Originally posted by BoeingBobby
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Originally posted by Evan View PostSo this "muppet" is the CEO of Boyd Group International, who is a self-professed "well known as an expert in futurist aviation issues".
This is March 13th and he's confident that we will have the MAX back in the air in two weeks. Because the software fix is only for the 'brown people' from 'sh*thole nations' with low hours who "really shouldn't be in the cockpit"?
And, as of April 8th, is anybody still considering him a "well known as an expert in futurist aviation issues"?
Cuz he don't know jack about this one.
https://www.youtube.com/watch?v=NbOdm7u8mfU
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Originally posted by NY TimesFormer Max engineers, including one who worked on the sensors, said adding a third [AoA] sensor to the Max was a nonstarter. Previous 737s, they said, had used two and managers wanted to limit changes.
“They wanted to A, save money and B, to minimize the certification and flight-test costs,” said Mike Renzelmann, an engineer who worked on the Max’s flight controls. “Any changes are going to require recertification."
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Originally posted by Evan View PostOriginally Posted by NY Times
Former Max engineers, including one who worked on the sensors, said adding a third [AoA] sensor to the Max was a nonstarter. Previous 737s, they said, had used two and managers wanted to limit changes.
“They wanted to A, save money and B, to minimize the certification and flight-test costs,” said Mike Renzelmann, an engineer who worked on the Max’s flight controls. “Any changes are going to require recertification."
There is not too much wrong, either, with not adding a 3rd sensor and keeping 2 sensors like in the previous generations of the 737.
But there is a lot wrong on having 2 sensors and then using only 1 of them for a system where, if this single sensor malfunctioned for whatever reason, can simultaneously trigger IAS disagree, alt disagree, FD disagree, false stickshaker and nose-down runaway trim. For God's sake, you don't need a PhD in aeronautical engineering to note that this is wrong. I don't understand the logic behind not using the 2 sensors already installed in the airplane. Was the MCAS code going to be more expensive with inputs from 2 sensors? Was the testing and certification going to be more expensive? I think not, not in any meaningful way at least. And if there was any slight difference, here goes the saying:
Those who think that safety is expensive should try an accident.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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On the subject of hours experience in the right seat and/or the left seat......
How do you get 5,000 hrs experience ?
Well, you start at 1 hour and........
.........................
On the subject of actual hands on per flight, I’m manually flying it, it’s not on autopilot hours......
On take off = maybe 5 minutes as a maximum.
On landing = maybe 10 minutes ‘ish.
Bobby, am I about right there ?
Following on from that, an intercontinental pilot on a 12hr or more flight gets the figures above just once in their working day.
A short haul pilot flying two hour sectors 5 times a day gets the same experience x5
Just a thought !If it 'ain't broken........ Don't try to mend it !
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Originally posted by Gabriel View PostThere is nothing intrinsically wrong with A, saving money and B, minimizing the certification and flight-test costs.
There is not too much wrong, either, with not adding a 3rd sensor and keeping 2 sensors like in the previous generations of the 737.
I also see dedicated Boeing engineers, some of the best in the business, being forced to comply. Hopefully they start talking and some stuffed shirts go to prison over this.
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in addition to jail for the chief players, boeing should be made to disgorge 100% of what it is calculated to have saved by cutting corners as it did, and 100% of that should be distributed to the families of those killed by boeing's greed. let this method of restitution stand as a warning to boeing and all others of the REAL price that will be exacted if they put money before safety.
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Originally posted by TeeVee View Postin addition to jail for the chief players, boeing should be made to disgorge 100% of what it is calculated to have saved by cutting corners as it did, and 100% of that should be distributed to the families of those killed by boeing's greed. let this method of restitution stand as a warning to boeing and all others of the REAL price that will be exacted if they put money before safety.
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Originally posted by TeeVee View Postin addition to jail for the chief players, boeing should be made to disgorge 100% of what it is calculated to have saved by cutting corners as it did, and 100% of that should be distributed to the families of those killed by boeing's greed. let this method of restitution stand as a warning to boeing and all others of the REAL price that will be exacted if they put money before safety.
We want to see the 797 rolled out over the coming decade, and for Boeing to reclaim the trust of the people who depend on it.
