Moderators: jsumali2, richierich, ua900, PanAm_DC10, hOMSaR

 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 3:05 pm

kalvado wrote:
par13del wrote:
kalvado wrote:
Add change of go-around procedure: no full cleanup, thrust and climb limitation, more noise; add flying entire approach below flap extension speed. Generally the same effect - significant disturbance of traffic pattern - probably not a big deal in a smaller airport. Is there a smaller diversion airport anywhere near LHR?

So would throwing the cut-off switches make the go around and landing more difficult than the noise and speed issue?
I take it we will now be regarding this as an emergency procedure?

I am not talking about emergency response, I am talking about handling situations when any of MCAS-related components develop problems, e.g. AoA disagree. These will stay with MAX until last of them retires to soda can plant.
In a situation like that, proactive procedures eliminating possibility of extreme AoA unstable flying are required. That should include:
- landing as soon as practical, with abnormal approach profile and abnormal go-around procedure. Would disturb traffic pattern at a busy airport.
-slow down and flaps out . Forget about ETOPS: an a situation like this, fuel burn goes up, so there will be no enough gas for HNL from mid-point, need to be close to the airport. This is not engine-out operation - ETOPS not affected strictly speaking, but somewhat similar as it dictates range to diversion airport, hence effectively caps ETOPS options.
Maybe something else?
Lack of ETOPS range is likely to trigger some interesting consequences, Hawaii and transatlantic ops come to mind...


It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 3:13 pm

morrisond wrote:
kalvado wrote:
par13del wrote:
So would throwing the cut-off switches make the go around and landing more difficult than the noise and speed issue?
I take it we will now be regarding this as an emergency procedure?

I am not talking about emergency response, I am talking about handling situations when any of MCAS-related components develop problems, e.g. AoA disagree. These will stay with MAX until last of them retires to soda can plant.
In a situation like that, proactive procedures eliminating possibility of extreme AoA unstable flying are required. That should include:
- landing as soon as practical, with abnormal approach profile and abnormal go-around procedure. Would disturb traffic pattern at a busy airport.
-slow down and flaps out . Forget about ETOPS: an a situation like this, fuel burn goes up, so there will be no enough gas for HNL from mid-point, need to be close to the airport. This is not engine-out operation - ETOPS not affected strictly speaking, but somewhat similar as it dictates range to diversion airport, hence effectively caps ETOPS options.
Maybe something else?
Lack of ETOPS range is likely to trigger some interesting consequences, Hawaii and transatlantic ops come to mind...


It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.

But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 3:19 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
I am not talking about emergency response, I am talking about handling situations when any of MCAS-related components develop problems, e.g. AoA disagree. These will stay with MAX until last of them retires to soda can plant.
In a situation like that, proactive procedures eliminating possibility of extreme AoA unstable flying are required. That should include:
- landing as soon as practical, with abnormal approach profile and abnormal go-around procedure. Would disturb traffic pattern at a busy airport.
-slow down and flaps out . Forget about ETOPS: an a situation like this, fuel burn goes up, so there will be no enough gas for HNL from mid-point, need to be close to the airport. This is not engine-out operation - ETOPS not affected strictly speaking, but somewhat similar as it dictates range to diversion airport, hence effectively caps ETOPS options.
Maybe something else?
Lack of ETOPS range is likely to trigger some interesting consequences, Hawaii and transatlantic ops come to mind...


It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.

But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.


I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236
 
kayik
Posts: 116
Joined: Thu Mar 14, 2019 10:58 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 3:33 pm

Xtra is suspected to deliver a miscalibrated AoA sensor to Lion Air. FAA shut Xtra down, just before the senate hearings, on the basis of following:

Xtra failed to complete and retain records in accordance with procedures in its repair station manual to support parts on its capability list. The company also did not substantiate that it had adequate facilities, tools, test equipment, technical publications, and trained and qualified employees to repair parts on its capability list.


But we had two crashes that killed 346 people. We all know what was going on at Boeing. Why Boeing still holds its manufacturing certificate after delivering over 300 hundred uncertifiable aircraft all over the world?
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 3:42 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.

But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.


I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.
 
planecane
Posts: 1572
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:08 pm

oschkosch wrote:
morrisond wrote:
scbriml wrote:

Does the deployment of flaps preclude the possibility of entering the flight envelope region where MCAS was deemed to be required?


Flaps out changes the Aerodynamics of the wing so the controls never get too light so MCAS is not needed.
So how come Boeing has not thought about this then? Obviously there must be more to mcas than we all know?

Gesendet von meinem SM-G950F mit Tapatalk


Huh? They did think of this. That's why MCAS isn't active with flaps deployed. It isn't needed in that situation. Had they made the max to always fly with flaps that would have led to a very inefficient and slow plane.
 
dstblj52
Posts: 455
Joined: Tue Nov 19, 2019 8:38 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:08 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.


I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.

That would also probably force Boeing to give bigger discounts as that fuel burn advantage over the NG was probably necessary to make some routes physically and economically viable, another concern, if AOA disagress causes land at nearest airport is boeing going to be on the hook for all the additional costs that creates and the reduced flow rates at airports?
 
User avatar
PixelFlight
Posts: 1019
Joined: Thu Nov 08, 2018 11:09 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:10 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.


I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.

Good analysis. This is an other point that show why reliable redundant FBW architecture is inevitably the future.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
User avatar
PW100
Posts: 4123
Joined: Mon Jan 28, 2002 9:17 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:15 pm

morrisond wrote:
Thunderbolt500 wrote:
Maybe they should scrap the plane.


Better to just scrap MCAS and give all MAX pilots EET (US Extended Envelope Training).


I've seen you bringing this forward, repeatedly. I wonder, what (if any) evidence have we seen that the US EET would be good enough for MAX sans MCAS?

