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Old 2nd May 2014, 20:41   #10401 (permalink)
 
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re atc tape. the time interval between 370 first on radio and signing off is 53 minutes. in the report the tape covering that time period only lasts 7 minutes so there must be plenty of splices perhaps explaining the noises-off. there were 7 minutes of real time between the repeats of level at 350. I am curious about another tape I have heard which had lumpur radar tell 370 to contact HCM three times. the aircraft did not respond until the third. will try to find tape again.
The recording corresponds with the transcript that was published earlier
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Old 2nd May 2014, 21:28   #10402 (permalink)
 
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Originally Posted by 2dPilot View Post
@LGMX. Lithium reacts with water to produce Lithium Hydroxide and Hydrogen. Lithium Hydroxide is already present in seawater in fairly high proportions (around 0.2 parts per million - around 230 billion tonnes of Lithium, world-wide) - a tonne extra would be, well, a drop in the ocean.
Technically true. However, lithium batteries don't contain metallic lithium. They (typically) contain lithium cobalt oxide, which is, I believe, chemically inert with regard to water.

The general problem with lithium batteries is that they pack a substantial amount of energy. A short in a fully charged lithium battery can easily heat it by 200 degrees Celsius. If there's another lithium battery nearby, this heat can short it and cause it to release its own energy, etc. in a chain reaction. That's why we have specific packing requirements for the transport of lithium batteries. We need the packaging to contain and isolate any individual short that occurs.
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Old 3rd May 2014, 00:34   #10403 (permalink)
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Quote:
The general problem with lithium batteries is that they pack a substantial amount of energy. A short in a fully charged lithium battery can easily heat it by 200 degrees Celsius. If there's another lithium battery nearby, this heat can short it and cause it to release its own energy, etc. in a chain reaction. That's why we have specific packing requirements for the transport of lithium batteries. We need the packaging to contain and isolate any individual short that occurs.
And the most important point about Lithium Ion batteries and Cargo compartments in aircraft. Their fire suppression systems are next to useless against these types of fires. That's why IATA gave them a drill code of 9FZ previously 9FL.
The "Z" code states that 'Fire may not be be extinguished by cargo fire suppression systems'
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Old 3rd May 2014, 01:51   #10404 (permalink)
 
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Lithium Ion batteries have nothing whatsoever to do with the disappearance of MH370.

Maybe someone should start a Lithium Ion battery thread and keep the focus here on MH370.
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Old 3rd May 2014, 02:51   #10405 (permalink)
 
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Re Heathrow Harry Post 10500

I suspect that there are large number of scientists and engineers worldwide who could have double checked the AAIB/Inmarsat calculations (and extended and improved the estimates of location) had the original calculations been released in detail. This might have led to searches in the most likely area before the FDR pinger batteries died. There are examples in this thread where the calculations have been almost replicated, but under untested/unknown assumptions. This worldwide expertise exists, but has been unused.

The reluctance to release these details makes no sense, except that is is "protocol"

A detailed tech report on the calculations, would have facilitated checking and advancement, with such tech details well over the heads of the spin doctors.

Arguably, in not providing the detail, the AAIB and Inmarsat (and the Malaysians)have impeded the refinement (after their undoubtedly good initial calculations) of location of MH370 at the most critical time.
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Old 3rd May 2014, 02:56   #10406 (permalink)
 
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This worldwide expertise exists, but has been unused.
What makes you so sure of that? Just because the data has not been 'officially' released to the public does not mean that it has not been checked by others. I can't see what good releasing all the data would do other than to satisfy the rabid demand of the media/public.
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Old 3rd May 2014, 03:31   #10407 (permalink)
 
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I suspect that there are large number of scientists and engineers worldwide who could have double checked the AAIB/Inmarsat calculations
There is indeed various scientific institutions looking a various data and providing independent analysis input to the search group. This is a fact.
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Old 3rd May 2014, 03:36   #10408 (permalink)
 
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My point about lithium batteries

