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FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

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Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#121

When the Boeing CEO had his press conference in April, he said "we've confirmed that the MCAS system as originally designed did meet our design and safety analysis criteria and our certification criteria."[1] I yelled at the screen "you know that means the criteria are flawed , right? If the procedures didn't catch this mistake, that means there are other mistakes that weren't caught!" A flabbergasted reporter then a…

You can't be serious! Did you literally yell those words at the screen?! That's pure madness.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#122

I hate the fact that all discussion focuses on the software and ignores the airframe.

What's the problem with the airframe? What's the problem with the larger engine nacelle causing a different pitching moment? I've yet to read either of those violate any portion of FAR 25. There is still an open question whether the MAX should have or will have a separate type certificate from other 737's, thereby requiring pilots of a type rating to fly the MAX, thereby requiring full disclosure and training on all differences.

Which pilots should have had anyway, even if it didn't require a new type rating.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#123
post #39

Earlier quoted context omitted.

It's worse than other such planes. For instance, the accident on Qantas Flight 72 is superficially similar - faulty data caused the Airbus A330's flight computer to ignore pilot input and abruptly pitch down, injuring a number of passengers - but it really wasn't. The Airbus engineers knew that angle-of-attack sensors fail, so unlike Boeing they designed their system to compare the input from multiple AOA sensors and…

> That pattern shouldn't have been possible Huh, this is new to me. I thought it was simply that two sensors failed, and their failed values outvoted the correct value in the quorum vote with the third sensor. What's the mystery about?

Section 5.3: https://www.atsb.gov.au/media/3532398/ao2008070.pdf#page225

A microprocessor failed and output corrupted data.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#124

Earlier quoted context omitted.

Of all the many problems of the Boeing 737Max situation, and there are several, for once I don't think the media reporting is one of the biggest. But, your basic point stands.

The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. The investigative reporting from The Seattle Times[0] indicates that safety engineers were pressured to avoid delays to rush out a competitor to the A320. Furthermore, their safety analysis was based on flawed assumptions to meet an artificial constraint of not requiring pilot simulator training in order to appease th…

Fukushima? That doesn't belong on the list. There is some limit to any engineering decision. Complaining about MCAS is totally reasonable, but it would be unreasonable to argue "The Air Max is not safe because if I hit it with enough Stingray missiles it won't fly anymore." Like, yeah? No kidding?

Fukushima was designed to survive the earthquake, and it did, it just wasn't designed to survive the earthquake and also the tsunami.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#125
post #51

Earlier quoted context omitted.

To be fair, ignoring user input could have potentially have saved Air France 447... I mean I actually can't think of an automated fool proof system that would've fixed 447, but incorrect input was a major factor.

IIRC, the cockpit voice recording included a comment from one of the co-pilots about how pulling back on the yoke couldn't cause a stall. The assumption was that the Airbus's fly-by-wire system would prevent it and ensure the aircraft still climbed as long as the pilot held back on the stick. The co-pilot apparently didn't realize that the sensor issue that disabled the autopilot also disabled the stall prevention. A…

Exactly - the computer had switched contexts, but the pilot hadn't. And expecting pilots to switch their mental map of expected behaviour when the computer does (and did so with, from the accounts I read, very minimal indication that it had done so) during a high stress situation, is asking for trouble.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#126

Earlier quoted context omitted.

Like the European Aviation Safety Agency?

So the FAA says "this is fucked" and and the EASA says "they're all good bro"[1], who do you side with? [1] feel free to flip flop regulatory agencies if you so desire.

The fact that they disagree is what is notable. The FAA lost credibility by being the last to ground the MAX. You side with the one that has a history of not being wrong.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#127
post #88

Earlier quoted context omitted.

The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. The investigative reporting from The Seattle Times[0] indicates that safety engineers were pressured to avoid delays to rush out a competitor to the A320. Furthermore, their safety analysis was based on flawed assumptions to meet an artificial constraint of not requiring pilot simulator training in order to appease th…

> The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. So the same problem that pervades society everywhere now? I’m not sure if that wasn’t the case before, but it feels to me that people previously wanted to make lots of money by building great products, and they’ve just left the ‘building great products’ part behind.

That is exaggerated. It doesn't pervade everywhere.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#128

I hate the fact that all discussion focuses on the software and ignores the airframe.

The aerodynamic/stability effects of moving the engine position is a complicated topic, and I haven't seen a really good thorough explanation of it yet that really goes into the gritty details. There's so many rules of thumb and generalizations in the vast majority of peoples' understanding of aircraft stability and forces, even for pilots or engineers in the field.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#129
post #79

Earlier quoted context omitted.

What amazes me about this whole sorry saga is what appears to be blatant deception on the part of Boeing. Boeing somehow tricked the FAA into believing, from the pilots perspective the 737-MAX and 737 were the exact same plane. That allowed the plane to enter service quickly as it meant the pilots would not require any flight simulator retraining. What we now know is the 737-MAX is nothing like the 737 and the level…

I don't think they "tricked [them] into believing". More like "talked them into accepting".

The only difference between these two descriptions is whether the FAA implicitly understood that the MAX is NOT the same as the 737. If yes, then they were talked into accepting it anyway. If no, then they were tricked (unless Boeing genuinely believed that there was no difference, which is clearly false.)

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#130
post #64
post #59

I'd be pretty comfortable flying it after all this attention and review. It will probably be the best reviewed passenger plane software developed in America, if not the world once this is over. Boeing deserves a 9-figure fine though, and its shareholders should lose massively to make sure this doesn't happen again.

I'm not convinced. The pressure on Boeing to fix this ASAP is immense. That is not a good environment for writing safety critical software. Especially if they are doing a "broader software redesign". I don't believe that software quality can be enforced from the outside.

For anyone writing software controlling machines it is pretty much the status quo. It has to be darn near perfect, updating it later if it is even possible will be expensive and inconvenient As much as it is a shitty environment if you have 6 months to fix it and all of the company resources you can think of to ask for that is lots of time.
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