E.U.’s Biggest Economies Ban Boeing Max 8 Jets • Hacker News Board

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#271

Post by DuskStar » Tue, Mar 12, 2019, 7:56 PM UTC

wikiwawa wrote: post #261

kharms wrote: post #189

Earlier quoted context omitted.

We have some idea of a crash rate for safe airplanes. Something like: P(Crash|Miles Flow & Hull Age) If we assume this airplane is safe, we can apply that probability to it and then ask P(2 Crashes|N Miles & 350 New Planes). You would then have a probability for this just being bad luck, and compare that against your prior that this is a safe plane. I haven’t done the math, but my gut says it would point to grounding…

The mean of a Beta Distribution (2, 348) ( https://www.wolframalpha.com/input/?i=beta+distribution+(2,+... ) is roughly half a percent, much higher than the 1 in 11 million across all flights ( https://www.quora.com/What-is-the-probability-for-an-airplan... ). (You can pretty much always make statistical inference, with uncertainty going up with the lack of data)

I highly doubt there have been 11 million airliners manufactured, though - and that's what the 348 number is.

If we assume that the average MAX 8 has been in service for a year (first delivery was a little less than 2 years ago), and conducts 4 flights a day, we get this [0] - a mean of 1/250000. Still worse than 1/11000000, but only by a factor of 50 instead of 50 thousand.

0: https://www.wolframalpha.com/input/?x=0&y=0&i=beta+distribut...

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#272

Post by anoncoward111 » Tue, Mar 12, 2019, 7:59 PM UTC

riazrizvi wrote: post #257

anoncoward111 wrote: post #119

Earlier quoted context omitted.

Two crashes in 6 months and there's only 350 planes in existence is a pretty bad safety record that is probably on par with Tupolev. The US can tacitly blame "third world" pilots all they want, but with 300 people dead already, I think it's important for the FAA and Boeing to say exactly what is going on, especially since the planes are in use in the USA. There is a debate over if the plane's hardware, software, or p…

The Boeing Max 8 entered service in May 2017. Assuming a linear deployment rate, the 350 planes in service have seen an average life of 10 months. Assume 4 flights/day, that's 420,000 flights so far. 2 have gone down. A best estimate of the likelihood that a plane goes down (MLE), p = X/n = 2/420,000 = 1/210,000 ~ Binomial(n=420,000, p=P(crash)). According to the Economist [1] the likelihood your plane goes down gene…

This is excellent data and calculation work. I really appreciate it!

I have a suspicion that if you were to remove all instances of terrorism and look at the crash rate of Boeing vs Tupolev, almost all Boeing planes would be way better except for the MAX 8.

That is probably a meaningful piece of data too.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#273

Post by notacoward » Tue, Mar 12, 2019, 8:01 PM UTC

xcyyyy wrote: post #202

mrdodge wrote: post #152

Earlier quoted context omitted.

Those were produced pre-FAANG, Boeing probably paid comparatively better then. Do the smartest software engineers flock to Boeing in 2019? I think the relatively low pay and status of software engineers outside of the Bay Area is a huge risk to society. We are going to start seeing it show up in interesting places.

God forbid that FAANG engineers ever work on aerospace software...

I work at a FAANG company, and I feel the same way. I don't mean that as a criticism of my coworkers. It's just a different ethos. Not only are no lives at stake, but all copies of the software are visible and modifiable at will. How's that system doing? Oh, it's slow because this part was tuned incorrectly? Boom, pushed a fix. People come to rely on it. They rely on it so much that anyone who emphasizes prevention too much will get dinged for moving too slowly.

It's actually a valid POV for that environment, but it has been difficult for me to adjust. I'm sure it's even harder for them to adjust the other way, to an environment where you don't even know who's running your code until they report a catastrophic failure. Prevention hardly seems like a waste of time then.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#274

Post by nas » Tue, Mar 12, 2019, 8:05 PM UTC

jimbru wrote: post #9

Areading314 wrote: post #3

Does anyone actually know or suspect what's wrong with these planes? Hardware issue? Software issue?

There's speculation that the crash was caused or contributed to by the MCAS system, which is new on the MAX 8. At this point it is just speculation. Here's a good answer from Reddit: https://www.reddit.com/r/aviation/comments/azzp0r/ethiopian_...

