How much longer to fix the 737 Max

Having worked for one of Boeing's competitors all my career, I am very familiar with their strengths, but also their weaknesses in technical management. But even with perfect engineering and technical management skills and processes, all companies have almost insurmountable problems when trying to make significant modifications to a seven-decade (almost) design: The RATIONALE behind all the design choices are lost to the mists of time. The current engineering staff are settlers, and not pioneers, and the original design history and culture have all died out. So, when all present analysis and current engineering logic indicate that a design change should be made in a certain way, once the change is incorporated and the change put into service, all sorts of snakes pop out of the system because the current generation of engineers don't really understand all the nuances incorporated into the underlying design by their predecessors. Sometimes, a blank-sheet redesign is required. It's the CTOs job to know which is which and to convince management, and the shareholders, as to the proper approach to take. It seems like Boeing may have made a strategic blunder with the MAX when the larger engines were viewed as a feasible modification to an existing airframe. (Blunders are well-intentioned decisions by diligent and well-informed people, but which are nonetheless wrong).
 
SaratogaPilot said:
Having worked for one of Boeing's competitors all my career, I am very familiar with their strengths, but also their weaknesses in technical management. But even with perfect engineering and technical management skills and processes, all companies have almost insurmountable problems when trying to make significant modifications to a seven-decade (almost) design: The RATIONALE behind all the design choices are lost to the mists of time. The current engineering staff are settlers, and not pioneers, and the original design history and culture have all died out. So, when all present analysis and current engineering logic indicate that a design change should be made in a certain way, once the change is incorporated and the change put into service, all sorts of snakes pop out of the system because the current generation of engineers don't really understand all the nuances incorporated into the underlying design by their predecessors. Sometimes, a blank-sheet redesign is required. It's the CTOs job to know which is which and to convince management, and the shareholders, as to the proper approach to take. It seems like Boeing may have made a strategic blunder with the MAX when the larger engines were viewed as a feasible modification to an existing airframe. (Blunders are well-intentioned decisions by diligent and well-informed people, but which are nonetheless wrong).
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Yes, but isn't a run away trim dealt with pretty much the same way in all planes. Crew training seems to me to be the causation of both accidents. The previous crew had no problem dealing with it.
 
1RTK1 said:
Yes, but isn't a run away trim dealt with pretty much the same way in all planes. Crew training seems to me to be the causation of both accidents. The previous crew had no problem dealing with it.
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What you say is true. But I will bet you a beer that when the NTSB final reports come out, a contributing factor will be the trim system and its lack of documentation. Boeing is at least as much at fault as the crew, IMO.
 
Greg Bockelman said:
What you say is true. But I will bet you a beer that when the NTSB final reports come out, a contributing factor will be the trim system and its lack of documentation. Boeing is at least as much at fault as the crew, IMO.
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I don't think it's about splitting the responsibility.

Boeing is 100% responsible for the unscheduled MCAS activations. They shouldn't have happened.

The pilot's inability, for whatever reason, to action the correct checklist is the reason why they weren't able to handle the emergency and land safely.

Now, everytime I say that people think I'm blaming the pilots, their experience, or "3rd world" training. I know very little of their experience and nothing of their training. All I know is that three crews encountered nearly identical failures. One crew completed the checklist, two did not. One landed, two did not.
 
Greg Bockelman said:
What you say is true. But I will bet you a beer that when the NTSB final reports come out, a contributing factor will be the trim system and its lack of documentation. Boeing is at least as much at fault as the crew, IMO.
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I am sure the NTSB will put lack of documentation as a major contributing factor. I do agree Boeing should have been more forthcoming with the new systems installed.
There were many contributing factors from maintenance, adequate training, and information from the manufacturer if I have been reading correctly.
The situation still should have been handled by the crew with a different outcome.
 
Larry in TN said:
Boeing is 100% responsible for the unscheduled MCAS activations. They shouldn't have happened.
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Would you allow that the operating airline bears some responsibility for failing to properly maintain or repair the angle of attack sensors without which, MCAS would have engaged? In the incident where the sensor was thought to be hit by a bird strike during the accident flight, obviously that wouldn't implicate the airline. But the failure to repair the one that had a prior incident?
 
I may have to go review the published details. Seems like a can of worms besides any MCAS activations.
 
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Fracpilot said:
Are you able to post the article? It requires a subscription to view the full article.
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Not sure why, but it opened for me. One good way is to download the latest Chrome browser and open incognito mode.
 
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PPC1052 said:
Would you allow that the operating airline bears some responsibility for failing to properly maintain or repair the angle of attack sensors without which, MCAS would have engaged?
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I don't think the failure of the AoA was the fault of Lion Air. I do question why the airplane flew five flights with symptoms caused by the failing/failed AoA, the last two of which included the full MCAS activation, but didn't fix it. Could be improper maintenance by the airline, deficient maintenance procedures in Boeing's AMM, or some combination of the two. No way for us to know at this point.