I would assume that for EET to be effective, approach to stall, and stall characteristics itself should meet certain basic standards. Would it be far fetched to assume that MAX sans MCAS would struggle to meet that?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
User avatar
JetBuddy
Posts: 2569
Joined: Wed Dec 25, 2013 1:04 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:33 pm

I think after this whole mess gets sorted - we need to have a good hard look at "grandfathering" and aircraft certification rules.

That's what it boils down to. Boeing has tried to play the system in their own favor. They put stock prices before safety. What's not talked much about yet, is the RCAS system. Boeing implemented this on late production 737NG only so that airlines could argue that the same system on 737MAX was no different, and required no training.

I don't believe RCAS necessarily is a big deal in itself, but it shows how Boeing is trying to play or "rig" the system in their favor. Over and over again.
 
asdf
Posts: 696
Joined: Tue Mar 18, 2014 12:03 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:36 pm

morrisond wrote:
scbriml wrote:
planecane wrote:
Instead of ridiculous procedures how about just slowing to flaps speed so MCAS isn't needed aerodynamically?


Does the deployment of flaps preclude the possibility of entering the flight envelope region where MCAS was deemed to be required?


Flaps out changes the Aerodynamics of the wing so the controls never get too light so MCAS is not needed.


Some Situations Checklist (AoA or Speed Sensor unreliable asks for „thrust“ ( and climb)

You cant do that with Flaps deployed
 
User avatar
PW100
Posts: 4123
Joined: Mon Jan 28, 2002 9:17 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:37 pm

morrisond wrote:
par13del wrote:
morrisond wrote:
On the NG and MAX there is nothing in there certification that that says you can't fly the whole flight with Manual trim if you choose too.
I suspect the procedure will be the same with MCAS V2.0 - but who knows - it may include an instruction to land at the nearest suitable airport.
.

Why continue on, its a question I had from the first Lion Air encounter with MCAS, once they resolved the issue and turned off the automation why continue the commercial flight, why did they not return to base? Is trim such a trivial issue for pax comfort that manual trim is seen as no big deal?

It shouldn't be that big of a deal. Assuming you stick to a normal flight profile - Manual trimming the aircraft to keep it in trim is totally doable and you can read reports on here and other forums of Pilots who do this routinely (Fly an entire flight with Manual Trim) to stay sharp. It's good airmanship.
The passengers would never know if the plane was in trim or out of trim - just whether or not it's descending or climbing.


Entire flight (in 737) with Manual Trim only (that is, without electric thump trimming)?
Can you provide a link for that?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:38 pm

PW100 wrote:
morrisond wrote:
Thunderbolt500 wrote:
Maybe they should scrap the plane.


Better to just scrap MCAS and give all MAX pilots EET (US Extended Envelope Training).


I've seen you bringing this forward, repeatedly. I wonder, what (if any) evidence have we seen that the US EET would be good enough for MAX sans MCAS?

I would assume that for EET to be effective, approach to stall, and stall characteristics itself should meet certain basic standards. Would it be far fetched to assume that MAX sans MCAS would struggle to meet that?



EET as it exists today, wouldn't help here at all. The simulator model used for EET isn't type specific, its a generic model not tailored to the specific aircraft type. The purpose of EET is to expose crews to things they possibly haven't seen in years, decades, or ever. And to reenforce some things that we never get a chance to practice.
 
oschkosch
Posts: 589
Joined: Mon Oct 29, 2018 3:41 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:45 pm

JetBuddy wrote:
I think after this whole mess gets sorted - we need to have a good hard look at "grandfathering" and aircraft certification rules.

That's what it boils down to. Boeing has tried to play the system in their own favor. They put stock prices before safety. What's not talked much about yet, is the RCAS system. Boeing implemented this on late production 737NG only so that airlines could argue that the same system on 737MAX was no different, and required no training.

I don't believe RCAS necessarily is a big deal in itself, but it shows how Boeing is trying to play or "rig" the system in their favor. Over and over again.



Absolutely correct. :checkmark:

The reverse grandfathering tactics (at least that is what I would like to call them) on the RCAS system really need to be looked at very closely. Probably there are many more examples of the same.
:stirthepot: :airplane: "This airplane is designed by clowns, who in turn are supervised by monkeys" :airplane: :stirthepot:
 
User avatar
PW100
Posts: 4123
Joined: Mon Jan 28, 2002 9:17 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:47 pm

morrisond wrote:
. . .
Normal MCAS activation would have just brought the AOA down - but you would still be climbing - MCAS failure uncorrected is what is dangerous at low altitudes as that could point you at the ground.


There is no way to control AoA.

AoA is the natural result of aerodynamics and dynamics of other controlled conditions like air speed, weight, rate of climb, OAT, pressure density, G-force, aircraft configuraion, thrust setting etc.
If you want to change to AoA, you change one of those other factors, and AoA change follows *as a result*.

Normal MCAS activation would have brought the nose down, thereby reducing rate of climb and/or G-force. Those factors would then result in lower AoA. If one would still be climbing is impossible to say without further details.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
mjoelnir
Posts: 9386
Joined: Sun Feb 03, 2013 11:06 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:57 pm

morrisond wrote:
mjoelnir wrote:
morrisond wrote:

It shouldn't be that big of a deal. Assuming you stick to a normal flight profile - Manual trimming the aircraft to keep it in trim is totally doable and you can read reports on here and other forums of Pilots who do this routinely (Fly an entire flight with Manual Trim) to stay sharp. It's good airmanship.

The passengers would never know if the plane was in trim or out of trim - just whether or not it's descending or climbing.


The moment the aircraft is significantly out of trim the manual trim wheel will not work. You will need the roller coaster approach. Known about since the 737 Jurassic. You will need height and space to do that.

It is well established that the manual trim wheel on the 737 does not work throughout the flight envelope. It was made worse in the NG with decreasing the diameter of the wheel. But it seems so conveniently to ignore this fact, does it not morrisond?


What does what we were talking about above have to do with the plane being significantly out of trim? We were talking about whether or not you could fly an 737 with Manual trim in the normal operating range and continue to destination.