Was not that they brought down the aircraft. It was about whether upon contact with seawater or upon decomposition/discharge/etc they might emit something that could be detected from a distance using satellite sensing technology. I read that overcharging them can cause the formation of cobalt but a chemist would know more.
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Old 3rd May 2014, 04:17   #10409 (permalink)
 
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Grrr ABOUT BATTERIES

PUUUHHHHLLEESE - all the speculation about finding traces of any so called chemical reaction traces in a few thousand square miles of salt water - OR that they had any significant effects on the routing- failure to comm- etc is simply that- and does not add at all to the subject. start a different thread-

Thank you !
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Old 3rd May 2014, 07:57   #10410 (permalink)
 
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So the Malaysian's "Prelim" report recommends the "real time streaming" of data....

I think they better read the report if that is their findings !

Their ATC protocols and practices are clearly "unsafe" or being ignored.
If they can't get that right, then what hope for the investigation.

Last edited by JamesGV; 3rd May 2014 at 08:23.
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Old 3rd May 2014, 08:58   #10411 (permalink)
 
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Originally Posted by Sheep Guts View Post
( maybe 20 hours rather than 2hrs though).
Not really necessary.
These things burn intensely/violently for less than 10s. The remainder will stop to smolder and burn in not much more than a minute if at all. It's this first minute that counts.
The important and difficult thing is to relieve the pressure and fireball that builds instantly without letting the hot gases ignite surrounding material or blow up the container. It's a bit like Black Powder. You mustn't allow it to build up pressure in its containment. If within 1 minute nothing else started burning the danger is more or less over.

Regular Suppression Systems are extremely important in order to extinguish surrounding material that was ignited by a LiIon fire. The volume of packs of cells should be small enough that the violent Initial fire doesn't directly cause structural or flight control damage. And the distance between packs of cells needed be sufficient that no direct heat Transfer between the packs can take place that would ignite the next pack. Fire suppresion must be capable of extinguishing other material that is stored between the packs. Then, everything should be OK. Putting all the packs in one Container is a bad idea since it enables one run away pack to ignite others and thereby creating a very violent fire.
Edit:
Regarding relevance for MH370: Probably very low. Almost 3t (!!!) of LiIon in one Container would in all likelyhood have brought the plane down in a few minutes once ignited. Hardly conceivable that it would smolder for hours.
The Trouble with the freighters is that they don't have suppression Systems (Which I consider a big mistake). Which means that the battery fire may be over after much less than 5 minutes but by then other flammable material will have caught fire and keep burning. The hint is in the smoke in those instances. LiIons create very little smoke when burning. Copious amounts of smoke indicate that other stuff has caught fire.

Last edited by henra; 3rd May 2014 at 09:39.
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Old 3rd May 2014, 09:32   #10412 (permalink)
 
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A thermal runaway in a lithium ion battery can be induced by either a heat source or a short across the terminals. Once one battery overheats it will induce a thermal runaway in other batteries close by.
This is the reason that there are strict rules about the carriage of these batteries. Some types of battery are CAO (Cargo Aircraft Only).
Having undertaken practical training in dealing with lithium ion battery fires, I doubt that this is the cause of this tragedy. These batteries are extremely explosive when in a state of thermal runaway so I doubt that the aircraft would continue to fly for several hours after the event.

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Old 3rd May 2014, 11:07   #10413 (permalink)
 
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Some thoughts on the ICAO report maps

The ICAO report analysis shows that routes can be generated from the start point to the final ping arc at a variety of speeds that are not impossible. Once a start point and a speed are selected there is only one choice for the Southern route (at least a route that has a chance of being close to the BFO data). I get speed changes of between 6 and 16degrees/hour for the first four route segments (a fit the red zone) and 1degree/hour for the 22:41-00:11 segment; the path looks roughly consistent with the report maps (figure 1). I get a slightly lower speed (311 against 323kt in the ICAO report) – the report analysis would have used wind corrections, I did not. Anyway, the precise route does not matter, the key issue is the BFO at the final ping arc(s).