Ethiopian, as you said, had a bird strike just after liftoff damaging the otherwise good AoA vane. My airline had exactly the same thing happen this summer on an 737 NG (no MCAS) out of a Central American city. Gave them the same unsilenceable stick shaker and IAS DISAGREE messages. Completely out of the control of the airline, as far as I can see.

My point, though, is that the failure of an AoA vane/sender shouldn't cause a runaway stabilizer. That is the problem that is 100% on Boeing.

Then, a runaway stabilizer shouldn't cause the loss of the airplane, either.

Two separate problems. They don't share blame. They are separate. Both must be addressed. We only seem to want to talk about the first one.
 
Larry in TN said:
The pilot's inability, for whatever reason, to action the correct checklist is the reason why they weren't able to handle the emergency and land safely.
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That's an oversimplification. The Ethiopian crew did follow the checklist, they just didn't follow it soon enough. Did the checklist tell them that if they don't do it before the airplane becomes excessively out of trim that they would never be able to recover? No.
 
I completely agree that they are two separate problems. My quandary is:
Larry in TN said:
My point, though, is that the failure of an AoA vane/sender shouldn't cause a runaway stabilizer.
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it's very peculiar that this failure mode was not more thoroughly vetted by Boeing up front.. I'm wondering why the fix is taking so long though, as others have pointed out in the other thread, it seems that tying the automation into two separate angle of attack indicators would seem to resolve this, where a disagreement in the two would alert the pilots and inactivate the system accordingly, etc

I am surprised though as a general rule they did not more readily recognize the runaway trim and deactivate it before it was too late. This isn't one of those phantom automation things, the pilots can see and feel the trim wheel cranking.. no?

Larry in TN said:
Then, a runaway stabilizer shouldn't cause the loss of the airplane, either.
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I wonder how other airplanes fly at high speeds and low altitude with a trim that is fully maxed out in one direction or the other.. even in something diminutive like a Piper Cherokee having the plane even slightly out of trim starts to really require a work out on the pilot.. actually most recent article "I learned about flying from that" in a Flying magazine talked about a piper cherokee pilot who was unfamiliar with the aircraft electric trim and struggled to trim the plane and fly it manually, noting that he had to brace the yolk against his knees

so my question is, is it reasonable to believe that any aircraft should be able to fly with the trim maxed out? And as a corollary to that question, why allow the trim to get that far out of whack. In my, admittely limited (<1k hrs), experience I've never needed to have the trim more than a few degrees away from neutral.. is it different on large commercial jets with possibly a much wider CG range?
 
dmspilot said:
The Ethiopian crew did follow the checklist, they just didn't follow it soon enough.
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They really didn't. They did one step on the checklist and they didn't do that until it was probably too late. Meanwhile, they did several others things that were contrary to the checklist and good airmanship and they didn't do the most basic thing that any pilot would do when their airplane starts to become out of trim. They didn't trim it back.
 
Larry in TN said:
...All I know is that three crews encountered nearly identical failures. One crew completed the checklist, two did not. One landed, two did not.
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Correct me if I’m wrong but I think the surviving crew consisted of 3 pilots and the incident occured in cruise whereas the other two crews were in takeoff mode and had about 3 to 5 minutes to figure it out. Now, why the LionAir flight took off after the previous crew had experienced the anomaly is another question.
 
Greg Bockelman said:
I’ve seen worse, Spike. But there is some merit to what kgruber suggests. The -900 series of the 737 is one step too far, IMO. It is in the size range of the 757. I understand commonality but enough is enough.
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I wasn’t here back when you said this Greg, but another friend who’s flown them probably about as long as you has said to me that a certain US carrier’s pilot group (one that likes 737s) has put pressure on Boeing for so long not to have different type ratings on the airframe that it’s getting stupid.

His point was the cockpit itself. Features clearly available in other Boeing cockpits for decades are disabled or unavailable in the newest 73s because “type rating” and it drives him bonkers.

The culpability of this market pressure to keep a single type rating isn’t getting much press in all of this, but you’re right, commonality and forcing one type is getting kinda beyond stupid on that fleet.

He also points out something else that’s just economics but true, he says the 73 was never that great of an aircraft. It was slapped together to compete with some other stuff at the time, which happens in this biz, but dragging the poor thing out this long without a clean sheet is kinda silly. It wasn’t that great to start with.

I probably disagree with him on that one, but he’s been flying them a looooong time. He jokes that his sim rides have turned into him showing the trainers stuff the sim and real airplane do differently and stuff the trainers, who are 20 years or more his junior, don’t know about the aircraft at all.

