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Boeing 737 MAX is stupidly designed

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Boeing 737 MAX is stupidly designed

Old 03-27-2019, 11:21 AM
  #241  
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Originally Posted by Rico2 View Post
Boeing messed up big-time.

End of story.

All you "know it all's" can say all you want, but design, communication, and/ortrainingwere substandard to say the least!!!!!

Lots of dead men women and children are the result.

You don't need to be an aerospace engineer to be able to apply common sense reasoning.

PS.....some of the most stubborn bullheaded people I've ever dealt with are engineers.
As proven in this thread.

Multiple brand new airplanes flying straight into the ground, and some people don't see a connection, SMH.
No, but you do need to have all of the facts to place blame on an incident. Something nobody on here has.


Is it likely Boeing screwed up?.... possibly.

Is it asinine to say "Boeing messed up big-time. End of story." without having the facts...... Absolutely
Old 03-27-2019, 11:24 AM
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Originally Posted by Kenny Powers View Post
No, but you do need to have all of the facts to place blame on an incident. Something nobody on here has.


Is it likely Boeing screwed up?.... possibly.

Is it asinine to say "Boeing messed up big-time. End of story." without having the facts...... Absolutely
Yeah I know you want more facts.
Engineer are you?

there are enough facts to know that either design training or communication were substandard. That's all I said, I never said that the plane was defective.
Old 03-27-2019, 11:28 AM
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Originally Posted by Rico2 View Post
Yeah I know you want more facts.
Engineer are you?

there are enough facts to know that either design training or communication were substandard. That's all I said, I never said that the plane was defective.
I agree with this. The problem is Training is not owned by Boeing.

But yes, engineer turned program manager, with a deep understanding of how part 121 pilot training works.
Old 03-27-2019, 11:37 AM
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Originally Posted by MUHSFINK07 View Post
Ok so instead of the common sense approach that the previous posted claimed what is YOUR explanation?
I don't have one yet, but it also appears from the available data that the pilots did not use the procedures that had been established - for decades - to disable automatic trim systems if there was an issue. It appears that on the previous flight it took a guest pilot to remind/inform the flight crew that it was the proper procedure, and when they did it, it resolved the issue and not only did not crash, but didn't even divert...they continued on their normally scheduled flight. It's early, but I'd be inclined to say "third world training" probably played some critical role too.
Old 03-27-2019, 11:47 AM
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Originally Posted by Kenny Powers View Post


Is it likely Boeing screwed up?.... possibly.


Here is one of Boeing's just announced fixes for the Boeing 737 MAX: "The plane's Maneuvering Characteristics Augmentation System, or MCAS automated flight control system, will now receive data from both angle of attack sensors, instead of just one."

I think any reasonable person can conclude with this corrective action on Boeing's part, that it was a design flaw to allow MCAS to be activated with data from a single angle of attack sensor instead of by two sensors especially given the fact that the angle of attack sensor had been replaced the day before the crash due to faulty readings in the Lion Air jet which crashed. There were 50 reported problems with angle of attack sensors in the USA in the past 5 years.
Old 03-27-2019, 11:58 AM
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Originally Posted by Kendall View Post
Here is one of Boeing's just announced fixes for the Boeing 737 MAX: "The plane's Maneuvering Characteristics Augmentation System, or MCAS automated flight control system, will now receive data from both angle of attack sensors, instead of just one."

I think any reasonable person can conclude with this corrective action on Boeing's part, that it was a design flaw to allow MCAS to be activated with data from a single angle of attack sensor instead of by two sensors especially given the fact that the angle of attack sensor had been replaced the day before the crash due to faulty readings in the Lion Air jet which crashed. There were 50 reported problems with angle of attack sensors in the USA in the past 5 years.
Speculating on the control laws here, but 2 could provide more problems than 1. What happens when there is a mismatch between the two sensors?.... Maybe then the MCAS system is disabled, I don't know.

If it's disabled then you've lost that safety feature when you could actually need it. The 737 AoA sensors are on opposite sides of the fuselage, so if a stall was entered and one wing dropped, the sensors would most certainly disagree.
Old 03-27-2019, 12:02 PM
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the sensors would trigger the MCAS system before one wing dropped. It is being reprogrammed to take input from both sensors as long as they are within 5.5 degrees of each other. If one exceeds that number then they disagree and the MCAS system turns off.
Old 03-27-2019, 12:06 PM
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Originally Posted by Kenny Powers View Post
Speculating on the control laws here, but 2 could provide more problems than 1. What happens when there is a mismatch between the two sensors?.... Maybe then the MCAS system is disabled, I don't know.

If it's disabled then you've lost that safety feature when you could actually need it. The 737 AoA sensors are on opposite sides of the fuselage, so if a stall was entered and one wing dropped, the sensors would most certainly disagree.