When do you throw the switches, when something happened to the trim. We talk here in this thread about MCAS. We talk about problems that grounded the 737MAX. So we talk about using the manual trim wheel when the frame is out of trim.
If you want to talk about something else make another thread., do not try to weasel out of the arguments here.

If nothing is wrong with the trim, you do not need the manual trim wheel. It is for emergencies and than it fails you.
 
User avatar
PW100
Posts: 4123
Joined: Mon Jan 28, 2002 9:17 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 4:59 pm

morrisond wrote:
kalvado wrote:
I am not talking about emergency response, I am talking about handling situations when any of MCAS-related components develop problems, e.g. AoA disagree. These will stay with MAX until last of them retires to soda can plant.
In a situation like that, proactive procedures eliminating possibility of extreme AoA unstable flying are required. That should include:
- landing as soon as practical, with abnormal approach profile and abnormal go-around procedure. Would disturb traffic pattern at a busy airport.
-slow down and flaps out . Forget about ETOPS: an a situation like this, fuel burn goes up, so there will be no enough gas for HNL from mid-point, need to be close to the airport. This is not engine-out operation - ETOPS not affected strictly speaking, but somewhat similar as it dictates range to diversion airport, hence effectively caps ETOPS options.
Maybe something else?
Lack of ETOPS range is likely to trigger some interesting consequences, Hawaii and transatlantic ops come to mind...


It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.


The trim state changes during flight as weight reduces due to fuel burn.
The reduced weigth will result in reduced lift requirement. Drag will reduce, which will change either thrust setting and/or IAS, as well as AoA. That all will effect trim state. Now, I'm not saying this is beyond the capability of an average airline pilot, just pointing out some issues with your thinking.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:04 pm

PW100 wrote:
morrisond wrote:
. . .
Normal MCAS activation would have just brought the AOA down - but you would still be climbing - MCAS failure uncorrected is what is dangerous at low altitudes as that could point you at the ground.


There is no way to control AoA.

AoA is the natural result of aerodynamics and dynamics of other controlled conditions like air speed, weight, rate of climb, OAT, pressure density, G-force, aircraft configuraion, thrust setting etc.
If you want to change to AoA, you change one of those other factors, and AoA change follows *as a result*.

Normal MCAS activation would have brought the nose down, thereby reducing rate of climb and/or G-force. Those factors would then result in lower AoA. If one would still be climbing is impossible to say without further details.



Um, you can absolutely control the AOA. You can fly, and land an airplane by reference to, and using AOA alone.
Last edited by AABusDrvr on Sun Jan 12, 2020 5:09 pm, edited 1 time in total.
 
User avatar
Revelation
Posts: 24357
Joined: Wed Feb 09, 2005 9:37 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:05 pm

The ST article from yesterday wrote:
On Friday, interim CEO Greg Smith sent an internal email to employees declaring that the messages “do not reflect who we are as a company or the culture we’ve created.”

I really wish someone would make him clarify that remark. I think the messages do reflect who at least one part of his company is, but he wishes they weren't. The first step in their recovery is admitting they have a problem. I suppose it is about the best thing he could get himself to say, but still it comes across as evasive at best and ignorant at worse.

JetBuddy wrote:
I think after this whole mess gets sorted - we need to have a good hard look at "grandfathering" and aircraft certification rules.

That's what it boils down to. Boeing has tried to play the system in their own favor. They put stock prices before safety. What's not talked much about yet, is the RCAS system. Boeing implemented this on late production 737NG only so that airlines could argue that the same system on 737MAX was no different, and required no training.

I don't believe RCAS necessarily is a big deal in itself, but it shows how Boeing is trying to play or "rig" the system in their favor. Over and over again.

I think I'd say the abuse of "grandfathering" needs to be examined.

It seems the financial pressure to avoid sim training drove so many decisions. I'm wondering if a stronger FAA could not have found a way to step in earlier and mandate at least one sim session as a starting point so such pressure could be avoided.
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
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:37 pm

AABusDrvr wrote:
PW100 wrote:
morrisond wrote:
. . .
Normal MCAS activation would have just brought the AOA down - but you would still be climbing - MCAS failure uncorrected is what is dangerous at low altitudes as that could point you at the ground.


There is no way to control AoA.

AoA is the natural result of aerodynamics and dynamics of other controlled conditions like air speed, weight, rate of climb, OAT, pressure density, G-force, aircraft configuraion, thrust setting etc.
If you want to change to AoA, you change one of those other factors, and AoA change follows *as a result*.

Normal MCAS activation would have brought the nose down, thereby reducing rate of climb and/or G-force. Those factors would then result in lower AoA. If one would still be climbing is impossible to say without further details.



Um, you can absolutely control the AOA. You can fly, and land an airplane by reference to, and using AOA alone.

Looks like at least one more parameter, maybe two, is needed. Airspeed and/or vertical speed?
 
wingman
Posts: 3955
Joined: Thu May 27, 1999 4:25 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:41 pm

Revelation wrote:
I think I'd say the abuse of "grandfathering" needs to be examined.

It seems the financial pressure to avoid sim training drove so many decisions. I'm wondering if a stronger FAA could not have found a way to step in earlier and mandate at least one sim session as a starting point so such pressure could be avoided.


One other positive in FAA mandates around sim time and training would be to negate the extreme pressure airlines (SWA for example) place on manufacturers to deliver new planes with leap gains in operational efficiency at zero conversion cost in terms of training. Training, sim time, classroom time..whatever the solution, should be mandated for new variants, and for pilots and operations/mechanics alike. My guess is more pilots than just these in-house Boeing jokers would've come across this death glitch and refused to accept the MAXs as built. With every passing day it feels more and more like Boeing needs a wholesale government-led house cleaning from top to bottom. Boeing has to take full responsibility in this but irrational customer demands need to be addressed as well.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:48 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
But this is a no-go from extreme maneuring perspective.
While we're at this: asking passengers to flap their hands is not an adequate substitute for an engine failure as well.


I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.


