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Comment by cletus | Hacker News Reader

One wonders if the problem of the MAX won't be effectively solved by the Covid-19 triggered recession. With people flying less, it's a pretty good reason to cut aircraft orders, no?

At some point the 737 gravy train was going to end. There's only so long you can maintain the same type rating on a traditional (ie not fly-by-wire) plane where you eventually want to change the handling (as the MAX did by putting on large engines and moving them to compensate).

So those who made the decision to go with the MAX rather than the engineer-favoured solution of a complete redesign (because the MAX was going to be ~2 years faster to market and have a captive market of 737 type rating airlines like Southwest) are ruing that decision. Or at least if they hadn't collected huge bonuses for years and were in any way held accountable for a bad call, which sadly they are not.

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However it resolves, COVID-19 should not be expected to have significant lasting effects on long distance travel. Worst case scenario is a slight sustained drop due to the global population being cut by as much as two percent.

And at the risk of being controversial or callous, the bulk of the deaths are likely to be the elderly. Premature deaths of elderly people wouldn’t have a long term effect on population.

> And at the risk of being controversial or callous, the bulk of the deaths are likely to be the elderly. Premature deaths of elderly people wouldn’t have a long term effect on population.

That’s assuming that the virus doesn’t mutate any further.

(Did not downvote you. It isn’t a good subject, but we do need to talk about it)

I agree, there's a lot of unknowns.

I'm gonna channel Nicholas Taleb and bring up a couple points:

1. Nobody really knows for sure. Predicting the future worst case by comparing it the worst instance from the past in the category is a fallacy (I get the sense you're comparing it to the spanish flu, but consider that the past "worst case" was already surprising to people back then because it was worse than the "past's past")

2. It's not enough to look at pure probabilities, it's also necessary to consider the magnitude of loss for each outcome. For example, Russian Roulette with 100 slots for $100 has a median gain of $100 per round, but you wouldn't want to play that game.

3. I'm not brave enough to put my money on the line but if you're confident you could buy long term options on airline companies and make out like a bandit when travel recovers.

4. this virus could have similarly severe outbreaks for years.

I've thought about this too. What is the probability this becomes endemic to China, and occurs annually in the fall/winter? Related question: why didn't swine flu become endemic (maybe it did, I haven't read anything about swine flu since 2009)?

because regardless of what you hear, china takes outbreaks very seriously and responds aggressively. the general population in china also takes it very seriously. normal behavior response in china looks like over reaction in the us. please watch this video by 3blue1brown https://www.youtube.com/watch?v=Kas0tIxDvrg china is past its inflection point and we have yet to determine where our inflection point will be. everyone should be changing your behavior now. the fact that sars-cov didn’t get as far in 2002 as sars-cov-2 virus is currently going should be concerning. the us could ignore prior outbreaks because china is aggressive to stop it.

I was in China during the swine flu scare (I'm Canadian originally). I agree that China takes these sorts of things very seriously based on what I saw.

That doesn't necessarily mean they'll succeed every time though, or that they'll respond as aggressively to a dangerous background virus as to a novel one.

I saw a recent paper which presented a model which did predict seasonal reinfection... provided the infection rate is low enough now and that infection rates are reduced in the summer vs winter. If all the mitigation efforts work well now and covid 19 is similar to flu in seasonality the model predicted we would have a lull from May a new outbreak in November.

Something to keep in mind Covid-19 has already taken a foot in multiple countries in the southern hemisphere, where they are going to enter fall pretty soon. This already reduces the possibility that it will totally fizzles out due to northern hemisphere summer.

There are far fewer people at the climates for a northern winter south of the equator.

Sydney winter for example is around 10C, and rarely drops to 5C. Joburg's winter mean is about 10C.

Compare that with London, New York and Beijing.

you could buy long term options on airline companies

Not right now. The implied volatility, aka the cost of options, is too high.

For example, American Airlines, symbol AAL, closed Friday at about $16 per share. If you go to January 2021, the cost of a $20 strike call is about $3. So you need AAL to rise from $16 to $23 just to break even. That's almost a 50% gain needed, in less than a year.

The cost of options will get much cheaper once the market settles down (even if current price levels stay the same). If the market sits in the doldrums for a few months (not moving up or down very much) then option prices will fall.

You need to buy options when they're cheap, not when they're crazy expensive.

I’m curious - why is that so? I would assume that with higher volatility there are more people participating in the futures markets, and the margina should be lower - not higher

Margins will be lower but the prices will still be higher.

In low vol periods: if stock is at $2, it is likely to stay at $2 since vol is low. So maybe a $3 option is worth 10 cents. But there are very few people in the market so there's going to be a large big-ask spread. Nobody's going to sell it at 10c; there are few other sellers so you can offer it at 15c and rip off the buyer since they have no choice.