The specific Boeing fixes do include addressing the problem you delineate. Here it is in their own words:
  • If those disagree by more than 5.5 degrees, the MCAS system will be disabled and will not push the nose of the plane lower.
  • Boeing will be adding an indicator to the flight control display so pilots are aware when the angle of attack sensors disagree.
Old 03-27-2019, 12:33 PM
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Originally Posted by dell30rb View Post
Boeing and the FAA certified an airplane with a system that could command full nose-down trim with no alerts or error messages if one AoA sensor goes haywire. This seems like a bad idea to me.

I believe the correct way to do this would be to put three sensors in three different locations. If the sensors do not all agree then the MCAS is disabled and the pilot gets a caution light.
Originally Posted by Kenny Powers View Post
hmmmmm.... Kind of defeats the purpose of MCAS then. If you're in a full stall, then it's pretty likely to have different alpha readings at different locations. It's outside the normal flight envelope, so turbulent flow is very plausible. So now you've got an MCAS system that MIGHT work as intended SOME of the time....
They can be located and designed to read true at high angles of attack. They don't need to agree precisely, but be within a plausable range of each other.
Old 03-27-2019, 12:34 PM
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Originally Posted by Kendall View Post
The specific Boeing fixes do include addressing the problem you delineate. Here it is in their own words:
  • If those disagree by more than 5.5 degrees, the MCAS system will be disabled and will not push the nose of the plane lower.
  • Boeing will be adding an indicator to the flight control display so pilots are aware when the angle of attack sensors disagree.
I rest my case. They should have hired me.

Last edited by dell30rb; 03-27-2019 at 12:47 PM.
Old 03-27-2019, 02:29 PM
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I'll re-state some questions I asked like 5 pages ago:

Do you think a team of aeronautical flight control engineers simply didn't think about what would happen if they lost one sensor? You know, because the control module is full of fully redundant chips, with different code versions to skip single points of failure... yet the just didn't care about 1 sensor? Clearly there is a engineering reason they used just one, maybe the risks were assessed wrong, or something else that we don't know about triggered the failures in the one thing that wasn't ever acounted for. While the end reports may blame Boeing, I for one can't accept they chose 1 sensor as input out of ignorance or laziness. I'll let the report tell me what happened.

The same goes for alerting the crew. They didn't just not think about doing that. Hell, the FAA themselves may have said you can't do that and stay in the type rating or something to that effect.
Old 03-27-2019, 02:42 PM
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Originally Posted by TurboJoe View Post
I'll re-state some questions I asked like 5 pages ago:

Do you think a team of aeronautical flight control engineers simply didn't think about what would happen if they lost one sensor? You know, because the control module is full of fully redundant chips, with different code versions to skip single points of failure... yet the just didn't care about 1 sensor? Clearly there is a engineering reason they used just one, maybe the risks were assessed wrong, or something else that we don't know about triggered the failures in the one thing that wasn't ever acounted for. While the end reports may blame Boeing, I for one can't accept they chose 1 sensor as input out of ignorance or laziness. I'll let the report tell me what happened.

The same goes for alerting the crew. They didn't just not think about doing that. Hell, the FAA themselves may have said you can't do that and stay in the type rating or something to that effect.
This whole thing about "just one sensor" is a bit misleading. Yes, it appears the MCAS relied on one physical sensor, but actually inside the sensor is two different sensors with independent outputs. There's "sin" and "cosine" outputs which can be used to determine if there is a signal from the sensor and if one of the circuits is somehow misbehaving. The signals are 90 degrees our of phase and should always correspond to one another. If not, the software could have diagnostics and make determinations on what to do if those two outputs aren't corresponding correctly.

However , those two outputs do rely on a single vane that is outside the aircraft. Damage to that vane or a bad installation (improper mounting) could lead to an offset between what the AOA sensor is telling the computer and what angle the aircraft is really at. All the complications that were discussed earlier apply when you start adding additional AOA sensors on the plane.
Old 03-28-2019, 06:56 AM
  #253  
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From today's article in Financial Times:


"Boeing has said a planned software fix for its 737 Max will “ensure that accidents like these will never happen again”, a TACIT ACKNOWLEDGEMENT the aircraft's flight control system COULD HAVE PLAYED A ROLE in two deadly crashes in five months. The upgrade would ensure that an anti-stalling system believed to be behind last October’s downing of a Lion Air flight NO LONGER RELIES ON ONE SENSOR ALONE to determine the proper angle of the aircraft’s nose."



