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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 24th Mar 2014, 02:24
  #7621 (permalink)  
 
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Anyone got a chemist friend who could comment on what "vigorously" might mean in this event?
Halons are haloalkanes -- carbon skeletons with fluorine, chlorine or bromine instead of hydrogen atoms.

The most common ones used as suppressants are called Halon 1211 and Halon 1301 (respectively, CF2ClBr and CF3Br).

The FAA did some tests on Halon 1301 and Li-Ion batteries a decade ago: http://www.fire.tc.faa.gov/pdf/04-26.pdf

From the executive summary:

"Halon 1301, the fire suppression agent installed in transport category aircraft, is ineffective in suppressing or extinguishing a primary lithium battery fire. Halon 1301 appears to chemically interact with the burning lithium and electrolyte, causing a color change in the molten lithium sparks, turning them a deep red instead of the normal white. This chemical interaction has no effect on battery fire duration or intensity.

The air temperature in a cargo compartment that has had a fire suppressed by Halon 1301 can still be above the autoignition temperature of lithium. Because of this, batteries that were not involved in the initial fire can still ignite and propagate.

The ignition of a primary lithium battery releases burning electrolyte and a molten lithium spray. The cargo liner material may be vulnerable to perforation by molten lithium, depending on its thickness. This can allow the Halon 1301 fire suppressant agent to leak out of the compartment, reducing the concentration within the cargo compartment and the effectiveness of the agent. Holes in the cargo liner may also allow flames to spread outside the compartment."
To answer the question, it does not appear that the vigorousness of the reaction with the halon is the main thing; rather, it is the participation of the intended suppressant in the fire and its consequent failure to extinguish it. The report suggests that the halon did not make the fire worse (which you would expect if the reaction added anything to the combustion process).

From p 9-10 you can see that the Li reaction is indifferent to the presence of the halon, but other reactions are affected:

"The color change of the lithium sparks indicated that a reaction was occurring between the lithium and the Halon 1301. This reaction had no effect on the fire progression, neither hindering nor promoting the spread of the battery fire. The vented electrolyte fires, normally pale red in color, turned bright red when exposed to Halon 1301.

The battery fire continued to propagate until all batteries were consumed, continuing long after the 1-propanol fire was extinguished. The halon also had no effect on the peak temperatures in the test chamber, peaking at about 1400°F. This is similar to the peak temperatures exhibited in previous unsuppressed fires. However, the overall temperature profiles were lower, due to the extinguishment of the 1-propanol and battery plastic coating fires."
The FAA also tested Halon 1211, which is also ineffective: http://www.fire.tc.faa.gov/pdf/09-55.pdf

I suspect this is likely because lithium is very reactive and, compared to fluorine and chlorine, bromine is the most reactive when attached to a carbon atom (the basis for, e.g., Grignard reagents). The two together are thus able to undergo reaction, especially given the temperatures produced by the primary failure. The whole thing is worth reading in its (scary) entirety.

All in all, a Bad Thing.

Last edited by auraflyer; 24th Mar 2014 at 02:26. Reason: messed up quote
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Old 24th Mar 2014, 02:25
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Chris2303

Most of airframe etc non magnetic and very deep water. Suggest MAD for merchant ship detection (after sinking)
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Old 24th Mar 2014, 02:33
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@LASJayhawk

But the mode S (ADS-b) lat/long data is present, just the altitude is missing (0?). How do you select which ADIRU is used by the SSR/ADS-b?
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Old 24th Mar 2014, 02:34
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Pardon my ignorance but if there was something at the bottom of the ocean surely the MAD in the Orions would find it?
Nope:

To reduce interference from electrical equipment or metal in the fuselage of the aircraft, the MAD sensor is placed at the end of a boom or a towed aerodynamic device. Even so, the submarine must be very near the aircraft's position and close to the sea surface for detection of the change or anomaly. The size of the submarine and its hull composition determine the detection range.
From: Magnetic anomaly detector - Wikipedia, the free encyclopedia
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Old 24th Mar 2014, 02:43
  #7625 (permalink)  
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SpannerTwister,

What would happen if a small or otherwise controllable lithium-battery fire occurred and the pilot discharged the Halon extinguishing system on it?
This is transcribed from the Emergency Response Guidance for Aircraft Incidents Involving Dangerous Goods manual Red Book.

Lithium Ion Batteries UN3480 have an ICAO Dangeroous Goods Emergency Response Drill code(issue 2013/2014) of 9 F Z

Meaning the following from the Table 4-1. Aircraft Emergency Response Drills


Drill No. 9

Inherent Risk-------- -------No general Inherent Risk

Risk to Aircraft- -------------As Indicated by drill code

Risk to Occupants- ----------As indicated by drill letter

Spill or leak procedure------ Use 100% oxygen; establish and maintain maximum ventilation if " A " drill letter

Fire Fighting Procedure------All agents according to availability- use water if available on " Z " drill letter; no water on "W" drill letter

Additional considerations----If " Z " drill letter consider landing immediately otherwise, none

ADDITIONAL RISKS:


DRILL LETTER : " F "--FLAMMABLE


DRILL LETTER: " Z "--- AIRCRAFT CARGO FIRE SUPPRESSION SYSTEM MAY NOT EXTINGUISH OR CONTAIN THE FIRE; CONSIDER LANDING IMMEDIATLEY


So basically use everything you have on lithium ion batteries but containment is not guaranteed. Seems insane to put Lithium Ion batteries on any pax /cargo aircraft in any quantity really.
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Old 24th Mar 2014, 02:50
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@Mahatma Kote

At sea-level pressure or lower it can only harm by displacing normal air completely and so eliminating the oxygen.
Precisely.

