131–140 of 164 posts
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As far as i know you use three sensors, so you can automatically compensate for one failing/misreporting sensor without human intervention.
You can't compensate because you don't know which one is wrong. However you can make MCAS inactive whenever the two sensors are disagreeing with each other.
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Was this aircraft even under FAA jurisdiction? I thought the FAA only had jurisdiction over airline flights to and from the US.
Certifying aircraft is a long and expensive process. So generally speaking, aviation authorities 'share the burden' by relying on each other. By the same token, the FAA will take an EASA certification of an Airbus aircraft as valid without much additional checking. FAA's reputation alone was good enough for other aviation authorities to accept its certification of Boeing's MAX 8, which is why the FAA matter despite h…
The 737MAX was designed to compete with A320NEO .. why Did Boeing have to move the engines forward while Airbus did not ? AFAIK the NEOs weren’t a complete redesign either
The 737 rides significantly lower. Check out the 737-700/800/900 series and you’ll notice the engine cowl (inlet) is not perfectly round at bottom because of ground clearance. This is likely a design choice leftover from the original 737 series that used JT8D engines which are turbojet engines rather than high bypass turbo fans that make modern airliners efficient. Because Boeing has been so set on retaining the orig…
Putting on the Wild Ass Guess hat. I remember reading that the MCAS system uses the exact same physical contacts as the pilot's electrical trim adjustment switches. I'm wondering if they're trying to change their software implementation to more cleanly separate the two abstractions in the code in order to avoid having to do a hardware or firmware change on the jackscrew motor controllers. If before, the signalling wa…
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That's an irrational position. After the Ethiopian Airlines initial report was released pilots were discussing refusing to fly them even for ferry flights (i.e. no passengers). The Ethiopian airlines crew followed Boeing's post-Lion Air safety bulletin and still crashed. There's no safe way to operate a 737 Max in its current state. The hypothetical recovery techniques (e.g. point nose down to release pressure on the…
> The hypothetical recovery techniques (e.g. point nose down to release pressure on the horizontal stabilizer) only work at high altitude That's not quite right. Manually operating the motorized trim as soon as unwanted nose-down trim is detected prior to disabling it with the cutout switches appears to be a viable means of recovery. It's also an undocumented, timing-sensitive procedure in a critical phase of flight,…
That's what the Lion Air crew did. They died. The Ethiopian Airlines crew followed Boeing's safety bulletin. They also died.
But I do take your point, which may prove to be correct. It is hypothetically possible to electronically trim against MCAS then immediately cut out the electronic trim system before MCAS has a chance to re-initiate (5 secs after last trim command). Then you mechanically trim for the remainder of the flight, which should be possible without too much pressure on the horizontal stabilizer.
It is crazy to think that that may ultimately be the life saving procedure here, given its complexity/nuance. Particularly for a largely undocumented (for flight crew) system.
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This isn't a story, and I am not a character. If that's what you were using it like, you are wrong. It'd make at least some sense if you incorrectly meant "irony" in the sense that fucking with the FAA, which I said was bad, is how the MAX was made so poorly. Your fake choice of definition is even worse than what you actually meant.
Wow. Not only do you not understand irony, you apparently don't understand literature either. All the world’s indeed a stage And we are merely players Performers and portrayers Each another’s audience Outside the gilded cage
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> The hypothetical recovery techniques (e.g. point nose down to release pressure on the horizontal stabilizer) only work at high altitude That's not quite right. Manually operating the motorized trim as soon as unwanted nose-down trim is detected prior to disabling it with the cutout switches appears to be a viable means of recovery. It's also an undocumented, timing-sensitive procedure in a critical phase of flight,…
> Manually operating the motorized trim as soon as unwanted nose-down trim is detected prior to disabling it with the cutout switches appears to be a viable means of recovery. That's what the Lion Air crew did. They died. The Ethiopian Airlines crew followed Boeing's safety bulletin. They also died. But I do take your point, which may prove to be correct. It is hypothetically possible to electronically trim against M…
I find the design of this system shockingly ill-considered. At the very least, it should require input from both sensors and not activate if the sensors disagree. It seems to me a better system would be to automatically add some nose-down trim if the pilot applies full forward pressure on the stick since the primary underlying concern is insufficient elevator authority in certain impending stall conditions for that standard pilot response to be effective.
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> The issues are eminently fixable Not really. I am no expert, that is why I no longer trust FAA/Boeing telling me it is safe any more, at least in this particular case. As a passenger, I would avoid buying tickets from this plane even it means more cost
What about it isn't fixable? Redundant (and thus more reliable) AOA sensors + a less aggressive MCAS system that at maximum displacement can't override the yoke would be more than enough of a fix for me.
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No, that was never proven, and as another poster pointed out, the independent audit of Toyota's practices suggests that random and uncharacterized faults in Toyota's ECUs cannot be ruled out as causes for the unintended acceleration episodes. As another sign of this, Toyota both stonewalled the investigation and later fired the director of the division in charge of ECU engineering, and rebuilt the division.
>the independent audit of Toyota's practices suggests that random and uncharacterized faults in Toyota's ECUs cannot be ruled out as causes for the unintended acceleration episodes. >cannot be ruled out That seems like a very weak statement. If you asked a software auditing firm to inspect your massive codebase they're not going to "rule out" any bugs either.
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>the independent audit of Toyota's practices suggests that random and uncharacterized faults in Toyota's ECUs cannot be ruled out as causes for the unintended acceleration episodes. >cannot be ruled out That seems like a very weak statement. If you asked a software auditing firm to inspect your massive codebase they're not going to "rule out" any bugs either.
Have you read the independent report? The point of the report was that their engineering practices (both software and hardware) were so extraordinarily dangerous, the ECU was impossible to test with any authority. Its behavior was effectively non-deterministic in many of their cars from that era.