So much speculation is going on. The angry mob has already concluded that the MCAS must be the cause. Greedy Boeing was too cheap to redesign the plane and made a cheap software hack to fix it. Sneaky computers are overriding the decisions of the poor helpless pilots. The FAA is too incompetent to certify aircraft, etc etc.

Based on what I read, the truth is a lot more complicated. The MCAS doesn't work the way most people seem to think it does. Maybe it is a factor in the crashes. We don't know that yet.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#275

Post by usrusr » Tue, Mar 12, 2019, 8:06 PM UTC

jakelarkin wrote: post #264

sfilargi wrote: post #146

I urge people to read the discussion by pilots regarding the 737 MAX. https://www.airlinepilotforums.com/safety/120514-ethiopian-7... It all comes down to this: "There are far too many aerodynamic bandaids that are permitted to pass the current standards. Not just this particular airplane, but a whole bunch of airframes. If the basic aerodynamics won't pass without the pushers, pullers and now AOA induced changes to…

"the plane should never have gotten the green light to fly." this is an overstatement. airframe fuel efficiency is a undoubtable good thing vis a vis climate change, costs, etc. Obviously they've reached a point were the aerodynamic profile of a modern, efficient airframe is difficult to control via manual pilot input alone in some scenarios. This was the case for stealth technology with fighter/bomber designs.. the…

An aerodynamically sound redesign to accommodate the high bypass engines would have been just as fuel efficient as the version with confusing software band-aids.

If it is cheaper to invent something like MCAS than to properly adapt the airframe, then maybe the processes that would be used for the latter are ripe for some efficiency optimization.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#276

Post by joe_the_user » Tue, Mar 12, 2019, 8:08 PM UTC

anovikov wrote: post #267

zanmat0 wrote: post #252

Earlier quoted context omitted.

>if you do as the pilots want and achieve very high aerodynamic stability through the air-frame instead of stability control systems (fly by wire essentially) it reduces the aerodynamic efficiency of the airliner It's crazy to me that that would be an acceptable compromise.

Obviously stability has to be achieved through fly by wire tech. Doing it through natural aerodynamic stability is a waste of resources of insane proportions as such airframes induce more drag and burn more fuel. If this sounds too scary for people in a forum of software developers it only puts a shame on our profession, from ourselves.

No one knows better than software engineers how difficult it is to make inherently reliable software and how much complexity can add to the difficulty of making reliable software.

That said, the cost of not using latest fuel efficient airplane would indeed be huge and the actual reliability of modern aircraft is very high and has been increasing over the years in which fuel efficiency also increased.

Sometimes, human can hit on a formula that produces objects that satisfy all the given parameters more fully rather than compromising on any of the requirement. But it's quite plausible that these formulas cannot be milked forever - thus the "Max" may be the point where tradeoffs stop working.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#277

Post by nas » Tue, Mar 12, 2019, 8:09 PM UTC

DannyBee wrote: post #16

swarnie_ wrote: post #7

Earlier quoted context omitted.

The speculation I've seen is around a change to the autopilot system which pilots ave been struggling with: > Following the Lion Air crash, US aviation authorities issued an emergency directive to carriers to update flight manuals with information on what to do when the aircraft’s anti-stall system is triggered by erroneous data from what’s called an “angle-of-attack” sensor. The flight system can react to that data…

Traditionally the fly-by-wire systems have at least 3 AoA sensors, which each "vote" on the output value. That way, if you have one faulty sensor, it gets outvoted. The MCAS system in the new 737-MAX's only have 2 AoA sensors, which means a single faulty sensor can cause bad things to happen.

MCAS is not a fly-by-wire system. Pages and pages of speculation by arm-chair aircraft designers going on. So depressing.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#278

Post by AsyncAwait » Tue, Mar 12, 2019, 8:12 PM UTC

bryondowd wrote: post #100

Svip wrote: post #38

Earlier quoted context omitted.

Over 300 people dead sounds pretty serious to me. It's probably safest to ground the plane model until we know more.

