SEU
Posts: 46
Joined: Wed Mar 13, 2019 7:21 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 7:45 pm

AABusDrvr wrote:
XRAYretired wrote:
AABusDrvr wrote:


The climb table you referenced above is for a 280KT/.76 M climb. Thats not the chart you would be using, if you were in the terminal area, intending to return and land. The "Terminal Area" table at the bottom of that page would be the correct table.

An informal poll of every first officer I've flown with recently has had 100% "unreliable airspeed" as the answer, when asked, "If you got a stick shaker right after rotation, what QRH procedure would you start with".


OK. Thanks for the info.

Can you speculate as to why 4 crews appeared to follow the former with 3 subsequently intending to return?
Ta.
Ray


Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 8:22 pm

XRAYretired wrote:
morrisond wrote:
However that was superseded by the Generic Boeing Instruction from 2015 on all Boeing models - this is a Memory item.

"A few days back I received a new procedure in my 737 QRH, for airspeed unreliable. We now have a set of thrust settings in combination with a specific pitch attitude, as memory items.
Config flaps up: 4 degrees pitch up, and 75% N1
Config flaps extended: 10 degrees pitch up and 80% N1

These pitch and power settings provide a simple reference setting for the crew to use for a short period of time while the initial steps of the checklist are accomplished. These settings do not ensure a level flight or constant airspeed at any particular altitude/airspeed/weight combination. However, they do ensure that at any and all weight/altitude combinations, the aircraft will accelerate from low speeds, and slow from a high speeds, as we cannot assume the aircraft is in stable flight when the NNC is run. It is more likely that the crew or the autopilot has destabilized the airplane as a result of erroneous airspeed indications prior to identification of the need to run the NNC. These memory item pitch and power settings often result in a significant climb (from lower altitudes) and can also result in a gradual descent (from higher altitudes)."

Great!. Are you able to share docs or relevant parts thereof?

Ray


I PM'd you
 
AABusDrvr
Posts: 25
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 8:22 pm

SEU wrote:
AABusDrvr wrote:
XRAYretired wrote:

OK. Thanks for the info.

Can you speculate as to why 4 crews appeared to follow the former with 3 subsequently intending to return?
Ta.
Ray


Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


The only answer I can give you is, I don't know. I've run through those scenarios many times in my mind (as I hope every other professional pilot in the world, no matter what they fly has). I'd like to believe I would have done some things differently, but hindsight is always 20/20, and those guys were way out into uncharted territory.

Any loss of life is tragic, and aviation is still an imperfect art. I hope that everyone, from the people who design and build airplanes, to the crews and maintainers can learn from these, and every other accident/incident and make flying safer.
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 8:27 pm

AABusDrvr wrote:
SEU wrote:
AABusDrvr wrote:

Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


The only answer I can give you is, I don't know. I've run through those scenarios many times in my mind (as I hope every other professional pilot in the world, no matter what they fly has). I'd like to believe I would have done some things differently, but hindsight is always 20/20, and those guys were way out into uncharted territory.

Any loss of life is tragic, and aviation is still an imperfect art. I hope that everyone, from the people who design and build airplanes, to the crews and maintainers can learn from these, and every other accident/incident and make flying safer.


Thank you for answering honestly. Do you mind sharing how much time your airline requires you to practice Non- Normal Procedures in the SIM's? What about trim using the manual trim control wheel? What do you practise in the Sim's?

I wouldn't ask you to say what airline you work for - but it is large or small? Asia/Europe/North America/South America?

Thanks
 
User avatar
PW100
Posts: 3489
Joined: Mon Jan 28, 2002 9:17 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 8:33 pm

planecane wrote:
XRAYretired wrote:
planecane wrote:
Pretense of what? If MCAS is a function added to STS what is the problem referencing it?

Its a function hosted by the FCC that commands electric trim same as AP is, AP is not described as part of STS.
Ray

From B737Theory
Speed Trim System (STS)
An electrical stabilizer trim input automatically controls certain aircraft attitude conditions when undergoing large thrust changes in the lower speed region, such as takeoff and go-around. These conditions require high thrust settings and are especially present with a low weight aircraft and a relatively aft center of gravity where the aircraft wants to “nose up”. The STS supports the crew during these conditions when manually controlling the aircraft without the use of an autopilot by an opposite stabilizer trim, commanding a nose down force by use of the autopilot trim.


Doesn't this sound exactly like MCAS except in a different part of the flight envelope? Therefore, isn't MCAS just STS applied in a different part of the flight envelope? I don't understand the obsession with it being a problem that Boeing says MCAS is an enhancement of STS. From everything I've read, that is exactly what it is.

And BTW, STS (and MCAS) both use AP trim when in manual flight. That's why AP is not described as part of STS, because it isn't. MCAS is described as part of STS, because it is.


Except, in previous 737 generations, STS could be turned off, while still keeping electric trimming (thump switch control column). With MCAS attached to STS, that's no longer an option.
Shut down MCAS, you shut down ALL electric trim operations, with only the manual handcrank wheel available for trimming.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
SEU
Posts: 46
Joined: Wed Mar 13, 2019 7:21 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 8:49 pm

AABusDrvr wrote:
SEU wrote:
AABusDrvr wrote:

Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


The only answer I can give you is, I don't know. I've run through those scenarios many times in my mind (as I hope every other professional pilot in the world, no matter what they fly has). I'd like to believe I would have done some things differently, but hindsight is always 20/20, and those guys were way out into uncharted territory.

