What - and return to the subject of the thread?
How dare you suggest that....
|Quoting AngMoh (Reply 99):|
It was stated in the local newspaper this morning that the fire originated in a passengers suitcase and was limited to 2 suitcases only.
I've not seen any other comments.
|Quoting bikerthai (Reply 85):|
I would venture to guess that the smoke coming out of the A330 did not get that bad until it reached the ground and the fire fighter opened the door when a fresh wharf of air rushed in and the fire could erupt again.
rcair can comment on this aspect.
It is a little hard to say - kind of depends on where the seat of the fire was relative to the door and any air introduced.
Fundamentally - going into a cargo bay fire by opening 1 door is not the ideal approach. When we attack a compartment fire (Fire fighter term for a fire in a "compartment" or "room") one of the step is ventilation.
A compartment fire will transition through 4 stages - Incipient (just starting - easily controlled), growing, fully developed and decaying. By recognizing the stages of the fire - what stage it is in - we can plan actions on how to attack that fire. An incipient fire - usually you can control by use of a fire extinguisher. This is your trash can fire that you put out.
In the case of this fire - remembering of course I know nothing but what little I've read about this fire - it probably went from incipient stage to a ventilation controlled growth stage. Basically - the fire can only grow as fast as the oxygen available allows it to. It will smolder - make heat and make short runs, but spread slowly. If the ventilation changes, either unexpectedly due to a compartment failure or due to tactics employed by the fire crew - it can rapidly grow to a fully developed state. This is "flashover" - the fire rapidly transitions from growing - particularly ventilation limited growth - to fully developed.
"Backdraft" - which many have heard of is essentially an explosive flashover induced by introduction of an outside air.
Ventilation - air available - is often the limiter to fire growth. So it is very common to approach a structure fire that is in this state. Fuels are super heated, ready to flash, but the oxygen is lacking. A door opens, a window breaks, boom - the fire is off to the races.
It may seem strange, but one of the key techniques we use as fire fighters on structure fires is ventilation. We carefully, and hopefully in a controlled fashion, introduce both a route in and out for smoke and gasses. Ideally we want to ventilate first on the 'out' part - open a path for the heat and smoke to go out. The roof, since the heat and smoke rises, is a good avenue - you ventilate the roof which immediately releases some of the super heated gas and smoke out. You then make entry and attack the fire from the "inside out". Basically - you are trying to chase the fire out the hole you created.
Often - roof ventilation is not possible, or too dangerous - so we will to a lateral ventilation. In this case - it is important to ventilate in a way the prevailing wind will help. You break a window downwind and then enter and attack.
What you don't want to do is open a window that introduces air and then spray water in it. A water stream actually carries a lot of air with it - so it is quite easy to push the fire into the structure and cause extension.
Back to this one.
I'm quite sure the fire in the hold was in a ventilation (and chemically) limited growth stage. It was smoldering and the lack of air and (I'm assuming) introduction of Halon was keeping it at bay. Obviously - it was not out.
Ideally - from a fire fighting standpoint (and I'm not a specialist in aircraft fires), you would want to locate the seat of the fire, then open a ventilation hole near it that was on the lee side (downwind). Then you would open the upwind side and attack from there.
Alternatively - and better - if you know where the fire is - you use a penetrating nozzle to get directly to it without introducing air.
In this case - it looks like they opened the cargo door and vented it that way - then went into a direct attack mode. By opening only 1 door - it is likely they limited introduction of the air - but it is also a bit risky (not that I'm saying they took a risk, or did something 'risky', but simply that there was risk involved. They may have had intelligence (information) on the temperature of the hold that allowed them to know that the was not a flashover risk. They may have had no choice. Perhaps they could see, using thermal imaging, that the fire was relatively localized.
I really don't know.... I just don't have the info.
As for 'producing more smoke when they opened it' - I'm thinking likely no. I'm thinking the hold was relatively full of smoke and they opened it and the smoke came out. Perhaps production of smoke ramped up a bit - but they obviously did not flash into a fully developed fire or we'd have a much higher level of damage. Whatever approach the a/c crew and fire crew took - it worked. Applause.