Unless proven otherwise there is no Catastrophic Instability at the edge of the envelope on a MAX. There may well be - and we should hear pretty soon as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.

In cruise you shouldn't really be that close to the edge of the envelope so MCAS should never really come into play - so flying without it shouldn't really be an issue.
 
snowkarl
Posts: 27
Joined: Fri May 24, 2019 7:48 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:49 pm

morrisond wrote:
mjoelnir wrote:
morrisond wrote:

It shouldn't be that big of a deal. Assuming you stick to a normal flight profile - Manual trimming the aircraft to keep it in trim is totally doable and you can read reports on here and other forums of Pilots who do this routinely (Fly an entire flight with Manual Trim) to stay sharp. It's good airmanship.

The passengers would never know if the plane was in trim or out of trim - just whether or not it's descending or climbing.


The moment the aircraft is significantly out of trim the manual trim wheel will not work. You will need the roller coaster approach. Known about since the 737 Jurassic. You will need height and space to do that.

It is well established that the manual trim wheel on the 737 does not work throughout the flight envelope. It was made worse in the NG with decreasing the diameter of the wheel. But it seems so conveniently to ignore this fact, does it not morrisond?


What does what we were talking about above have to do with the plane being significantly out of trim? We were talking about whether or not you could fly an 737 with Manual trim in the normal operating range and continue to destination.

Do you think a plane should be certified if the plane is in realistic risk of being forced into manually trimming when it is well known that the trim wheel on said plane is non-functional within the flight envelope?

Sounds unsafe, to say the least.

I wonder what would happen if said plane had a faulty aoa sensor, causing its software to force the nose down at below 10k feet, without sufficient height to perform the necessary rollercoaster maneuever to recover - since the manual trim wheel had been reduced to the size of a lego wheel?

There is no way any of this speculation is acceptable for a modern plane that wants to certificied to fly commerically.
 
snowkarl
Posts: 27
Joined: Fri May 24, 2019 7:48 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:52 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.


Unless proven otherwise there is no Catastrophic Instability at the edge of the envelope on a MAX. There may well be - and we should hear pretty soon as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.

In cruise you shouldn't really be that close to the edge of the envelope so MCAS should never really come into play - so flying without it shouldn't really be an issue.


Fascinating. I wonder why they even added MCAS in that case? Since you seemingly claim it isn't even needed.

I don't think a plane is certified on the basis of "it flies well in cruise in good weather, literally zero malfunctions, within gliding range of an international sized airport". There's a reason you need to be able to make maneuevers and for the plane to handle the upper limits of the envelope - you never know what can happen, what could break or what mistakes can be made.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:54 pm

PW100 wrote:
morrisond wrote:
Thunderbolt500 wrote:
Maybe they should scrap the plane.


Better to just scrap MCAS and give all MAX pilots EET (US Extended Envelope Training).


I've seen you bringing this forward, repeatedly. I wonder, what (if any) evidence have we seen that the US EET would be good enough for MAX sans MCAS?

I would assume that for EET to be effective, approach to stall, and stall characteristics itself should meet certain basic standards. Would it be far fetched to assume that MAX sans MCAS would struggle to meet that?


From what I saw in this forum way back when but has now been deleted it really was a stick force issue (from a Boeing insider who should not have been publishing the information in public) and not weird stall characteristics - the data showed that the stick force which was about 6lbs fell to 4 instead of increasing to 7.

If the MAX does have really weird Stall Characteristics then it should be scrapped. I hope EASA makes public the results of it's test flights without MCAS.
 
oschkosch
Posts: 589
Joined: Mon Oct 29, 2018 3:41 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:54 pm

morrisond wrote:
........ as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.


Nope. The test flights are expected to happen from 15th January onwards - maybe.

https://www.livemint.com/news/india/faa ... 04853.html

Gesendet von meinem SM-G950F mit Tapatalk
:stirthepot: :airplane: "This airplane is designed by clowns, who in turn are supervised by monkeys" :airplane: :stirthepot:
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 5:56 pm

asdf wrote:
morrisond wrote:
scbriml wrote:

Does the deployment of flaps preclude the possibility of entering the flight envelope region where MCAS was deemed to be required?


Flaps out changes the Aerodynamics of the wing so the controls never get too light so MCAS is not needed.


Some Situations Checklist (AoA or Speed Sensor unreliable asks for „thrust“ ( and climb)

You cant do that with Flaps deployed


Yes you can - easily Modern Airliners have a lot of thrust to overcome the extra drag of flaps - and I don't think anyone was saying deploy flaps 40 - flaps at 5 degrees would be enough to turn off MCAS logic.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:01 pm

PW100 wrote:
morrisond wrote:
. . .
Normal MCAS activation would have just brought the AOA down - but you would still be climbing - MCAS failure uncorrected is what is dangerous at low altitudes as that could point you at the ground.


There is no way to control AoA.

AoA is the natural result of aerodynamics and dynamics of other controlled conditions like air speed, weight, rate of climb, OAT, pressure density, G-force, aircraft configuraion, thrust setting etc.
If you want to change to AoA, you change one of those other factors, and AoA change follows *as a result*.

Normal MCAS activation would have brought the nose down, thereby reducing rate of climb and/or G-force. Those factors would then result in lower AoA. If one would still be climbing is impossible to say without further details.


Yes you are right - I was just trying to supply a simple answer that didn't require a lesson on the Physics of Flight.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:04 pm

PW100 wrote:
morrisond wrote:
kalvado wrote:
I am not talking about emergency response, I am talking about handling situations when any of MCAS-related components develop problems, e.g. AoA disagree. These will stay with MAX until last of them retires to soda can plant.
In a situation like that, proactive procedures eliminating possibility of extreme AoA unstable flying are required. That should include:
- landing as soon as practical, with abnormal approach profile and abnormal go-around procedure. Would disturb traffic pattern at a busy airport.
-slow down and flaps out . Forget about ETOPS: an a situation like this, fuel burn goes up, so there will be no enough gas for HNL from mid-point, need to be close to the airport. This is not engine-out operation - ETOPS not affected strictly speaking, but somewhat similar as it dictates range to diversion airport, hence effectively caps ETOPS options.
Maybe something else?
Lack of ETOPS range is likely to trigger some interesting consequences, Hawaii and transatlantic ops come to mind...


