I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

cpd wrote:

oldannyboy wrote:

747megatop wrote:

Boeing seems to be in the unique position of having had 2 types grounded; 1st the 787 and now the 737-MAX. Let's hope they don't make this a habit.

I hope not, but on the other hand we should de-stigmatize a "cautionary grounding". In this regard Boeing should have behaved much more maturely, and immediately propose themselves a grounding of the MAX variant. Thing is, at the end of the day, the MAX was going to end up grounded anyway [it was pretty evident from the onset], and they should/could have handled this a lot better. This is not only proving to be a technical nightmare (with seemingly financial and image repercussions), but also a PR disaster - which was ultimately not necessary.

Finally a couple of people who’ve not been drinking the Kool-Aid. This whole thing is a disaster for Boeing and they should have been more proactive in dealing with it. It’s looking like their version of VW/Audi dieselgate.

I hope they can recover. And with any luck the FDR will yield useful information- despite how smashed up it is.

Contrary to popular belief, Boeing is actually in a no-win solution.

737 Maxes are grounded/recalled: Boeing gets flamed by customers, regulators, stockholders, and passengers alike.

737 Maxes continue flying: Boeing gets flamed by customers, regulators, stockholders, and passengers alike.

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

I think that's actually how they solved the issue when moving from the -200 to the -300 (although the -300 has an entirely new tail in addition to the larger engines and slightly longer fuselage and wings as well). Might be wrong on the why, but the stabilizers are definitely much larger on the Classic than on the -100/200.

IADCA wrote:

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

I think that's actually how they solved the issue when moving from the -200 to the -300 (although the -300 has an entirely new tail in addition to the larger engines and slightly longer fuselage and wings as well). Might be wrong on the why, but the stabilizers are definitely much larger on the Classic than on the -100/200.

Thanks and interesting. Am I maybe not completely off here?

mat66 wrote:

IADCA wrote:

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

I think that's actually how they solved the issue when moving from the -200 to the -300 (although the -300 has an entirely new tail in addition to the larger engines and slightly longer fuselage and wings as well). Might be wrong on the why, but the stabilizers are definitely much larger on the Classic than on the -100/200.

Thanks and interesting. Am I maybe not completely off here?

Beyond that tidbit, I believe we stand equal in our ignorance. Or stupidity, as the case may be.

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

Apologies if this question has been answered already , but I'm wondering if the added length ( and weight) of the Max 9
and Max 10 help offset the CG issues the new engines are causing?

Likewise , would the shorter fuselage of the Max 7 make the CG worse than the Max 8's?

Sooner787 wrote:

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

Apologies if this question has been answered already , but I'm wondering if the added length ( and weight) of the Max 9
and Max 10 help offset the CG issues the new engines are causing?

Likewise , would the shorter fuselage of the Max 7 make the CG worse than the Max 8's?

Who told you it is a CG issue?
It is a center of drag issue. increasing with AoA the nacelles create a pitch up moment.

Please bear with me, I'm no expert in technical issues. IF the MCAS is to blame, because it corrects the AoA incorrectly (at times), after Lion Air's crash, weren't pilots suppossed to know of its existance and be able to disable it? how difficult is it to realize you are not climbing or flying at daytime?

WIederling wrote:

Sooner787 wrote:

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

Apologies if this question has been answered already , but I'm wondering if the added length ( and weight) of the Max 9
and Max 10 help offset the CG issues the new engines are causing?

Likewise , would the shorter fuselage of the Max 7 make the CG worse than the Max 8's?

Who told you it is a CG issue?
It is a center of drag issue. increasing with AoA the nacelles create a pitch up moment.

Ok, I change my question. I made it quite clear that this is total amateur hour from my part. Could larger horizontal stabilizers solve the center of drag problem?
I came up with this by comparing it to the huge stabilizers of the A340-5/600 compared to the the A340-300. bigger more powerful engines which probably would cause the same pitch up problems.

Bradin wrote:

cpd wrote:

oldannyboy wrote:

I hope not, but on the other hand we should de-stigmatize a "cautionary grounding". In this regard Boeing should have behaved much more maturely, and immediately propose themselves a grounding of the MAX variant. Thing is, at the end of the day, the MAX was going to end up grounded anyway [it was pretty evident from the onset], and they should/could have handled this a lot better. This is not only proving to be a technical nightmare (with seemingly financial and image repercussions), but also a PR disaster - which was ultimately not necessary.

Finally a couple of people who’ve not been drinking the Kool-Aid. This whole thing is a disaster for Boeing and they should have been more proactive in dealing with it. It’s looking like their version of VW/Audi dieselgate.

I hope they can recover. And with any luck the FDR will yield useful information- despite how smashed up it is.

Contrary to popular belief, Boeing is actually in a no-win solution.

737 Maxes are grounded/recalled: Boeing gets flamed by customers, regulators, stockholders, and passengers alike.

737 Maxes continue flying: Boeing gets flamed by customers, regulators, stockholders, and passengers alike.

I think it is nobody's interest in letting Boeing fall. In this age of globalism, would it be possible for the global governments force Airbus help Boeing to make 737 safe again? Better A737 than 737RIP?

