The worst case scenario (for Boeing), at this point, is the FAA and/or other aviation regulators, decide that the differences require different type certification for the aircraft and therefore mandate a unique type rating by pilots to fly the plane. That would require they be trained about those differences.
And
https://www.seattletimes.com/seattle-news/times-watchdog/the...
There are more than enough reasons to reasonably decertify the aircraft. When you start doing things that "fly-in-the-face" of industry best practice, and begin requiring the most liberal interpretation possible of regulations as written, it's time to start dialing back what you're willing to let slide.
Even with these "minor tweaks" to every fuselage, the airframe can reasonably be assumed to have further problems.
As a for instance, what happens if a dual flameout in flight occurs? Does the Ram Air Turbine make enough power to run the Flight Control Computer and all it's dependencies to ensure the MCAS functionality stays intact until the plane can be safely touched down?
If not, will there be simulator training so pilots are prepared?
There is more than enough publicly available information to be cause for concern.
Isn't MCAS a solution to address greater nose pitch-up due to stronger thrust vectoring effects from the new engines? In a dual engine flameout where all thrust is lost, doesn't thrust vectoring cease to be an issue?
That's why this damn kludge of a system is so concerning. It's an active airworthyness hack to counter a passive aerodynamic characteristic of the airframe.
So if a double flameout occurs, killing all power, and killing the Flight Control Computer due to unreliable voltage being supplied from the Ram Air Turbine, the pilots are stuck flying a glider that'll try to pitch into a stall on them if they aren't careful.
Again, normally wouldn't worry about something like this, but they missed/intentionally left out the single AoA sensor...
So...yeah... I have severe concerns about this design, and the effort put into known, unlikely, but highly severe failures.
Maybe you shouldn't post such strong statements about a technology you know very little about.
First: The 737 does not actually have a RAT.
Second: On types that have a RAT (e.g. the A320) it isn't electrical, it provides hydraulic power to operate the flight controls.
If you need emergency electrical power from a RAT equipped aircraft it will be from an haudraulically driven AC generator through a constant speed drive. It will not have voltage fluctuations, only risk is frequency being off and aircraft systems are designed to deal with that.
The article you cite doesn't even mention FAR 25. The strongest statement it makes is this: “to address potentially unacceptable nose-up pitching moment at high angles of attack at high airspeeds,”
For my purposes, that whole statement is rendered useless bullshit by the word "potentially". It's like saying "maybe, maybe not, who is to say?"
That statement in the article implicates the 737 MAX as not conforming specifically with FAR 25.173(c), but does not come right out and say that. Further, no source has said, one way or another, that the FAA permits computers as an aid to certifying airworthiness for designs that without computers would not be certified under FAR 25.
There is not enough public information to decertify the plane. Realize exactly what you're really saying: the airplane should not have been certified airworthy to begin with. You can't really decertify it without, in effect, saying malfeasance has happened. It isn't merely that MCAS wasn't good enough. It's that it should never have been considered appropriate to use software to paper over aerodynamic problems in the first place.
Am I suspicious that's what has happened? Yes. But is my suspicion evidence or a relevant fact that demonstrates it has happened? No. And all we have with articles thus far is speculation and suspicion. Where are the facts that prove this?
I can't account for what pile of fecal matter will be shoveled on the FAR's to justify the MAX, and to be honest cmurf, I believe it was a post of yours that ended up galvanizing for me that something is incredibly wrong with the MAX. The fact is, regulations in the United States seem to become negotiable after a certain size actor starts coming into play, and like it or not, that's the way it's worked since I've been around to see it.
Seattle Times found documented proof of non-compliant curves. You might find 'potentially' magically turns something into 'bullshit', but as someone who works in risk management, and is well versed in the physical sciences, "potentially" means that something is likely enough not to be trivially discounted, and requires an effort to remediate. It means "the potential exists; there is no known law or other invariant that reasonably discludes or prevents outcome X from being the case". If there is anything to being an Engineer, you have to admit that the the word "potentially" means something coming from them.