Any loss of life is tragic, and aviation is still an imperfect art. I hope that everyone, from the people who design and build airplanes, to the crews and maintainers can learn from these, and every other accident/incident and make flying safer.


Cheers for the answer. Its scary stuff.
 
AABusDrvr
Posts: 25
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 9:09 pm

morrisond wrote:
AABusDrvr wrote:
SEU wrote:

Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


The only answer I can give you is, I don't know. I've run through those scenarios many times in my mind (as I hope every other professional pilot in the world, no matter what they fly has). I'd like to believe I would have done some things differently, but hindsight is always 20/20, and those guys were way out into uncharted territory.

Any loss of life is tragic, and aviation is still an imperfect art. I hope that everyone, from the people who design and build airplanes, to the crews and maintainers can learn from these, and every other accident/incident and make flying safer.


Thank you for answering honestly. Do you mind sharing how much time your airline requires you to practice Non- Normal Procedures in the SIM's? What about trim using the manual trim control wheel? What do you practise in the Sim's?

I wouldn't ask you to say what airline you work for - but it is large or small? Asia/Europe/North America/South America?

Thanks


I'm currently with a reasonably good size, North American airline.

Something everyone needs to understand about airline training, is it's extremely expensive. Not just the cost of the simulators, and their operation, but also the pay for the instructors, check airman, and the crews in training. Also the hotels, and the loss of the crews in training, from flying the line. I'm not familiar with any airline that will train much beyond whats regulatory required, due to the costs.

A typical recurrent simulator period is two days, four hours in the simulator each day. That time includes the check ride. It would be impossible to train each crew, for every possible abnormal, or emergency procedure. So what happens, is every year they pick a few abnormals/emergencies from various systems on the airplane, and we do those. The next time through, it will be something different. Usually, abnormals are combined with everything else we have to train/demonstrate. For example, a hydraulic failure, followed by a partial flap RNP approach, or an engine failure during a missed approach, checks two boxes at the same time. Since AF447, unreliable airspeed has been part of every training course I've done, and now extended envelope training is included.

Initial training on a new aircraft goes much more in depth with systems, and abnormals. We used the manual trim in initial, but I'd bet money I'll see it next time through recurrent.
 
Saintor
Posts: 25
Joined: Wed Mar 13, 2019 10:35 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 9:37 pm

AABusDrvr wrote:
Let me start by saying I don't lay blame on the crews in either of these incidents.


You say this and then enumerate many, many [legit] reasons why they should possibly have some.
 
expert7700
Posts: 26
Joined: Thu Oct 01, 2015 4:30 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 9:44 pm

uta999 wrote:
I just love all these armchair 'pilots' who seem to think the ET crew should have recognised what was going on, and done the runaway trim checklist.

Let's think about what was going on in that flight deck. A brand new aircraft, normal take-off, alarms sound / shaker, followed by repeated pitching down like a roller-coaster, while probably 500' above the ground. The a/c was quite heavy and flying in tropical heat from a high altitude airport and its associated terrain. Factor in MCAS did not exist publicly, nor that it would repeatedly nose-down at least ten times. Reaching for a manual or iPad probably impossible. It was lucky they kept her in the air as long as they did.

The MAX should not fly again. Boeing are putting a sticky plaster on a leg amputation.


Forget armchair pilots, plenty of ACTUAL pilots say they'd have single handedly saved the flight.

This weekend a senior Southwest captain (one of their few 737 ETOPS pilots) showed my son and I the cockpit. My son immediately asked if he could see and use the manual trim wheel.

The captain said if only the pilots in Ethiopia had done just that, all those poor souls would have been saved. Way to downplay, and he was totally unaware that the pilots DID try that. No mention they were dealing with more issues all at once than most pilots encounter in their entire career.

Scary and deadly mindset to have. And plenty of other pilots like him may be back in the air with a MAX soon, with no new simulator training.

I don't want a guy who has taken an ipad scenario to say 'yeah, I got this' just because their airline didn't buy a MAX simulator or their corporation was told simulator training is optional.

Also.. Simulators are in short supply guess what isn't? ACTUAL New / 737 MAX aircraft. By the hundreds. Boeing could fly a couple hundred test/certification flights per day, training pilots from around the world on the exact MCAS scenarios. If every pilot flying commercial passengers on a MAX passes a hands on flight without crashing, THEN I'll feel safe enough to board as a passenger.
 
OldAeroGuy
Posts: 3793
Joined: Sun Dec 05, 2004 6:50 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 10:00 pm

AABusDrvr wrote:
XRAYretired wrote:
AABusDrvr wrote:


The climb table you referenced above is for a 280KT/.76 M climb. Thats not the chart you would be using, if you were in the terminal area, intending to return and land. The "Terminal Area" table at the bottom of that page would be the correct table.

An informal poll of every first officer I've flown with recently has had 100% "unreliable airspeed" as the answer, when asked, "If you got a stick shaker right after rotation, what QRH procedure would you start with".


OK. Thanks for the info.

Can you speculate as to why 4 crews appeared to follow the former with 3 subsequently intending to return?
Ta.
Ray


Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Thanks for the comprehensive post.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
AABusDrvr
Posts: 25
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 10:04 pm

Saintor wrote:
AABusDrvr wrote:
Let me start by saying I don't lay blame on the crews in either of these incidents.


