cledaybuck
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 12:54 pm

ArgentoSystems wrote:
Some1Somewhere wrote:
I think he's saying the opposite. Putting shielding around the computer can make things worse.

Please explain how it could make things worse

Not to speak for Wlederling, but:
Material shielding can actually be counterproductive.
High energy particles can kick off an avalanche of secondary particles in the shielding volume that have exponentiated bit flip potential.
As we celebrate mediocrity, all the boys upstairs want to see, how much you'll pay for what you used to get for free.
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:18 pm

cledaybuck wrote:
ArgentoSystems wrote:
Some1Somewhere wrote:
I think he's saying the opposite. Putting shielding around the computer can make things worse.

Please explain how it could make things worse

Not to speak for Wlederling, but:
Material shielding can actually be counterproductive.
High energy particles can kick off an avalanche of secondary particles in the shielding volume that have exponentiated bit flip potential.

Is this even remotely supported by physics? I'm sorry, but it sounds like you just made it up. Nobody makes shielding out of enrich Plutonium, you know...
 
f1restate
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:21 pm

You might find that paper from Los Alamos regarding neutron induced upsets and the architecture proposed as a solution interesting :

https://permalink.lanl.gov/object/tr?wh ... UR-06-0452

In the case of the 737 FCC, if I remember correctly, the two CPUs inside were given different tasks , and also they are diffrent architectures themselves, so this solution is obviously not exactly applicable.

Sent from my SM-G975F using Tapatalk
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:49 pm

ArgentoSystems wrote:
Some1Somewhere wrote:
I think he's saying the opposite. Putting shielding around the computer can make things worse.

Please explain how it could make things worse


to repeat:
High energy particles can kick off an avalanche of secondary particles in the shielding volume
that have exponentiated bit flip potential.

Capture volume for bit flips in a semiconductor is the thin active layer.
capture in the remaining wafer volume can lead to triggering the intrinsic thyristor diode ( doping feature )
causing a supply voltage short circuit ( latch up. )
You get around that issue by placing the active layer on a non conductive substrate ( like silicon in sapphire )

Shielding has a larger capture volume.
capture can cause an avalanche of particles increasing the capture rate in the active semicon layer.
Murphy is an optimist
 
boerje
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:50 pm

ArgentoSystems wrote:
cledaybuck wrote:
ArgentoSystems wrote:
Please explain how it could make things worse

Not to speak for Wlederling, but:
Material shielding can actually be counterproductive.
High energy particles can kick off an avalanche of secondary particles in the shielding volume that have exponentiated bit flip potential.

Is this even remotely supported by physics? I'm sorry, but it sounds like you just made it up. Nobody makes shielding out of enrich Plutonium, you know...


You might want to check cosmic ray spallation.

"Cosmic rays cause spallation when a ray particle (e.g. a proton) impacts with matter, including other cosmic rays. The result of the collision is the expulsion of large numbers of nucleons (protons and neutrons) from the object hit. This process goes on not only in deep space, but in Earth's upper atmosphere and crustal surface (typically the upper ten meters) due to the ongoing impact of cosmic rays."

https://en.wikipedia.org/wiki/Cosmic_ray_spallation
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:55 pm

boerje wrote:
ArgentoSystems wrote:
cledaybuck wrote:
Not to speak for Wlederling, but:
Material shielding can actually be counterproductive.
High energy particles can kick off an avalanche of secondary particles in the shielding volume that have exponentiated bit flip potential.

Is this even remotely supported by physics? I'm sorry, but it sounds like you just made it up. Nobody makes shielding out of enrich Plutonium, you know...


You might want to check cosmic ray spallation.

"Cosmic rays cause spallation when a ray particle (e.g. a proton) impacts with matter, including other cosmic rays. The result of the collision is the expulsion of large numbers of nucleons (protons and neutrons) from the object hit. This process goes on not only in deep space, but in Earth's upper atmosphere and crustal surface (typically the upper ten meters) due to the ongoing impact of cosmic rays."

https://en.wikipedia.org/wiki/Cosmic_ray_spallation

Proton will never even reach the shield of the FCC. They will be dissipated by hull of the aircraft. The only thing that you need to be protected against is neutrons.
Actually not even that. Protons won't even reach an atmosphere. Look up magnetosphere..
Last edited by ArgentoSystems on Thu Aug 08, 2019 2:02 pm, edited 1 time in total.
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 1:59 pm

WIederling wrote:
ArgentoSystems wrote:
Some1Somewhere wrote:
I think he's saying the opposite. Putting shielding around the computer can make things worse.

