Boeing - Design Issues...

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Vigilant1

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I can't find the Ethiopian chart yet but this article shows the data from the previous Lion Air crash and you can see for yourself that the pilots override the MCAS dozens of times before it finally destroyed the aircraft. At the end the jack screw jams and you can see the control forces jump hugely.
And this is the point: If at >any time< during those 2 dozen times when the Lion Air crew re-trimmed the aircraft back to normal, they had executed the published procedures (turning off the autopilot trim and the electric trim and then using the trim wheel to trim off yoke pressures), they could have flown that plane home. BTW, it's virtually the same procedure used for "runaway trim."

As for the Ethiopian pilots, I saw a chart of the black box recording and they made two attempts to fix trim with the power trim before MCAS did a huge negative trim for some reason even though the pilots had clearly been trying to use the power trim to override it. That's when they cut the power and tried the manual trim, which the voice recording shows was jammed.
Right--over 2 minutes after the anomaly began, and as airspeed continued to build, they finally turned off the trim and kept it off. At that point the control pressures may have been too great for use of the manual wheel >or< the trim motors to have had any effect. Analogy: Discharging the fire bottle after watching the fire light blink for two minutes--the spar has burned through. That's not a "defect."

This is all covered in previous threads and posts here.
 
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Doggzilla

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It is not covered already, you literally just ignored all of the data I just posted and repeated the same information that has been disproven already. What you are saying does not agree with any of the black box information on either flight or the technical limitations.

As I previously linked, above 230 knots the forces are too high and the jack screw only goes one way when overloaded. Down.

Using the trim controls temporarily disabled the MCAS, but couldn't counter the trim change and bring it back to level. Every time the MCAS reengaged it went further down but wouldn't come back up.

Don't forget the entire reason the MAX is not certified as a new aircraft is because it would not pass modern standards. The system is ancient 1950s tech in a 1960s regional budget aircraft. It was not a particularly well designed aircraft even at the time it was released.
 

TXFlyGuy

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And now you know why one of my career goals was to never fly a 737. And besides, they are too slow.

Ever get stuck behind one on departure?
 

TXFlyGuy

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As far as I know, the FAA decides whether or not any new US airliner receives certification. Boeing made some questionable design, documentation and training missteps here for the new aircraft but surely the FAA is also partly responsible here if we want to place blame outside of these 4 pilots behind the curve in these 2 crashes. The FAA must not have considered the design, training program and documentation to be unsafe or they would have sent Boeing back to fix the issues. The system had the ability to be overpowered and disconnected once a fault was recognized in it. That must have satisfied the FAA.

In the end, these pilots crashed 2 airplanes into the ground/ ocean in visual conditions while still having the ability to recover pitch control. In the latter crash, it appears no simple cross checks on the ASI, GPS or looking out the window (high speed, low altitude) was ever done. Throttles still way up with a clearly visible horizon. If they had a stick shaker or high AOA warning, it should have been immediately obvious it was invalid. If this was in IMC, would have taken a bit longer to make that determination. These guys clearly didn't understand the system so they had little hope to do the right things. Almost certainly, these two aircraft would never have crashed with competent flight crew aboard IMO.
My good friend, Southwest 737 Captain, agrees with you 100%. And yes, he has flown the MAX.
 

davidb

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And this is the point: If at >any time< during those 2 dozen times when the Lion Air crew re-trimmed the aircraft back to normal, they had executed the published procedures (turning off the autopilot trim and the electric trim and then using the trim wheel to trim off yoke pressures), they could have flown that plane home. BTW, it's virtually the same procedure used for "runaway trim."

Right--over 2 minutes after the anomaly began, and as airspeed continued to build, they finally turned off the trim and kept it off. At that point the control pressures may have been too great for use of the manual wheel >or< the trim motors to have had any effect. Analogy: Discharging the fire bottle after watching the fire light blink for two minutes--the spar has burned through. That's not a "defect."

This is all covered in previous threads and posts here.
Perhaps a better analogy is delaying putting in rudder with an engine failure or putting in the wrong rudder. Certain things require quick and correct pilot actions lest one finds oneself in an unrecoverable situation. Among other things, we practice engine failures regularly, but runaway stab trim accompanied with continuous stick shaker wasn’t exactly like anything these crews were trained to handle. Prior to these crashes, a safe assumption was crews would instinctively keep the airplane trimmed and nothing physically prevented the crews from doing just that. I suspect the continuous stick shaker was a very significant factor in distracting these crews away from the correct actions. Again, the crews didn’t have specific knowledge and training to deal with this. It’s just as much a training shortfall as it is a design shortfall, IMO.