Figure 1: Fit to the ICAO report start point and red-zone using a constant speed route of 311kt. To be clear this in not intended to prove the aircraft went to the red zone
Example Fit To The Positions In The ICAO Report Using A Constant Speed Course Of 311kt. Is Not Intended To Show That The Red-zone Is Correct Photo by RichardC10 | Photobucket

Red/yellow/green zones meaning: In the report map the 00:11 markers for speeds 323, 332 and 344 are marked with 30000, 15000 and 3000ft respectively. The ping-arc data is very slightly sensitive to the absolute height and the BFO not at all sensitive, so if heights has been used in these plots it must have used a change of height in the modelling. Also, if the fuel was exhausted at 00:18, flying at 344kt/3,000ft would not give a longer range than 323kt/30,000ft so these values are not height for the whole route. The rate of climb/descent is part of the overall Doppler due to the aircraft's own motion and is not corrected by the on-board system (as is clear by the change of BFO at 1710UT in the original Inmarsat graph - top of climb). So if the aircraft was descending at 00:11 the BFO value at the final ping arc would have been changed, giving a lower value.

The red-zone track states a final height of 30000ft, so no descent. The required descent rate for the 344kt track at 00:11 (green zone) to bring the BFO value back to that predicted for the 323kt track (red zone) is 230ft/min (4.2Hz in BFO). That would give a change of height of 21000ft in the 1.5hrs between 22:41 and 00:11, so compatible with the difference between the supposed height of 30000ft at 22:41 and the marked 3000ft at 00:11. Presumably work in the simulator has indicated some basis for this.

So in summary, the hypothesis:

a) The final BFO data (which we do not have – we have only the initial set released to the families) is a fit to the Red Zone.

b) The Red, Yellow and Green zones refer to possible rates of descent after 22:41. The red zone is the best match to the (assumed) 00:11 data with the aircraft level at 30000ft. If the aircraft was descending at 230ft/min the green zone would be the best match to the 00:11 data. It is taken here that some work on the aircraft analysis has given a basis for this.

c) This explains why there is no green or yellow zone North of the red zone. The aircraft is not expected to climb from 30000ft, so the BFO cannot be changed to deflect the final position North.

Again, here I am trying to understand the presented analysis, not offering some alternate model.
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Old 3rd May 2014, 11:49   #10414 (permalink)
 
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Thanks, RichardC10, great analysis.

To be resolved for me remains:

- flight was well above F300 at MEKAR, otherwise no radar contact from Butterworth was possible. It should have made good GS 460 kts from IGARI to MEKAR, otherwise times do not work.

- GS of 311 to 340 kts, needs a lower level to stay above minimum clean ; or non-clean flying; or circling; too low level would reduce range significantly (people with 777 flight manual will tell)

- the curved track cannot be flown with autopilot in HDG mode as magnetic variation is not consistent (maybe with any lateral mode off?)
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Old 3rd May 2014, 12:41   #10415 (permalink)
 
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Quote:
the curved track cannot be flown with autopilot in HDG mode as magnetic variation is not consistent (maybe with any lateral mode off?)
The report analysis does not require a 'curved' track, that is to say a continuous turn. As I noted, the rate of change of heading (averaged over each leg) is not constant so each leg just averages to a heading. Small heading changes make little impact on the average speed over that leg so do not invalid the analysis.

All the way through the AMSA/JACC maps, the possible tracks have been labelled with speeds, implying an assumption of constant speed (but not heading).