It should be well within the capabilities of any 737 type rated Pilot to continue an HNL ETOPS flight on Manual trim from the midpoint.

Set it once for your given cruise speed and altitude - probably once for descent and one for final approach.


The trim state changes during flight as weight reduces due to fuel burn.
The reduced weigth will result in reduced lift requirement. Drag will reduce, which will change either thrust setting and/or IAS, as well as AoA. That all will effect trim state. Now, I'm not saying this is beyond the capability of an average airline pilot, just pointing out some issues with your thinking.


Yes I understand you are right - and it's such a marginal change over time - any pilot should be able to do it without thinking. It's basically just slightly moving the wheel every once in a while if the controls start to get too light/heavy.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:12 pm

oschkosch wrote:
morrisond wrote:
........ as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.


Nope. The test flights are expected to happen from 15th January onwards - maybe.

https://www.livemint.com/news/india/faa ... 04853.html

Gesendet von meinem SM-G950F mit Tapatalk


Good - I hope the make results public.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:14 pm

mjoelnir wrote:
morrisond wrote:
mjoelnir wrote:

The moment the aircraft is significantly out of trim the manual trim wheel will not work. You will need the roller coaster approach. Known about since the 737 Jurassic. You will need height and space to do that.

It is well established that the manual trim wheel on the 737 does not work throughout the flight envelope. It was made worse in the NG with decreasing the diameter of the wheel. But it seems so conveniently to ignore this fact, does it not morrisond?


What does what we were talking about above have to do with the plane being significantly out of trim? We were talking about whether or not you could fly an 737 with Manual trim in the normal operating range and continue to destination.


When do you throw the switches, when something happened to the trim. We talk here in this thread about MCAS. We talk about problems that grounded the 737MAX. So we talk about using the manual trim wheel when the frame is out of trim.
If you want to talk about something else make another thread., do not try to weasel out of the arguments here.

If nothing is wrong with the trim, you do not need the manual trim wheel. It is for emergencies and than it fails you.


Yes it will - if you do not know how to control your airspeed.
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:19 pm

kalvado wrote:
AABusDrvr wrote:
PW100 wrote:

There is no way to control AoA.

AoA is the natural result of aerodynamics and dynamics of other controlled conditions like air speed, weight, rate of climb, OAT, pressure density, G-force, aircraft configuraion, thrust setting etc.
If you want to change to AoA, you change one of those other factors, and AoA change follows *as a result*.

Normal MCAS activation would have brought the nose down, thereby reducing rate of climb and/or G-force. Those factors would then result in lower AoA. If one would still be climbing is impossible to say without further details.



Um, you can absolutely control the AOA. You can fly, and land an airplane by reference to, and using AOA alone.

Looks like at least one more parameter, maybe two, is needed. Airspeed and/or vertical speed?


If you were trying to do an instrument approach with any accuracy, you would probably need vertical speed, but if you can visually control the flight path, AOA alone would work. Fighter types use AOA on landing, especially navy guys landing on the carrier. They never reference airspeed, only AOA, and flight path.

The wing only cares about AOA. Thats why you can stall the wing at any airspeed, or in any attitude. Exceed the critical AOA, it will stall. One of the training evolutions in EET is to reenforce that the only way to recover from a stall, is to reduce AOA, even if that means giving up altitude.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:40 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

I don't understand your point on the first - can you please elaborate?

ETOPS assumes that you can make your destination or alternate on one engine at any point in the flight. Of course loss of two engines would make you hope you had a Canadian crew on board (I'm sure there are others who could do it as well) and hopefully a suitable place to land within gliding distance. See the Gimli Glider and Air Transat 236. Both don't say much about Canadian Maintenance/servicing - but the pilots sure did a good job to get the aircraft down safely.

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

https://en.wikipedia.org/wiki/Air_Transat_Flight_236

MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.


Unless proven otherwise there is no Catastrophic Instability at the edge of the envelope on a MAX. There may well be - and we should hear pretty soon as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.

In cruise you shouldn't really be that close to the edge of the envelope so MCAS should never really come into play - so flying without it shouldn't really be an issue.

You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:44 pm

AABusDrvr wrote:
kalvado wrote:
AABusDrvr wrote:


Um, you can absolutely control the AOA. You can fly, and land an airplane by reference to, and using AOA alone.

Looks like at least one more parameter, maybe two, is needed. Airspeed and/or vertical speed?


If you were trying to do an instrument approach with any accuracy, you would probably need vertical speed, but if you can visually control the flight path, AOA alone would work. Fighter types use AOA on landing, especially navy guys landing on the carrier. They never reference airspeed, only AOA, and flight path.

The wing only cares about AOA. Thats why you can stall the wing at any airspeed, or in any attitude. Exceed the critical AOA, it will stall. One of the training evolutions in EET is to reenforce that the only way to recover from a stall, is to reduce AOA, even if that means giving up altitude.

I am thinking more in terms of that you have two controls - stick and throttle - so you need 2 inputs to make things work. The way I read your comment is if you can set throttle somewhere close enough and eyeball vertical, you can stay out of trouble by looking at AoA - which is probably true...
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:47 pm

kalvado wrote:
morrisond wrote:
kalvado wrote:
MCAS exists to mitigate catastrophic instability at the edge of envelope*. Once MCAS is not available, for one reason or the other, airplane has to be flown with appropriate precautions. Flap extension is proposed as a mitigation scenario. However, flaps-out flight increases fuel burn, hence limiting range to nearest airport from the time MCAS-disabling failure occurs. Otherwise, carrying appropriate reserves may be an option. I still doubt that MAX will have enough tankage to complete the flight from LAX-HNL midpoint with flaps out, at reduced speed, and lower altitude. Extreme tankage also would cost a lot in fuel burn.
This is not engine-out scenario, but this is a similar consideration which will limit overwater operations.
This has nothing to do with pilot proficency. This is about hazards of flying with safety system disabled and mitigation procedures in place. Exact same logic why engine-out is a diversion to the nearest airport, not "a competent pilot can fly on one engine much further than that".