Interesting to look back a few months in this thread and see the various debate angles knowing the heads are starting to roll in the FAA certification process side of things. Congress is relatively cranky with them right now.
 
Silvaire said:
Correct me if I’m wrong but I think the surviving crew consisted of 3 pilots and the incident occured in cruise whereas the other two crews were in takeoff mode and had about 3 to 5 minutes to figure it out. Now, why the LionAir flight took off after the previous crew had experienced the anomaly is another question.
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There was a jumpseater. I don't know if he was just hoping a ride, as are most jumpseasters in the US, or if he had some other function such as a line check.

My recollection is that their failure also started at liftoff but can't seem to find a reference for that now.
 
Here is an explanation for the delay, they are changing their approach on how they're fixing the software.

https://www.seattletimes.com/busine...software-redesign-of-737-max-flight-controls/

The flight-control system will take input from both of the airplane’s flight computers and compare their outputs. This goes beyond what Boeing had previously decided to do, which is to adjust the MCAS software so that it took input from two angle of attack sensors instead of one.

The problem with that earlier approach is that if something serious goes wrong with the single flight computer receiving this input — whether it’s the bit flipping issue, or a memory corruption or a chip failure of any kind — then the computer output to the flight controls could be wrong even if both angle of attack sensors are working correctly.​
 
dmspilot said:
Here is an explanation for the delay, they are changing their approach on how they're fixing the software.

https://www.seattletimes.com/busine...software-redesign-of-737-max-flight-controls/

The flight-control system will take input from both of the airplane’s flight computers and compare their outputs. This goes beyond what Boeing had previously decided to do, which is to adjust the MCAS software so that it took input from two angle of attack sensors instead of one.

The problem with that earlier approach is that if something serious goes wrong with the single flight computer receiving this input — whether it’s the bit flipping issue, or a memory corruption or a chip failure of any kind — then the computer output to the flight controls could be wrong even if both angle of attack sensors are working correctly.​
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Redesigning it to how it should have been designed in the first place.
 
So it looks like Airbus may also have some AoA pitch issues: https://www.flightglobal.com/news/a...tentially-vulnerable-to-pitch-up-scen-460046/

upload_2019-8-5_14-41-21.png

I always wondered why the AoA data is not fed through a "reasonability" assessment by referencing a known and reliable source of airspeed and pitch.. or at least tie it to a system of several AoA for cross referential data. The SF50 Vision Jet had issues, as do the Airbus A320 family NEO jets
 
Sluggo63 said:
Horrible article. Well, horrible headline, at least. Airlines are leasing 737s to fill the gap with the Max grounded. But they’re leasing -700s and -800s. Then the article goes on a tangent saying how some small Canadian airline is still flying -200s because you can use them on unimproved strips. Good ol’ Jalopnik...
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Headline writers do love to sensationalize things!
 
New FAA head during swearing in said it won’t fly until he’s happy and there is no timeline on FAA.

CNBC is making hay with it to help the Boeing shorts out today. LOL.
 
[QUOTE="ElPaso Pilot, post: 2798829, member: at puts unprepared pilots in the cockpit is just as[/QUOTE]

It’s about time. Yes the design was flawed in that a single sensor could cause a malfunction, but as a guy who flies 737s for a living there aren’t many of us who believe getting the stab trim switches off (old memory item) and hand flying the aircraft wouldn’t have saved it. Why does the rest of the world, when there’s a problem, go to the autopilot? In the US, for the 30 years I’ve been flying jets, the first thing to go when there’s a problem is the autopilot! Fly the friggin’ aircraft.

This is no longer a safety issue and geopolitics is driving the bus here!

Get them back in the air. Yesterday.


Sent from my iPhone using Tapatalk
 
One quote from that article. Apparently the co-pilot in the Indonesian crash, rather than continuing to fight the MCAS, starting praying - “He gave a few feeble inputs of nose-up trim with his thumb switch and began calling on God for a miracle.”
 
My motto: "When you're at the controls, don't be a passenger!"

Or as my first flight instructor always said, "Make that airplane do what YOU want it to!"
 
The newly installed chief of the U.S. Federal Aviation Administration tested Boeing Co.’s 737 Max simulator on Thursday as part of an attempt to get up to speed on the grounded jetliner and the controversy surrounding the agency’s approval of it two years ago. Is this just more spin by Boeing PR to cover Boeing not having any real idea when this will end. Is it possible the Max will never fly again with those engines or without major modification of the aircraft.
 
the spin machine is bout ready to spin a bearing ......beyond 30,000 rpms. lol ;)

Dickson is the real deal.....old school and well needed.
 
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