71–80 of 142 posts
A rather well-written piece. My takeaway is that the French investigators are pros and the Egyptians are hacks. And that safety culture matters. One must not bend the facts to draw a desired conclusion. One must review the data without bias, or else recuse oneself.
"Even though passengers have been forbidden from smoking on airplanes for 25 years, the rules about smoking in the cockpit are less straightforward, and international regulations appear to invest the captain with the authority to decide whether smoking will be allowed or not."On a somewhat related note, Egyptian science tends to suffer from a massive scientific misconduct (fraud) problem - see for example this paper by Egyptian authors, which covers the medical field: https://www.medrxiv.org/content/10.1101/2023.02.20.23286195v... Maybe the attitude towards "truth vs. face" is similar in Egyptian governmental institutions. Egypt in general is a low-trust society, scoring lower than India…
Of course it is, it's a brutal military dictatorship where the last (and only) democratically elected leader was overthrown by the army and died in prison. Those kinds of systems, where people are convinced their opinions and convictions don't matter, lead to problems like this
Earlier quoted context omitted.
> That's not actually quite how it works. What you wrote is not contradicting the parent, who just said that it was “super effective at starving the fire of oxygen”. You just described the mechanism. You also contradict yourself by first saying that halon is inert, and then that it neutralises oxide ions by swapping halogens, which is the opposite of non-reactive. The effect of that is that it immobilises reactive ox…
Typically, "starving of oxygen" means that there's not enough oxygen around anymore. That's how CO2 extinguishers work, for example. They literally remove enough of the oxygen to make the combustion stop. Halon does NOT remove the oxygen, there's always plenty of it available. Instead, it stops the chain reaction. > You also contradict yourself by first saying that halon is inert, and then that it neutralises oxide i…
That makes me wonder if any of the original designers of the oxygen system considered whether a halon-oxygen mix would've been better than pure oxygen.
Tragedy from a Swiss cheese failure - several small holes/failures all line up. The issue of halon extinguishers versus oxygen-powered combustion producing many toxins while failing to extinguish is interesting - good that: > Halon fire extinguishers are scheduled to be phased out of most commercial aircraft by the end of 2025.
This really is a non-issue. If you're at the point where toxins from halon pyrolysis are a problem, then you're likely already dead from other factors (heat, smoke, etc.). Halon can works even at concentrations of just 2-5% by volume. This is entirely safe to breathe for humans. There's a video of a person discharging a halon extinguisher in a room, and then proceeding to try to light a cigarette. The matches go out…
Earlier quoted context omitted.
Of course it is, it's a brutal military dictatorship where the last (and only) democratically elected leader was overthrown by the army and died in prison. Those kinds of systems, where people are convinced their opinions and convictions don't matter, lead to problems like this
This might get the causality backward. Most high trust societies were high trust before, not after, they became democracies.
In all tests, the fire, propelled by the oxygen leak, produced a terrifying “blowtorch” effect, and the flames were literally white-hot. Sufficient concentrations of oxygen can cause even steel to burn: https://en.wikipedia.org/wiki/Thermal_lance There must be a reason they use pure oxygen, as regular compressed air, also breathable, would not have the same intense reactivity.
Pure oxygen at 1/5th standard pressure has the same effect as air at standard pressure, and assuming nitrogen and oxygen compress similarly you can either fit 5 times more in the same canister, or you can have a canister 1/5th the size and weight.
Earlier quoted context omitted.
In commercial aviation the vast majority of tragedies are Swiss cheese failures, at this point. The system has worked very hard to optimize out the possibility of any one individual failure leading to catastrophe. But the explosion of potential combinations - along with the extremely low odds of them ever occurring - makes preparing for one of them much less feasible.
I'm surprised that a catastrophic runaway oxygen leak is possible on an aircraft in todays day and age. Aircraft design is dominated by strict safety regimes that take into account even far fetched scenarios. Putting one valve in the rubber hose sounds sub optimal. Gas station pumps, for example have a valve that closes if the hose gets torn away. (which does happen when people forget about the pump and drive off). F…
While there is some amount of proactivity in aircraft safety I'm not sure there are people with enough free time that they can make up failure modes or trawl through every minor incident report until (again as in the case of TFA) prompted by an actual failure, unless one of the minor incidents is itself proactively raised as a major risk avoided by blind luck.
With all the high speed trains in Europe, I'm wondering why we don't see more security around them. It seems a much easier target than airplanes.
People are generally not afraid of terrorists hijacking or bombing trains, so security theater isn't necessary there.
Bruce Schneier book "beyond fear" is over 20 years old and not outdated a bit.