Boeing 737 MAX - software wouldn't fix faulty airframe

nsaspook

Joined Aug 27, 2009
8,897
The Airline Passengers Association now has a new motto:

"If It's On A Boeing, I Ain't Going".

The way this 737 Max 8 debacle is turning out, looks like Boeing and the FAA must have been recent graduates of the Richard Nixon School Of Ethics with a major in lying and covering up.
You can always book a Ilyushin Il from Aeroflot if you want the intimate in passage comfort and safety.
 

justtrying

Joined Mar 9, 2011
435
You can always book a Ilyushin Il from Aeroflot if you want the intimate in passage comfort and safety.
ИЛ 76 is a military transport airplane. How are you putting the two in the same sentence?

And yes, before you jump on me, there are a lot of crashes associated with this model that has been in service in multiple countries going back to soviet times. There ia quite a lot of information out on it in russian. I do not know what transport plane compares to it in the west.
 

nsaspook

Joined Aug 27, 2009
8,897
ИЛ 76 is a military transport airplane. How are you putting the two in the same sentence?

And yes, before you jump on me, there are a lot of crashes associated with this model that has been in service in multiple countries going back to soviet times. There ia quite a lot of information out on it in russian. I do not know what transport plane compares to it in the west.
It's called argumentum ad absurdum.
 

WBahn

Joined Mar 31, 2012
26,398
ИЛ 76 is a military transport airplane. How are you putting the two in the same sentence?

And yes, before you jump on me, there are a lot of crashes associated with this model that has been in service in multiple countries going back to soviet times. There ia quite a lot of information out on it in russian. I do not know what transport plane compares to it in the west.
Probably the most comparable would be the C-141 Starlifter.

Of the 285 Starlifters built, 19 were lost in crashes (6.7% of the fleet). The vast majority of the crashes were due to factors unrelated to the aircraft.

Of the 960 Il-76's built, 80 have been lost in crashes (8.3% of the fleet). I can't find anything that gives me a feeling for whether a disproportionate share of these were due to aircraft factors.

By comparison, there have been 10,478 Boeing 737's built and 184 have been lost in crashes (1.8% of the fleet).
 

cmartinez

Joined Jan 17, 2007
7,513
Probably the most comparable would be the C-141 Starlifter.

Of the 285 Starlifters built, 19 were lost in crashes (6.7% of the fleet). The vast majority of the crashes were due to factors unrelated to the aircraft.

Of the 960 Il-76's built, 80 have been lost in crashes (8.3% of the fleet). I can't find anything that gives me a feeling for whether a disproportionate share of these were due to aircraft factors.

By comparison, there have been 10,478 Boeing 737's built and 184 have been lost in crashes (1.8% of the fleet).
It would be interesting to know how many of those crashes had total fatalities.
 

WBahn

Joined Mar 31, 2012
26,398
It would be interesting to know how many of those crashes had total fatalities.
If, by "total fatalities" you mean everyone on board died, then most of them -- survivors in aircraft crashes are rare enough to begin with, but in aircraft of this size it is quite rare for anyone to survive because of the speeds and energies involved, not to mention the large quantities of jet fuel being thrown about, atomized, and ignited.
 

cmartinez

Joined Jan 17, 2007
7,513
If, by "total fatalities" you mean everyone on board died, then most of them -- survivors in aircraft crashes are rare enough to begin with, but in aircraft of this size it is quite rare for anyone to survive because of the speeds and energies involved, not to mention the large quantities of jet fuel being thrown about, atomized, and ignited.
Yeah, that's what I meant. I made the mistake of making a literal translation between languages, and that usually doesn't work very well.

Anyway, that's what I thought. Commercial aircraft crashes seldom have any survivors. For the exact reasons you've mentioned. I was just wondering how small that number really is.
 

WBahn

Joined Mar 31, 2012
26,398
Yeah, that's what I meant. I made the mistake of making a literal translation between languages, and that usually doesn't work very well.

Anyway, that's what I thought. Commercial aircraft crashes seldom have any survivors. For the exact reasons you've mentioned. I was just wondering how small that number really is.
Most large aircraft crashes that have survivors are ones that occur on the ground are during take-off and landing, primarily because the speed of impact tends to be much lower in those situations.
 

crutschow

Joined Mar 14, 2008
28,156
The most amazing accident that had a significant number of survivors I'm aware of, was the DC-10 crash landing at Sioux City, Iowa.
It had a tail engine failure, with the shrapnel from that damaging all three redundant hydraulic control systems which were all run together through a narrow conduit to the tail (basically turning the system into a single-point failure node), leaving the pilots with no normal controls.
The pilots managed to somewhat control the plane by adjusting the throttles of the two remaining engines, to get to the airport and crash land the plane, coming in at over 6 times the normal sink speed. :eek:
The plane broke up on impact and ended upside down.
111 did die but 185 survived.
 
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justtrying

Joined Mar 9, 2011
435
It will be very interesting if they can determine why turning the system off didn't help them recover from the control problem they apparently had.
So far I have read a few things... but they are all speculations. I do wonder whether the cut out switch does not fully shut off the system but disingages it temporarily until the nest event? This would be software design gone horribly wrong indeed, but I have seen it happen in my field.

