connecting the ELT to the outside world.

• Four 22AWG wires to transmitter unit
provide full functionality

[HighWind]

Something could indicate that some aircraft batteries are experiencing more frequent thermal events than consumer batteries. Why!, Size difference?

As others have already mentioned, protection of a battery cell against over current and over-voltage does not help if there is an internal fault in the cell.

As I see it, small cells have a significant lower probability of experiencing a thermal event, since they are more likely discharged before a fault in the foil (hotspot) reaches the autoignition temperature. And since they are small they can better conduct the heat from the hot-spot to the case of the cell.

A larger cell have:
1) More foil area, higher risk of faults in the foil → Higher probability of fire.
2) More foil area, more electrical energy to disparate in a fault. → Higher probability of fire.
3) Larger thermal resistance from fault location, to case. → Higher probability of fire.

[md80fanatic]

In the transmission business, a good ground plane is essential in getting a solid signal off the antenna, while using the least amount of power. In a traditional metal fuselage, that ground plane would obviously be the fuselage itself. In this bird however, a large piece of conductor for the antenna to work against may be more difficult to come by, especially at the ELT's required frequencies of operation (121.5 and 406 MHz).

If the ELT was activated some how, there is a possibility that a highly inefficient transmission scenario was occurring. This usually results in higher transmitter temperatures and/or higher battery drain.

[LASJayhawk]

I don't have a Honeywell ELT battery, but here is a picture of the lithium pack for an Artex C-406

http://i1365.photobucket.com/albums/r745/LASJayhawk/406eltbattery_zpsc3dfebb9.jpg (http://s1365.photobucket.com/user/LASJayhawk/media/406eltbattery_zpsc3dfebb9.jpg.html)

The 4 green cells are each about the size of a D battery. The small circuit board has 2 fuses and a small ic for monitoring the condition of the battery.

You can see 4 small black parts, 1 across each cell. They are diodes so if a cell goes flat it won't see reverse polarity.

But if one of those diodes short, you will have a dead short across that cell.

I am trying to work up the nerve to short a diode out and see what happens, but I'm a little chicken at this point. :} And the boss said if I burn down the hanger I'll be in trouble. :eek:

[DWS]

From a few friends involved in 787, and a few not well publicized comments/documents about the 787. One selling feature was to be able to have higher humidity in the 787 than on a regular aluminum bodied airliner due to less or virtually zero corrosion issues resulting from passenger breath and temperature deltas in flight, along with a lower cabin altitude.

But during early flight tests, some wags considered renaming it the rainliner, due gto unexpected amounts of condensation in the cabin. Which admittedly was not in a well finished cabin configuration, but filled with instrumentation racks, exposed insturmentation wiring, etc.

Business & Technology | Dreamliner's woes pile up | Seattle Times Newspaper (http://seattletimes.com/html/businesstechnology/2013713745_dreamliner19.html)

. . .
The latest delay will at least give engineers more time to test design fixes, including some for less consequential troubles, not uncommon on new jets, such as the maddening drip, drip, drip of "rain in the plane." On 787 flight tests, drip trays padded with squares of absorbent cloth are positioned to collect the condensation.
Fancher said "a good design fix" to dehumidify the interior is being installed and will be tested when the Dreamliners resume flying.
Employees working on the 787 complain about insufficient oversight of suppliers and a management system that the senior engineer called "totally broken."
"This program is not like anything we've seen," said the veteran 787 employee. "It's a screwed-up mess." . . .




Now add to that the wonderous decision to use predominately aluminum wiring to save weight instead of copper or copper/silver alloy or similar.

http://www.safran-group.com/IMG/pdf/EN_mag2_29-31-2.pdf

Now for flight data and computer data lines with low voltage and low current, aluminum ** might ** be an acceptable choice.

But years ago, the push for house wiring of aluminum met eventually with corrosion or similar problems due to buildup of non conductive films on aluminum, resulting in hot spots and IF I RECALL a few fires.

Check your local replacement power plug or switch in the us and the warning re cu aluminum and the availability of a cu-al grease/coating to preven oxidation.

Surely BA would have considered that ???????????

[MurphyWasRight]

With 6000 similar ELT units in service it would be hard to believe that this was the first one to sufffer a battery problem.

It would be interesting to know how many batteries have been replaced, per qouted 10 year life any replacement would be a failure not end of life.

The really ineresting question would be the condition of the replaced cells,
what if failure is "rare but happens" but on metal aircraft "thermal event" energy is insufficient due to heat sinking etc to light a fire or even be noticed?

[olandese_volante]

md80fanatic
If the ELT was activated some how, there is a possibility that a highly inefficient transmission scenario was occurring. This usually results in higher transmitter temperatures and/or higher battery drain.
Large ground planes are a requirement with transmitters operating on much lower frequencies. That's why cellphones don't use the 27MHz band ;)

The 121.5MHz transmitter in the ELT works at very low power, a mere 150mW. I wouldn't worry too much about power drain, even with a not-so-efficient antenna configuration, unless I'd want to power the thing from a 9V transistor battery.
The 406MHz transmitter has a rated output of 5W, but at such a high frequency you really do not need a large ground plane - a piece of alu foil a foot square would be quite OK. Also, the 406MHz signal is made up of short bursts, with a low duty cycle: overall power drain is fairly modest.