Please explain how it could make things worse

High energy particles can kick off an avalanche of secondary particles in the shielding volume
that have exponentiated bit flip potential.

So you are saying an aircraft can undergo spontaneous nuclear explosion? Because if one particle can cause an avalanche of others and those other cause 100s more avalanches, things will turn to nasty real quick.

In actual reality only small atoms can be easily split, like H and He. That is why shielding is made from materials that don't fissure easily.
 
oOfredOo
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:00 pm

MrBretz wrote:
XRAYretired wrote:
MrBretz wrote:
I just have no clue how you recover in the case I mentioned. Maybe having 2 machines running makes the probability so low that that solves the problem? I dunno....but thanks anyway.


There is still something like a watchdog timer to reset the CPU to a known state and start executing again after any kind of halt.
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:06 pm

ArgentoSystems wrote:
WIederling wrote:
ArgentoSystems wrote:
Please explain how it could make things worse

High energy particles can kick off an avalanche of secondary particles in the shielding volume
that have exponentiated bit flip potential.

So you are saying an aircraft can undergo spontaneous nuclear explosion? Because if one particle can cause an avalanche of others and those other cause 100s more avalanches, things will turn to nasty real quick.

In actual reality only small atoms can be easily split, like H and He. That is why shielding is made from materials that don't fissure easily.


No large nucleus are easily split. Spliting a H nucleus is really hard.

Secondly as the material for shielding is not „active“ u lose enegy so a high energy neutron hits a nucleus in the shield and this then emits 2 low energy neutrons for example. Now this neutrons have to low energy to start a chain reaction (unlike material used in nuclear power plants) but the two neutrons can still affect the electronics. This leads to an increase in the chance to cause an upset as there are now two particles.
 
arcticcruiser
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:18 pm

This thread is turning into something totally beyond the grasp of a mere pilot. My take-away? Keep my tin foil hat firmly on. Don´t need more flips...
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:37 pm

FluidFlow wrote:
Secondly as the material for shielding is not „active“ u lose enegy so a high energy neutron hits a nucleus in the shield and this then emits 2 low energy neutrons for example. Now this neutrons have to low energy to start a chain reaction (unlike material used in nuclear power plants) but the two neutrons can still affect the electronics. This leads to an increase in the chance to cause an upset as there are now two particles.


That can only be true if you assume that whoever designs the shield is complete idiot. Properly constructed shield works as intended.
 
majano
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:39 pm

arcticcruiser wrote:
This thread is turning into something totally beyond the grasp of a mere pilot. My take-away? Keep my tin foil hat firmly on. Don´t need more flips...

Not to mention a mere accountant... :D
 
asdf
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:49 pm

ArgentoSystems wrote:
FluidFlow wrote:
Secondly as the material for shielding is not „active“ u lose enegy so a high energy neutron hits a nucleus in the shield and this then emits 2 low energy neutrons for example. Now this neutrons have to low energy to start a chain reaction (unlike material used in nuclear power plants) but the two neutrons can still affect the electronics. This leads to an increase in the chance to cause an upset as there are now two particles.


That can only be true if you assume that whoever designs the shield is complete idiot. Properly constructed shield works as intended.


Shielding works pretty simple if it is grounded
not that easy to do on a plane
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 2:51 pm

majano wrote:
arcticcruiser wrote:
This thread is turning into something totally beyond the grasp of a mere pilot. My take-away? Keep my tin foil hat firmly on. Don´t need more flips...

Not to mention a mere accountant... :D

Keep interested, I'm sure the thread will turn back less etherial subjects. In the mean time, if the techies make sure its done right, pilots are safer and there are less exceptionals off the bottom line!

Ray
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 3:58 pm

I would think that the bit flipping possibility could be more of an issue (even on an NG) in normal flight with the autopilot. Couldn't flipped bits cause the autopilot to do something crazy and then not disengage?

In manual flight, other than STS and MCAS, is the FCC really doing much on a 737? If it causes a runaway stabilizer, the "grasp and hold" method will stop the trim from moving. I have seen a youtube video where a pilot demonstrates it on an NG on the ground. He holds the thumb switch with one hand and grasps and holds the wheel with the other and it stops turning.
 