You say this and then enumerate many, many [legit] reasons why they should possibly be.


You are correct, I should have said I don't lay blame solely on the crews. I think there will be a large human factors component in both final reports.
 
AirBoat
Posts: 27
Joined: Sun Jan 18, 2015 11:58 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 10:09 pm

The MCAS software update does not make sense.
The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According to the Boeing information , the critical AOA is lower at higher speeds. So climbing hard at max. speed can possibly get you in to trouble)
I would hope that Boeing puts a minimum of 3 sensors on the thing.
The word MCAS is also misleading, There is no constant protection through the whole flight envelope. Only edge of envelope protection. (Is there some really bad behaviour during a full stall?)
The manual trim that can not be used at high speed is unacceptable. This needs to be placarded on the speed tape.
FXL
 
Saintor
Posts: 25
Joined: Wed Mar 13, 2019 10:35 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 10:28 pm

Airboat wrote:
There never was trained in that situation.


As an amateur, thanks to AF447, I learnt 10 years ago that in doubt of reliable speed, thrust should be set at 80% (for an Airbus admittedly). ET302 was at 94%, seriously over speeding for that altitude and penalizing their ability to manually trim, ... and it was training's fault?

Just asking...
 
EvanWSFO
Posts: 974
Joined: Sun Mar 04, 2018 9:22 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 10:41 pm

Just heard a report on NBC News, it's unlikely the MAX will get airborne before the end of the summer.
I have been on this site 15 years. A unrecoverable email account led me to starting over. Those of you who call me a rookie, you may stop ok?
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Mon May 13, 2019 11:00 pm

expert7700 wrote:
uta999 wrote:
I just love all these armchair 'pilots' who seem to think the ET crew should have recognised what was going on, and done the runaway trim checklist.

Let's think about what was going on in that flight deck. A brand new aircraft, normal take-off, alarms sound / shaker, followed by repeated pitching down like a roller-coaster, while probably 500' above the ground. The a/c was quite heavy and flying in tropical heat from a high altitude airport and its associated terrain. Factor in MCAS did not exist publicly, nor that it would repeatedly nose-down at least ten times. Reaching for a manual or iPad probably impossible. It was lucky they kept her in the air as long as they did.

The MAX should not fly again. Boeing are putting a sticky plaster on a leg amputation.


Forget armchair pilots, plenty of ACTUAL pilots say they'd have single handedly saved the flight.

This weekend a senior Southwest captain (one of their few 737 ETOPS pilots) showed my son and I the cockpit. My son immediately asked if he could see and use the manual trim wheel.

The captain said if only the pilots in Ethiopia had done just that, all those poor souls would have been saved. Way to downplay, and he was totally unaware that the pilots DID try that. No mention they were dealing with more issues all at once than most pilots encounter in their entire career.

Scary and deadly mindset to have. And plenty of other pilots like him may be back in the air with a MAX soon, with no new simulator training.

I don't want a guy who has taken an ipad scenario to say 'yeah, I got this' just because their airline didn't buy a MAX simulator or their corporation was told simulator training is optional.

Also.. Simulators are in short supply guess what isn't? ACTUAL New / 737 MAX aircraft. By the hundreds. Boeing could fly a couple hundred test/certification flights per day, training pilots from around the world on the exact MCAS scenarios. If every pilot flying commercial passengers on a MAX passes a hands on flight without crashing, THEN I'll feel safe enough to board as a passenger.


It's actually debatable that they even tried the Manual trim wheel or if they did extended the fold out handle. We need to hear the full Cockpit recorder to be sure. There is another report further up in this thread that a longtime 737 pilot had a new Co-pilot in the plane with him and the Co-pilot was unaware the fold out existed and didn't even go over it on his type rating.
 
dampfnudel
Posts: 378
Joined: Wed Oct 04, 2006 9:42 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 12:52 am

EvanWSFO wrote:
Just heard a report on NBC News, it's unlikely the MAX will get airborne before the end of the summer.

I guess airlines with the MAX in their fleet are now making contingencies for the MAX to possibly be out of service for the rest of the year. I hope Boeing is accelerating their plans for a replacement with an announcement in the next 2-3 years.
A313 332 343 B703 712 722 732 73G 738 739 741 742 744 752 762 76E 764 772 AT5 CR9 D10 DHH DHT F27 GRM L10 M83 TU5

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planecane
Posts: 559
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 1:04 am

PW100 wrote:
planecane wrote:
XRAYretired wrote:
Its a function hosted by the FCC that commands electric trim same as AP is, AP is not described as part of STS.
Ray

From B737Theory
Speed Trim System (STS)
An electrical stabilizer trim input automatically controls certain aircraft attitude conditions when undergoing large thrust changes in the lower speed region, such as takeoff and go-around. These conditions require high thrust settings and are especially present with a low weight aircraft and a relatively aft center of gravity where the aircraft wants to “nose up”. The STS supports the crew during these conditions when manually controlling the aircraft without the use of an autopilot by an opposite stabilizer trim, commanding a nose down force by use of the autopilot trim.


Doesn't this sound exactly like MCAS except in a different part of the flight envelope? Therefore, isn't MCAS just STS applied in a different part of the flight envelope? I don't understand the obsession with it being a problem that Boeing says MCAS is an enhancement of STS. From everything I've read, that is exactly what it is.

And BTW, STS (and MCAS) both use AP trim when in manual flight. That's why AP is not described as part of STS, because it isn't. MCAS is described as part of STS, because it is.