*I know, "some stick lightening". On a similar note - "some shadow on x-ray" often means advanced-stage cancer.


Unless proven otherwise there is no Catastrophic Instability at the edge of the envelope on a MAX. There may well be - and we should hear pretty soon as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.

In cruise you shouldn't really be that close to the edge of the envelope so MCAS should never really come into play - so flying without it shouldn't really be an issue.

You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.


As it should be. They should do the non-MCAS test flights.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:52 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:

Better to just scrap MCAS and give all MAX pilots EET (US Extended Envelope Training).


I've seen you bringing this forward, repeatedly. I wonder, what (if any) evidence have we seen that the US EET would be good enough for MAX sans MCAS?

I would assume that for EET to be effective, approach to stall, and stall characteristics itself should meet certain basic standards. Would it be far fetched to assume that MAX sans MCAS would struggle to meet that?


From what I saw in this forum way back when but has now been deleted it really was a stick force issue (from a Boeing insider who should not have been publishing the information in public) and not weird stall characteristics - the data showed that the stick force which was about 6lbs fell to 4 instead of increasing to 7.

If the MAX does have really weird Stall Characteristics then it should be scrapped. I hope EASA makes public the results of it's test flights without MCAS.

Problem is - this is exactly describing ugly stall characteristics.
The way things work, arm controls force rather than position. Did you ever try non-spring loaded joysticks? Nightmare...
So, the way trouble goes is: pilot pulls stick to what would be 10 deg AoA from 8 deg AoA, force goes down; arm moves further to 12 deg AoA, force goes down, arm moves to 15 - and plane stalls before pilot realizes what goes wrong. You need to train some very counterintuitve muscle memory to avoid that.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 6:53 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

Unless proven otherwise there is no Catastrophic Instability at the edge of the envelope on a MAX. There may well be - and we should hear pretty soon as I believe EASA flew the MAX last week if there is- but as there were no reports of MAX crashes last week - if there was Catastrophic Instability - they were able to recover.

In cruise you shouldn't really be that close to the edge of the envelope so MCAS should never really come into play - so flying without it shouldn't really be an issue.

You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.


As it should be. They should do the non-MCAS test flights.

Yeah, but imagine headlines: THIRD MAX CRASHES DURING CERTIFICATION FLIGHT. BOEING FILES CHAPTER 7.
I suspect this possibility is what limits non-MCAS RTS
 
hivue
Posts: 2078
Joined: Tue Feb 26, 2013 2:26 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 7:14 pm

morrisond wrote:
hivue wrote:
par13del wrote:
I guess we have information overload, but the documents released from day one has stated that autopilot engaged and flaps down disables MCAS.


The reason for the existence of MCAS is to provide control column focres that meet the regulations in parts of the envelope where those forces get too light.in the MAX. The AP obviously doesn't need any particular "control column feel" so no need for MCAS when it is on.

Although changed aerodynamic forces from slats/flaps being deployed will change the control column feel, I have wondered from day 1 whether having MCAS disabled when flaps are out was a tacit admission by Boeing that MCAS activation might be dangerous at low altitude.


Normal MCAS activation would have just brought the AOA down - but you would still be climbing - MCAS failure uncorrected is what is dangerous at low altitudes as that could point you at the ground.


Correct. That was my point. An anomalous activation of MCAS 1.0 could, from Boeing's original point of view, have been handled by the runaway pitch trim procedure. But they may have realized that this was playing with fire close to the ground.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
oschkosch
Posts: 589
Joined: Mon Oct 29, 2018 3:41 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 7:20 pm

To summarise it: IF a flight without mcas would solve it all and would be easy peasy, then Boeing would have already done it ages ago.

Gesendet von meinem SM-G950F mit Tapatalk
:stirthepot: :airplane: "This airplane is designed by clowns, who in turn are supervised by monkeys" :airplane: :stirthepot:
 
MildBlueYonder
Posts: 20
Joined: Sun Apr 08, 2018 6:30 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 7:59 pm

wingman wrote:
I've been on this site for 20 years backing and supporting Boeing in most debates. When I fly now, and it's it's every other week at minimum on AS, I breathe a sigh of relief every time I see it's an ex-Virgin bird and not a 737. I don't care what version it is, I know it's designed by a company that lost its way so badly it ended up abandoning every core principle that ever mattered. The whole place needs to be gutted and rebooted.


Feel exactly the same way. My interest in aviation started with Boeing and the 21st Century Jet documentary in the late 90s; really admired them as a kid and would have firmly been in the B-supporter camp in recent A vs. B conversations. Not now though. Sad to see how far the company has fallen since the Alan Mulally + 777 heyday. As someone who flies GA regularly out of RNT, I don't see Boeing when I look across the ramp these days...I see McD.
 
Interested
Posts: 887
Joined: Thu May 19, 2016 12:19 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:06 pm

TurboJet707 wrote:
Dutch newspaper De Volkskrant had an interesting story on the MAX fiasco yesterday:

https://www.volkskrant.nl/nieuws-achter ... ~bdb9f623/
(Dutch only, but Google/Bing Translate is your friend...)

The reporter spoke with Ed Pierson, a former assembly hall manager, who testified in Congress after resigning from Boeing, being fed up with the culture and the way his concerns were ignored (his words).