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

AtomicGarden wrote:

Please bear with me, I'm no expert in technical issues. IF the MCAS is to blame, because it corrects the AoA incorrectly (at times), after Lion Air's crash, weren't pilots suppossed to know of its existance and be able to disable it? how difficult is it to realize you are not climbing or flying at daytime?

So are you suggesting these planes are only safe enough to fly in daylight then?

This is getting silly now

Why would we ever want to rely on pilots intervening to fix planes that aren't safe enough to fly as they are?

speedking wrote:

In this age of globalism, would it be possible for the global governments force Airbus help Boeing to make 737 safe again? Better A737 than 737RIP?

boeing is capacible of building great FBW planes, arent they?

they have the 787
isnt it 100% FBW ?

they simply need to adopt that system to the 737 plattform
but thats a lot of work
and probably its easier to start from zero than try to adopt a 60 jear old draft

asdf wrote:

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

You mean like cars that have manual boosted brakes with electronic anti-skid systems? We must all be insane.

You are conflating the mechanism to achieve stability versus the result.
The mechanism doesn't matter, the results matter.

Dieuwer wrote:

Der Spiegel - AFAIK a very respectable magazine - is suggesting a conspiracy:

But there was a catch. The engineers who were performing all of these miracles of rejuvenation knew full well that they were making compromises they never would have tolerated in a newer model. The consequences of that corner-cutting may now be revealing themselves.

The pilots wouldn't even notice the software's intervention -- at least that was the idea. In fact, Boeing didn't even consider it necessary to inform pilots about the newfangled MCAS, or "Maneuvering Characteristics Augmentation System."

[my emphasis]

Two words come to mind: "Criminal Negligence".

http://www.spiegel.de/international/eur ... 57608.html

DER SPIEGEL is generally quite respectable, but tends to be a bit alarmist when it comes to aviation matters. And before anybody says "Oh, they're bound to be critical of Boeing as they're headquartered in Hamburg, which has a major Airbus presence": They're actually downright nasty when it comes to Airbus. The story goes that their long-gone editor in chief was very miffed indeed when a protected part of the Elbe river was filled up so the Airbus runway could be extended for the A380F (yes, the freighter).
Even after that guy's departure, DER SPIEGEL have retained more than a healthy dose of scepticism when it comes to all matters Airbus.

Anyway, I don't think the article is suggesting a conspiracy. It just sums up what we now all know regarding the genesis of the MAX and of MCAS in particular. Yes, they do imply that engineers made some compromises that they wouldn't have on a brand new design. Here we have a bit of alarmism, as in the last paragraph which suggests Boeing might have to scrap the MAX and do a new plane.
Which I don't think anybody with knowledge of the matter really expects at this point. The general expectation is still that any issue is fixable on the MAX and will ve fixed, similar to the 787.

asdf wrote:

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

OK, that‘s tough, but actually confirms my thinking of the MAX being just one step too far. Anyway, Boeing will of course fix this and thousands of MAX will fly for decades.

speedking wrote:

I think it is nobody's interest in letting Boeing fall. In this age of globalism, would it be possible for the global governments force Airbus help Boeing to make 737 safe again? Better A737 than 737RIP?

The basic mindset is fully incompatible. US culture thinks in terms of winning. winning requires losers. the "looser" the better.
( in that scope it is easier to sabotage a competitor than to excel over that competitor. One must see all these gimmicky little wins as up front advantage that paints one into a corner in the long run. surmounted more and even further over the top "competitive" activity. In another domain problems turning untractable is called "blowback".

OT:
Some time ago I proposed that Boeing buy A320 ( or license build them) , rebadge them ( US MoO change the chromium trim every year ( again US MoO and sell it as the Boeing 7820. Boeing could earn money by the barrel.

Interested wrote:

AtomicGarden wrote:

Please bear with me, I'm no expert in technical issues. IF the MCAS is to blame, because it corrects the AoA incorrectly (at times), after Lion Air's crash, weren't pilots suppossed to know of its existance and be able to disable it? how difficult is it to realize you are not climbing or flying at daytime?

So are you suggesting these planes are only safe enough to fly in daylight then?

This is getting silly now

Why would we ever want to rely on pilots intervening to fix planes that aren't safe enough to fly as they are?

That's not what I meant. What I want to know is how hard is it for a pilot to realise your plane is heading to the ground because of MCAS malfunction (if that were the case). It's exactly the opposite, shouldn't it be easier to see the error? also, can the system be deactivated?

I am no pilot, I am not criticizing anyone, I just want to understand the case.

So the same software fix they've been working on since November is needed to be finished and tested before they can fly again. And FAA saying it's months from being complete!

Must be an incredibly tough software fix with the amount of resource they could put behind it?

Chemist wrote:

asdf wrote:

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

You mean like cars that have manual boosted brakes with electronic anti-skid systems? We must all be insane.

You are conflating the mechanism to achieve stability versus the result.
The mechanism doesn't matter, the results matter.

well
as i checked last time MY anti-skid system was designed to compensate different friction
and not to compensate missing balance of the rim ....

AtomicGarden wrote:

Interested wrote:

AtomicGarden wrote:

Please bear with me, I'm no expert in technical issues. IF the MCAS is to blame, because it corrects the AoA incorrectly (at times), after Lion Air's crash, weren't pilots suppossed to know of its existance and be able to disable it? how difficult is it to realize you are not climbing or flying at daytime?