Except, in previous 737 generations, STS could be turned off, while still keeping electric trimming (thump switch control column). With MCAS attached to STS, that's no longer an option.
Shut down MCAS, you shut down ALL electric trim operations, with only the manual handcrank wheel available for trimming.


True, however the runaway stabilizer NNC says to move both switches to cutout. If there is a runaway stabilizer on the NG or MAX you will end up shutting down all electric trim anyway.

The idea of the NNC seems to be that if you've gotten back in trim before cutting off the electric trim, the manual trim wheel will be usable to be able to make an emergency landing without requiring superhuman strength or the roller coaster procedure.
 
Vladex
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 1:12 am

Ethiopian Airlines CEO : If we fly it , we will be the last one

https://www.youtube.com/watch?v=7MDCDC36J3s
 
Passedv1
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:58 am

AirBoat wrote:
The MCAS software update does not make sense.
The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According to the Boeing information , the critical AOA is lower at higher speeds. So climbing hard at max. speed can possibly get you in to trouble)
I would hope that Boeing puts a minimum of 3 sensors on the thing.
The word MCAS is also misleading, There is no constant protection through the whole flight envelope. Only edge of envelope protection. (Is there some really bad behaviour during a full stall?)
The manual trim that can not be used at high speed is unacceptable. This needs to be placarded on the speed tape.
FXL


Having no MCAS is far better than having the airplane trimming when it shouldn't be. The MCAS is not necessary to recover from a stall. The pilots would still have the shaker as well as the normal a/s indication.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:59 am

AirBoat wrote:
The MCAS software update does not make sense.
The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According to the Boeing information , the critical AOA is lower at higher speeds. So climbing hard at max. speed can possibly get you in to trouble)
I would hope that Boeing puts a minimum of 3 sensors on the thing.
The word MCAS is also misleading, There is no constant protection through the whole flight envelope. Only edge of envelope protection. (Is there some really bad behaviour during a full stall?)
The manual trim that can not be used at high speed is unacceptable. This needs to be placarded on the speed tape.
FXL


The manual trim wheel can be used at high speed. The problem is when severely out of trim where high speed makes it even harder.

To your point about the software. I'm sure (well, I'd hope) there will be an AoA disagree checklist. I'm sure this checklist will include parameters to stay away from the part of the flight envelope where MCAS is needed.

In reality, SOP should be doing that anyway in normal flight. Your concern about not having MCAS protection if the high AoA value is the correct one is not an issue in normal flight.

No transport aircraft should ever be approaching a stall especially with passengers on board. MCAS is needed because it is possible to put the 737MAX into that part of the flight envelope, not because it is normal to do so.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:14 am

SEU wrote:
AABusDrvr wrote:
XRAYretired wrote:

OK. Thanks for the info.

Can you speculate as to why 4 crews appeared to follow the former with 3 subsequently intending to return?
Ta.
Ray


Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


I don't know if I would. It would depend on what I thought was going on initially.

The thing I don't hear being talked about much is how much the trim wheel normally turns uncommanded by the pilot during nor.al operations.

There are a couple of computer systems that turn the trim independent of pilot input. My hypothesis is that since we are so used to this movement of the trim, it might delay the recognition of a trim problem to the crew. Couple this with a brand new type that nobody has yet developed a feel for what is "normal", I can see a pilot taking a bit longer to recognize the nature of their emergency. These few several seconds of confusion can make all the difference down low, causing the crew to get "behind the airplane" making recovery impossible.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:33 am

Passedv1 wrote:
SEU wrote:
AABusDrvr wrote:

Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


I don't know if I would. It would depend on what I thought was going on initially.

The thing I don't hear being talked about much is how much the trim wheel normally turns uncommanded by the pilot during nor.al operations.

There are a couple of computer systems that turn the trim independent of pilot input. My hypothesis is that since we are so used to this movement of the trim, it might delay the recognition of a trim problem to the crew. Couple this with a brand new type that nobody has yet developed a feel for what is "normal", I can see a pilot taking a bit longer to recognize the nature of their emergency. These few several seconds of confusion can make all the difference down low, causing the crew to get "behind the airplane" making recovery impossible.


It does "seem" that both crews recognized that something was wrong with the trim as they both used manual trim to counteract MCAS.

Do you think you would reach that conclusion when it got to the point of having to use abnormal force to pull back on the column or would you just instinctively trim out the required force without realizing that the trim system is causing the problem?
 
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SomebodyInTLS
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 10:05 am

XRAYretired wrote:
morrisond wrote:
However that was superseded by the Generic Boeing Instruction from 2015 on all Boeing models - this is a Memory item.

"A few days back I received a new procedure in my 737 QRH, for airspeed unreliable. We now have a set of thrust settings in combination with a specific pitch attitude, as memory items.
Config flaps up: 4 degrees pitch up, and 75% N1
Config flaps extended: 10 degrees pitch up and 80% N1

These pitch and power settings provide a simple reference setting for the crew to use for a short period of time while the initial steps of the checklist are accomplished. These settings do not ensure a level flight or constant airspeed at any particular altitude/airspeed/weight combination. However, they do ensure that at any and all weight/altitude combinations, the aircraft will accelerate from low speeds, and slow from a high speeds, as we cannot assume the aircraft is in stable flight when the NNC is run. It is more likely that the crew or the autopilot has destabilized the airplane as a result of erroneous airspeed indications prior to identification of the need to run the NNC. These memory item pitch and power settings often result in a significant climb (from lower altitudes) and can also result in a gradual descent (from higher altitudes)."

