It will do alot of damage, hence the use of double knock detection where supression is fitted.

Lessor of the two evils ?

Alot of the kit is low voltage and whilst electronics component may burn, they will burn out and not spread to neigbouring products, alas the static invertor EJ instance out of Liverpool. Still nasty though if you read the report.

Signs of Charing on Material Recovered From "Crash Site"?
 

Have been following this post since news about the unfortunate loss of the Egypt Air flight first broke. Obviously it's far too early to determine what exactly was the cause of the loss of the aircraft. However - and apologies if someone has posted this already - with regard to the theory that an on-board fire may have been a contributory factor, given the smoke-detector messages received via the ACARS transmission...

I just happen to watch the following video on the BBC website of debris recovered from the sea that are purported to originate from flight MS804. If you look at the sky blue material (with what looks like the Egypt Air logo on the reverse side) that is shown from about 4 seconds in, the edge towards the right of the picture seems to show discolouration akin to synthetic cloth being exposed to a head source. At about 7 seconds into the video the shot moves to close up on the material, and centre right of the picture a blackened edge to the material can be clearly seen, which appears to be charring. EgyptAir: Submarine searches for missing flight data recorders - BBC News

Looking at the following interior shot from a Egypt Air 737 - have been unable to find a comparative shot from and A320/1 but someone may be able to help there - one of the seats to the left of shot appears to have a pillow upon it which is covered in a very similar material in terms of colour and logo to that seen in the video. http://www.seatmaestro.com/wp-conten...50_1024_WM.jpg

May be nothing, but given the - limited - information we have to hand at present thought I would just mention it.

Class 3 EFBs that interact with the aircraft are hard wired into the aircraft and are considered installed equipment.
.
Class 1 (iPads) and 2 (laptops) are a either assigned to the pilot or the aircraft depending on the operators policy but none that I'm aware of are considered installed equipment.

Class 2 EFBs can receive data from the aircraft but don't push anything to the aircraft. Class 1 EFBs are simply document viewers.

Class 1, 2, and 3 be powered by the aircraft's electrical supply one way or another.

Signs of Charing on Material Recovered From "Crash Site"?
 

@ Edinburgher - I commented a couple of pages back (before BBC got hold of the video - from the link here?) that there did not appear to be any sign of burning or charring on the debris - but admitted that it was possible that the aircraft broke up before any fire could spread to the part that the debris was from.

Looking again at the video, I can't tell if the dark edges are charring or (I suspect) shadow. Remember that the sun is usually very bright at that sort of latitude and will give very noticeable shadows. I tried to run that section, from 4 to 7 seconds in, several times but could not decide. Coincidence that this effect was visible only on the side farthest from the camera?

There is no "fire suppression equipment" in the avionics bay.


The "smoke detector" is situated in the air extraction duct of the avionics ventilation system. It's purpose is to detected smoke and provide (an) alert(s).
A single chime. A master caution light. An ECAM caution. A "smoke" light on the Emergency Electrical Power panel. And on the Ventilation panel, the "Blower" and "Extract Fault" light up.


Note. The sensor alerts you to the fact there is "smoke in the ventilation extraction duct", not that there is "a fire in the avionics compartment".

@ Edinburgher


To me that just looks like a play of shadow and light, I see no trace of charring.

Andrasz

This aircraft impacted the Sea at high speed and may have broken up in the way down with wreckage scattered over a large area
How do you know that the bits your looking at are from anywhere near the burnt section ?

It is now being reported that the pilot (a pilot) of MS804 was in contact with Cairo (several minutes long) before the crash.


It is reported that he informed Cairo about the "smoke which had engulfed parts of the aircraft" and had "decided to make an emergency descent to try and clear the fumes".


This report is not confirmed by any investigating authority, but is receiving wide spread media coverage.


EgyptAir pilot spoke with air traffic control 'for several minutes before flight MS804 crash' | Africa | News | The Independent

You might be surprised to learn that in the event of a cabin fire the pax are not given O2 it is isolated to prevent the O2 feeding the fire.

Yes, but what does that have to do with this accident?


You do not want to tell me that a fire of LiIon Battery in an IPad would have brought this Airliner down from 37kft in less than 6 minutes?!
Seriously.
A fire in an inaccessible Electronics compartment and close to the FCC's is a whole different beast, though.

Andrasz,

you stated earlier:

It was reported in the NY Times today that the on board security personal on Egypt Air does all of these checks you mentioned, except in European airports.