I am not talking of a plane that has depressurized, I am talking about a plane with normal pressurization, somewhat a little higher than sea-level.

If such quantities as shown in the Mexican pool example were liberated, then this nitrogen would rarefy oxygen. It could be another oxygen-scavenging gas than nitrogen (but we'd need a chemist to tell us which).

If the liberation of the gas was slow and not due to explosion, but due to damage to containers, and if the placement of the nitrogen allowed it to seep to cabin and cockpit through defective venting systems (air conditioning, pressure differentials between different parts of the aircraft), then one could posit that there would be a slow hypoxia onset for all living things in the plane.

That theory of slow-setting hypoxia, where I put forward that such damage to nitrogen (or other similar gas) cylinders may have been caused by a lithium battery fire (although it could be something else I suppose), is the simplest that takes care of all aspects of the flight, the behavior of the pilots and the end result.

Ohoh, I've been mod-ded too!!! Better quickly save the interesting posts before they disappear...
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Old 24th Mar 2014, 02:50
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I wondered why it took so long for this CNN story to show up on this forum. What happened to the 45,000 feet deal??? This is just another example of most of the "facts" all these gullible "experts" are going by, are ones they get via the Malaysian government and are subject to change at any time. I don't want to hear any more of this "We all know..." stuff, when NO, we don't "all know..."!
Keep in mind that CNN's 12000ft story came from "sources" too - so whether it's any more or less accurate than anything else we've heard is debatable.

The story has changed so much and so many times that I'm not even totally sure there ever was an airplane.
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Old 24th Mar 2014, 02:58
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Quote:
"Halon 1301, the fire suppression agent installed in transport category aircraft, is ineffective in suppressing or extinguishing a primary lithium battery fire. Halon 1301 appears to chemically interact with the burning lithium and electrolyte, causing a color change in the molten lithium sparks, turning them a deep red instead of the normal white. This chemical interaction has no effect on battery fire duration or intensity.

The air temperature in a cargo compartment that has had a fire suppressed by Halon 1301 can still be above the autoignition temperature of lithium. Because of this, batteries that were not involved in the initial fire can still ignite and propagate.

The ignition of a primary lithium battery releases burning electrolyte and a molten lithium spray. The cargo liner material may be vulnerable to perforation by molten lithium, depending on its thickness. This can allow the Halon 1301 fire suppressant agent to leak out of the compartment, reducing the concentration within the cargo compartment and the effectiveness of the agent. Holes in the cargo liner may also allow flames to spread outside the compartment."
Is it possible if an aircraft still used a Halon fire suppression system, that, in the course of fighting a Lithium-Ion battery fire, that all the Halon might be emptied from the tanks and extinguishers in a futile attempt to extinguish the fire, and all the Halon expelled displaced enough oxygen aboard the aircraft, to make everyone pass out? I know in places I've worked that employed Halon fire suppression, there was an audible alarm along with a strobe light that warned that the Halon system was about to go off, and you had a certain number of seconds to either get out or disable a false alarm, because you couldn't breathe, once the Halon came out.

Last edited by Coagie; 24th Mar 2014 at 05:12. Reason: Punctuation worse than usual
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Old 24th Mar 2014, 03:05
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Keep in mind that CNN's 12000ft story came from "sources" too - so whether it's any more or less accurate than anything else we've heard is debatable.
I kept it in mind. We all should.
The story has changed so much and so many times that I'm not even totally sure there ever was an airplane.
Jugopropwash, I'm with you there!
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Old 24th Mar 2014, 03:05
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Cockpit Voice Recorders: The output from vastly updated technology is now available and ready to record hours of audio and video activity on the flight deck. However, it appears that concerns of pilot privacy still forbid their full use. 30 minutes max and no video. Is there a conflict here?

We bereft pax are left to wonder what the point is of spending millions to retrieve this piece of evidence from the bottom of the ocean, only to find there's nothing on it.