So are you suggesting these planes are only safe enough to fly in daylight then?

This is getting silly now

Why would we ever want to rely on pilots intervening to fix planes that aren't safe enough to fly as they are?

That's not what I meant. What I want to know is how hard is it for a pilot to realise your plane is heading to the ground because of MCAS malfunction (if that were the case). It's exactly the opposite, shouldn't it be easier to see the error? also, can the system be deactivated?

I am no pilot, I am not criticizing anyone, I just want to understand the case.

Yes I understand that. I'm sure it no doubt can be recognised and dealt with. It's just the premise that we should even consider it acceptable for a known issue that clearly has potential to cause disasters to have the solution that pilots should be trained to recognise the fault and be able to take action to deal with it. Why should/would we ever accept that as a solution? Surely the minute we know there's a fault like this. Either the fault has to be fixed or the planes don't fly.

Whereas we already know now that having established they needed to update software to make these planes safe after the Lion crash they've allowed them to still fly whilst they fix it?

Imagine youve lost someone in your family in the second crash? How does this make you feel. It. Makes me angry and I don't know anyone involved.

PixelPilot wrote:

JetBuddy wrote:

remcor wrote:

Interesting new commentary today by aviation analyst Leeham News:

https://leehamnews.com/2019/03/13/comme ... nsparency/

Yes very good article. And it's worrying that Boeing CEO allegedly tried to lobby the President to not allow FAA to ground the type.

"Reports of a phone call between Boeing CEO Dennis Muilenberg and US President Donald Trump reportedly imploring the latter not to allow the FAA to ground the MAX provides additional reason for doubt. To wit, why lobby the White House to override the FAA if the technical evidence is clearly on Boeing’s side? This flies in the face of any Boeing public statements about putting safety first."

How can we know what they talked about over the phone?
This is reaching the "because Russia" territory.

At a time when CAA's worldwide are grounding 737Max left and right, I doubt the CEO was enquiring POTUS how his Russian investments were doing . . .

Interested wrote:

AtomicGarden wrote:

Interested wrote:

So are you suggesting these planes are only safe enough to fly in daylight then?

This is getting silly now

Why would we ever want to rely on pilots intervening to fix planes that aren't safe enough to fly as they are?

That's not what I meant. What I want to know is how hard is it for a pilot to realise your plane is heading to the ground because of MCAS malfunction (if that were the case). It's exactly the opposite, shouldn't it be easier to see the error? also, can the system be deactivated?

I am no pilot, I am not criticizing anyone, I just want to understand the case.

Yes I understand that. I'm sure it no doubt can be recognised and dealt with. It's just the premise that we should even consider it acceptable for a known issue that clearly has potential to cause disasters to have the solution that pilots should be trained to recognise the fault and be able to take action to deal with it. Why should/would we ever accept that as a solution? Surely the minute we know there's a fault like this. Either the fault has to be fixed or the planes don't fly.

Whereas we already know now that having established they needed to update software to make these planes safe after the Lion crash they've allowed them to still fly whilst they fix it?

Imagine youve lost someone in your family in the second crash? How does this make you feel. It. Makes me angry and I don't know anyone involved.

All I wanted was to better understand ET's crash. If maneuvering difficulties (that shouldn't happen) have to be constantly fixed by the crew, we agree that the plane is not airowrthy.

If my car steers to the left and the solution by the carmaker is telling me to compensate it with constant corrections, it's definitely their fault if I end up crashing. However, while I'm not blaming the pilots, my question still stands, you have the right to ignore it and go on with your life.

Interested wrote:

BBC:

All Boeing 737 Max 8 and 9 aircraft will remain grounded at least until May after the fatal Ethiopian Airlines crash on Sunday, the US Federal Aviation Administration (FAA) has said.
The aircraft will not fly until a software update can be tested and installed, the US regulator said.
Sunday's crash, shortly after take-off from Addis Ababa, killed 157 people from 35 nations.
It was the second crash involving a 737 Max in six months.
Some people have pointed to similarities between the incidents, with some experts citing satellite data and evidence from the crash scene as showing links between Sunday's disaster and October's crash in Indonesia of the Lion Air jet that killed 189 people.
US Representative Rick Larsen said the software upgrade would take a few weeks to complete, and installing it on all the aircraft would take "at least through April".
The FAA said on Wednesday that a software fix for the 737 Max that Boeing had been working on since the Lion Air crash would take months to complete.

So they aren't doing anything different due to new info then?
They are just completing what they were doing already?

I'm curious to know how Boeing is going to fix this without introducing something that might exceed the certification for the -MAX. For example, could they install a third AOA vane or would that be too much of a variation from the -NG? Could additional data from GPS and/or inertial sensors be integrated?

I know that we still don't have complete information on Lionair, let alone ET.

Would/could Boeing be on the hook for pretty large compensation costs to the airlines considering the grounding is costing them millions of dollars a day?

It's obvious that ungrounding the 737 MAX is entirely up to Boeing now. Ball is in their court. They need to come up with a fix for MCAS and publicly demonstrate that the plane is safe. Faster they move, sooner the 737 MAX will fly again.They control the timeline.

VonRichtofen wrote:

Would/could Boeing be on the hook for pretty large compensation costs to the airlines considering the grounding is costing them millions of dollars a day?