What I do not like reading so far is comments on what pilots should have done to save the plane in the few minutes they had... They did what they could and were not successful. Someone else might have fared better. We are not supposed to be fighting machines feeding us wrong data, but this seems to be daily occurence now.
 

nsaspook

Joined Aug 27, 2009
8,897
https://arstechnica.com/information...ax-anti-stall-system-then-it-turned-on-again/

As more information comes out, certain things will be getting confirmed. I hope that those who blamed the "third world" countries and pilots are prepared to eat their words. No one wants to die on the job

http://www.b737.org.uk/mcas.htm
From the WSJ article:
It wasn’t immediately clear why the pilots turned the automated system back on instead of continuing to follow Boeing’s standard emergency checklist, but government and industry officials said the likely reason would have been because manual controls to raise the nose didn’t achieve the desired results.
After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said.
We will see that really happened after the preliminary report is done but maintenance reports logged other Ethiopia Airlines pilots having similar problems on that plane in the days just before the crash where stabilizer trim “cutout” switches worked to regain manual control.

https://abcnews.go.com/Politics/dam...nes-737-max-triggered-fatal/story?id=62139860
The Ethiopian Airlines Boeing 737 MAX, which crashed in March and killed 157 people, suffered a damaged angle-of-attack sensor upon takeoff from a bird or foreign object, triggering erroneous data and the activation an anti-stall system -- called MCAS -- sending the pitch of the plane downward and ultimately crashing into the ground, two aviation sources familiar with the investigation told ABC News.
...
As the jet was nose diving, the Boeing 737 MAX pilots did not try to electronically pull the nose of the plane up before following Boeing's emergency procedures of disengaging power to the horizontal stabilizer on the rear of the aircraft, according to the sources.

One source told ABC News that they manually attempted to bring the nose of the plane back up by using the trim wheel. Soon after, the pilots restored power to the horizontal stabilizer.

With power restored, the MCAS was re-engaged, the sources said, and the pilots were unable to regain control and the plane crashed.


The preliminary findings in the crash investigation are expected to be released by transportation officials in Ethiopia on Thursday morning.

Earlier Wednesday, Boeing released a statement that said, "we urge caution against speculating and drawing conclusions on the findings prior to the release of the flight data and the preliminary report."
The reports seems to say the pilots turned the stabilizer trim “cutout” switches back on after following the correct procedure of turning it off. :(

 
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nsaspook

Joined Aug 27, 2009
8,897
This will not go away any time soon...

https://nader.org/2019/04/04/boeings-homicide-will-give-way-to-safety-reforms-if-flyers-organize/

His niece died on the Ethiopian airline flight...
This is ridiculous.
The overriding problem is the basic unstable design of the 737 Max. An aircraft has to be stall proof not stall prone.

A stall or near stall is a common part of a successful flight. What's needed are good stall characteristics in aircraft. The 737 MAX seems to have a coffin corner that makes it very hard to manually retrim from once the plane has a MCAS fault. This interaction (stabilizer aerodynamic forces vs human mechanical force to retrim) is a design deficiency in every 737 built that very unfortunately has been triggered by the MCAS auto-trim (it's not a anti-stall system) system moving the trim jackscrew to compensate for a non-existent AOA.
 
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justtrying

Joined Mar 9, 2011
435
This is ridiculous.


A stall or near stall is a common part of a successful flight. What's needed are good stall characteristics in aircraft. The 737 MAX seems to have a coffin corner that makes it very hard to manually retrim from once the plane has a MCAS fault. This interaction (stabilizer aerodynamic forces vs human mechanical force to retrim) is a design deficiency in every 737 built that very unfortunately has been triggered by the MCAS auto-trim (it's not a anti-stall system) system moving the trim jackscrew to compensate for a non-existent AOA.
Consumer advocate's niece has been killed on that flight. He can be wrong about everything at this point, he has some background of success. A law suit has been filed by his niece's family.

From your own comment, why is there only one sensor? I work on xray equipment, xray tables I work on have 2 sensors for each movement, and they cannot kill more than one person? Just curious.
 

nsaspook

Joined Aug 27, 2009
8,897
Consumer advocate's niece has been killed on that flight. He can be wrong about everything at this point, he has some background of success. A law suit has been filed by his niece's family.

From your own comment, why is there only one sensor? I work on xray equipment, xray tables I work on have 2 sensors for each movement, and they cannot kill more than one person? Just curious.
I'm truly sad for his loss and think the law suit is completely proper in this case but don't make statements that undermine your case.

With two sensors how do you know which one is correct if they differ but are still operational? Do you split the difference/keep running or just turn automation off and maybe warn the pilot? Two sensors gives one unit failure redundancy but the pilots still must decide about a operational AOA sensor pair disagreement. The optional disagree lamp option does this for them but they can see both AOA guages to make the same determination without it.
 
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justtrying

Joined Mar 9, 2011
435
I'm truly sad for his loss and think the law suit is completely proper in this case but don't make statements that undermine your case.

With two sensors how do you know which one is correct if they differ but are still operational? Do you split the difference or just turn automation off? Two sensors gives one unit failure redundancy but the pilots still must decide about a operational AOA sensor pair disagreement. The optional disagree lamp option does this for them but they can see both AOA guages to make the same determination without it.
You are right, you do not. We still do not know what exactly happened on the last crash. I fundamentally disagree with the design decisions taken by Boeing and approved by FAA to put this plane in the air.

As I have said, I see this all the time in medical industry, post design fixes. The only reason there is no outcry is because one person is affected at a time and if they do die, you can say they died because they were sick... Right now GE is struggling to fix their last software bug on an anaesthesia unit. Guess what? That is life support equipment. Heard anyone complain about it?
 
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