NY Times:
This adds a bit of intrigue to the security situation in Paris.... :rolleyes:

Common Halon simply starves the fire of O2- little damage- BUT does little to cool hot objects which can reignite. Water cools and is used fo major computer installations on the ground- really with little damage to commercial grade electronics. Damage to avionics fires in an airplane is far down on list of priority issues.

There is technology out there that introduces nitrogen via a generator to the local atmosphere at expense of oxygen. This provides around a 7% shift in the ratio of the two, with N2 increasing to around 86%. That shift is enough to prevent a fire starting. Obviously not for the cabin though.

These figures are based on ground level.

I don't, and never claimed that. All I said is that I do not see any burn marks on the parts displayed on the BBC video.


However I did say, and maintain until proven otherwise, that the wreckage shown suggests that the aircraft came down in one piece at high speed. The reasoning on p26.

yep- basically a molecular sieve ( strips out oxygen from air ) - and used in fuel tanks to prevent explosion and fire from overheated fuel.

Conso. Halon is banned and has been for along time.

Production of halons is banned, which is why the contents of existing extinguishers are recovered for reuse in new ones when they become time-expired. They're still the most effective extinguishers for knocking down in-aircraft fires.

The rest of this "purge the fuselage with gas" stuff is nonsense, though - and I look forward to hearing it repeated by TV experts later this evening.

Although not really pertinent to the discussion at the present time, This is an incorrect and misleading comment. The manufacture of some, maybe all, CFC compounds has be prohibited for some years, existing stocks are recycled as far as possible - and, I believe, still used in aircraft in certain fire extinguishing systems.

The sort of "fire" resulting from major electrical shorts and perhaps with added bottled oxygen isn't going to look like or behave like a pool of burning oil (or brandy in a hot frying pan). Take away the O2 with an extinguisher and the arc-welding effect continues unabated, sparks, vast amounts of heat, masses of noxious smoke and molten metal flying around and eventually after several seconds the extinguisher runs out of puff and you're back to square 1. No change. Taking away the electricity may work - eventually, but short of flooding the avionics bay with water extinguishers won't do much in the long term while the power flows. Burning molten metal can obtain oxygen from all sorts of sources, it doesn't need air. Think arc welding. Think chucking water on a magnesium fire.

The sort of "fire" obtained by an electrical arc is outside the scope of any extinguisher we carry on board, partly because it isn't actually a fire in the conventionally meant sense.

Could an ipad bring down an aircraft in 6 minutes? Why not?
As a purely speculative suggestion to illustrate the possibility one might imagine a scenario where the ipad or notebook in the side stowage brewed up, FO fled his seat, Capt dons mask so comms v. difficult. FO can't get at device due smoke, heat and molten metal spraying from the burning batteries. It's but a short step then to the crew oxygen mask lines and wiring behind the side panelling in which reside high current window heat cables and more...
How quickly might that then develop?

Although I am in no way suggesting it as a scenario in this incident my guess is that such a progression is perfectly possible.

Quote:
How about? How about? How about? How about waiting until the recorders have been found and analysed by trained experts in the field of accident investigation?
Exactly ...

I was thinking of posting regarding an anti-terrorism theory but why bother ... I can outsmart people but I'm damned if I'll outstupid them!

So, curious then as to why you are posting?
Why not await the comments of said trained experts ?

Probably a lot safer, as nobody felt the need to smoke in the toilets.
Smoking was stopped not because of the fire risk but to avoid the airlines being sued for long term health damage to crew and other passengers.

Mike Vivian ex CAA Head of Ops was on BBC this morning. He is the only "expert' that speaks common sense and loads of knowledge

Four words:
Kapton. Swissair Flight 111.

Thanks Organfreak..interesting piece re that one
Swissair 111 Reconsidered | Airliners.net
& from that:"Even though the use of Kapton wire and Mylar/MPET insulation in the construction of new aircraft has been banned, there is still an enormous number of aircraft flying that contain these dangerous and defective components. "
That was written in late 2007. I wonder how many planes still in service have this wiring?

I know there is lot of talk about iPads, but what about ubiquitous cheap power banks everyone happily buying for long trips and vacations.

Just out of curiosity, are all of the Flight Control Computers located in the same physical place on FBW aircraft, such as the A320 ? In my job (IT), it's best practice to have redundancy of not just data, but of the hardware - including having the failover system in a different location.

If there were a fire in the avionics bay, severe enough to take out all computers in there, is there any chance the A320 could still remain flyable ? I know there's no cable system so I suppose I've answered my own question haven't I ?

