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I think that you make a lot of interesting points until your final paragraph. If I'm reading the details properly (and I may not be; you seem to be far more in
by jMyles 7y ago
I think that you make a lot of interesting points until your final paragraph. If I'm reading the details properly (and I may not be; you seem to be far more informed than I am), then the particular test in question may have detected the problem about which Mr. Barnett is complaining, where other tests might not:
> Mr Barnett says that when he was decommissioning systems which had suffered minor cosmetic damage, he found that some of the oxygen bottles were not discharging when they were meant to. He subsequently arranged for a controlled test to be carried out by Boeing's own research and development unit.
> This test, which used oxygen systems that were "straight out of stock" and undamaged, was designed to mimic the way in which they would be deployed aboard an aircraft, using exactly the same electric current as a trigger. He says 300 systems were tested - and 75 of them did not deploy properly, a failure rate of 25%.
...or am I reading this incorrectly?
- soapboxrocket 7y agoYou are reading that correctly, but as someone who worked on the system over a decade ago, I bet he didn't have it setup exactly like the plane. I bet he tried to fire all the cylinders at once, a 25% failure rate in this configuration actually isn't bad. But on the actual aircraft they don't fire all of the cylinders at once, they are staged front to back because the power draw is too big to fire all the pyrotechnic devices at once.
- radus 7y agoReading heavily between the lines now but I would think that this person also had enough (though maybe not as direct) experience to know to stagger the deployment, no?
- soapboxrocket 7y agoNo. As a quality guy he probably has a lot of experience with the single units, but not the system as a whole. No line inspector would have a reason to test a full ship-set of units off aircraft, so I can't imagine a lab setup to do this test with the proper staging.