They stopped delivering new jets. So there could jets be sitting around for months. Don't know what is written down in contacts in such eventualities, but penalties for this alone could be quite stiff.

How was this handled with the 787 grounding, quite a similar situation in this regard.

DocLightning wrote:

I'm curious to know how Boeing is going to fix this without introducing something that might exceed the certification for the -MAX. For example, could they install a third AOA vane or would that be too much of a variation from the -NG? Could additional data from GPS and/or inertial sensors be integrated?

I know that we still don't have complete information on Lionair, let alone ET.

We are all curious about this, but first they need to analyze what happened before looking for a solution. Perhaps a 3rd AoA might solve it, perhaps something else is needed.

Apologies if this has already been posted elsewhere in this long thread...
"The captain of a doomed Ethiopian Airlines jetliner faced an emergency almost immediately after takeoff from Addis Ababa, requesting permission in a panicky voice to return after three minutes as the aircraft accelerated to abnormal speed, a person who reviewed air traffic communications said Thursday."
"Controllers also observed that the aircraft, a new Boeing 737 Max 8, was oscillating up and down by hundreds of feet — a sign that something was extraordinarily wrong."
NY Times

DocLightning wrote:

I'm curious to know how Boeing is going to fix this without introducing something that might exceed the certification for the -MAX. For example, could they install a third AOA vane or would that be too much of a variation from the -NG? Could additional data from GPS and/or inertial sensors be integrated?

I know that we still don't have complete information on Lionair, let alone ET.

My guesses are:

- reduce stall warning activation angles and disable MCAS. Would directly impact aircraft perfomance
- Use both aoa sensors to control MCAS. Don’t know if there is cross communication between both FCC computers to allow this
- Include another mechanism to disable MCAS in cases of erroneous commands.
- Include a Logic which does not allow MCAS to command continuously

Dutchy wrote:

VonRichtofen wrote:

Would/could Boeing be on the hook for pretty large compensation costs to the airlines considering the grounding is costing them millions of dollars a day?

They stopped delivering new jets. So there could jets be sitting around for months. Don't know what is written down in contacts in such eventualities, but penalties for this alone could be quite stiff.

How was this handled with the 787 grounding, quite a similar situation in this regard.

About a week after ET302, Boeing stock continues to slide and some Asian airline are now having second thoughts on their order.
Boeing pauses 737 MAX deliveries in wake of deadly crash
Read more at https://www.channelnewsasia.com/news/wo ... h-11346480

Boeing, airlines face tough path after 737 MAX grounding
Read more at https://www.channelnewsasia.com/news/wo ... --11346450

Ethiopian Airlines crash puts US$633 billion worth of Boeing 737 MAX jet orders in jeopardy
Read more at https://www.scmp.com/news/hong-kong/tra ... rth-boeing

asdf wrote:

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

The issue with MCAS would be the same if it was FBW. Isn't stab trim FBW anyway? I was under the impression that the jackscrew was turned by a motor. MCAS was poorly designed because it could fail by a single sensor failure.

However, if you disable MCAS, it doesn't make the aircraft unflyable. It just requires input from the pilot (either elevator or trim) to keep from stalling under some flight envalope edge cases. MCAS was put in so that the pilot wouldn't notice any difference between the NG and MAX in those situations and therefore wouldn't need to be trained for the differences.

Based on the information available, I find it hard to imagine that the ET crash was primarily caused by MCAS behavior. Maybe it contributed in the end but the reports of them having severe controllability issues immediately upon lifting off the ground points to another failure. The reason that I don't disagree with the grounding is that it is important to make sure whatever was the initial cause of the ET crash is not a design issue with the MAX in addition to MCAS.

Honestly, I don't think that the criteria for lifting the grounding order should be the implementation of the MCAS software fix. Stabilizer trim runaway due to MCAS can be solved easily with the cutout switches. I think the criteria should be the preliminary determination of casue of the ET crash. If it does not appear to be something pointing ot another MAX design flaw, then lift the ban.

mat66 wrote:

WIederling wrote:

Sooner787 wrote:

Apologies if this question has been answered already , but I'm wondering if the added length ( and weight) of the Max 9
and Max 10 help offset the CG issues the new engines are causing?

Likewise , would the shorter fuselage of the Max 7 make the CG worse than the Max 8's?

Who told you it is a CG issue?
It is a center of drag issue. increasing with AoA the nacelles create a pitch up moment.

Ok, I change my question. I made it quite clear that this is total amateur hour from my part. Could larger horizontal stabilizers solve the center of drag problem?
I came up with this by comparing it to the huge stabilizers of the A340-5/600 compared to the the A340-300. bigger more powerful engines which probably would cause the same pitch up problems.

The A340NG has a much bigger wing, that has more to do with the need for a bigger horizontal stabilizer. Also the weight of the aircraft.

Probably the same for the 737, bigger wing and bigger plane => bigger tail.

Interested wrote:

So the same software fix they've been working on since November is needed to be finished and tested before they can fly again. And FAA saying it's months from being complete!

Must be an incredibly tough software fix with the amount of resource they could put behind it?