Great!. Are you able to share docs or relevant parts thereof?

Ray


Interesting... our "interested part-time GA hobbyist" (who posts a surprising amount of consistently on message posts for such) seems to have an awful lot of Boeing procedures to hand in a jiffy...
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 10:08 am

SomebodyInTLS wrote:
YYZLGA wrote:
It's definitely having a knock-on effect. I just had to deal with a travel agent for some people who invited me to something, and she told me she was had changed my booking to switch me onto a different flight because the original booking was a 737-800. I stifled my laugh, since the flight she switched me onto was much more convenient.


I went to get my hair cut at the weekend and was genuinely surprised when the guy asked out of the blue if the 737 was doing Airbus any favours!

So what did you reply? :scratchchin:
 
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SomebodyInTLS
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 11:18 am

N14AZ wrote:
SomebodyInTLS wrote:
YYZLGA wrote:
It's definitely having a knock-on effect. I just had to deal with a travel agent for some people who invited me to something, and she told me she was had changed my booking to switch me onto a different flight because the original booking was a 737-800. I stifled my laugh, since the flight she switched me onto was much more convenient.


I went to get my hair cut at the weekend and was genuinely surprised when the guy asked out of the blue if the 737 was doing Airbus any favours!

So what did you reply? :scratchchin:


It might surprise you, but I said I thought it was a tragedy and we had every sympathy for all those involved, including the engineers who must be under a lot of stress right now. I then said it pointed to some questionable practices within Boeing as an organisation but that I hoped this would be a moment to fix things in their corporate culture. I literally said that there's no feeling of gloating from the Airbus camp, only concern.
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
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N14AZ
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 11:52 am

SomebodyInTLS wrote:
N14AZ wrote:
SomebodyInTLS wrote:

I went to get my hair cut at the weekend and was genuinely surprised when the guy asked out of the blue if the 737 was doing Airbus any favours!

So what did you reply? :scratchchin:


It might surprise you, but I said I thought it was a tragedy and we had every sympathy for all those involved, including the engineers who must be under a lot of stress right now. [...]

No, it does not suprise me. I did not expect any kind of gloating from you or from Airbus in general. That's what I like about this duoploy. They treat each other very well in these kind of situations because both know it can and it will/did happen to both of them.

Best regards
N14AZ
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 12:06 pm

SomebodyInTLS wrote:
XRAYretired wrote:
morrisond wrote:
However that was superseded by the Generic Boeing Instruction from 2015 on all Boeing models - this is a Memory item.

"A few days back I received a new procedure in my 737 QRH, for airspeed unreliable. We now have a set of thrust settings in combination with a specific pitch attitude, as memory items.
Config flaps up: 4 degrees pitch up, and 75% N1
Config flaps extended: 10 degrees pitch up and 80% N1

These pitch and power settings provide a simple reference setting for the crew to use for a short period of time while the initial steps of the checklist are accomplished. These settings do not ensure a level flight or constant airspeed at any particular altitude/airspeed/weight combination. However, they do ensure that at any and all weight/altitude combinations, the aircraft will accelerate from low speeds, and slow from a high speeds, as we cannot assume the aircraft is in stable flight when the NNC is run. It is more likely that the crew or the autopilot has destabilized the airplane as a result of erroneous airspeed indications prior to identification of the need to run the NNC. These memory item pitch and power settings often result in a significant climb (from lower altitudes) and can also result in a gradual descent (from higher altitudes)."

Great!. Are you able to share docs or relevant parts thereof?

Ray


Interesting... our "interested part-time GA hobbyist" (who posts a surprising amount of consistently on message posts for such) seems to have an awful lot of Boeing procedures to hand in a jiffy...


Yes - it took me at least 3 seconds to Google "New Boeing 737 unreliable airspeed checklist" and read the first result that came up - it's a good discussion by pilots on another forum just like this one.

I've always been a contrarian - If 20 people say something is black I'll say wait a second maybe you are missing something maybe it's white.

It helps me in my Day Job as a portfolio manager - PM me and I'll give you proof of who I am if you don't believe me.
 
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SomebodyInTLS
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 1:44 pm

morrisond wrote:
I've always been a contrarian - If 20 people say something is black I'll say wait a second maybe you are missing something maybe it's white.

It helps me in my Day Job as a portfolio manager - PM me and I'll give you proof of who I am if you don't believe me.


No, it's okay. I think your first line explains a lot... :)
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:00 pm

morrisond wrote:
expert7700 wrote:
uta999 wrote:
I just love all these armchair 'pilots' who seem to think the ET crew should have recognised what was going on, and done the runaway trim checklist.

Let's think about what was going on in that flight deck. A brand new aircraft, normal take-off, alarms sound / shaker, followed by repeated pitching down like a roller-coaster, while probably 500' above the ground. The a/c was quite heavy and flying in tropical heat from a high altitude airport and its associated terrain. Factor in MCAS did not exist publicly, nor that it would repeatedly nose-down at least ten times. Reaching for a manual or iPad probably impossible. It was lucky they kept her in the air as long as they did.

The MAX should not fly again. Boeing are putting a sticky plaster on a leg amputation.


Forget armchair pilots, plenty of ACTUAL pilots say they'd have single handedly saved the flight.