Part of the training moving forward is a demonstration of just how nearly uncontrollable the aircraft becomes when the trim is allowed to runaway to the extremes. But, it is still recoverable IF one is trained for it. The important thing is to realize one should always strive to keep it trimmed and know enough about the systems and procedures to achieve that.
 

rv6ejguy

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Sulley backed up a main point I made in this thread earlier. While all the blame was heaped on Boeing (and they certainly deserve some), few people talked about the role of the FAA here in approving a design with only one AOA input and huge pitch authority. How did that ever pass engineering review? They should have told Boeing to make changes right there before the first test flight even.
 

Hephaestus

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Can I ask a ridiculous question?

Why isn't there a big switch with guards and safeties with absolutely no way to accidentally flip it.

That turns off all the computer interventions? Takes the plane back to basic stick, rudder and throttles? Clearly it doesn't solve everything and we still have issues like air france where SA is an issue. But being able to return to training and "flying the plane" should be possible shouldn't it?
 

plncraze

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Washington Post had a long article today about Boeing issues and the FAA having hard time forcing Boeing to take action even after promising to do so.
 

BJC

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Washington Post had a long article today about Boeing issues and the FAA having hard time forcing Boeing to take action even after promising to do so.
If there are / were compliance issues (as opposed to “it would be nice ...” issues), why did the FAA have a hard time ..?

Thanks,


BJC
 

Doggzilla

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Well, politics is off limits here and most of our members don't want to hear that their favorite political party neutering the authority of safety agencies actually has real life consequences.

We caught an employee illegally hauling guns because he had a lifetime ban, and the TSA and DOT were completely unable to do anything to enforce the regulations.

I was also told by a DOT agent that the statute of limitations on safety violations was now reduced to 90 days, and that anonymous reports or reports from third person were not allowed either now.

This administration has butchered the authority and reach of safety agencies.

Many agencies now require all complaints go through their websites, but do not provide more than a handful of complaint types to file. Everything else cannot be filed.

The FMCSA is a perfect example. No verbal complaints allowed, all digital, and almost all of the violation categories have been removed. Making it impossible to report most transportation related crimes.
 

rv6ejguy

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Hmmm if the FAA doesn't approve, you don't fly your new design and you don't make any money.

Boeing bullies or disregards the FAA? That doesn't sound right...
 

TFF

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The biggest problem now is the FAA is gun shy. They can’t look like fools so they are going to be so cautious that it might be quicker to design a new airplane. Of course that’s not true, but this one thing is being super scrutinized yet they are clueless on any other system that may be a problem.

As for a switch to make it fly like a basic plane, probably not 100% possible. The fancy systems are designed to mimic the simple airplane. If the plane was designed without these systems, it would have to be considered a clean sheet design. That’s the whole point, no extra training if everything works like it’s supposed to. Less training; more pilot crossover. One pilot fits all is the goal. That is the dream goal for all airlines.
 

Hephaestus

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As for a switch to make it fly like a basic plane, probably not 100% possible. The fancy systems are designed to mimic the simple airplane.
By that same logic then it should work too right?

Airline pilot does annual checkride in a 737max sim anyway. So to pass your checkride we're going to turn off the computers and do a circuit without automation. We're not talking a dynamically unstable aircraft it just flies a bit different than a 70s 737... no different than me jumping from a Cherokee into a cherokee 6 - different, but my insurance doesn't require I do substantial training.
 

davidb

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By that same logic then it should work too right?

Airline pilot does annual checkride in a 737max sim anyway. So to pass your checkride we're going to turn off the computers and do a circuit without automation. We're not talking a dynamically unstable aircraft it just flies a bit different than a 70s 737...
There’s actually no “Max” simulators in operations at US carriers as of yet. The Max actually feels and handles more like older versions of the 737.

The issues are probably better described as a divergence between engineering and training. The engineers didn’t do a good job of analyzing failure modes. Furthermore, the assumptions of pilot reactions weren’t reflective of current training practices. Us older guys probably had enough old school knowledge to handle the challenging situations but current training (especially for countries whose pilots were new to the 737) was not adequate.
 

Hephaestus

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plncraze

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If there are / were compliance issues (as opposed to “it would be nice ...” issues), why did the FAA have a hard time ..?

The article said Boeing had internal procedures which never were never followed and quality issues (assembly tools left in wings and safety wires missing) and a lot of lobbyists. Ideally the FAA would go in and force the issue of quality. In reality they probably we're waiting to allow Boeing to get caught and then public pressure would be the leverage the FAA needed to act.
 
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