It might not be justified by a theoretical formal proof. It irks me that a lot of the HN population seems to always want to reason using formal proofs like if it was a silver bullet.
In this situation, bayesian inference is appropriate, and tells us that grounding planes is highly justified. This succession of two relatively similar events in a new plane is enough to raise the probability of "this aircraft model has a problem" a lot, and definitely enough to justify grounding them.
Also, the risk / benefit ratio is not symmetric, what is better:
- Ground them for nothing and lose money
- Not ground them to save money, and see a third crash happen, killing 150 again
If you take into account those two effects, it's clear that grounding the planes is a sane option.
Finally ask yourself: would you board this plane today if you had a ticket? What would you think when there is turbulence after takeoff and the plane suddenly pitches down for a second? What color would your pants be?
- Ground them for nothing and lose money
- Not ground them to save money, no crash happens before the cause is found and a fix is deployed
- Not ground them to save money, and see a third crash happen, killing 150 again
And that also doesn't consider secondary effects, like the loss of confidence from the public on that aircraft type, or the potential confusion from the public between 737-MAX8 and 737-800.
The third scenario is the worst case, if there's a third accident with the same cause (or at least perceived to have the same cause), the reputation of the 737-MAX8 will get tainted, and that taint could even spill to other 737 variants (less knowledgeable people don't know or care about the many variants of the 737, to them "737" is the airplane type).
Yes. And the recorders have angle of attack data. We'll know within days if it's another AOA sensor problem.
Southwest, the biggest US operator of 737 MAX aircraft, bought the "AOA Disagree" option on their aircraft, and recently added an AOA indicator. Many operators didn't get that option; Lion Air didn't have it. If you have that, you get a warning that the flight control system is seeing bogus AOA data. It is somewhat less of a safety issue if you have the backup systems.
Why this aircraft was ever offered without "AOA Disagree" sensing is unclear. The single active AOA sensor can force the nose down. The pilots can switch to the other flight control computer and use the other AOA sensor, but at that point they're losing control of the aircraft.
How can something that important be an option?
Based on other comments here and in other discussions, it seems like adding that feature would increase the training requirements for the pilots since it is an additional instrument in the cockpit. I don't know whether it was Boeing, Boeing's customers, or both who pushed for the instrument to be an option. Any combination is plausible, and I'm not going to rush to judgement like a couple of my sibling commenters just because it's the fun and popular thing to do.
Basically everything about this plane boils down to "it should require more training but it didn't"
This seems like an important factor. I wonder if that's the reasoning behind the FAA not grounding the planes and assuming most US airlines have this system in place.
Could you substantiate the above claim ? Whatever I have read indicates Ethiopian has a very good safety record.
e.g. The airline has a safety rating of six stars out of a possible seven on respected aviation site AirlineRating.com. Source: https://thepointsguy.com/news/despite-recent-crash-ethiopian...
The prudent thing would be to err on the side of caution and suspend it until we know. What's millions of dollars (which I think is way exaggerated for a temporary suspension until the evidence is in) compared to a real risk of loss of human lives?
Thinking like that does not result in 'suspending any beneficial activity with any possible risk', it just suspends this activity with a roughly 0.5% risk of incidence until the causes are clear.
There are plenty of other aircraft in the world, also many non-Max 737's.
This is the 737-max, a new plane with very little history, barely used, and had been involved in two crashes with similar circumstances in the last 6 months.
Who in their right mind downvotes this? I realize HN is not representative of America, but I think if you take a moment to notice all the homeless people you step over on your way to work in SV you'd reconsider.
Except, in which universe do airlines hands out their revenue to the poor ?
Because scarce resources are a real thing, there necessarily should be a value to life, otherwise you are just ignoring reality.
Then when they board a flight on their own: "millions is not too much to spare! No cost is too great for my life!"
It is a double standard.
If it were a Boeing airplane, you can bet the EU would have grounded them. Given the E.U. has provided about $22 billion in subsidies to Airbus, it makes perfect business sense for the E.U. to ground Boeing 737s, but not ground Airbus when there are Airbus crashes.
In 2012, Australian safety engineers called for the grounding of the A380 due to significant structural cracks, in Qantas and Singapore airplanes, yet Airbus refused. Is it fair to say that the E.U. and Airbus cared more about profits than safety back in 2012? Has the E.U. ever grounded an Airbus plane ever?
Let’s not make the mistake of assuming benevolence that which is better explained by profit or politics.
Was there a similar-seeming crash of the same model a few months before?
And if it turns out there is a fault, hundreds of lives can be saved. What losing side of the wager do you want to be on?
Nobody knows why this plane crashed. The flight recorders have just been recovered and so far there has been nothing in the news about what was on them.
The plane might be to blame. The airline or the pilots might be to blame, and by the way, that airline has a bad safety record. It might have been a bomb, or a fire caused by a passenger, or many other things.
The sudden rush to judgment on this case is unjustified by the evidence. If it turns out this was not Boeing's fault, a lot of people are going to have to eat their words, and millions of dollars will have been wasted for nothing.