So, the following speculation (and I know nothing about B777s so this bit could be gibberish).

a. The analysis (after the turn) is based on the autothrottle being engaged, but at an unknown speed.
b. There is no heading autopilot maintenance mode engaged and the aircraft heading is wandering left and right, but with a general trend to the left which reduces with time during the flight.
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Old 3rd May 2014, 13:06   #10416 (permalink)
 
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Thanks, Richard,

a. (N1 selected) and b. are the same assumptions I made.
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Old 3rd May 2014, 14:20   #10417 (permalink)
 
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Lithium Ion Phobia

For those waxing poetic about Lithium Ion batteries, you have not traveled in an aircraft in the last 5 years that has not had tens of lithium ion batteries in the aircraft hold and passenger cabin. Even the Cathay Pacific rules upthread would allow 2 extended life laptop batteries (random packed by pax with cables and USB drives) in their checked bags - so in a widebody you have the potential for several hundred of these. And there HAVE been fires in the passenger cabin due to laptop fails.

Now as also said you have to come up with a practical way that a fire in the hold that would immediately trigger an alarm in the cockpit, could stop ACARS, SSR transponder and the three independent VHF radios in the short period of a simple change of frequency usually by selecting the 'other box' - without any distress call from the crew.

This would be a really severe fire.

Yet the aircraft flew a zigzag course across the Malaysian peninsula around the top of Indonesia and then flew South for another ~6 hours with continuous power to the SATCOM equipment.

So apply a modicum of logic to these theories.
I also second the idea of moving the detailed discussion on 'safety of LiIon Batteries' to the Tech Log in a new thread as it seems to excite 'heated reactions' in some posters here.

Last edited by Ian W; 3rd May 2014 at 14:25. Reason: add note on SATCOM
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Old 3rd May 2014, 14:38   #10418 (permalink)
 
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Richard

Quote:
b. There is no heading autopilot maintenance mode engaged and the aircraft heading is wandering left and right, but with a general trend to the left which reduces with time during the flight.
The team may correct me but I think that with a serviceable 777 autopilot engaged you're always going to have some form of "firm", non random non wandering lateral mode, even if it's as basic as some variation of attitude hold.
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Old 3rd May 2014, 15:15   #10419 (permalink)
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Ian W,
Quote:
Now as also said you have to come up with a practical way that a fire in the hold that would immediately trigger an alarm in the cockpit, could stop ACARS, SSR transponder and the three independent VHF radios in the short period of a simple change of frequency usually by selecting the 'other box' - without any distress call from the crew.
You are quite right About 3 different VHF sets and obviously there are 3 different antennas for these radios and different power Buses aswell. But how are the coaxial connections and coax run through the airframe to these antennas? That's what we don't know unless we have some B777 Avionics guys out there to tell us. If there are wire bundles or coax bundles, that could have been severed simultaneously because they were collocated .If that's been discussed and answered before please forgive me.

I agree with your "Lithium Ion phobia"synopsis. We have been flying many Lion batts for years. And it will only increase with the proliferation of Lithium Ion power sources and applications. That's why rules of carriage for the items need constant adjustment as new technologies are used. It needs to be proactive rather than reactive.

Last edited by Sheep Guts; 3rd May 2014 at 15:46.
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Old 3rd May 2014, 16:21   #10420 (permalink)
 
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Oxygen Fed versus Lithium Ion - Different animals

If the favoured theory is fire being the cause of the MH370 disappearance, I'd tend towards a known quantity, the cockpit oxygen fire - rather than the Lithium Ion battery cargo-fire. From the SAA's ZS-SAS (the Helderberg) Nov 87 downing onwards, all instances of Li Ion fires have tended to be self-sustaining and progressive, in particular those with large quantities of batteries - whether containerized or not. MH370 was carrying two metric tonnes of them. The Helderberg 747 Combi was carrying a large quantity of Li Ion watch batteries in its aft cargo compartment. Worthy of note is that its self-sustaining fire ate its way through the container and aft cargo compartment bulkhead into the forward pax area over a number of hours, enabling the crew to communicate their plight and inability to locate or quell the fire.
South African Airways Flight 295 - Wikipedia, the free encyclopedia

By comparison, the known quantity and prior experience of a 777 cockpit oxygen fire would:

a. make the flight deck more or less instantly (or at least quickly) uninhabitable due to intense heat and flaring (F/O's side first most probably).