I've seen a number of people pointing at this likely being more an issue with untrained pilots than the plane itself. EI, the flight crew on the crashed planes may have had considerably less experience than the minimum requirements most major airlines and all US airlines set for flying these planes.

This seems like corporate PR blaming "3rd world pilots" and am not sure it's such a smart move. If your plane requires substantially different handling & the interface does not accommodate it, it seems to me the problem is not the pilot.

It seems more likely that the plane suffers from some elemental design problems that were insufficiently patched over to pass inspection in order to protect the already invested capital.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#279

Post by edoloughlin » Tue, Mar 12, 2019, 8:12 PM UTC

anovikov wrote: post #267

zanmat0 wrote: post #252

Earlier quoted context omitted.

>if you do as the pilots want and achieve very high aerodynamic stability through the air-frame instead of stability control systems (fly by wire essentially) it reduces the aerodynamic efficiency of the airliner It's crazy to me that that would be an acceptable compromise.

Obviously stability has to be achieved through fly by wire tech. Doing it through natural aerodynamic stability is a waste of resources of insane proportions as such airframes induce more drag and burn more fuel. If this sounds too scary for people in a forum of software developers it only puts a shame on our profession, from ourselves.

such airframes induce more drag and burn more fuel

As a curious bystander, I assumed using fly by wire tech to achieve stability would involve using control surfaces, which increase drag by their nature. How would an airframe that's naturally stable and doesn't require control inputs burn more fuel?

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#280

Post by briandear » Tue, Mar 12, 2019, 8:12 PM UTC

anoncoward111 wrote: post #119

eric_b wrote: post #109

At the gym today, on all the TVs, the media talking heads were crucifying the FAA for being "unsafe" or playing fast and loose with passenger safety (for not grounding the planes). I've always held the FAA in high regard, and think they do a good job. Are they really being negligent here? Or is the media just looking for something to spark outrage? Can anyone with more specific knowledge of aircraft safety weigh in?

Two crashes in 6 months and there's only 350 planes in existence is a pretty bad safety record that is probably on par with Tupolev. The US can tacitly blame "third world" pilots all they want, but with 300 people dead already, I think it's important for the FAA and Boeing to say exactly what is going on, especially since the planes are in use in the USA. There is a debate over if the plane's hardware, software, or p…

How is the FAA responsible for crashes outside of its jurisdiction? There haven’t been any 737 Max 8 crashes in the US. I can’t speak for Ethiopian, but Lion Air and Indonesia in general have a pretty bad safety record. Lion Air was removed from the EU safety blacklist in 2016. In 2013 another Lion Air 737 (not the Max 8) crashed into the ocean near Bali. Lion Air has had pilot test positive for crystal meth (2012). Lion Air has had multiple major incidents with various 737s over the past years.

The Ethiopian Air copilot only had 200 total hours of experience. In the US, you need an ATP certificate with a minimum of 1500 hours to even be a first officer.

Before we start throwing sand at the FAA, why not ask how a 200 hour pilot gets into the copilot seat of an airliner. Let’s also ask why Lion Air failed to fix a problem with the airspeed indicator. During a previous flight the day before the crash, the pilot reported a problem with the airspeed indicator and deactivated the anti-stall system. Lion Air didn’t fix the problem and the airplane crashed the next day. But that’s Boeing’s fault? Lion Air is a shit airline with a horrible safety record. Southwest Airlines uses only 737s and you can count their major incidents on one hand and their fatalities in over 47 years? Just 1.

Lion Air fatalities? Hundreds over multiple incidents. Ethiopian Air? Much safer than Lion Air, but much less safer than Southwest. Ethiopian has a fleet of 108 airplanes and Southwest has a fleet of 754, including 35 Max 8 planes — yet not a single incident despite flying an order of magnitude more frequently than those other airlines.

Air Canada has 24 8 Maxes in the air as does American. Along with Southwest, that’s hundreds of flights per day without incident, but then there is a crash with some third world Lion Air plane where maintenance is provided with proverbial duct tape and Ethiopia Air who has a student pilot as the first officer? Perhaps instead of grounding specific airplanes, we should ground specific airlines, because it’s clear than Ethiopian and Lion Air ought not be flying until they can figure out the basics such as maintenance and pilot training.