I’m not an aviation expert, just an enthusiast, but I can speak to software issues with a fair amount of authority. It’s likely the software fix has been built and running in some form since 2018 - a change like this was probably a few engineering weeks, tops. The time involved here will be in validation, testing, certification, and likely even flight testing. Boeing has to ensure that this fix really does solve all MCAS-related issues before pushing it out to the fleet.

I expect them to have hugely increased resources devoted to validation this week. I suspect the 38M flights mentioned here that occurred near Moses Lake were related, for example.

The fix will probably be held until we understand what’s on the CVR/FDR from ET302, but assuming that also points to an MCAS issue: once they can test that the fix would have also prevented that situation I expect it to roll out very quickly thereafter.

tl;dr the actual development time is a fraction of what it takes to test, refine and validate the changes.

juliuswong wrote:

Dutchy wrote:

VonRichtofen wrote:

Would/could Boeing be on the hook for pretty large compensation costs to the airlines considering the grounding is costing them millions of dollars a day?

They stopped delivering new jets. So there could jets be sitting around for months. Don't know what is written down in contacts in such eventualities, but penalties for this alone could be quite stiff.

How was this handled with the 787 grounding, quite a similar situation in this regard.

About a week after ET302, Boeing stock continues to slide and some Asian airline are now having second thoughts on their order.
Boeing pauses 737 MAX deliveries in wake of deadly crash
Read more at https://www.channelnewsasia.com/news/wo ... h-11346480

Boeing, airlines face tough path after 737 MAX grounding
Read more at https://www.channelnewsasia.com/news/wo ... --11346450

Ethiopian Airlines crash puts US$633 billion worth of Boeing 737 MAX jet orders in jeopardy
Read more at https://www.scmp.com/news/hong-kong/tra ... rth-boeing

The stock is sliding, but to put things into perspective, their stock closed higher today than it did the day before the Lionair crash. Their stock will recover.

planecane wrote:

asdf wrote:

mat66 wrote:

Could larger horizontal stabilizers solve the center of drag problem?

if you damage your rim at your car the steering wheel will pull to one side
would you think that mounting a larger steering wheel would be a reasonable measure?


if you deside to build a plane which is not neutral in behavement then you have to build it as a full FBW plane from the scratch

to take a conventional manual flying plane
and chance the attiutude over a certain limit
and try to "fix" that with a lousy electronic solution which is based on a single sensor source is just insane

The issue with MCAS would be the same if it was FBW. Isn't stab trim FBW anyway? I was under the impression that the jackscrew was turned by a motor. MCAS was poorly designed because it could fail by a single sensor failure.

Raised the same issue earlier this week. FBW / no FBW is irrelevant. 777X is a bigger aircraft with bigger engines from the same company. FAA needs to assess whether MCAS, likely with a new name, lurks within, with potentially similar deficiencies.

Interested wrote:

So the same software fix they've been working on since November is needed to be finished and tested before they can fly again. And FAA saying it's months from being complete!

Must be an incredibly tough software fix with the amount of resource they could put behind it?

It probably is the validation that the fix doesn’t introduce any other problems under various failure conditions that takes most of the time.

WIederling wrote:

Sooner787 wrote:

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

Apologies if this question has been answered already , but I'm wondering if the added length ( and weight) of the Max 9
and Max 10 help offset the CG issues the new engines are causing?

Likewise , would the shorter fuselage of the Max 7 make the CG worse than the Max 8's?

Who told you it is a CG issue?
It is a center of drag issue. increasing with AoA the nacelles create a pitch up moment.

Center of drag?

planecane wrote:

The issue with MCAS would be the same if it was FBW. Isn't stab trim FBW anyway? I was under the impression that the jackscrew was turned by a motor. MCAS was poorly designed because it could fail by a single sensor failure.

However, if you disable MCAS, it doesn't make the aircraft unflyable. It just requires input from the pilot (either elevator or trim) to keep from stalling under some flight envalope edge cases.

MCAS was put in so that the pilot wouldn't notice any difference between the NG and MAX in those situations and therefore wouldn't need to be trained for the differences.

That's true, but not the whole truth. It's also placing the cart in front of the horse. Boeing did not install MCAS to be nice to the pilots....

MCAS was put in to protect against some unpleasant handling aspects that could bite plenty of ordinary airline pilots, even if they did have 1500 hrs.
This and making the handling indistinguishable from the NG allowed grandfathering, quick and easy certification, and all that comes with that. This is the core of the reason. (Mainly $$$ profit)

In most cases the aircraft is still flyable without MCAS (as you rightly say), except that potentially places an additional workload on the pilots, and would be illegal if disabling MCAS became standard operational procedure.

planecane wrote:

The reason that I don't disagree with the grounding is that it is important to make sure whatever was the initial cause of the ET crash is not a design issue with the MAX in addition to MCAS.

I suspect we are broadly in agreement, and what I have written above simply echoes your own understanding.

mat66 wrote:

I‘ve got a probably stupid question here. The software nose down solution was added due to increased pitch because of more forward moving center of gravity. Would larger horizontal stabilizers have solved this issue? Just curious. It would have been the far more expensive solution, of course.

Some of the many more knowledgeable here can correct me if I'm wrong, but the addition of MCAS was ONLY to allow the same type rating for existing 737 drivers and is there to make the control column feel the same to the pilots as it does on the NG at attitudes close to a stall.