Seattle Times also broke the story on how Boeing regressed switch functionality in order to make sure the Stabilizer Trim cutout procedure lined up with what was already documented, but failed to provide educative material as to why the change, or also ensuring that pilot's who knew they could isolate the autopilot from the trim motor without cutting out their trim switches no longer could.
60 Minutes reported on active attempts to circumvent FAA scrutiny (decision to go with the single sensor input). I won't go as far to put names on actors, but there is more than enough stink of malfeasance that the poor engineering decisions, the motivations behind changing the focus of the company from high quality aircraft design to shareholder value generator, and the actions of current regulators in dragging their feet to deal with the problems that have been uncovered should stoke righteous indignation at the nerve of people who purport themselves to be responsible stewards of the public's safety to be so sheepishly approaching what is one of the biggest demonstrable breaches of the public trust of our time. These are not suspicions. These are not suppositions. This happened. You want to know where the facts are? Grab a pencil, some paper, and a computer, and crack open a few books on aerodynamics, numerical methods, CFD, and simulations. Then, run down as many dimensions as you can. This will act as the foundation for your coming aerodynamics analysis. Read through some white papers. Reason. Look at different plane designs, understand how different trade-offs effect the machine.
Don't feel like becoming an aerodynamicist in all but the job/paycheck? Then you'll have to live with the outputs generated by the media like everybody else, or say screw it, and do your best to understand the science anyway.
You can wait for the lawyers; I've worked through enough to assure myself that if the rest of the world dropped the issue tomorrow, I'd still not put anyone I cared about on those planes on principle, and on the basis of too many unanswered questions. I have no compulsion to do anything to help Boeing's image, and the shots I fire I ensure have sufficient grounding in what is reasonably deduceable from publicly available information to not be a bad faith hindrance. If they want things cleared up. They can put all the information where God and everyone can see it. The concern with the RAT being deduced from the Gimli Glider iincident; where the electronics getting knocked out ended up leaving pilot's with very few automation aids to land the plane. Just because it happened due to a fuel screwup doesn't mean it's outside the realm of possibility of happening from something else.
Boeing thought suppressing difficult questions would save them money when their product is on the drawing board; they have no right to expect us, the public to accept their 'reasoned gamble' for the sake of their shareholders.
I'd rather get ideas out there and looked at now, while the scrutiny is hot, that nothing else slips through the cracks.
I'm not going to make this personal cmurf. I'm just not.
But I'm not going to stand by idly either and project an image that everything is a-okay, in the air, totally not worth getting in a fuss over. It isn't, and we shouldn't pretend it is. I'm not out to warp words. I'm out to chase every damn thread to see where it goes, or to inspire someone else to do so if there is someone with the means and access to ensure the truth sees the light of day.
60 Minutes https://m.youtube.com/watch%3Fv%3DaO7_indbfME&ved=2ahUKEwji6...
Culture shift: https://www.bloomberg.com/news/features/2019-05-09/former-bo...
Switch regression: https://www.seattletimes.com/business/boeing-aerospace/boein...
Gimli Glider: https://en.m.wikipedia.org/wiki/Gimli_Glider#History
See the previous article from Seattle Times for the history. Call their investigative reporter if you are truly that concerned w.r.t the provenance of his information.
I don't need to make anything up. Boeing took care of that for us. It's up to us to be informed, and make sure in no uncertain terms is anything remotely like this ever deemed acceptable again.
Also, the thrust change nose-up moment is not much different to a 737 classic or 737 NG; MCAS is required due to the lifting moment of the engines, which are in front of the center of gravity (thus pulling the nose up when in a positive AoA situation).
The actual risk is complex, an airline with more capacity depending on the new model has more risk as they take on new planes and retire old ones, but does the contract reflect that complexity? I have no idea. For all I know, there's generic terms for handling all certification problems that crop up, including airworthiness directives from the FAA that affect A&P's rather than pilots. It might be the two sides split the cost 50/50 for all I know, or maybe they use binding arbitration to keep the airing of dirty laundry as much out of the public view as possible.