|
[quote=Ian W;9385147]
Originally Posted by capewrath
(Post 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. 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 ' |
Seems there may be a lot more information not being shared with the public, just yet. |
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.
|
Originally Posted by funfly
(Post 9385080)
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. |
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.
|
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. Simply what I saw on the video, not endorsing one method over the other. |
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? 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. |
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. 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. |
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. |
Originally Posted by CONSO
(Post 9385271)
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 |
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.
|
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.
. |
http://s33.postimg.org/9wkag8ki7/Clipboard01.jpg
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. |
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.
|
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. |
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):
http://takata1940.free.fr/1_com.jpg http://takata1940.free.fr/2_com.jpg http://takata1940.free.fr/3_com.jpg |
Originally Posted by PiggyBack
(Post 9381287)
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. - 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. |
Originally Posted by thf
(Post 9385291)
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.
|
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. |
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 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. |
Originally Posted by West Coast
(Post 9385223)
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.
If I'm understanding correctly, the issue is that ice doesn't melt quickly enough to cool the battery cells and thus it winds up acting more as an insulator instead, letting them get even hotter. Similarly, Halon alone doesn't work well because it only takes away the flames - it doesn't help cool off the battery at all. Since this is a "thermal runaway" the battery will continue heating itself up further (without oxygen or anything else external) until it is brought below a certain temperature threshold to stop the chain reaction. According to the video water is best because it absorbs lots of heat and it's easy to douse the battery thoroughly. (And with modern Li-ion batteries, evidently there's not enough pure lithium to cause a problematic reaction with the water itself). |
re: reports on French media and the NYP about "contact" to Egyptian ground stations
On May 23rd 2016 the French BEA as well as Egypt's Civil Aviation Authority, in response to media reports of an emergency call on Egypt's frequency, stated, that no such communication has been received on any frequency. Egypt's CAA said: "What was published on media today concerning a recording of a conversation between the pilot of EgyptAir MS804 and Cairo Air traffic control is totally false; the aircraft did not make any contact with Egypt’s Air traffic control. [...] |
This morning both the French BEA and the Egyptian CAA state clearly that no voice communication took place as asserted by the French channel M6.
Hopefully at least this particular speculation will cease on this thread... |
Did they formally exclude both ATC communications and possible company communications with egypt air HQ?
|
No. The Egyptian statement only referred to ATC comms.
Presumably they saw no need to deny something that hasn't actually been alleged anywhere. |
Egyptian authorities have a history of fitting the the facts to whatever theory is politically correct.
Egypt Air Flight 990 ... "The two investigations came to very different conclusions: the NTSB found the crash was caused by deliberate action of the relief first officer Gameel Al-Batouti;[1] the ECAA found the crash was caused by mechanical failure of the aircraft's elevator control system" https://en.wikipedia.org/wiki/EgyptAir_Flight_990 |
*cough cough* metrojet *cough*
|
Originally Posted by Stratopause
(Post 9385394)
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. However, obviously in the case of a fuselage break up for whatever reason or even violent maneuvers the capability to transmit to the INMARSAT or Iridium networks may not be feasible, so there will always be a need for survivable on aircraft DFDR/CVR. However, there must be better in-water or in remote area location systems. MH370 may never be found, even MS804 may not be found, this is not really acceptable just because bean counters didn't want to pay for a larger battery and engineers were not allowed to come up with a pinger that was more powerful, cleverer but perhaps a little heavier. The pinger could also have its last recorded GPS position encoded into the pinger signal. Because of the MH370 case ICAO has now agreed to track ADS-B - despite ADS-B, ACARS and SSR being (switched?) off in MH370 case. Brilliant. :D It is not only the public that is getting increasingly incredulous. |
@IanW
Chances are that the system you describe won't last much longer than the ADS-B system itself or the ACARS transmissions and will fail at the same moment. There may be more data received at the end, but that doesn't mean that it will be easier to locate the wreckage. AF447 sent its last known GPS position not that long before it crashed, but it still took 2 years to find it (agreed that it may have been different if it sent its position one second prior to impact, but obviously that would not have been possible for MS804). |
Weight of the actual battery is not the issue, % of lithium makes the difference MH370 may never be found, even MS804 may not be found |
Modern electronic components use materials that don't support fire, nor do the printed circuit boards. If a component fails and burns out, then there may be localised charing of the printed circuit and surrounding components, but any localised fire would self extinguish. Also, the avionics boxes are metal, often diecastings, so any internal fire would be contained. If there was a fire around the avionics systems, then it must have had an external cause...
|
@IanW
There is no guarantee satellite link will be active for 30 seconds even with multiple antennae. Cost of Ka band equipment installation ranges from $100,000 - $200,000 per plane plus Inmarsat subscription fees are huge. Not many airlines can afford. Read about DRS Technologies Automatic Deployable Flight Records ADFRs. Cheap ($20,000) and fail safe. https://vimeo.com/109276008 |
@IanW Re FDR and CVR
Agree whole heartedly Something a few of us have posted on this thread and of course it's common knowledge it desperately needs addressing. However it should be the FAA who are culpable here and should be making am mends. Bean counters never will.... |
FAA and the industry ?. A cynic might see that as a a similar situation to vehicle engine testing, where the industry has been gaming the system for years in collusion with the regulators. Not a conspiracy, but realistic regulation based on risk analysis, cost and the state of the art in terms of available technology. You can't gold plate everything based on a very low risk...
|
How often do iPads catch fire?