The larger nacelles on the Leap engines create their own lift at high angles of attack at which point, and only with flaps retracted and in manual control (else there would be no need to adjust the feel of the control columns) it applies nose down trim with no additional notification to the pilots other than the trim wheels moving. MCAS might well help prevent a stall, but that is not its direct purpose.

A different horizontal stabilizer might also achieve the same thing, but that would have required a new certification of the aircraft (I believe, and so a new type rating too).

To sell the MAX in the numbers required to make a difference, especially with pressures from existing operators to keep the same type rating as the NG, MCAS was necessary.

MSPNWA wrote:

It's not a red herring, and you know it. It tells us who we should be concerned about in regards to safety. It's impossible to make a plane completely foolproof. Laying the burden on the manufacturer to construct an airplane that can't be crashed is ridiculous. Are there areas to improve a plane? Absolutely. But it's still a fallible object at some point. It will stop doing what we want it to do.

Not having a flight control system that has a single point of failure is pretty basic....

JetBuddy wrote:

Yeah, maybe in a metroliner.

To be fair, 1500 hours in the "Death Pencil" should qualify you for anything. Including psychiatric therapy.

32andBelow wrote:

It’s going to be embarrassing for the whole world when the accident cause is unrelated.

How do you know the accident cause is unrelated. Please share.

Floridaguy74656 wrote:

Tell that to the Boeing Employees whose livelihood is on the line and the stockholders whose retirement is getting wiped out. I'm sure they think grounding a plane based on nothing more than conjecture is a great thing too right ?

Yes, financial returns are far more important than aviation safety. Also, please google "diversification". If one's wealth is tied entirely to one company, then that person is not a very savvy investor.

AirbusA6 wrote:

The impression left is that Trump (or someone close to him) has taken this decision over the heads of the FAA

Either way, it's the only credible decision to take. Once Canada grounded them, there's no way that the US could have continued as the only country allowing the Max to fly.

I don't have a lot of good things to say about the president, but he absolutely made the right call here and should be commended as such.

1ffb2002 wrote:

Social media hysteria rules the day. American Airlines reported in 14,000 flights, there have be NO REPORTS of any flight management irregularities with the MAX 8. I repeat, no irregularities.

Wrong again.
https://www.apnews.com/0cd5389261f34b01a7cbdb1a12421e27

The pilot reports were filed last year in a data base compiled by NASA. They are voluntary safety reports and do not publicly reveal the names of pilots, the airlines or the location of the incidents.

It was unclear whether the accounts led to any actions by the FAA or the pilots’ airlines.

In one report, an airline captain said that immediately after putting the plane on autopilot, the co-pilot called out “Descending,” followed by an audio cockpit warning, “Don’t sink, don’t sink!”

The captain immediately disconnected the autopilot and resumed climbing.

“With the concerns with the MAX 8 nose down stuff, we both thought it appropriate to bring it to your attention,” the captain wrote. “Best guess from me is airspeed fluctuation” due to a brief weather system overwhelming the plane’s automation.

On another flight, the co-pilot said that seconds after engaging the autopilot, the nose pitched downward and the plane began descending at 1,200 to 1,500 feet (365 to 460 meters) per minute. As in the other flight, the plane’s low-altitude-warning system issued an audio warning. The captain disconnected autopilot, and the plane began to climb.

The pilots talked it over later, “but can’t think of any reason the aircraft would pitch nose down so aggressively,” the co-pilot recounted.

Wallhart wrote:

Ite embarrassing people are still clinging on to the "lets keep them flying" until we find the facts out mantra.

Yes. I guess it makes absolutely clear what people's biases are. Once the interim report is released for Ethiopian, I think a few people will be quite embarrassed.

ELBOB wrote:

And stop complaining about the cockpit noise!

Surely I'm not the only one who likes the sound of the 737's trimwheels?

planecane wrote:

The issue with MCAS would be the same if it was FBW. Isn't stab trim FBW anyway? I was under the impression that the jackscrew was turned by a motor. MCAS was poorly designed because it could fail by a single sensor failure.

MCAS will never be on a FBW plane. On a FBW plane the yoke or sidestick commands a certain roll or pitch change. The computer translates the command into relevant control surface movements depending on flight data (speed, AoA etc.).

If the command approaches a stall, then the plane screams "don't do that" (soft protection), or it limits the command to safe limit (hard protection).

All FBW planes have three AoA sensors with voting out a bad guy.

The 737 is the only large passenger airliner still being produced without FBW control. It is now almost 40 years since the last all new western airliner was designed from scratch without FBW (767).

If 737 had been a FBW plane, then the NG to MAX changes wouldn't have needed MCAS. Instead some figures in the computer software would have been changed to change the elevator movements as needed. The horizontal stabilizer trim system would never be involved. That's the same way for instance Airbus makes an A319 feel exactly like an A320. Or A321.

AtomicGarden wrote:

Interested wrote:

AtomicGarden wrote:

That's not what I meant. What I want to know is how hard is it for a pilot to realise your plane is heading to the ground because of MCAS malfunction (if that were the case). It's exactly the opposite, shouldn't it be easier to see the error? also, can the system be deactivated?

I am no pilot, I am not criticizing anyone, I just want to understand the case.

