EgyptAir 804 disappears from radar Paris-Cairo

[CONSO]

[quote=Ian W;9385147]

Originally Posted by capewrath

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.

In probably forlorn hopes of properly describing the Li battery fire issue and Halon usage I've provided the following document that goes a way towards the issue of Li batteries on aircraft- specifically 787- which was as much mis-repoted by the media as factual andsomehow devolved to the laptop batteries, cell phone batteries, etc.

Note in this case- the batteries at issue are MUCH more poweful etc. Also note that Halon will help to prevent spread of fire- but NOT cool down molten metal

NATIONAL TRANSPORTATION SAFETY BOARD
Office of Aviation Safety
Washington, DC 20594
March 7, 2013
Interim Factual Report
NTSB Case Number: DCA13IA037
Location: Boston, Massachusetts
Date:
Aircraft/Operator:
January 7, 2013
Boeing 787-8, JA829J, Japan Airlines

Please read the footnote on page 3 re halon.

try http://www.ntsb.gov/investigations/A...ual-report.pdf

The ultimate- final cure in this case was to put the batteries in a steel case vented to the outside in case of ' meltdown-arcing, etc '

[vmandr]

Seems there may be a lot more information not being shared with the public, just yet.

True, but expected as you go SE. Part of the culture there. Sharing - anything - its not their 'forte' so to speak.

[horizon flyer]

I don't think flooding any metal fire with water is a good idea as normally the metal rips the oxygen out of the water leaving hydrogen, sand is a better choice. Just throw sodium in to water and see what happens. Even in a central heating system the gas that has to be vented from radiators is hydrogen ripped from the water by the iron in the rad. The better lithium battery to day and should have been used in the 787 is Lifepo4, it does not catch fire like lithium ion, check out the number of fires after crashes of Tesla cars Li ion against GM Volt Lifepo4 that have never caught fire.

[henra]

Originally Posted by funfly

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

Yes but the pack in the R/C Heli was also probably at least 0,5kg if not more. And it burns only very briefly intensely, usually about 2-3secs per cell if they are fully charged. (I have burnt a few/witnessed a few burning. The last 5 cell pack (0,5kg) last Saturday after it was damaged we drove a nail through it -for educational purposes). The subsequent smoldering is not very violent.
They have to be handled with care but I repeat -a 0,1kg LiIon or LiPo will not bring an airliner down as long as it is in an accessible place. It gets dangerous if it can ignite other stuff and is not accessible.

[Hotel Tango]

Chronus and vmandr, that's because they won't share anything (as you put it) until they 1) have facts and 2) want to share them with the general public. I don't think they're too bothered about keeping the PPRuNe community informed. Every possibility has to be investigated at length. As for the ATC aspect, I already covered that way back.

[West Coast]

Ian

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.

There seems to be a couple of viewpoints on the effectiveness of water. Last recurrent there was a FAA video that compared a laptop fire suppressed with ice and another water. Ice seemed to be better at suppressing another flare up.

Simply what I saw on the video, not endorsing one method over the other.

[vapilot2004]

Wouldn't feeding the fire with fresh air make it more intense? I also read that the flight deck has a halon portable fire extinguisher, any reason why inaccessible areas of aircraft don't have inbuilt halon extinguishers?

StormyKnight:

That may be true for fires fueled by combustible materials, however the EE bay contains mainly electronics cards, wiring, and aluminium racks and equipment cases. These items 'burn' primarily due to electric current providing the input heat and not combustibles contained within.

Generally, EE bay 'fires' are limited to smoke events where no amount of oxygen deprivation will quench them because they are typically self sustaining until power is removed.

Note on detection on the A320 series (and most aircraft types) - EE/Avionics bay uses an ionization type detector while some aircraft's lavs use photo type detectors - photo detectors being of the type that can be fooled by condensation fog.

[vapilot2004]

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.

The A320 series FAC, FMGC units, the core of the FBW system, are located on the same equipment rack within inches of one another in the avionics bay, however they are contained within metal boxes and are powered by separate busses for redundancy.

One some other aircraft, this arrangement is further enhanced by physically locating any dual/triple redundancy (flight critical) units about a meter away from one another.

Design differences aside, the level of power (available current and voltage) input to computer IRU's is low enough to prevent a catastrophic failure of one box from affecting its neighbouring unit, even if they are installed right next to one another.

[CONSO]

About " Halon " - there isa bit of confusion about the current versions versus the "old" versions of several decades ago.

start with this link for up to date facts and data and how used, tech specs, etc

Halotron ? Halotron I

Note on Halon - Halon is an oxygen displacement suppression system and as such not ideal in areas of the aircraft where passengers or crew are present as an automatic system. The EE/AV bay is not isolated from the cockpit air - only by ducting and air pressure differences are the two areas kept separate.

[HeavyMetallist]

Originally Posted by CONSO

About " Halon " - there isa bit of confusion about the current versions versus the "old" versions of several decades ago.

start with this link for up to date facts and data and how used, tech specs, etc

Halotron ? Halotron I

Halotron I isn't just a "current version" of Halon 1211/BCF, it's a quite different product. For all its undoubted environmental advantages, it isn't as effective as Halon, and has to be used in greater quantities to achieve the same extinguishing performance, which is why Halon is still recycled for use in aerospace applications - such as handheld aircraft fire extinguishers.

[thf]

According to Greek primary radar data, reported on Avherald, the left hand turn of 90 degrees started at 00:37. The first ACARS messages about computer failures and smoke were sent with timestamp 00:26. A sudden catastrophic event (bomb, missile etc.) is getting more unlikely.

