kalvado wrote:qf002 wrote:yeogeo wrote:On this subject, what struck me when watching the video (in post 8) was the mishaps on the slides- people bumping into each other, turning backwards, falling over every which way, that and the fact that there are many people on the slide simultaneously was shocking (naive, I know)... and then to bring a roller bag into the mix! Ouch - that has to hurt! No wonder they are so many injuries in evacuations.
I'm wondering what impact this could (or should) have on the way evacuation capacity is measured/tested. It's all well and good proving that 500 people can get off in under 90 seconds but what about 500 people plus 500 large suitcases?
And what is so special about 90 seconds anyway?
Sounds like more or less random number. 90 seconds is pretty fast; but why not aim at 60 or 120, why 90 was chosen? Something may explode 30 seconds after evacuation started, or it may take 5 minutes for things to go north. Or problem can be contained without actually endangering anyone in the cabin to begin with...
Years ago, the standard was set that a full cabin needed to be evacuated in 90 seconds, in the dark, with half the exits blocked, in order to achieve certification.
At the time, research suggested that 90 seconds would be a reasonable limit in terms of a burning aircraft approaching flashover point. Moreover, back then, seat cushions actually had TONS of toxic materials and so inhalation and so even if crash impact was deemed survivable, fatalities occurred because of fire, toxic inhalation, etc.
So the materials and construction have improved, but the standard should never be relaxed. Other crashes have informed evac discipline too--such as aisle path lighting, which was an NTSB recommendation and finally became universally adopted.