Yes I understand that. I'm sure it no doubt can be recognised and dealt with. It's just the premise that we should even consider it acceptable for a known issue that clearly has potential to cause disasters to have the solution that pilots should be trained to recognise the fault and be able to take action to deal with it. Why should/would we ever accept that as a solution? Surely the minute we know there's a fault like this. Either the fault has to be fixed or the planes don't fly.

Whereas we already know now that having established they needed to update software to make these planes safe after the Lion crash they've allowed them to still fly whilst they fix it?

Imagine youve lost someone in your family in the second crash? How does this make you feel. It. Makes me angry and I don't know anyone involved.

All I wanted was to better understand ET's crash. If maneuvering difficulties (that shouldn't happen) have to be constantly fixed by the crew, we agree that the plane is not airowrthy.

If my car steers to the left and the solution by the carmaker is telling me to compensate it with constant corrections, it's definitely their fault if I end up crashing. However, while I'm not blaming the pilots, my question still stands, you have the right to ignore it and go on with your life.

And in this case, it steers abruptly to the left, and the solution is to stomp three times on the brake pedal and turn off the headlights. If you don’t manage to do it and end up in oncoming traffic you are badly trained.

DL717 wrote:

Lion air out about 4 NGs into the ocean. They would put a320s into the ocean no doubt. So no we shouldn’t disrupt the safety aviation system in the world due to incidents in the developing world.

Indeed. That’s one scary ass track record.

FWIW until JT610, Lion had only one prior fatal accident.

DL717 wrote:

You don’t ground a fleet without data to back it up.

Here's some data:
Crash rate per million flights:
Airbus A340 - 0

Boeing 737NG: 0.11

Airbus A320: 0.15

Boeing 737MAX: 4.

777Jet wrote:

You have mentioned "number of bodies" several times as a reason for a grounding; just one lost full A380 would easily surpass the 350 mark.

The A380 has twelve years of safe operations behind it. If two A380s nosedived into the ground in a very short space of time, I would be happy for the fleet to be grounded whilst preliminary investigations take place. That you are trying to argue hypothetically that the A380 - a plane with a perfect safety record - is less safe than the 737MAX is laughable and shows how biased you are on this matter.

777Jet wrote:

Is it Boeing's fault that Lion Air decided to fly a specific aircraft that should have been in the hanger with a known problem that was not yet fixed? Would the JT610 crash have happened if Lion Air did the correct thing and fixed that aircraft instead of let it fly that day?

Red herring yet again. Pitot tubes fail inflight and AOA indicators do too. To believe otherwise is just stupid. The failure of those should not be the difference between a flight being safely operated and it nosediving uncontrollably to Terra Firma.

32andBelow wrote:

Lion air out about 4 NGs into the ocean. They would put a320s into the ocean no doubt.

And yet, despite Lion's Batik Air operating more than 40 A320s, they haven't.

Varsity1 wrote:

Interested wrote:

Varsity1 wrote:

The stick shaker and stick pusher are using the same AOA sensor. If the sensor is faulty, we would be getting reports of the stick shaker and pusher activating on 737 max flights. Yet, there hasn't been a single one.

Documents reveal that pilots flying last November reported engaging autopilot only for the aircraft's nose to pitch lower, prompting the warning system to exclaim: "Don't sink! Don't sink!"
Two US pilots reported separate incidents involving the 737 Max's automatic anti-stalling system in November.
The feature, which was new to the 737 Max family, is designed to keep the plane from stalling.
The system prevents the aircraft from pointing upwards at too high an angle, where it could lose its lift.
However, according to filings with the US Aviation Safety Reporting System, which pilots use to disclose information anonymously, it appeared to force the nose down.
In both cases, pilots were forced to intervene to stop the plane from descending.

From BBC news

The don't sink calls are from the EGPWS, not the AOA vane.

We would have reports of the stick shaker activating in flight if the vane were faulty.

...If the aircraft was approaching stick shaker speed.

Varsity1 wrote:

MCAS doesn't work with the autopilot engaged, so what BBC is describing probably isn't related. /facts

Something else that Boeing needs to fix before the airplanes are ungrounded then.

oldannyboy wrote:

I am wondering what the long-term repercussions for Boeing will be, because I am pretty certain there will be some...I am left wondering whether a part of the travelling public will now look at Boeing products with suspicion, and not because they might be inherently unsafe or anything, but simply because a crucial fault was addressed in such casual manner.
It pains me greatly to see one of the two greatest aircraft manufacturers approach what has turned to be a seriously critical and potentially lethal issue with one of their top products in such a shallow, non-committal, hush-hush kind of way. Big reality check for them as well as the public, AS WELL AS their customers... I expected far better of them - heck, They CAN do a lot better.

This also demonstrates that a cosy duopoly in the aviation market is not only unhealthy but potentially downright dangerous.

To be honest, I think it's something deep within Boeing's company culture. The belief that their products are superior and to not consider credible any evidence/allegations/possibility that this might not be the case. Lauda Air 004; Boeing did all they could to blame the pilots. They insisted nothing was wrong with the 737 rudder PCUs until the NTSB completely proved them wrong. With JT610 Boeing was very quick to blame the pilots and as we've seen here, certain users (dare I say shills?) have already determined that the crash was most likely due to the low hour first officer, rather than anything to do with the aircraft.

kruiseri wrote:

What if the MAX cannot be fixed within the original design parameters ? ie. Same type rating as NG for the pilots ?