[MountainBear]

What is most telling about the ACARS list posted in this thread is not what it says but what it doesn't say. With either a fire or a bomb what one expects is a cascade of faults more numerous than what we see in this situation. This suggests to me a real problem rendered worse by pilot mishandling.

.

[StormyKnight]

To me there is a definite difference in the colour between the right & the left of the circled area, even though they are under the same lighting. Shadow from object to right show sun positioning.

In addition the arrowed point looks black.

It looks like what a fire resistant material would look like when heated. It doesn't burn easily but it does discolour.

There is a definite difference between the left & right of this image in terms of colour.

[olster]

Shocking levels of speculation with limited access to facts or an understanding of Airbus fbw systems. Currently away from the UK and 'captain' Mike Vivian - apparently a former head of CAA flight operations' glibly announced on BBC world news that this was 'almost certainly' a terrorist event. The lack of discretion in the aftermath of such a tragic event beggars belief. However, unsurprising level of drivel from former CAA operatives is de rigeur. Of course a nice fat 'consultancy' fee for spouting garbage is sop. Makes me gag that these individuals benefit from shocking aviation disasters. RIP to the crew / passengers.

[PersonFromPorlock]

To me there is a definite difference in the colour between the right & the left of the circled area, even though they are under the same lighting.

Thanks for posting the quality image. While the 'discoloration' could be an optical illusion, the whole right edge of the fabric does look melted rather than torn.

[takata]

Beside being not powered in ELEC EMER CONF, it looks like maintenance ACARS message are not transmitted during voice call using the system (if something like that was actually used; I'm not saying it was though):

[Stratopause]

Originally Posted by PiggyBack

I do not normally comment at such an early stage because it is speculative and ghoolish but what possible benefit would realtime telemetry bring in this situation? The motivation is clearly morbid curiosity rather than safety because in this as in almost all cases the data recorders will be recovered and any lessons that can be learned will be. However even morbid curiosity woudl almost certainly not be satisfied as in all probability the telemetry broadcast would simply have halted when whatever occured occurred.

The reality is that realtime telemetry would need to be backed up by data recorders to ensure data communications problems did not result in lost data. The safety value is only in those cases where the recorders cannot be recovered which is rare. Rather than safety it is the cost of searching for and recovering data recorders that needs to be balanced against the cost of implementing such a system. If it existed the data should not in any case be released until after an accident investigation.

Real time telemetry does not replace the FDR/CVR but it has advantages:
- much better final position and trajectory than you get from the fringes of radar and ADS-B ground rx
- if there is an issue either with security at an airport or with an aircraft type, earlier data = faster response
- in some cases the flight recorders aren't recovered at all, sp it's nice to have a backup
- an entire FDR image is 138MB. The average web page is 2MB. 70 pax on the IFEC @ 1 single web page = an entire FDR. We need to get our priorities straight on that one and rapidly falling costs mean that it isn't cost prohibitive.

The conventional flight recorders have been very good but they are built on 1950's technology later converted to solid state storage. An increasingly incredulous public cannot understand why we 'lose' aircraft and frankly I can't blame them. Time to get into the 21st Century on this one.

[Rwy in Sight]

Originally Posted by thf

According to Greek primary radar data, reported on Avherald, the left hand turn of 90 degrees started at 00:37. The first ACARS messages about computer failures and smoke were sent with timestamp 00:26. A sudden catastrophic event (bomb, missile etc.) is getting more unlikely.

With some experience on Hellenic Air Force Radar and some info into it we should consider some lack of syncronization between radar data and ACARS.

[A310bcal]

Just an observation....but the 90' turn is the classic manoeuvre prior to commencing an Emergency Descent, i.e. to not descend through the Airway. If indeed the plane was suffering smoke in the cockpit and loss of significant instrument displays, compounded by it being the middle of the night, it is not too hard to envisage a poor outcome, especially with PNF struggling through a checklist in dire conditions and thus losing some of his monitoring ability. The big question of course remains , what triggered the problem in the first place and realistically, only the black boxes will tell us that answer if and when they are found.

Another sad loss.

[StormyKnight]

I found this interesting from

ATSB TRANSPORT SAFETY REPORT
Aviation Occurrence Investigation – AO-2009-027
In-flight fire
427 km south-west of Guam
10 June 2009
Airbus A330-202, VH-EBF

https://www.atsb.gov.au/media/250036...27%20final.doc
From p15

Window heat computer (WHC) inspection
It was reported to the ATSB that upon opening of the number-2 WHC’s external case, some internal electrical circuits exhibited damage to discrete components and circuit boards. Based on that damage, the WHC manufacturer concluded that excessive voltage from the windshield temperature sensor wires had been conducted through to the WHC, and upon exposure to that voltage, the internal components and circuitry became damaged from electrical overstress. It was also concluded that the last ‘hard-fault’ as contained in the PFR relevant to the number-2 WHC, was written by the central maintenance computer at 1524 when the WHC ceased functioning.

In that case it was the plug to the windscreen that had overheated & melted, BUT....the Windscreen Heater Computer also suffered electrical damage as the power applied to the heater elements was fed back down the sensor element wiring back into the WHC. The heater elements are supplied with 200VAC at up to 3.6kw. It would be assumed that the circuit breakers would not detect a fault if the current was below the 3.6kw normal limit.

In a worse case scenario, this would led to a fire in the WHC in the avionics bay.

EDIT: Additional note, the cabling was also damaged, so fire/smoke could have been generated along the entire length of the sensor/power cable.