This weekend a senior Southwest captain (one of their few 737 ETOPS pilots) showed my son and I the cockpit. My son immediately asked if he could see and use the manual trim wheel.

The captain said if only the pilots in Ethiopia had done just that, all those poor souls would have been saved. Way to downplay, and he was totally unaware that the pilots DID try that. No mention they were dealing with more issues all at once than most pilots encounter in their entire career.

Scary and deadly mindset to have. And plenty of other pilots like him may be back in the air with a MAX soon, with no new simulator training.

I don't want a guy who has taken an ipad scenario to say 'yeah, I got this' just because their airline didn't buy a MAX simulator or their corporation was told simulator training is optional.

Also.. Simulators are in short supply guess what isn't? ACTUAL New / 737 MAX aircraft. By the hundreds. Boeing could fly a couple hundred test/certification flights per day, training pilots from around the world on the exact MCAS scenarios. If every pilot flying commercial passengers on a MAX passes a hands on flight without crashing, THEN I'll feel safe enough to board as a passenger.


It's actually debatable that they even tried the Manual trim wheel or if they did extended the fold out handle. We need to hear the full Cockpit recorder to be sure. There is another report further up in this thread that a longtime 737 pilot had a new Co-pilot in the plane with him and the Co-pilot was unaware the fold out existed and didn't even go over it on his type rating.


It is also debatable if said senior Southwest captain ever tried to use the manual trim wheel at similar conditions (= severe out-of-trim condition). Words to that effect that failure to use the manual trim wheel was a significant factor in the accident borders on disinformation.

There is plenty of evidence (if one wants to see it) that the manual trim wheel won't work in the conditions they were in (which was a severe out-of-trim situation). It has been demonstrated some time ago by Mentour Pilot (and he explained why that is), and AviationWeek is now also reporting the same thing from experienced American (= country, not necesarily airline) pilots.
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morrisond
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:04 pm

PW100 wrote:
morrisond wrote:
expert7700 wrote:

Forget armchair pilots, plenty of ACTUAL pilots say they'd have single handedly saved the flight.

This weekend a senior Southwest captain (one of their few 737 ETOPS pilots) showed my son and I the cockpit. My son immediately asked if he could see and use the manual trim wheel.

The captain said if only the pilots in Ethiopia had done just that, all those poor souls would have been saved. Way to downplay, and he was totally unaware that the pilots DID try that. No mention they were dealing with more issues all at once than most pilots encounter in their entire career.

Scary and deadly mindset to have. And plenty of other pilots like him may be back in the air with a MAX soon, with no new simulator training.

I don't want a guy who has taken an ipad scenario to say 'yeah, I got this' just because their airline didn't buy a MAX simulator or their corporation was told simulator training is optional.

Also.. Simulators are in short supply guess what isn't? ACTUAL New / 737 MAX aircraft. By the hundreds. Boeing could fly a couple hundred test/certification flights per day, training pilots from around the world on the exact MCAS scenarios. If every pilot flying commercial passengers on a MAX passes a hands on flight without crashing, THEN I'll feel safe enough to board as a passenger.


It's actually debatable that they even tried the Manual trim wheel or if they did extended the fold out handle. We need to hear the full Cockpit recorder to be sure. There is another report further up in this thread that a longtime 737 pilot had a new Co-pilot in the plane with him and the Co-pilot was unaware the fold out existed and didn't even go over it on his type rating.


It is also debatable if said senior Southwest captain ever tried to use the manual trim wheel at similar conditions (= severe out-of-trim condition). Words to that effect that failure to use the manual trim wheel was a significant factor in the accident borders on disinformation.

There is plenty of evidence (if one wants to see it) that the manual trim wheel won't work in the conditions they were in (which was a severe out-of-trim situation). It has been demonstrated some time ago by Mentour Pilot (and he explained why that is), and AviationWeek is now also reporting the same thing from experienced American (= country, not necesarily airline) pilots.


Don't forget the severe overspeed either.
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:09 pm

SomebodyInTLS wrote:
morrisond wrote:
I've always been a contrarian - If 20 people say something is black I'll say wait a second maybe you are missing something maybe it's white.

It helps me in my Day Job as a portfolio manager - PM me and I'll give you proof of who I am if you don't believe me.


No, it's okay. I think your first line explains a lot... :)


And the funny thing is that I end up being right a lot more than I end up being wrong when I see things others don't. Sometimes it takes a while but eventually it proves out.

There are big issues with Boeing's engineering efforts on the MAX and the FAA's oversight - but you are in real denial if you don't think there are similar issues in the training system.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:10 pm

planecane wrote:
PW100 wrote:
[Except, in previous 737 generations, STS could be turned off, while still keeping electric trimming (thump switch control column). With MCAS attached to STS, that's no longer an option.
Shut down MCAS, you shut down ALL electric trim operations, with only the manual handcrank wheel available for trimming.


True, however the runaway stabilizer NNC says to move both switches to cutout. If there is a runaway stabilizer on the NG or MAX you will end up shutting down all electric trim anyway.

The idea of the NNC seems to be that if you've gotten back in trim before cutting off the electric trim, the manual trim wheel will be usable to be able to make an emergency landing without requiring superhuman strength or the roller coaster procedure.


True. But then again, when the runaway stabelizer NNC was initially devised, it was aimed at a "real runaway stablizer", not the sort of intermittent MCAS commanded intermittent action, with much more embedded authority and speed than when the NNC was initially devised.

And this is where the differences between older 737 generations and MAX come to surface in terms of pilot training. Pilots must now understand that the runaway stabelizer NNC must also be applied when it is not a real runaway, but a sort of runaway, or some sort of uncommanded/undesired stabelizer trim action. Which becomes even more difficult if so many different functionalities are embedded as STS and MCAS, with different,and even conflicting characteristics - how does one decide when it is uncommanded. By the time that has been determined, one may have run out of time and find itself in a severely-out-of-trim situation, where the manual trim wheel may not work anymore.

In hindsight, it is utterly amazing the poor level of differences-training pilots received and were cleared to operate the MAX.
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:16 pm

planecane wrote:
AirBoat wrote:
The MCAS software update does not make sense.
The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According to the Boeing information , the critical AOA is lower at higher speeds. So climbing hard at max. speed can possibly get you in to trouble)
I would hope that Boeing puts a minimum of 3 sensors on the thing.
The word MCAS is also misleading, There is no constant protection through the whole flight envelope. Only edge of envelope protection. (Is there some really bad behaviour during a full stall?)
The manual trim that can not be used at high speed is unacceptable. This needs to be placarded on the speed tape.
FXL


The manual trim wheel can be used at high speed. The problem is when severely out of trim where high speed makes it even harder.
To your point about the software. I'm sure (well, I'd hope) there will be an AoA disagree checklist. I'm sure this checklist will include parameters to stay away from the part of the flight envelope where MCAS is needed.
In reality, SOP should be doing that anyway in normal flight. Your concern about not having MCAS protection if the high AoA value is the correct one is not an issue in normal flight.
No transport aircraft should ever be approaching a stall especially with passengers on board. MCAS is needed because it is possible to put the 737MAX into that part of the flight envelope, not because it is normal to do so.


Best post so far. Really, this is the heart of the MCAS thing and how to recover the situation.

Then there is also such thing as root casue: how did we arrive at MCAS 1.0 being accepted (and certified), and how do we know there aren't other gremlins that slipped thropugh the mazes of the same net . . . ?
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:19 pm

So we didn't need it but it was made stronger (and even beefed up again) than what the pilots can counter. Doesn't seem to make sense?
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:24 pm

morrisond wrote:
SomebodyInTLS wrote:
XRAYretired wrote:
Great!. Are you able to share docs or relevant parts thereof?

Ray

It helps me in my Day Job as a portfolio manager - PM me and I'll give you proof of who I am if you don't believe me.


Ahh, makes sense now. You would lose a lot of $$$, if Boeing share continue to slide :D
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:28 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:

It's actually debatable that they even tried the Manual trim wheel or if they did extended the fold out handle. We need to hear the full Cockpit recorder to be sure. There is another report further up in this thread that a longtime 737 pilot had a new Co-pilot in the plane with him and the Co-pilot was unaware the fold out existed and didn't even go over it on his type rating.


It is also debatable if said senior Southwest captain ever tried to use the manual trim wheel at similar conditions (= severe out-of-trim condition). Words to that effect that failure to use the manual trim wheel was a significant factor in the accident borders on disinformation.

There is plenty of evidence (if one wants to see it) that the manual trim wheel won't work in the conditions they were in (which was a severe out-of-trim situation). It has been demonstrated some time ago by Mentour Pilot (and he explained why that is), and AviationWeek is now also reporting the same thing from experienced American (= country, not necesarily airline) pilots.


Don't forget the severe overspeed either.


That certainly won't help. But then again, the FDR traces suggest the same thing going on before they were approaching overspeed territory.

TBH, from the ET crew performance point of view I find the (over)speed discussion, much more intersting then your manual trim wheel thing, which seems to be a bit of a red herring to me. I surely hope the investigation team will spend a lot of time trying to figure out and understand how/why their air speed was (mis-)managed. I'm very curious to know if that is in any way related to (your) "declining pilot standards world wide", or that their were other factors in play that made their decision profile somewhat more understandable.
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:34 pm

Amexair wrote:
morrisond wrote:
SomebodyInTLS wrote:
It helps me in my Day Job as a portfolio manager - PM me and I'll give you proof of who I am if you don't believe me.


Ahh, makes sense now. You would lose a lot of $$$, if Boeing share continue to slide :D


Nope - I haven't owned it in my Portfolio's for clients for a few years as I thought it was over-valued.

In fact in my personal account I had Put options on Boeing that expired the day before the second crash (I was betting on an overall market correction and Boeing being one of the most over-valued). Although I would have made a lot of money if they expired a day or two later - I'm glad they expired the day before as I would not have wanted to profit from a situation where loss of life was involved.

Just like I want people to focus more on training issues so when planes do unexpected things or parts fail it does not lead to loss of life in the future.

Boeing would probably have to decline a good 50% from here before I would think of buying it for clients - although people seem to think an up business cycle and up aircraft order cycle are now immortal - they never are. I'm very patient.
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 2:55 pm

PW100 wrote:
morrisond wrote:
PW100 wrote:

It is also debatable if said senior Southwest captain ever tried to use the manual trim wheel at similar conditions (= severe out-of-trim condition). Words to that effect that failure to use the manual trim wheel was a significant factor in the accident borders on disinformation.

