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Wreckage of MH370 washing up on Reunion Island?

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wasyoungonce:

--- Quote from: SeanB on August 03, 2015, 06:12:26 pm ---Cargo of used lithium cells, and one in the middle is almost at failure. At take off it is fine, but as the hold depressurises to cabin cruise pressure it expends slightly, then this triggers the cell to short internally.  It heats up from the stored energy, and heats up the other used cells in the same pack. The cell protection will not prevent this, as the cell is failing internally. The failing cell eventually bursts and the vapour released catches fire, fuelled by the heat and the ambient air and the hot cells around it. This then triggers the other cells, and they also start to vent and burn the plastic housings. The smoke released, along with the CO and other toxic chemicals in the smoke are circulated by the plane's AC system, and as the first vents are the cockpit the CO starts to build up. The pilots might then notice smoke in the cockpit, and  start to initiate a RTO immediately, programming in the waypoints in reverse order to get there. By now the smoke probably has triggered a loud cargo hold smoke alarm, a fire warning alarm and a few caution warnings as the smouldering fire starts to burn cargo hold wiring. The pilots, thoroughly confused, wearing possibly masks, are trying to contain and triage this sudden unexpected pattern of events, not covered fully in the simulator, where an engine fire is the most common simulation. Thus one or the other mistypes a waypoint, and confirms without checking, setting the autopilot on a track to some far off waypoint via a great circle. Fire by now has burnt through control wiring for the cabin entertainment, and trips breakers, taking out at the same time one AC bus and one DC bus. Aircraft systems reconfigure to a failed state but keep running in degraded mode, and there are suddenly a whole load of new warnings on an already overloaded crew.  fire burns through control wiring and half the cabin instrumentation goes dead, and kills the comms systems and radios. Fire burns through bottom of cargo hold, and vents cabin pressure at a rapid rate, dumping the smoke, but the crew have already lost consciousness from the sudden pressure loss popping the masks off them, and they fall down unconscious.Impact.

--- End quote ---

Good points...but any fire that takes out comms and NAV would have disable all Inmarsat systems (no handshake pings), avionics and flight controls.   Swiss AIR 111 is a typical example, though fire was near cockpit.

kosmonooit:
Like I suggested earlier it could be partial avionics and power circuits failure due to thermal stresses  - cutting out the comms, leaving some instruments on line, source could be a dodgy connection, chaffed live, whatever, has happened before, electrical fires are hectic. Details can only be pure speculation, but have 'they' been looking at possible scenarios? But its this vs the suicide plane, that I have difficulty with. As any student of aviation safety will know, expect the unexpected, in terms of things going wrong, how humans react, most of the accidents are not due to one single cause, but a number of smaller things, that in themselves would not be significant or fatal.

Li Ion cargo sounds more like a conspiracy theory, yes there have been issues in the past, but surely aviations authorities would not be complacent about that if there were indeed tangible dangers for them as cargo? Beside the overheating due to over charging, which is well know, and also temp problems with high/ long current drain like Solar Impulse recently experienced (Tesla has a liquid cooling system in their battery pack) Remember the Dreamliner Li Ion problems? they just did workarounds "The causes of the battery failures are still unknown"

https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems

But batteries in the hold, out of any circuit ...? hmmmm (as Dave would say)

Wytnucls:
Lithium ion batteries are not allowed in the cargo holds of airliners anymore.
The 777 has class C cargo holds with smoke detection and halon fire suppression.

cimmo:

--- Quote from: AG6QR on August 03, 2015, 08:47:51 pm ---There is NO unpressurized cargo area in a modern airliner.  There are areas that lack forced-air ventilation, with no temperature control, and these areas are unsuitable for pets and other live animals.  But they are at the same pressure as the cabin.

--- End quote ---

Exactly. In point of fact, there were a few accidents involving cargo door failures (DC10s mostly) that depressurised the cargo area so quickly that the cabin floor failed due to the differential pressure. In one case the failing floor cut (or jammed) flight surface control cables and the aircraft was lost (Turkish DC10).

That is why in newer designs (and retrofitted to older aircraft) there are now weakened blow out panels or vents in the floor that allow the pressure differential to quickly equalise to avoid further structural damage.

BTW, typical pressure differentials are around 8-9PSI (~0.6Bar) - I'll leave it as an exercise to calculate the total forces involved for a large airliner fuselage.

wxm145:
feel very sad for mh 370 :'(

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