b. alarm the flight-crew immediately to the extent that they would understandably misinterpret it as an electrical fire (thinking uppermost of Swissair 111 pilot errors of plodding through a lengthy checklist that kept power on the wires)....and they'd quickly start monitoring off all non-essential busses (quickly followed by flight essential busses - thus killing the comms and transponder). I'd guess that soon after the aircraft rolled out on its pilot-selected heading for Pulau Langkawi, all aboard could have expired - due to the limitations of cabin drop-down oxygen and the inability of the pilots to regain the cockpit and initiate or hasten any descent. The fact that MH370 did roll out on heading would tend to suggest that the autopilot was still functioning.... at least up to that point. Forget all priorities of aviate/navigate/communicate in any such instantaneous development. Personal survival would understandably be the paramount concern for the pilots. You cannot operate in an inferno.

c. An oxygen fire would burn out quite quickly with damage limited to very adjacent and localized equipments and control panels only (example being the early 1980's cockpit fire that destroyed the cockpit of P3B Orion A9-300 on the ground at RAAF Base Edinburgh South Australia). That fire was due to oil-induced combustion (not a chafing of electrics) and it was initially intense but not persistent or self-sustaining. After the initial flash-fire subsided, it simply smouldered. An airborne fire that pierced the 777's cockpit side-wall would have allowed any smouldering to quickly self-extinguish, even permit a surviving pilot to revisit what remained of the flight-deck.

d. An oxygen-based cockpit flash-fire would cause a rapid depressurization at Flt Lvl 350 due to hull burn-through - and consequent unconsciousness and death from hypoxia of all aboard. The piercing of the hull would tend to extinguish any interior fire.... but manual control via yoke may not have been an option (see photo below).

e. Pilots would have / may have found it necessary to quickly abandon the cockpit. Even if they made it to a portable oxygen bottle, it's a dubious proposition that they would have been able to return to and man the flight deck (let alone manually fly the airplane). They may have been later able to operate or restore some systems and even initiate a descent.

A Li Ion battery-initiated fire just doesn't fit the bill for the rapidity of known events aboard MH370. But it's logical that an oxygen flash fire (oxygen-fed only to the extent and so long as the cockpit oxygen pipes and pressure-hull remained intact) would be about the only other non-hijacking explanation for the instantaneous cascade of issues that led to the sudden loss of comms and squawk and the protracted MH370 ghost flight. Whether or not the pilot (or someone?) regained the cockpit and restored some electrics, selected a waypoint, autopilot etc after the fire subsided? Maybe, but depends on numerous factors. However the aircraft (due to its active controls and inherent stability) would still have been capable of autopilot-off flying a roughly sustained heading and tending to climb back up to height as fuel burnt off over the next six hours - due to its static trim state. Southbound and with a hole below the RH cockpit window might explain the Inmarsat-derived gradual arc to its right (i.e. due slight drag-induced asymmetry). Pilot(s) may have sustained fire injuries that caused one or both to succumb or to be unable to sustain themselves with portable oxygen bottles. The possibilities are many - but the plausibility for an oxy fire is intact.

Final Rule was only released by FAA a few days ago (the initiating ramp incident was in Cairo to an Egyptair 777 over three years ago).
"We are adopting a new airworthiness directive (AD) for certain Boeing Company Model 777F series airplanes. This AD was prompted by a report of a fire that originated near the first officer's seat and caused extensive damage to the flight deck. This AD requires replacing the low-pressure oxygen hoses with non-conductive low-pressure oxygen hoses in the stowage box and supernumerary ceiling area. We are issuing this AD to prevent electrical current from passing through an internal, anti-collapse spring of the low-pressure oxygen hose, which can cause the low-pressure oxygen hose to melt or burn and lead to an oxygen-fed fire near the flight deck.
UNIFIED AGENDA
Airworthiness Directives
1 action from October 2014"




The Most Likely Cause of the MH370 Loss and Ghost Flight)

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