The MCAS is a vast difference from the NG. It obfuscates from the pilot the handling differences between the two types in certain phases of the flight. OK; you can add redundancy to it by adding multiple data sources like a third AoA vane etc, but it does not change the underlying fact that it is still a separate independent system that can always go haywire ==> pilots need to be trained for that possibility. And that means that they must be trained differently than NG pilots, would that then ruin the common type rating feature ?

Boeing has no choice but to make it work.

N47 wrote:

SuperGee wrote:

Right now, the FAA only has an acting director, Michael Herta for the past 2 years. I don’t know anything about him. He may be very good in that job or he may not be.

Michael Huerta was the administrator of the FAA from 1/2011 to 1/2018. It is Dan Elwell who is the current acting administrator.

In another note:

Its not a secret that FAA works very closely with its stake holders, of which the most important is the flying public, followed by ATC/operators, aircraft manufacturers etc. However, some of what has been suggested on this thread goes a little too far in terms of politics.

Dan Elwell is a professional lobbyist. The revolving door between the upper echelons of government and industry continues again.

anfromme wrote:

DER SPIEGEL is generally quite respectable, but tends to be a bit alarmist when it comes to aviation matters. And before anybody says "Oh, they're bound to be critical of Boeing as they're headquartered in Hamburg, which has a major Airbus presence": They're actually downright nasty when it comes to Airbus. The story goes that their long-gone editor in chief was very miffed indeed when a protected part of the Elbe river was filled up so the Airbus runway could be extended for the A380F (yes, the freighter).
Even after that guy's departure, DER SPIEGEL have retained more than a healthy dose of scepticism when it comes to all matters Airbus.

Thanks - I've always what the reason for their disdain for Airbus was.

afgeneral wrote:

It's obvious that ungrounding the 737 MAX is entirely up to Boeing now. Ball is in their court. They need to come up with a fix for MCAS and publicly demonstrate that the plane is safe. Faster they move, sooner the 737 MAX will fly again.They control the timeline.

Well, hopefully it will also be up to aviation authorities to certify that Boeing's fix is safe.

From Reuters just now:

BREAKING: Investigators of Ethiopian crash found piece of stabilizer with trim in unusual position similar to doomed Lion Air jet - sources

remcor wrote:

From Reuters just now:

BREAKING: Investigators of Ethiopian crash found piece of stabilizer with trim in unusual position similar to doomed Lion Air jet - sources

Okay, but how did it get in that position?

I thought MCAS trim movement was limited?

We have way too much conflicting info to draw any technical conclusion on the root cause of the error.

zkojq wrote:

777Jet wrote:

You have mentioned "number of bodies" several times as a reason for a grounding; just one lost full A380 would easily surpass the 350 mark.

The A380 has twelve years of safe operations behind it. If two A380s nosedived into the ground in a very short space of time, I would be happy for the fleet to be grounded whilst preliminary investigations take place. That you are trying to argue hypothetically that the A380 - a plane with a perfect safety record - is less safe than the 737MAX is laughable and shows how biased you are on this matter.

777Jet wrote:

Is it Boeing's fault that Lion Air decided to fly a specific aircraft that should have been in the hanger with a known problem that was not yet fixed? Would the JT610 crash have happened if Lion Air did the correct thing and fixed that aircraft instead of let it fly that day?

Red herring yet again. Pitot tubes fail inflight and AOA indicators do too. To believe otherwise is just stupid. The failure of those should not be the difference between a flight being safely operated and it nosediving uncontrollably to Terra Firma.

Your failed interpretation of my post is laughable.

1) The A380 scenario was ONLY in relation to the number of victims being a criteria for grounding. Try to follow the conversation unless your intention is to intentionally missquote (which would not surprise me).

2) No crap that parts on planes fail. But when a plane supposedly gets fixed for flying in a particular way, then continues that kind of flying on the first flight immediatley after being looked it, you work on fixing the issue again. You don't just dispatch it on another flight.

Again, what was done with the aircraft in Jakarta during the time between arriving from the Bali (site of the first 'fix') and taking off on the fatal flight given what happened during that penultimate flight?

cpd wrote:

oldannyboy wrote:

747megatop wrote:

Boeing seems to be in the unique position of having had 2 types grounded; 1st the 787 and now the 737-MAX. Let's hope they don't make this a habit.

I hope not, but on the other hand we should de-stigmatize a "cautionary grounding". In this regard Boeing should have behaved much more maturely, and immediately propose themselves a grounding of the MAX variant. Thing is, at the end of the day, the MAX was going to end up grounded anyway [it was pretty evident from the onset], and they should/could have handled this a lot better. This is not only proving to be a technical nightmare (with seemingly financial and image repercussions), but also a PR disaster - which was ultimately not necessary.

Finally a couple of people who’ve not been drinking the Kool-Aid. This whole thing is a disaster for Boeing and they should have been more proactive in dealing with it. It’s looking like their version of VW/Audi dieselgate.

I hope they can recover. And with any luck the FDR will yield useful information- despite how smashed up it is.

Dieselgate is not a once off. It is a cultural disease affecting business globally.