Hacker News Reader

Comment by twblalock | Hacker News Reader

Lots of jumping to conclusions going on in this thread, blaming the FAA, lobbyists, and politicians for being in the pocket of Boeing.

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.

View on HN

> The sudden rush to judgment on this case is unjustified by the evidence.

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?

And there is a perfectly plausible scenario in Lions air and preliminary data on the new crash point in the same direction (erratic altitude before the crash). It’s not like there is nothing, there are technical details that do match.

There are three scenarios, not two:

- 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.

Those secondary effects are all part of the first point: "lose money".

I'd say it's the opposite: the first scenario (ground the aircraft type) would suffer less from those secondary effects. Once all the airlines on your region are no longer flying that aircraft type, people no longer worry about whether they're flying on a MAX8 or a non-MAX8; they know they're flying on the "safe ones", so they have less reason to memorize the name, to check the aircraft type on their tickets, to tell their loved ones "avoid that airplane", etc.

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).

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.

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.

> Southwest, the biggest US operator of 737 MAX aircraft, bought the "AOA Disagree" option on their aircraft...If you have that, you get a warning that the flight control system is seeing bogus AOA data

How can something that important be an option?

It's starting to seem like the plane is not safe to fly without that option (and potentially some other changes that haven't been finalized yet). I'm surprised; I thought that the "nothing at the expense of safety" ethos was still followed in the airplane industry.

> 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.

Makes sense, thanks for the explanation.

Basically everything about this plane boils down to "it should require more training but it didn't"

> 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.

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.

Presumably the trim wheel spins/clicks when the mcas is doing its thing? Occasional weird electric stab trim behaviour has been a thing since the classic. I heard that 737 pilots are generally aware the electric trim can be switched off, or the trim wheel manually held for a more visceral solution. These things are not airbuses, the yoke is still connected to the elevators right?

> that airline has a bad safety record

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 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.

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?

Millions of dollars could save a lot of human life right now, even in America.

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.

Sure, then let's fly other unsafe planes types as well to save money, and hand the benefits to the poor!

Except, in which universe do airlines hands out their revenue to the poor ?

That's not the point. The point is that the comparison between people's lives and money is invalid.

Because scarce resources are a real thing, there necessarily should be a value to life, otherwise you are just ignoring reality.

I like how people downvote this, yet when stepping over homeless people in SV think "I only make $100,000+, and I need every bit of it, even if $20 could drastically improve this human's welfare.

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.

There is risk most any human activity. Your prudent thing would result in suspending any beneficial activity with any possible risk. The a prudent thing would be to err on the side of still receiving the benefits of 737 air travel.

Nobody is talking about ground the 737 - a very safe plane used thousands of times a day

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.

Nonsense. This plane right now has two out of about four hundred that crashed, which for a new plane is more than enough reason to hit the 'pause' button for a bit until we know or least think we know what went wrong.

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.

Did the E.U. ground the A320 when the Germanwings suicide pilot crashed the plane in the Alps, killing 150? Investigators didn’t know what brought that plane down for several days. Wouldn’t the prudent thing to do be to ground all Airbus A320s until the cause was confirmed? Did they ground the A320 after the Egyptair crash? They still aren’t sure what brought that plane down. But they didn’t ground the fleet. How about the Metrojet flight that crashed just a year earlier? At least 3 A320 crashes in as many years, but they don’t ground Airbus.

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.

Your comment is a very nice example of whataboutism. Let's remain on topic about two crashes, with very similar characteristic, with two brand new aircraft of the same model. This is unheard of in this day and age of stellar aircraft safety. If that's not reason for concern, I don't know what is. Another commenter has said to err on the side of caution, that's something the US / FAA should do in this case, but somehow is not. You can give all the reasons you want, but the facts take precedent: ~350 people killed in the same model aircraft and in a similar way, the FAA should act.

> Did the E.U. ground the A320 when the Germanwings suicide pilot crashed the plane in the Alps, killing 150?

Was there a similar-seeming crash of the same model a few months before?

Interesting that you mentioned Australia, who also grounded the plane. Clearly they're in the EU's pocked, right? Despite that Qantas' Boeing fleet is more than twice as numerous as their Airbus fleet.

> 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.

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?

Let it be clear that even if Boeing is not at fault grounding the plane is the best course of action in front of the limited evidence. Insight is 20/20, but we don’t have it. There are 2 planes whose altitude was erratic before their crash and a plausible common scenario to explain them.

I have a hard time feeling bad for Boeing in this scenario — playing ball in aviation means assuming a huge amount of risk, and meeting a ridiculously high standard. In return they have a fairly captured market, and a huge amount of political power. Historically that means you ground a plane and take the loss until you figure out what’s going on.

Reply on news.ycombinator.com