Organfreak. TKT = Teflon/Kapton/Teflon (that's a much safer aromatic polyimide wiring insulation). That was the smart Airbus move.
Most of the Kapton is now in the boneyards in a vast array of military aircraft and airliners. In most cases, it was predominantly the Kapton that put them there. In many cases, because of the expensive innards (such as in P-3 Orions and S-3 Vikings) it was always cheaper to rewire at a major scheduled refit.

Electrical arcs are a kind of short circuit and should be disconnected by circuit breakers. The circuit is shortened by good conductive ionized air. Of cause the protection function of CBs is not absolute.

Do you have any experience with LiPo fire? I guess not.
While those things are not quite hamless, they are no nuclear bombs either.
I have removed a burning ~1kg LiPO from the Trunk of an estate car by grabbing it at the cables of the charger. (Notice to self: Will not load LiPos again in the Trunk of a car).
Although it was quite a fire, with 5x 1 Liter bottles of water the 1kg battery could be relatively quickly extinguished.
In an iPad you have a <0,1kg battery.
I have no idea where the notion comes from that you can't get to within 1m of a burning iPad. You probably will have some burns on your fingers afterwards and there will be quite some smoke but come on... when your Life (and that of dozens of others for that matter) is at stake.

anengineer: #586

As you say, pure fbw, with no mechanical backup.and the a/c cannot fly at all without the electronics. .It's surprising therefore that there is no fire suppressant around the avionics systems. Assuming an electrical short taking out power supplies, even redundant systems could fail, or in the case of serious fire, the various systems could fail one by one over time as the heat reaches them. I know the acars is fragmentary evidence, but whatever happened seems to have happened over just a few minutes, which would need a fairly aggressive fire to heat all those systems to non operational state, because of the thermal mass involved...

Henra, Most iPads have L-ion batteries. Li-Po batteries (from my rc helicopter days) will not extinguish in water- they'll reignite once out of it and make its own oxy. The only way is put them under a layer of sand for this reason.

A320 Mechanical back up
 

More Conjecture! Lets let the Aircraft accident investigators do their jobs, please.
I hope the sub finds the black box soon.


Anengineer, it appears you do not know or understand the A320, so please do not write bull.
The A320 has mechanical back up.
Speaking hypothetically of the A320
Also, You can also put the aircraft into a emergency electrical configuration, with the RAT, powering the electrical system, independantly, and the A320 is flyable in this condition providing you can see through the smoke to the instruments. If you go into the emergency electrical configuration, powering the RAT, you have isolated the electrical system.

¨As you say, pure flw, with no mechanical backup.and the a/c cannot fly at all without the electronics.¨

A320 MECHANICAL BACK UP
PITCH
Mechanical backup enables the pilot to control the aircraft during a temporary complete loss of electrical power.
He does this in pitch by manually applying trim to the THS.
The PFDs display “MAN PITCH TRIM ONLY” in red.
LATERAL
The pilot uses the rudder pedals as the mechanical backup to laterally control the aircraft .

I've had a Li-Po battery blow up (because of a short) and it was pretty dramatic. Lot of heat and smoke.
Only a comment to illustrate that these batteries can be scary. Not any suggestion that this was part of the 804 problem

So there is a minimal control, but sounds fairly primitive in terms of safely landing the a/c, especially if flight displays are compromised. Also, would the engines keep running, fuel pumps etc ?. Modern electronic systems are very, very reliable, but only ever as good as their power source...

Ummmmmmm, I'm well into my second decade on the 'R' model, but I can't seem to recall an FE ever looking over my shoulder. On the 707, of which I only have a couple thousand hours in command, we had them, but they were mainly there to make fun of the FOs.

So, I guess I'm calling bs

It is still used and allowed for aircraft and certain other critical areas. It does not work well for Li fires. Production is allowed but restricted.

perhaps they were running checks without success as systems decayed.

communication among themselves might have taken up their time.

[quote=capewrath;9384881]That is only true of normal fires. But the lithium battery fires do not need any of those to start. They are 'fueled' by chemical/electrical energy and do not need oxygen. All you can do is cool them ideally flooding them with water removing the heat from the exothermic reaction. Many IEDs are made of critical mixes of reducing and oxidizing agents that will 'explosively' react even under water - initiation may be as minor as a knock or vibration or a flash of light. If the mix is varied the reaction may not be explosive but be a violent high temperature fire, A 'peaceful' use of such a mix is a thermite lance which is often used underwater.

Waiting for enough firm evidence to base any action upon.