Here's one interesting excerpt that I ran through Google Translate:

(...) "That sensor was really not the only problem, says Ed Pierson, a former manager in the assembly hall of the 737 Max, who rang the bell at the management in the summer of 2018 because he saw problems everywhere. "The workload became much too high. Many parts were delayed, the work sequence started to mix, people were put to work in places other than where they actually worked. I knew for sure: that's how we're going to make mistakes. "

Pierson, who testified before Congress in December about his experiences on the shop floor, tells this Tuesday afternoon in his hometown of Bremerton, a place on a cove one hour's boat ride from Seattle, about how management's demands could have disastrous effects on quality of the aircraft that were built at the time.

"Due to delays in the supply of parts, we were already lagging behind our delivery schedule. The management then decided to catch up - we had to make 52 rather than 47 aircraft per month. That only made the chaos bigger. We rolled out planes that had no engines underneath, which sometimes lacked parts of the hull. They all had to be finished at a time and in a place that was not meant for that. Teams were pulled apart, people did odd jobs at places in the assembly line that were not meant for that at all. Supervision was difficult, safety was at stake, both for employees and future passengers. "

For example, a hastily manufactured angle sensor was installed in that hectic pace. "We don't know on which aircraft that sensor is all," says Pierson. "What I would like in any case is for the FAA to sound the alarm and check them all."

Management thought to have a solution for the delays. It abolished the usual work transfer between teams and instead started organizing two or three times a day shame meetings in which employees had to stand up in front of about a hundred colleagues and explain why they had not reached a certain milestone. "That only increased the pressure," says Pierson. "It only got worse. It was an unstable environment.

"In June 2018, he [Pierson] sent a first letter to Scott Campbell, the manager of the 737 Max program. "Sorry to say so," he wrote, "but for the first time in my life I hesitate to let my family fly into a Boeing." Pierson, a man who has flown with the navy for years, looks pained. "He let me come and I told him to stop the production line to put things in order. I said: I have seen operations in the navy being stopped for less. Then he said: yes, but the navy does not have to make a profit. "

Pierson was struck dumb, he says. "It was the worst thing he could say. He actually said: no matter how bad the situation is, money is more important. "

Pierson resigned a few weeks later. "I didn't want to be part of that anymore."

Two months later, the first 737 Max crashed, less than five weeks old. "I was sick when I heard it," says Pierson. When he got over the worst shock, he tried to get in touch with the Boeing experts who would help investigate the causes of the accident, to point out the problems in the assembly line. He sent an email to the highest boss, Muilenburg. He had a lawyer call back, but Pierson did not get in touch with the researchers. He sent his findings to all members of the Supervisory Board, all of them a printed package, but he received no reply. Then the second plane crashed.

All over the world the aviation authorities immediately said: that 737 Max is no longer allowed to fly. In the US, the FAA only came to that conclusion after three days. Then the device was finally grounded.

Pierson searched databases and discovered that the 737 Max had thirteen incidents in addition to the two fatalities in those first months of his flying existence. Problems with the hydraulics, a failed engine, the anti-ice system, the steering. "It's incredible that new planes have so many problems," he says.

He tried to raise his concerns with the NTSB accident council and the FAA regulator, but got zero there. Only after his testimony to Congress in December, the FAA promised to call him. "That hasn't happened yet," says Pierson.

In a statement, Boeing states that "the suggestion of a link between Mr. Pierson's concerns and recent accidents is completely unfounded" and that "none of the authorities investigating the accidents found anything to indicate that production conditions in the 737 plant contributed in any way to the accidents. "
(...)

Gives an impression of a corporate culture that has gone completely wrong. Appalling if you ask me.


It will all be in the next bunch of documentaries

I can see them now

The PR for Max and Boeing is going to get a lot worse
 
Interested
Posts: 887
Joined: Thu May 19, 2016 12:19 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:13 pm

morrisond wrote:
Thunderbolt500 wrote:
Maybe they should scrap the plane.


Better to just scrap MCAS and give all MAX pilots EET (US Extended Envelope Training).

Although as 2173501 says the lengthy grounding doesn't really seem to be about MCAS but the Bit Flip issue.

Given the extremely low probably of the bit flip issue happening I can't help but thinking of the Knights of Ni demanding a shrubbery every time I read about it.


Why compromise any safety at all?

Nobody will want to buy Max now and 50 per cent of passengers won't want to fly on it as all the negative PR reaches the public

Cut the losses and start again with a new plane. Why are we all having to bend over backwards to get this awfully designed plane back in the air

Nobody owes Boeing any favours here. They've made their bed let them lie in it.

Boeing will survive in some form without Max.
 
MSPNWA
Posts: 3698
Joined: Thu Apr 23, 2009 2:48 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:27 pm

kalvado wrote:
You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.


"No issues" is incorrect. That's not real-world safety. Thousands of aircraft are flying today with known, potentially dangerous issues (and airlines too, but that's another avenue).

It begs the question as to why the MAX must be held to a different standard. Real-world safety has a cost angle to analyze. So much for Boeing being the only perpetrator of toeing that line.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:34 pm

kalvado wrote:
morrisond wrote:
PW100 wrote:

I've seen you bringing this forward, repeatedly. I wonder, what (if any) evidence have we seen that the US EET would be good enough for MAX sans MCAS?

I would assume that for EET to be effective, approach to stall, and stall characteristics itself should meet certain basic standards. Would it be far fetched to assume that MAX sans MCAS would struggle to meet that?


From what I saw in this forum way back when but has now been deleted it really was a stick force issue (from a Boeing insider who should not have been publishing the information in public) and not weird stall characteristics - the data showed that the stick force which was about 6lbs fell to 4 instead of increasing to 7.

If the MAX does have really weird Stall Characteristics then it should be scrapped. I hope EASA makes public the results of it's test flights without MCAS.

Problem is - this is exactly describing ugly stall characteristics.
The way things work, arm controls force rather than position. Did you ever try non-spring loaded joysticks? Nightmare...
So, the way trouble goes is: pilot pulls stick to what would be 10 deg AoA from 8 deg AoA, force goes down; arm moves further to 12 deg AoA, force goes down, arm moves to 15 - and plane stalls before pilot realizes what goes wrong. You need to train some very counterintuitve muscle memory to avoid that.