LASJayhawk
But if one of those diodes short, you will have a dead short across that cell.
A silicon diode like the one in the picture shorting out spontaneously is a very unlikely event. More so when, as in this type of circuit, they are not under any significant stress.
short a diode out and see what happens
Well, if you want to do a little experiment, here's how I'd do it:
Solder a few feet of heavy gauge wire (12AWG) to both cell terminals, connect the other ends to a heavy duty switch (make sure the switch is open!).
Close the switch and get away real quick.
The total circuit resistance will be in the order of 0.03 ohms or so if the connections are nice and solid and you use a good quality, 30A rated switch.

Of course you'd only ever do this out in the open, away from any flammable materials.

[BARKINGMAD]

Is this another Swissair MD11 accident, except it happened on ground, without crew & pax being involved and too far from professional firefighters with proper kit?

I reword the question I posed in the original 787 grounding discussion:

Was there one or more grumpy old f**t with a long flying/line-engineering pedigree on the Boeing design team, and if not, then why not?

Perhaps such an animal would ask questions and quote incident/accident reports which would make the rest of the "Children of Magenta" team squirm uneasily in their seats and possibly think long and hard before venturing down the Li-On and other innovative but risky solutions?!

Other postings here imply that all is not harmonious sunshine and happiness in the Boeing family, so maybe those at the top of the food chain there had better review their choice of whizz-kids who drool at the thought of new and unproven technology and get back to K I S S basics whilst still producing good kit, or Monsieur HiTecq in Toulouse may win the war in the end? :eek:

[Goddamnslacker]

They presume it was the ELT, it hasn't been confirmed, why let this dangerous aircraft fly, again they should all be grounded until the cause of the fire is established. The C of A should be revoked!
I wouldn't fly in one of these death traps! :=

[Una Due Tfc]

Aluminium wiring has been used in cabins for years to save weight. Back when I was an avo I dealt with it regularly in AB cabins. Just wack up the voltage and it works fine. Only area you MUST use copper is around the engines and APU due to temperatures (melting point of copper being higher). I havn't worked in an MRO for years so I'm sure somebody else who has can elaborate.....

[jolihokistix]

While we stretch for ever more remote possibilities, just wondering if they had flown through an electrical storm on their last flight and if so whether lightning dispersal across the 787 skin could have set off a slow reaction within the ELT batteries?

[twochai]

GD Slacker, get a life!!

Transportation of goods or people, by whatever form, involves risk. The trick is to be able to assess probabilities dispassionately.

You clearly cannot!l You probably take bigger risks when you cross the street!

:D:D

[LASJayhawk]

olandese:

Seems like a diode shorting or a major defect in the cell are the only reasons I can think of for an ELT to decide to self immolate.

More curious to me is why we need a 50+ hour transmit time on a 406 ELT. The Satellites should get a very good position fix in under an hour, even if the ELT isn't reporting last known position. It's not like we're using a loop antenna on 121.5 to find the position anymore. Maybe go back to alkaline batteries and accept an under 12 hour transmit time??

[Basset hound]

So, should we pull these same units out of the 777's now?

[Speed of Sound]

If the ELT was activated some how

Isn't the presumption that it didn't activate as the first alert would have been from the monitoring system rather than a vigilant ATC seeing smoke from the aircraft?

The AAIB report would also have mentioned if an alert had been generated by the transmitter.

[quentinc]

So, should we pull these same units out of the 777's now?

I don't think that's what will end up happening. The three paragraphs in the section Emergency Locator Transmitter (ELT), on page 3, read to me as:

The device is not a new design and has a proven history. The AAIB are looking into the possibility that a short, external to this device, caused the problem with this device, on this plane.

By the way... and just putting it out there... but before everyone got focused on the main battery/apu battery catching fire... I think there were reports of these batteries being flat/failed and having to be replaced...

[Mark in CA]

According to the report in today's NY Times:

Federal officials said the lack of definitive evidence about the cause of the fire — and the fact that none of the transmitters had been known to cause a fire in more than 50 million flight hours — suggested they should take more time in reviewing the matter.

Either Boeing has extremely bad luck to have this happen on a 787, or there is something else going on here.

[Speed of Sound]

The Honeywell datasheet claims that this unit is connected by 4 x 22AWG wires. This picture shows at least 33 connections as well as the antenna.


http://i1280.photobucket.com/albums/a481/SoS57/RESCU-406-AFN289867_zps40310599.jpg (http://s1280.photobucket.com/user/SoS57/media/RESCU-406-AFN289867_zps40310599.jpg.html)

Does anyone know what the other 29 or more connections are, and if any of them are likely to be carrying anything other than data/control signals which will most likely be no more than a few milliamps?

[lomapaseo]

The device is not a new design and has a proven history. The AAIB are looking into the possibility that a short, external to this device, caused the problem with this device, on this plane.


Yea, I suspect as much else all these things sitting around on shelves as spares would be popping off right and left.

So what kind of summer sunlight heat load can they take at the top of a composite aircraft ?

[Romulus]

Don't think this link has been posted here before, they seem to be eeping a pretty good track of events.

Airchive Blog re 787 Fire incident (http://airchive.com/blog/2013/07/12/analysis-boeing-787-dreamliner-in-the-hot-seat-again-after-fire-at-heathrow-airport/?utm_source=buffer&utm_campaign=Buffer&utm_content=bufferd01ab&utm_medium=twitter)

[green granite]

Does anyone know what the other 29 or more connections are, and if any of them are likely to be carrying anything other than data/control signals which will most likely be no more than a few milliamps?

Speed of Sound Follow the link in post #477 and it will tell you that it's used for a programming interface.

[ionagh]

Does anyone know what the other 29 or more connections are

There are interfaces to remote alarms, switches, aircraft warning systems and the navigation bus for Lat/Long position data.