If anyone you know says they are incapable of making a mistake now and then, they would be lying to you. We all make the occasional blunder, some of them trivial and some monumental. But not many of us make the kind of mistake that can kill whole loads of souls, this whopper being reported by Aero News Network here:
The Australian Transport Safety Bureau confirmed Saturday it's investigating how, and why, engineers at Qantas accidentally filled emergency oxygen tanks on a Boeing 747 with nitrogen instead. The incident occurred at Melbourne Airport, reports The Sydney Morning Herald, and triggered an immediate check of over 50 planes serviced by the apparently mis-labelled nitrogen gas cart.O.K., you might think they have checks and balances in place to prevent such an awful and potentially deadly mistake. But in this case, you'd be wrong...again from ANN:
Qantas reportedly took delivery of the nitrogen cart 10 months ago, and "it looked exactly like the old oxygen cart. When the attachments did not fit they went and took them off the old oxygen cart and started using it.Jeez, Louise...hasn't anyone over in Australia ever heard of a PLACARD?
Since not all my readers are chemistry majors, I cannot assume they all get the implications of this post. So today I went sniffing around the Internets to find out exactly what happens when the cockpit loses pressurization and both pilots strap on the nitrogen masks...and it ain't pretty:
A typical human breathes between 12 and 20 times per minute. Normal air is about 78 percent nitrogen, 21 percent oxygen, and 1 percent argon, carbon dioxide, and other gases. After just two or three breaths of nitrogen, the oxygen concentration in the lungs would be low enough for some oxygen already in the bloodstream to exchange back to the lungs and be eliminated by exhalation. Unconsciousness in cases of accidental nitrogen asphyxia can occur within 1 minute. Loss of consciousness may be accompanied by convulsions and is followed by cyanosis and cardiac arrest. About 7 minutes of oxygen deprivation causes death of the cerebral cortex and presumably the medulla oblongata, which controls breathing and heart action.WOW. Now with something that deadly hanging around the shop, you might wonder if they should have giant green and red nozzles that are two different shapes to fit on two different nipples, one for oxygen and one for nitrogen. Maybe paint the oxygen cart orange, and the nitrogen cart purple...anything to allow even Bozo the freakin' Clown to tell them apart. You'd think the airline industry by now would have figured out a bulletproof solution to absolutely and completely eliminate the risk of this kind of mistake being made...ever.
Oh yeah, you'd think.