At high vol periods everyone wants to be in the market so the price will actually be close to the 10c theoretical price - less spread (what you. All margin). But since there is high vol the stock is more likely to get to $3 so the option could be worth 20 cents instead of 10.

Volatility affects price; market volume affects spread.

If you think options are overpriced you can sell options too. They're crazy expensive because people think they'll print.

Actually if this results in a lot of young people staying at home what you will probably see is a mini baby boom, same as what happened in previous recessions.

Since airlines are cutting schedules, the virus should theoretically reduce the compensation Boeing has to pay airlines for lost revenue while the plane is grounded.

There's nothing wrong with the concept of MCAS. Just it's implementation.

Its implementation and the corporate culture that pushed for that.

Just as there's nothing wrong with communism, just the Soviet Union's implementation.

> Just as there's nothing wrong with communism, just the Soviet Union's implementation.

There are many who would make exactly this argument, FWIW.

Do they all happen to work for Boeing?

Have you seen a good implementation yet?

In the US: https://en.wikipedia.org/wiki/Twin_Oaks_Community,_Virginia

I don't know, I feel like designing a system to prevent a pilot from lifting nose too high up seems to make more sense than a system that actively pushes the nose down after it being lifted. If nothing else, passengers would feel a bit of a discomfort of a sudden nose down movement. Not sure if I missed something in the current design.

> I feel like designing a system to prevent a pilot from lifting nose too high up seems to make more sense than a system that actively pushes the nose down after it being lifted

Lifting the nose too high can induce a stall, which is very dangerous at low altitude.

Yep. Also pitching the nose to far down to prevent a stall.

No it's not about comfort. MAX engine shroud is too far forward to the point it act as canards creating pitch up force at high AoA, in a self reinforcing manner into a belly up into irrecoverable stall. MCAS prevents this by quickly pushing nose down back into airstream.

I believe there were discussions earlier on that the FAA requires all civilian airliners to have positive static stability, aka CoL comfortably behind CG so air resistance straightens the attitude without inputs.

The opposite of positive static stability is Fly By Wire based 4th-gen onwards jet fighters like F-16, that has CoL only barely aft of CG, that replace aerodynamic stability with electronic PID controllers multiplexed with manual axis inputs for each axes. Those planes could go into a spin over some axis that make sense if at any moment FBW loses control.

The fact that MAX needed MCAS, an FBW-like system, to meet FAA standards is itself wrong, and implementation to make it a ghetto nonredundant trim system rather than full FBW is also wrong.

> into irrecoverable stall

My understanding is it wasn't enough to push it into a stall, the MCAS would just moderate the pitch up slightly so it behaved like the 737.

> to meet FAA standards is itself wrong

The FAA mandates that all jet airliners since the 707 have a yaw damper to correct for "dutch roll" instability. Augmented controls are normal on jets.

> The opposite of positive static stability is Fly By Wire based 4th-gen onwards jet fighters like F-16

The risks introduced by fighter jet lack of static stability are mitigated by the installation of ejection seats. That's a tough sell for passenger aircraft.

The 737 MAX is statically stable. There are quite a lot of uninformed comments floating around that compare the plane to fighter jets like the F-16, but these are pure nonsense. An F-16 would tear itself to pieces in seconds if the flight control software malfunctioned.

It seems more to be that people use the word "stable" while maybe another word should've been used. The main criticism during the "stable" criticisms is that something like MCAS was added. The design of the plane should've been in such a way that MCAS wouldn't be needed. So instead of adding MCAS, the problem leading to MCAS should've been solved with a (huge) redesign.

Note: Purely responding to the "stable" word. If people compare it to stuff like an F-16, then yeah.. they don't know / nonsense.

>MCAS, an FBW-like system

As WalterBright says, there is nothing 'FBW' about stability augmentation systems. In various forms these have been installed on all commercial jets for decades. 'Fly by Wire' simply means that there is no mechanical/hydraulic linkage between the stick and the control surfaces. The 737 MAX is not an FBW aircraft by any stretch of the imagination.

There's a lot wrong with the existence of the MCAS being a lie on top of a compromise made for other compromises. Being inessential if it was not born on the love of 'not doing it right because it is difficult'. Additionally it was f*d up in the process, yes.

There is a lot wrong with a plane intended to transport people that requires such a system in order to be safe to fly.

It requires the system to avoid training pilots.

And, yet, it does require proper training after all...

Only training to do what they are supposed to do anyway - use the cutoff switches when experiencing runaway trim.

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