I have flown an 172 in Turbulence where the controls go negative - it's not that hard to counter and all training tells you to not rely on feel - rely on your instruments and outside visual reference.

It takes probably a good 15-20 seconds on an 737 beyond the point where the controls get a little light to get into an actual stall - it's not as dramatic as you are making out.
Last edited by morrisond on Sun Jan 12, 2020 8:44 pm, edited 1 time in total.
 
morrisond
Posts: 2732
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:36 pm

kalvado wrote:
AABusDrvr wrote:
kalvado wrote:
Looks like at least one more parameter, maybe two, is needed. Airspeed and/or vertical speed?


If you were trying to do an instrument approach with any accuracy, you would probably need vertical speed, but if you can visually control the flight path, AOA alone would work. Fighter types use AOA on landing, especially navy guys landing on the carrier. They never reference airspeed, only AOA, and flight path.

The wing only cares about AOA. Thats why you can stall the wing at any airspeed, or in any attitude. Exceed the critical AOA, it will stall. One of the training evolutions in EET is to reenforce that the only way to recover from a stall, is to reduce AOA, even if that means giving up altitude.

I am thinking more in terms of that you have two controls - stick and throttle - so you need 2 inputs to make things work. The way I read your comment is if you can set throttle somewhere close enough and eyeball vertical, you can stay out of trouble by looking at AoA - which is probably true...


You do know that AABusDrvr is type rated on the 320, the 737, has flown the MAX and is check pilot - don't you?
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:38 pm

MSPNWA wrote:
kalvado wrote:
You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.


"No issues" is incorrect. That's not real-world safety. Thousands of aircraft are flying today with known, potentially dangerous issues (and airlines too, but that's another avenue).

It begs the question as to why the MAX must be held to a different standard. Real-world safety has a cost angle to analyze. So much for Boeing being the only perpetrator of toeing that line.

Because this is about permitting to start operation for a previously problematic design - vs continuing operations for situations where problems are known to be managable.
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:40 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

From what I saw in this forum way back when but has now been deleted it really was a stick force issue (from a Boeing insider who should not have been publishing the information in public) and not weird stall characteristics - the data showed that the stick force which was about 6lbs fell to 4 instead of increasing to 7.

If the MAX does have really weird Stall Characteristics then it should be scrapped. I hope EASA makes public the results of it's test flights without MCAS.

Problem is - this is exactly describing ugly stall characteristics.
The way things work, arm controls force rather than position. Did you ever try non-spring loaded joysticks? Nightmare...
So, the way trouble goes is: pilot pulls stick to what would be 10 deg AoA from 8 deg AoA, force goes down; arm moves further to 12 deg AoA, force goes down, arm moves to 15 - and plane stalls before pilot realizes what goes wrong. You need to train some very counterintuitve muscle memory to avoid that.


I have flown an 172 in Turbulence where the controls go negative - it's not that hard to counter and all training tells you to not rely on feel - rely on your instruments and outside visual reference.

It takes probably a good 15-20 seconds beyond the point where the controls get a little light to get into an actual stall - it's not as dramatic as you are making out.

Can you elaborate what "controls go negative" means in terms of common control loop differential equations?
 
kalvado
Posts: 2849
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:42 pm

morrisond wrote:
kalvado wrote:
AABusDrvr wrote:

If you were trying to do an instrument approach with any accuracy, you would probably need vertical speed, but if you can visually control the flight path, AOA alone would work. Fighter types use AOA on landing, especially navy guys landing on the carrier. They never reference airspeed, only AOA, and flight path.

The wing only cares about AOA. Thats why you can stall the wing at any airspeed, or in any attitude. Exceed the critical AOA, it will stall. One of the training evolutions in EET is to reenforce that the only way to recover from a stall, is to reduce AOA, even if that means giving up altitude.

I am thinking more in terms of that you have two controls - stick and throttle - so you need 2 inputs to make things work. The way I read your comment is if you can set throttle somewhere close enough and eyeball vertical, you can stay out of trouble by looking at AoA - which is probably true...


You do know that AABusDrvr is type rated on the 320, the 737, has flown the MAX and is check pilot - don't you?

That is why we're having an interesting and educative, pretty technical discussions with @AABusDrvr. I actually invite you to evolve to that level with my previous comment....
 
MSPNWA
Posts: 3698
Joined: Thu Apr 23, 2009 2:48 am

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:48 pm

kalvado wrote:
Because this is about permitting to start operation for a previously problematic design - vs continuing operations for situations where problems are known to be managable.


Nice try moving the goalposts, and no, I'm not talking about "manageable" issues. You implied real-world safety is having no issues (which in real-life is wrong - the world doesn't work that way). You didn't imply that real-word safety means you can't start (in this case restart) operations with an issue. But even if true (the real-world says it's not), that logic proves that there's a cost/benefit angle to safety. If you have thousands in the air? More leniency. Safety isn't worth it. Illogical, but it's the route you've praised with the MAX.
Last edited by MSPNWA on Sun Jan 12, 2020 8:51 pm, edited 2 times in total.
 
Interested
Posts: 887
Joined: Thu May 19, 2016 12:19 pm

Re: Boeing 737MAX Grounding, General Discussion Thread, January 2020

Sun Jan 12, 2020 8:48 pm

MSPNWA wrote:
kalvado wrote:
You're thinking Boeingish safety. Real world safety works different - MAX remains grounded until proven to have no issues.


"No issues" is incorrect. That's not real-world safety. Thousands of aircraft are flying today with known, potentially dangerous issues (and airlines too, but that's another avenue).

It begs the question as to why the MAX must be held to a different standard. Real-world safety has a cost angle to analyze. So much for Boeing being the only perpetrator of toeing that line.


Do you not think Boeing with their duopoly should not be forced to set higher standards?

Are you just excusing everything now just to help Boeing get out of a huge mess they've created entirely themselves?

Accepting second best?

Really?

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos