|MadSci Network: Engineering|
Dear Friend: To carry on a safe jump from an airplane some special conditions must be taken into account. Air temperature, as well as atmospheric pressure are very important to our body life functions. Itīs impossible for someone to survive more than 20 seconds or so in the high altitudes usually flown by most airliners nowadays (more than 35,000 ft) without some kind of "astronaut" clothes. Itīs impossible to breath, the temperature is very low (-50 degrees below water freezing temperature), everybody looses consciousness in less then 30 seconds, freeze in less than one minute. Thereīs no time to free-fall and reach a lower (and warmer) altitude. But, what about a low altitude accident? In that case the time elapsed from the alarm failure and emergency procedures until the hipotetical parachute evacuation of the airplane (remember, just two or four doors for almost 200 passengers...) is so high that itīs almost certain that the plane had already chashed in the meantime. Also, airliners doors are not prepared to be fully open during flight, so as you can see parachute and big airplanes does not team very well... The only situation that I can imagine where parachutes would be useful is, perhaps, more common than accidents: highjacks. I think a controlled evacuation could be attempted. However the air speed impact over the passengers and the structure problems that would arise from opening doors are not predictable. I hope to have been helpful in showing you some interesting points about that parachute business. Best regards, Fernando Grau ps. just for the sake of curiosity, there is a new aircraft (a little one, just four seats) that has a new integrated parachute system for the hole airplane!! It have been already tested and approved by FAA (Federal Aviation Administration, responsable for aircrafe security).
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