Lot's of ideas related to the FO's iPad catching fire and taking out the aircraft, so I thought it worth trying to find out how often iPads catch fire generally...
So, this isn't truly a scientific search, but try typing in "iPad battery fire" or "iPad fire" into Google and see what you get? Not very much at all, and certainly I couldn't find one video of an iPad catching fire without an external source or of the remains after a fire caused by the battery igniting. I'm not saying it isn't possible but it just seems very, very, very unlikely, given it clearly is incredibly rare generally. As far as I can see an iPad fire seems about just as likely as the aircraft being hit by a falling satellite part, when it comes to probabilities. I understand it is human nature to want to fit a solution to the puzzle pieces we have to date, but I am firmly of the believe that it's just too soon and we just don't have enough info for anything to be meaningful. |
@GarageYears - dont know if EgyptAir carries ipads or laptops - but may be a good idea to separate these from their batteries and their chargers. Each have different issues.
A number of years ago a specific make of laptop, of what normally is a quality supplier, experienced a very large number of fires. I am not sure if it was the charger or the battery pack that caught fire. I do remember that many thousands had to be returned/replaced by the manufacturer. Which also points out that for a proper technical discussion you may have to distinguish between manufacturing batch issues and more fundamental issues related to the specific technology. Another issue, that certainly has to be included, is aging of batteries and packs. Older lions keep showing 100% but their actual capacity over time gets less. Also, older lions and rechargeables may be hotter than when they were new while charging. A number of years ago i was involved in a system that heavily depended on lion batteries. We experienced a number of operational issues with them. At the time it surprised me how little information there was on them for operational users. So at the time, for that (radio and comms related) system, i started collecting my own. An example of the lack of information is how to charge an iPad. Do you charge it to 100% and unplug it. Or is it better if you leave it plugged. And if you leave it plugged, is that when you dont use it, or (as some say Apple recommends) is it better to unplug it if you start using it. Simple questions but very hard to get a clear answer. Some of the above is the reason why i asked if earlier, if for example an iPad is part of the aircraft configuration or part of the 'pilot configuration'. @nnco provided information about Class 1,2,3 EFB's. To answer the issues mentioned above you would require a more detailed classification system. In a way you might compare these issues with earlier issues concerning the introduction of In Flight Entertainment Systems. It took a fatal accident with heavy (including NTSB) criticism of the FAA before old lessons were relearned. If you are unsure about facts, then you still have some more work to do. |
It seems that the airmchair quarterbacks around here have never heard of the KISS principle, AKA Occams Razor.
There is, for example, a very simple possible solution. If a wiring bundle is incorrectly secured it can chafe against the structure until some insulation is damaged. This has happened many times in the past. This can cause an electrical arc without tripping the associated breaker. The arc causes a chain of insulation damage to adjacent wires in the bundle which will either short or go open circuit depending on wire thickness. We now have multiple and confusing errors with apparantly random breakers tripping and a probable drop to alternate or direct law, all accompanied by choking insulation smoke. At this point loss of control is very likely due to confusion and pilot overload. There are, of course, other events which could explain the known facts and it is premature to draw conclusions until all of the evidence is in. History tells us that the "swiss cheese" model almost always applies with a simple failure completing a chain of hazards. |
They are using a submarine craft normally used for oil work and capable of depths of 3000mtrs apparently.
|
According to today's Times, it's actually a SUBmersible. A French-built remotely-operated piece of kit, used for oil-rig work etc. Capable of 10,000' so it says.
Simplthebeast. You posted while I was typing! |
Originally Posted by Herod
(Post 9386031)
According to today's Times, it's actually a SUBmersible. A French-built remotely-operated piece of kit, used for oil-rig work etc. Capable of 10,000' so it says.
The submersible that Mr. Sisi said was headed for the search zone on Sunday is operated by the country’s Petroleum Ministry and can descend to a depth of 9,800 feet. The vessel was not manned and is normally used for oil and gas exploration, said Hamdy Abdel Aziz, a spokesman for the Petroleum Ministry. Mr. Sisi said he hoped the submersible would find the flight voice and data recorders, although experts said it was not clear whether it had the necessary equipment to find them. |
| All times are GMT. The time now is 15:14. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.