N292UX
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 4:08 pm

I haven't really kept up on the current status of the grounding recently. Could someone give me a (brief) rundown of what the current situation is?
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 4:15 pm

asdf wrote:
Shielding works pretty simple if it is grounded
not that easy to do on a plane

OMG. You are confusing with EM shielding, which, by the way don't need to be grounded either. And that is completely different.

shield against neutrons does not even need to be metal.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 4:21 pm

f1restate wrote:
In the case of the 737 FCC, if I remember correctly, the two CPUs inside were given different tasks , and also they are diffrent architectures themselves, so this solution is obviously not exactly applicable.

From what I read, 737 has two FCCs, and each FCC has two CPUs, one primarily for logic, the other primarily for data input/output.

asdf wrote:
Shielding works pretty simple if it is grounded
not that easy to do on a plane

Easy to do on a MAX, just nail a ground rod into the ground next to it, run a copper wire to the card cage, simples!

(See, I can make MAX jokes too!)

N292UX wrote:
I haven't really kept up on the current status of the grounding recently. Could someone give me a (brief) rundown of what the current situation is?

The current situation is they are all still grounded, except that we saw the MAX-7 do what Boeing called an engineering flight requested by FAA yesterday, and Boeing's CEO reiterated handing off a fix to FAA in September and return to flight early Q4. So, not much has changed recently.
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Wake now, discover that you are the song that the morning brings
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IADFCO
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 4:47 pm

XRAYretired wrote:
majano wrote:
arcticcruiser wrote:
This thread is turning into something totally beyond the grasp of a mere pilot. My take-away? Keep my tin foil hat firmly on. Don´t need more flips...

Not to mention a mere accountant... :D

Keep interested, I'm sure the thread will turn back less etherial subjects. In the mean time, if the techies make sure its done right, pilots are safer and there are less exceptionals off the bottom line!

Ray

My bills are paid by writing simulation math models and control laws, and I'm learning a lot about this cosmic rays and bit flipping business -- I had no idea it was so real and practical. I have also learned a lot, by the way, from the hardware discussions of a few pages ago. Thanks to all that contributed.
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 5:11 pm

asdf wrote:
Shielding works pretty simple if it is grounded
not that easy to do on a plane


What especially does grounding do for high energy particles?
Murphy is an optimist
 
Exeiowa
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 5:20 pm

I am only a mere chemist, but my guess is that the intial neutral high energy particle when it colides with something will generate charged particles (of opposite charges to balance out the total charge) and these will be what grounding would deal with. Being at higher altitudes there are more cosmic particles (less have had opportunity to collide with other atoms ie the atmosphere) and therefore a cause of concern.
 
DenverTed
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 5:54 pm

What would the bit flip affect on the NG, mach trim, STS, yaw damper, anything the computer controls? Luckily nothing critical, or B, grounding the NG fleet doesn't have the traction of the MAX based on emotional issues and the pragmatic need to have the NG flying to have a functioning air travel system, not a logical safety path that would lead wherever it goes.
 
Palop
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 6:04 pm

To keep harping on about cosmic neutrons and problems with shielding. The issue isn’t so much about generating more neutrons from banging on cores and creating new isotopes, as it is what happens when you slow down high energy neutrons. When you slow down neutrons, the scattering cross section goes up, meaning that the probability for a neutron interacting with the surroundings goes up for a given path. So with incomplete shielding you go from a situation where the neutrons would woosh through the sensitive area with a small but non-zero chance of interacting, to a situation where you have slow moving neutrons with a large chance of interacting. This increasing effect is really starting to be noticeable for energies less than 100 eV, which is smack dab in he middle of where electronics can get into real problems.
This is how insufficient neutron shielding can be worse than no shielding at all.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 6:06 pm

DenverTed wrote:
What would the bit flip affect on the NG, mach trim, STS, yaw damper, anything the computer controls? Luckily nothing critical, or B, grounding the NG fleet doesn't have the traction of the MAX based on emotional issues and the pragmatic need to have the NG flying to have a functioning air travel system, not a logical safety path that would lead wherever it goes.

The Seattle Times article says when the computer fails it just reverts to manual control i.e it expects the pilots to fly the plane.

The trick is to keep the odds of failing so low that the odds of it happening at a crucial phase of flight are low enough to meet regulations.

The cosmic ray thing never happened in 200M hours of NG flights, and odds are said to be in the range of one in ten trillion per day (see earlier posts).

Much lower than single engine failure which has happened with NG often enough.

Also, I'd think that the 737 computer going off line is not the same kind of impact as a full FBW system with full flight envelope protection.

It's very simplicity should make its absence a less dramatic event.

One of the many tragedies of MCAS 1.0 was how relatively difficult it was to disengage the damn thing.
Wake up to find out that you are the eyes of the world
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Wake now, discover that you are the song that the morning brings
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XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 6:15 pm

WIederling wrote:
asdf wrote:
Shielding works pretty simple if it is grounded
not that easy to do on a plane


What especially does grounding do for high energy particles?

Keeps them out of trouble? But if they're anything like mine, they'll sneak out when you are not looking anyway.
 
hivue
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 6:50 pm

MrBretz wrote:
I almost thought I could fly the thing. I am good at turning nobs.


You just about could. Engage LNAV and VNAV right after gear up, get no curve balls thrown at you by ATC en route, no unpredicted weather, an airplane and a runway equipped for auto-land, someone to point to the right knobs and just about the only things you would need help with are takeoff, roll out, and the radio work.

Of course, if some of the automation acts quirky or totally quits on you (think "MCAS" if you want), well...
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 7:00 pm

hivue wrote:
MrBretz wrote:
I almost thought I could fly the thing. I am good at turning nobs.


You just about could. Engage LNAV and VNAV right after gear up, get no curve balls thrown at you by ATC en route, no unpredicted weather, an airplane and a runway equipped for auto-land, someone to point to the right knobs and just about the only things you would need help with are takeoff, roll out, and the radio work.

Of course, if some of the automation acts quirky or totally quits on you (think "MCAS" if you want), well...


Does the A380 automatically retract/deploy slats and deploy gear before landing?
 
kalvado
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 8:03 pm

Revelation wrote:
DenverTed wrote:
What would the bit flip affect on the NG, mach trim, STS, yaw damper, anything the computer controls? Luckily nothing critical, or B, grounding the NG fleet doesn't have the traction of the MAX based on emotional issues and the pragmatic need to have the NG flying to have a functioning air travel system, not a logical safety path that would lead wherever it goes.

The Seattle Times article says when the computer fails it just reverts to manual control i.e it expects the pilots to fly the plane.

The trick is to keep the odds of failing so low that the odds of it happening at a crucial phase of flight are low enough to meet regulations.

The cosmic ray thing never happened in 200M hours of NG flights, and odds are said to be in the range of one in ten trillion per day (see earlier posts).

Much lower than single engine failure which has happened with NG often enough.

Also, I'd think that the 737 computer going off line is not the same kind of impact as a full FBW system with full flight envelope protection.

It's very simplicity should make its absence a less dramatic event.

One of the many tragedies of MCAS 1.0 was how relatively difficult it was to disengage the damn thing.


You don't know if it happened or not, computer glitch would be a non-event in manually controlled plane. it could be reported as autopilot disconnect or something along those lines - manual override is always there. Uneventful restart of a car computer in case of a problem is one of basic requirements to car systems, for example
MAX demonstrated a worst fear of FBW approach - computer having enough authority to crash the plane, and actually doing so for a random reason. So re-certification of control system for FBW standard is a must to avoid that very scenario.
286 era computers - and this is what we're talking about here - had memory failure rate of the order of 1 bit per megabyte-day at ground level. It can be technologically reduced, in a few ways - isotopically pure glass was one of big things -, but that is the ballpark of problem rate we may be talking about for those old machines.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 8:34 pm

kalvado wrote:
Revelation wrote:
DenverTed wrote:
What would the bit flip affect on the NG, mach trim, STS, yaw damper, anything the computer controls? Luckily nothing critical, or B, grounding the NG fleet doesn't have the traction of the MAX based on emotional issues and the pragmatic need to have the NG flying to have a functioning air travel system, not a logical safety path that would lead wherever it goes.

The Seattle Times article says when the computer fails it just reverts to manual control i.e it expects the pilots to fly the plane.

The trick is to keep the odds of failing so low that the odds of it happening at a crucial phase of flight are low enough to meet regulations.

The cosmic ray thing never happened in 200M hours of NG flights, and odds are said to be in the range of one in ten trillion per day (see earlier posts).

Much lower than single engine failure which has happened with NG often enough.

Also, I'd think that the 737 computer going off line is not the same kind of impact as a full FBW system with full flight envelope protection.

It's very simplicity should make its absence a less dramatic event.

One of the many tragedies of MCAS 1.0 was how relatively difficult it was to disengage the damn thing.


You don't know if it happened or not, computer glitch would be a non-event in manually controlled plane. it could be reported as autopilot disconnect or something along those lines - manual override is always there. Uneventful restart of a car computer in case of a problem is one of basic requirements to car systems, for example
MAX demonstrated a worst fear of FBW approach - computer having enough authority to crash the plane, and actually doing so for a random reason. So re-certification of control system for FBW standard is a must to avoid that very scenario.
286 era computers - and this is what we're talking about here - had memory failure rate of the order of 1 bit per megabyte-day at ground level. It can be technologically reduced, in a few ways - isotopically pure glass was one of big things -, but that is the ballpark of problem rate we may be talking about for those old machines.

Yes, you've both said the same thing really. There could have been hundreds of bit flip effects that would not be identified without thorough investigation. However, if there are no associated significant events, this wont happen.

Also I think it is likely that analysis of potential bit flip has been performed in the past, maybe NG maybe MAX maybe both, that likely did not identify any hazardous or catastrophic outcomes and that is where it rested.

Things have changed with MCAS V2.0 (FBW in effect) having significant authority of a flight control surface and, subsequently, the apparent rejection of the practice of downgrading outcomes on the basis of the pilot coming to the rescue, such that a catastrophic outcome potential is now observed and requires action.

Ray
 
gadFly
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Aug 08, 2019 11:30 pm

Ben Smith, current CEO of Air France KLM gave his first extensive interview since he became boss last year. WHen asked about fleet renewal for Transavia (owned by the group), he rejected the purchase of MAXs "thus far", saying they would go NG and just buy used ones. The article is behind a paywall (Figaro, 7/31/19), but here's the quote in French:

Nous n’achèterons pas de 737 Max pour l’instant. Nous pourrons acheter des 737 NG d’occasion. Il y en a des milliers dans le monde. KLM en possède déjà 50.
 
hivue
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:21 am

kalvado wrote:
MAX demonstrated a worst fear of FBW approach


The MAX is not a FBW airplane. If it were, we would not be having this discussion.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 3:06 am

Revelation wrote:
I haven't really kept up on the current status of the grounding recently. Could someone give me a (brief) rundown of what the current situation is?
The current situation is they are all still grounded, except that we saw the MAX-7 do what Boeing called an engineering flight requested by FAA yesterday, and Boeing's CEO reiterated handing off a fix to FAA in September and return to flight early Q4. So, not much has changed recently.


I don't know that anyone could believe this timing so I don't know why he would say it other than to present some mood of optimism. A major fix involving changes to fundamental architecture in September for a number of complex issues is going to require some in depth testing and evauluation. Then a return to flight the very next month in October?
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 4:49 am

ArgentoSystems wrote:
FluidFlow wrote:
Secondly as the material for shielding is not „active“ u lose enegy so a high energy neutron hits a nucleus in the shield and this then emits 2 low energy neutrons for example. Now this neutrons have to low energy to start a chain reaction (unlike material used in nuclear power plants) but the two neutrons can still affect the electronics. This leads to an increase in the chance to cause an upset as there are now two particles.


That can only be true if you assume that whoever designs the shield is complete idiot. Properly constructed shield works as intended.


I answered your question why there is no „spontaneous“ ignition of aircraft as you threw out there and explained you how the effect works. I do not really care how competent the engineer is. You insist that this effect is not there or that shielding works all the time and so on and on.

Just accept that the physics are known and actually understood and thats why the FAA insisted on Boeing changing the setup to minimize the chance of an upset. Redundancy is the key here and thats how it is solved.
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 6:39 am

XRAYretired wrote:
WIederling wrote:
asdf wrote:
Shielding works pretty simple if it is grounded
not that easy to do on a plane


What especially does grounding do for high energy particles?

Keeps them out of trouble? But if they're anything like mine, they'll sneak out when you are not looking anyway.


I found you have to keep a peeled eye on the blue ones.
Murphy is an optimist
 
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 9:31 am

hivue wrote:
kalvado wrote:
MAX demonstrated a worst fear of FBW approach


The MAX is not a FBW airplane. If it were, we would not be having this discussion.


True, because then the architecture would constantly check itself for errors. Sensor, flight control computer and such things would at least have triple redundancy, and isolating one faulty sensor / computer would be easy and automatic.
 
ACATROYAL
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 10:38 am

My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 11:00 am

ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...


My guess is that only a minority of "grandfathering" misuses have been exposed yet.
( here: ignore the changed environment/fallout from upgrading aspects of the 737
while retaining the "jurassic" elements of the certification because "its still a 737". )
Murphy is an optimist
 
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flyingturtle
Posts: 5613
Joined: Mon Oct 31, 2011 1:39 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 11:05 am

ACATROYAL wrote:
so I will now predict it will hit 100+ pages by the time it gets authorized to fly again.


Naaah, we'll have a Q4, a Q1, a Q2, and another Q3 thread again...


What really worries me is the safety culture at Boeing. The SPIEGEL report tells about a German engineer who has worked for Boeing. He tried to inform FAA about deficient 787 hulls, but was turned back. Then he checked with a lawyer specializing on whistleblower protection, and then sent his documents to EASA.

In the long term, Boeing should concede that Airbus was right in their design philosophies. That FBW with envelope protection is the way to go.
Reading accident reports is what calms me down
 
RickNRoll
Posts: 1707
Joined: Fri Jan 06, 2012 9:30 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 11:43 am

flyingturtle wrote:
ACATROYAL wrote:
so I will now predict it will hit 100+ pages by the time it gets authorized to fly again.


Naaah, we'll have a Q4, a Q1, a Q2, and another Q3 thread again...


What really worries me is the safety culture at Boeing. The SPIEGEL report tells about a German engineer who has worked for Boeing. He tried to inform FAA about deficient 787 hulls, but was turned back. Then he checked with a lawyer specializing on whistleblower protection, and then sent his documents to EASA.

In the long term, Boeing should concede that Airbus was right in their design philosophies. That FBW with envelope protection is the way to go.


That is the way all modern Boeing planes are designed. It's not a matter of Boeing not believing in FBW, it was a matter of budgets.
 
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:15 pm

flyingturtle wrote:
In the long term, Boeing should concede that Airbus was right in their design philosophies. That FBW with envelope protection is the way to go.

I thought the 787 was FBW, or are you thinking about the CFRP fuselage versus panels?
 
planecane
Posts: 990
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:17 pm

RickNRoll wrote:
flyingturtle wrote:
ACATROYAL wrote:
so I will now predict it will hit 100+ pages by the time it gets authorized to fly again.


Naaah, we'll have a Q4, a Q1, a Q2, and another Q3 thread again...


What really worries me is the safety culture at Boeing. The SPIEGEL report tells about a German engineer who has worked for Boeing. He tried to inform FAA about deficient 787 hulls, but was turned back. Then he checked with a lawyer specializing on whistleblower protection, and then sent his documents to EASA.

In the long term, Boeing should concede that Airbus was right in their design philosophies. That FBW with envelope protection is the way to go.


That is the way all modern Boeing planes are designed. It's not a matter of Boeing not believing in FBW, it was a matter of budgets.


Yes. Currently 2/3 of the passenger models (I'm not counting the 747-8 because I don't think anybody will order a passenger model again) they offer are FBW. Whenever the NMA is launched (which I assume they are waiting for a public announcement of even authority to offer until the MAX is back flying) it will be 3/4.

Also, contrary to the belief of some, Boeing FBW does have envelope protection.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:17 pm

par13del wrote:
flyingturtle wrote:
In the long term, Boeing should concede that Airbus was right in their design philosophies. That FBW with envelope protection is the way to go.

I thought the 787 was FBW, or are you thinking about the CFRP fuselage versus panels?


It is and so is the 777.
 
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Revelation
Posts: 20898
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:28 pm

RickNRoll wrote:
Revelation wrote:
I haven't really kept up on the current status of the grounding recently. Could someone give me a (brief) rundown of what the current situation is?
The current situation is they are all still grounded, except that we saw the MAX-7 do what Boeing called an engineering flight requested by FAA yesterday, and Boeing's CEO reiterated handing off a fix to FAA in September and return to flight early Q4. So, not much has changed recently.


I don't know that anyone could believe this timing so I don't know why he would say it other than to present some mood of optimism. A major fix involving changes to fundamental architecture in September for a number of complex issues is going to require some in depth testing and evauluation. Then a return to flight the very next month in October?

I think it's plausible because at the time the first reports of the "microprocessor problem" arose there were some reports of a major (architectural?) change to address the issue having been started much earlier, perhaps last year. I think that changes the time line that is in most people's heads.

ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...

Well, we have covered cosmic rays causing spontaneous aircraft ignition, so I guess you're right, we have been pretty thorough.

It seems we do so much of this, that the fact that Boeing flew a FAA test flight clearly doing the kinds of things that should trigger MCAS without the plane splashing into the ocean largely gets ignored.

Maybe Boeing has a grip on things and maybe October isn't that unreasonable after all...

I guess it's more exciting to talk about things few here have a grip on, such as high energy particles causing bit flips in microprocessor elements.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
XRAYretired
Posts: 482
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 12:44 pm

ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...

Just like cosmic ray spallation, throw in a random post and you get a splatter of secondary articles. (as above).

Ray
 
AIRT0M
Posts: 74
Joined: Thu Mar 01, 2018 8:54 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 1:40 pm

ACATROYAL wrote:
This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...


Hardly. "Boeing 737MAX Grounded Worldwide Q4 2019" is coming up in a few weeks and it's back to page 1.
 
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tistpaa727
Posts: 164
Joined: Sat May 05, 2007 5:23 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 4:37 pm

Revelation wrote:

It seems we do so much of this, that the fact that Boeing flew a FAA test flight clearly doing the kinds of things that should trigger MCAS without the plane splashing into the ocean largely gets ignored.

Maybe Boeing has a grip on things and maybe October isn't that unreasonable after all...

I guess it's more exciting to talk about things few here have a grip on, such as high energy particles causing bit flips in microprocessor elements.


Agreed and I really do hope they have a grip on this situation. And...nothing more creeps up on them. It seems a lot of this thread is about more than just MCAS but all of the other problems arising / coming to light due to the increased scrutiny. In the end, I believe this will be one hell of a safe plane. So much scrutiny will have been placed on every aspect of this aircraft.

Off topic: The bit flip cosmic ray occurrence is considered one of the reasons for the Toyota runaway vehicles a while back where people would press the brake pedal and nothing would happen. See this story from 2013. https://www.eetimes.com/document.asp?doc_id=1319903#
Don't sweat the little things.
 
ACATROYAL
Posts: 48
Joined: Mon Aug 20, 2007 11:25 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 5:29 pm

Good topic discussion on Toyota cars... interesting...
 
speedking
Posts: 67
Joined: Thu Nov 15, 2018 3:00 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 9:25 pm

XRAYretired wrote:
ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...

Just like cosmic ray spallation, throw in a random post and you get a splatter of secondary articles. (as above).

Ray


Protons.. Neutrons.. I think a shield from Morons is needed.
 
User avatar
PITingres
Posts: 1235
Joined: Fri Dec 21, 2007 1:59 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 10:45 pm

speedking wrote:
XRAYretired wrote:
ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...

Just like cosmic ray spallation, throw in a random post and you get a splatter of secondary articles. (as above).

Ray


Protons.. Neutrons.. I think a shield from Morons is needed.


And from bogons.
Fly, you fools! Fly!
 
MrBretz
Posts: 349
Joined: Tue Jun 14, 2016 9:13 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Fri Aug 09, 2019 11:12 pm

speedking wrote:
XRAYretired wrote:
ACATROYAL wrote:
My god, it seems that in this thread every possible component of the 737 MAX has been dissected, scrutinized and debated. I can't believe that there's anything left to discuss but I suspect some people will always find something else to analyze. This thread is now on its 40th and still counting page, so I will now predict it will hit 100+ pages by the time it gets authorized to fly again. I don't know what more can be said but it will be interesting to see...

Just like cosmic ray spallation, throw in a random post and you get a splatter of secondary articles. (as above).

Ray


Protons.. Neutrons.. I think a shield from Morons is needed.


How did the astronaunts ever get through the Van Allen belts? Those poor computers. Luckily, the FAA didn’t have to approve that. I know why: travel to the moon was faked. I will now leave my bozone area. Can we start the Q4 thread early?

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