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Originally posted by BoeingBobby View PostI am a commercial rated glider pilot as well. Still soar as often as I can. Soloed in a sailplane on my 14th birthday
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Originally posted by Evan View PostTell that to the certifying authorities in the mid-1980's, when you wanted to have a computer override pilot control. Don't be naive Gabriel, Boeing knew very well that such systems require a fail-operational level of redundancy to be truly safe. They took a roll of the dice to reduce costs and avoid a costly and lengthy re-certification process, and we were the chips on the table. Their greatest concerns seem to have been 'time-to-market' and 'time-to-profitability'. It appears to me that every decision at that time was driven by shareholder value. Take a peek at the stock price from beginning around the time the Max was announced to the present and you see a lot of wealth suddenly being generated, when, in reality, they had already dropped the ball on the 737 replacement and were caught off-guard by Airbus. I see the desperate efforts of a toxic executive culture with a short-term focus and a willingness to deceive both customers and investors--and cut corners on safety--in return for market share and market capitalization.
I also see dedicated Boeing engineers, some of the best in the business, being forced to comply. Hopefully they start talking and some stuffed shirts go to prison over this.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by Gabriel View PostI don't think you got my point. Please re-read my post. I wont argue that 3 sensors is better than 2 but would you argue that 2 is way better than 1 (i.e. fail operational is better than fail passive but fail passive is way better that fail push down) and that 2 sensors were already available and that only code was needed to use these 2? (code that was also needed for 1, since there was no pre-existing code for the MCAS).
The reasoning behind the single-sensor method is apparently driven by the system architecture. As I understand it, the left sensor feeds the CPT-side FCC and the right feeds the FO-side FCC, so whichever is dominant determines which sensor is being exclusively relied upon. The dominant FCC in use changes with every flight cycle. To fix this, Boeing must add comparator software and a second sensor input to each side. It might not be so simple. These are 90's vintage avionics. I hope some clarity on this obsolete systems architecture results from this investigation.
My point is that the certifying authorities established a new standard, back in the 80's, for flight-control avionics that interpret or override pilot commands and Boeing has somehow skirted those standards.
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Originally posted by Evan View PostYes, I agree that any redundancy is better than no redundancy. But this sort of thing requires a system that can compare at least three sources to verify the erroneous one. Your suggestion of 'sensorless' AoA might be a solution, but it is a very new technology. I would prefer a third sensor requirement here.
The reasoning behind the single-sensor method is apparently driven by the system architecture. As I understand it, the left sensor feeds the CPT-side FCC and the right feeds the FO-side FCC, so whichever is dominant determines which sensor is being exclusively relied upon. The dominant FCC in use changes with every flight cycle. To fix this, Boeing must add comparator software and a second sensor input to each side. It might not be so simple. These are 90's vintage avionics. I hope some clarity on this obsolete systems architecture results from this investigation.
My point is that the certifying authorities established a new standard, back in the 80's, for flight-control avionics that interpret or override pilot commands and Boeing has somehow skirted those standards.
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Originally posted by BoeingBobby View Post[ATTACH=CONFIG]23329[/ATTACH]. All it would have taken. Know your aircraft and it's systems. That is what the type rating is about.
THE TRIM MECHANISM OF 737's GENERALLY JAM AT EXTREME SETTINGS AND HIGH SPEEDS.
It's in writing.
Gabieee explained it above (in somewhat nicer terms).
The report indicates that the crew did a seemingly acceptable job trobleshooting their problem (which included stick shakers and speed disagree an INTERMITTENT nose overs), and DID REALIZE THEY SHOULD KILL THE TRIM AND DID KILL IT and did attempt to nose up with manual trim and elevator inputs...
The trim apparently was jammed by aerodynamic forces.
Did I say that the trim tends to jam by aerodynamic forces?
It's one thing to see a stand-alone trim runaway...It's another thing to see intermittent trim input when multiple OTHER warnings are going off...a little delay, and the trim tends to jam up.
Did I mention that the trim can jam by aerodynamic forces, in a long-known response to extreme control and trim settings?...Like when the plane is sneakily, but aggressively nosing over because it's convinced it's stalled...
and the trim basically locks up...
If the crew did something wrong- it appears they weren't reading ass-hat parlour talking aviation forums about strange nose-over behavior of Lion air...Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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