Let's hear from some of you pros out there.
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Old 24th Mar 2014, 03:08
  #7631 (permalink)  
 
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But the mode S (ADS-b) lat/long data is present, just the altitude is missing (0?). How do you select which ADIRU is used by the SSR/ADS-b?
you don't
i agree, i was irritated by these transmissions, too
but the answer is likely the behaviour of the transponder when it is switched to off or stby or the cb is pulled
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Old 24th Mar 2014, 03:15
  #7632 (permalink)  
 
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Originally Posted by LowObservable
Mere SLF here - albeit 40-year, 2-million-plus-mile SLF - but I don't recall seeing a lot of wooden pallets being loaded on aircraft.
Much air cargo gets loaded on “unit load devices”, e.g. (metallic) aircraft pallets and also in cargo containers like lower deck containers and igloos. However, a lot of said cargo is trucked into the airport on smaller wooden pallets, and that cargo is often forklifted (together with the underlying pallets) directly onto 125 x 96 inches aircraft pallets and the like. So a lot of wooden truck-type pallets fly without this being noticeable to even attentive passengers, I think. The wooden pallets serve to keep the load forkliftable, not only for assembling the aircraft pallet load, but also for subsequent surface transport.
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Old 24th Mar 2014, 03:22
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Request clarification on fuel load

As per the confirmed report the flight took on board 53 tons of fuel at KUL.

Query: would this include the reserve fuel from prior sector of aircraft on board or the fresh uptake only?

If it is the fresh uptake only would that not add about 800 km or another hour to the flight being calculated?

Assuming another 800 km range and the aircraft continued to fly south from where the last ping to IMERSAT, is there sattelite coverage in that area to pick up subsequent pings 30 minutes later or this really the black hole as being described.

Thank you
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Old 24th Mar 2014, 03:24
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I am only a simple seaman but I know two things that are relevant here:

1. As I said in 7608, Halon does not suppress a lithium ion battery runaway.

2. The biggest cause of loss of life amongst merchant seamen is entry into enclosed spaces with unsafe atmospheres: we are taught that if the atmosphere in the space, always tested before entry, is anything other than 20.9% O2 we do not enter the space, because if the O2 content is below normal, it has been replaced with something else.
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Old 24th Mar 2014, 03:30
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Capt Kremin (#7676, 24th 0211Z), the posted tracks do not take account of wind. For the 197M constant magnetic track coordinates: text, kmz.
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Old 24th Mar 2014, 03:36
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Thumbs up Li Ion batteries

You do realize that Li Ion batteries are the MAIN backup batteries on the Boeing 787 ?
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Old 24th Mar 2014, 03:39
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Much air cargo gets loaded on “unit load devices”, e.g. (metallic) aircraft pallets and also in cargo containers like lower deck containers and igloos. However, a lot of said cargo is trucked into the airport on smaller wooden pallets, and that cargo is often forklifted (together with the underlying pallets) directly onto 125 x 96 inches aircraft pallets and the like. So a lot of wooden truck-type pallets fly without this being noticeable to even attentive passengers, I think. The wooden pallets serve to keep the load forkliftable, not only for assembling the aircraft pallet load, but also for subsequent surface transport.
Even though a wooden pallet could be on an aircraft, it doesn't mean anything, because wooden pallets are all over the place, all over the world. I'd be surprised if they didn't find one!
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Old 24th Mar 2014, 03:42
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Its possible he turned back with out telling anyone
Not really...

They would have mashed the mic button and told ATC they were returning, if for no other reason than to request the equipment. And there are plenty of other reasons to tell ATC, including basic professionalism.
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Old 24th Mar 2014, 03:46
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You guys are serious right?? A fire developed, the crew failed to declare an emergency, switched off the ATC and ACARS, then the plane flew for 7 hours down the Indian Ocean??
No.

I do know what occurs when halons are used on a Li ion fire. That is fact and I recounted it, with FAA citations. I also gave my thoughts (based on my own first hand experience) as to why it might be that halons are ineffective in that kind of case (as a matter of fairly simple chemistry).

That is ENTIRELY separate from suggesting that something along those lines did or might have occurred here. I have not done so (read my post carefully); indeed, my own (irrelevant) opinion is that the deliberate course changes indicate it didn't happen.
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Old 24th Mar 2014, 03:49
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Originally Posted by Coagie
Is it possible if an aircraft still used a Halon fire suppression system, that, in the course of fighting a Lithium-Ion battery fire, that all the Halon might be emptied from the tanks and extinguishers in a futile attempt to extinguish the fire, and all the Halon expelled displaced enough oxygen aboard the aircraft, to make everyone pass out? I know in places I've worked, that employed Halon fire suppression, there was an audible alarm along with a strobe light that warned that the Halon system was about to go off, and you had a certain number of seconds to either get out or disable a false alarm, because you couldn't breathe, once the Halon came out.
It's not possible.

Halon is used for fire suppression in enclosed spaces. One of the nice features of Halon is that it is not particularly toxic (despite the alarms) and it efficiently suppresses most fires at concentrations of only ~5%. It would not be able to prevent all lithium batteries from burning, but it would prevent the fire from spreading to other materials, as long as the cargo hold remains in one piece and reasonably airtight.

In the event that the fire is so inconveniently located that it burns through the bulkheads separating the cargo hold from the passenger cabin, halon would leak through the holes and would fail as a fire suppressant, but it would not by itself kill anyone or displace oxygen anywhere.
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