Even Boeing is tacitly acknowledging that there were design problems with the Boeing 737 Max according to Financial Times.
Old 03-28-2019, 07:06 AM
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Originally Posted by Kendall View Post
From today's article in Financial Times:


"Boeing has said a planned software fix for its 737 Max will “ensure that accidents like these will never happen again”, a TACIT ACKNOWLEDGEMENT the aircraft's flight control system COULD HAVE PLAYED A ROLE in two deadly crashes in five months. The upgrade would ensure that an anti-stalling system believed to be behind last October’s downing of a Lion Air flight NO LONGER RELIES ON ONE SENSOR ALONE to determine the proper angle of the aircraft’s nose."



Even Boeing is tacitly acknowledging that there were design problems with the Boeing 737 Max according to Financial Times.

CYA for sure at lawyers behest im sure!
Old 03-28-2019, 09:32 AM
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Originally Posted by HeidiMarie View Post
1) It is actually pretty common to have to turn away and deal with pulling circuit breakers during certain emergency checklist procedures. 2) Sometimes those CB's or switches are in awkward places. 3) Some emergencies may even warrant a crew member to leave the flight deck all together.
1) If you've flown a DC-9 or its bigger brother the MD-80 Series, you will know very well where C/Bs K-10 and J-11 are! Behind the Capt's seat.

2) We got on a 737-200 in Orlando and the Capt (a great fisherman from Key West BTW!) could not get the Standby Hyd Pump to check correctly. We learned the Hard Way, that the CB was hidden down low by the Jump Seat Mic cord dangling down, totally covering it up! Ooops!

3) My AirTran 737-200 students usually did not believe me that if the gear had to be extended manually, that the F/O would have to go back in the aisle, over the wing, kneel down in the aisle, pull up a piece of the carpet and peer down into a special glass 'periscope' that was designed so that he/she could look for red lines that were painted onto the landing gear legs. If those red lines, all lined up correctly, that main gear was 'down and locked'. Looking the other way, he/she would verify the other gear! I had to show them that (at least in these older 737s) that they'd need to look on the ceiling for a small red dot which was directly over the place to pull the carpet back! Haven't flown a 737 in a long time but next time I'll look if these new 737s still have those red dots!

Also, the 'periscope; was covered/protected with a small, round, thin wooden disk! Yes, wood! I have never confirmed it but the story was that all Boeings have at least one piece of wood in them. Why? Because Bill Boeing started out making amphibians/float planes which were of course made out of wood!

In one of my AirTran classes, we had a loud mouth F-16 jock. When I described the periscope procedure, he seriously asked "Will we have to do that before every landing?" Amazed, I answered, "Yes Richard, haven't you seen pilots do that on any of your airline flights?" Sheesh.......

I did not have Richard as a Sim Student but was teaching a different pair of guys out at DalFort Aviation Training out near DFW. I saw Richard's instructor at the hotel one day.

"I have a new name for Richard. We need to call him 'Fireball' from now on!" With my eyebrows raised, he went on.

"Last night we were working on engine failures on take off. Richard over-rotated the airplane and pulled up quickly right as I punched the Engine Failure on the Instructor's Panel. We got up to about 600 feet with the nose way high and we slowly rolled over and went straight back down into the Runway! We 'crashed' before I could turn off the Sim! You've never seen such a 'fireball' that the Sim Visuals gave us! Pure Fire! And we 'hit' so hard that my flight bag flew up and landed near the back door to the Sim!

Be very afraid. 'Fireball' got hired at Northwest and since they merged, he's now a Delta Captain!

Here's an older 737 Sim. The 'bridge' will lift away and the Sims are mounted on six, big hydraulic 'jacks'. It is those that make the Sim move and with you inside, the visuals will tell your brain that what you see, is what you feel. It's pretty cool.......



Old 03-28-2019, 11:15 AM
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DId the cancellations from Boeing ripple into GE also?
Old 03-28-2019, 11:30 AM
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With all the online Google wizards available its clear to me that actual engineers and pilots should be prohibited from aircraft design and analysis. From here on all such decisions will be made by an online mob of morons.
Old 03-28-2019, 11:38 AM
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Originally Posted by Gary M View Post
1)

Here's an older 737 Sim. The 'bridge' will lift away and the Sims are mounted on six, big hydraulic 'jacks'. It is those that make the Sim move and with you inside, the visuals will tell your brain that what you see, is what you feel. It's pretty cool.......


Damn that's an old trainer. Hydraulics haven't been used for quite some time now.
Old 03-28-2019, 02:00 PM
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Originally Posted by Kenny Powers View Post
Damn that's an old trainer. Hydraulics haven't been used for quite some time now.
I've put in a call to the Pan Am International Training Academy to see what types they have.

I'm guessing that you and I are both correct.....
Old 03-28-2019, 02:08 PM
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Originally Posted by Gary M View Post
I've put in a call to the Pan Am International Training Academy to see what types they have.

I'm guessing that you and I are both correct.....
Ya, those in the picture are definitely hydraulic. FlightSafety did the first electrics in 2006; and the industry quickly followed suit.

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