Originally Posted by craftmaster
Suffice to say I am not satisfied with where we are.
I agree wholeheartedly! Neither am I. I am not sure if I know anyone who is happy with the current situation.
I think the pressing issue, though, is cargo, because very very probably people have died, in more than one accident, and it is not clear the measures are in place to prevent it happening again.
Originally Posted by DERG
Once one of these batteries has gone off in a cargo hold...seriously..with more of them in the whole consignment..is there ANYTHING you can do?
Yes. General thoughts go along the following lines. First, you put cargo in containment vessels which are somewhat more robustly designed than current pallets. The containment vessels can contain thermal sensors (I am not sure if they already do, or only for self-declared "dangerous" cargo) which signal to the suppresion mechanisms. Then you starve the space of oxygen ASAP (flood with CO2, say). And then you cool it.
Wonderful in principle, but there are issues, as follows.
1. Designing the new pallets. This comes up regularly. The first time, I believe, concerning bomb-proofing after Lockerbie. Someone came up with a design that more or less worked (tried out on an old 747 in England), but it didn't prevail. Price-performance, I think. Since then, there have only recently been the computer-printer bombs that anyone has discovered, and none have gone off. The disadvantage to any pallet redesign is the cost. It will likely take a decade for a new design to become pervasive - pallets will be replaced as older ones are scrapped.
2. Thermal sensing and signalling to a airplane fire-suppression system. I think this is technically a solved problem, including the reliability of such systems. If the cargo airlines can control the pallets 100%, then pallet-level suppression might be an easier technical solution. However, all pallets would then need to be considered potentially-dangerous goods (there are suspicions that many clients fail to declare lithium batteries as "dangerous goods", for a variety of reasons ranging from ignorance to cost) and it is not clear this would be the more cost-effective solution.
3. Starving the fire of oxygen. I am not sure how well this is solved. In normal leaky spaces, if suffices to flood the immediate vicinity with something else, but in an airplane pressure vessel the displaced air needs to go somewhere, and that means pumping it out. Pumping stuff out violates the containment principle - maybe you would be pumping out flaming gas?
4. Cooling. I am not sure at all what people are thinking about this. I am not sure how well you can localise a cooling agent, and if you don't localise it then you are going to be cooling a largish airplane structure and that is going to have airworthiness consequences (though unlikely to be as pressing as the airworthiness consequences of an unsuppressed fire.
PBL