There is plenty of evidence (if one wants to see it) that the manual trim wheel won't work in the conditions they were in (which was a severe out-of-trim situation). It has been demonstrated some time ago by Mentour Pilot (and he explained why that is), and AviationWeek is now also reporting the same thing from experienced American (= country, not necesarily airline) pilots.


Don't forget the severe overspeed either.


That certainly won't help. But then again, the FDR traces suggest the same thing going on before they were approaching overspeed territory.

TBH, from the ET crew performance point of view I find the (over)speed discussion, much more intersting then your manual trim wheel thing, which seems to be a bit of a red herring to me. I surely hope the investigation team will spend a lot of time trying to figure out and understand how/why their air speed was (mis-)managed. I'm very curious to know if that is in any way related to (your) "declining pilot standards world wide", or that their were other factors in play that made their decision profile somewhat more understandable.



I keep reading this excerpt from the Preliminary report.

At 05:41:20, the right overspeed clacker was recorded on CVR. It remained active until the end of
the recording.
At 05:41:21, the selected altitude was changed from 32000 ft to 14000 ft.
At 05:41:30, the Captain requested the First-Officer to pitch up with him and the First-Officer
acknowledged.
At 05:41:32, the left overspeed warning activated and was active intermittently until the end of the
recording.
At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied
that the trim was not working and asked if he could try it manually. The Captain told him to try. At
05:41:54, the First-Officer replied that it is not working.


They were overspeed on both sides of the cockpit at his point in the flight where even if Electric Trim was functional may not have worked that well either. Overspeed is as bad as being Underspeed in terms of the aircraft staying in the air and the controls being functional.

The debatable part is whether or not the Co-Pilot took the Pilots order as "try the Electric Trim manually" or "try the trim wheel".

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.

We need the cockpit voice recorders to know the full story.

I think the biggest contributor to the Overspeed is over reliance on Auto-Throttle. Crews are trained to rely on it heavily so they don't have that much experience hand flying without it - it was big contributor to the Asiana 214 crash in SFO.

I think it was also help to explain a lot of the runway overruns - if you don't have manual control of the thrust it's hard to balance pitch so that you land on the numbers and don't float down the runway if the throttle does something unexpected.

A great explanantion on Auto-throttle here - for reference I believe ET302 never left TOGA mode http://www.flaps2approach.com/journal/2 ... tions.html
 
User avatar
spinotter
Posts: 431
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:34 pm

SEU wrote:
AABusDrvr wrote:
XRAYretired wrote:

OK. Thanks for the info.

Can you speculate as to why 4 crews appeared to follow the former with 3 subsequently intending to return?
Ta.
Ray


Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


From someone who knows nothing about a flying a plane, but after reading many comments on the MAX accident threads, it seems to me that the measures which needed to be taken to save JT and ET were just too complicated for ordinary human beings. Does it have to be so extremely complex? You'd like to think that a pilot is the equivalent of the sensory/motor activities of a bird in flight? Do birds have MCAS?
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:46 pm

spinotter wrote:
SEU wrote:
AABusDrvr wrote:

Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


From someone who knows nothing about a flying a plane, but after reading many comments on the MAX accident threads, it seems to me that the measures which needed to be taken to save JT and ET were just too complicated for ordinary human beings. Does it have to be so extremely complex? You'd like to think that a pilot is the equivalent of the sensory/motor activities of a bird in flight? Do birds have MCAS?


Hand flying an aircraft is not that hard - recognizing when the auto-nannies are screwing up and knowing when to turn them off is the part that requires some training and basic skills - However no pilot should be afraid of turning everything off and should feel confident in there ability to fly without the helpers.

It's really not that complex.
 
XRAYretired
Posts: 313
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:48 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:

Don't forget the severe overspeed either.


That certainly won't help. But then again, the FDR traces suggest the same thing going on before they were approaching overspeed territory.

TBH, from the ET crew performance point of view I find the (over)speed discussion, much more intersting then your manual trim wheel thing, which seems to be a bit of a red herring to me. I surely hope the investigation team will spend a lot of time trying to figure out and understand how/why their air speed was (mis-)managed. I'm very curious to know if that is in any way related to (your) "declining pilot standards world wide", or that their were other factors in play that made their decision profile somewhat more understandable.



I keep reading this excerpt from the Preliminary report.

At 05:41:20, the right overspeed clacker was recorded on CVR. It remained active until the end of
the recording.
At 05:41:21, the selected altitude was changed from 32000 ft to 14000 ft.
At 05:41:30, the Captain requested the First-Officer to pitch up with him and the First-Officer
acknowledged.
At 05:41:32, the left overspeed warning activated and was active intermittently until the end of the
recording.
At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied
that the trim was not working and asked if he could try it manually. The Captain told him to try. At
05:41:54, the First-Officer replied that it is not working.


They were overspeed on both sides of the cockpit at his point in the flight where even if Electric Trim was functional may not have worked that well either. Overspeed is as bad as being Underspeed in terms of the aircraft staying in the air and the controls being functional.

The debatable part is whether or not the Co-Pilot took the Pilots order as "try the Electric Trim manually" or "try the trim wheel".

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.

We need the cockpit voice recorders to know the full story.

I think the biggest contributor to the Overspeed is over reliance on Auto-Throttle. Crews are trained to rely on it heavily so they don't have that much experience hand flying without it - it was big contributor to the Asiana 214 crash in SFO.

I think it was also help to explain a lot of the runway overruns - if you don't have manual control of the thrust it's hard to balance pitch so that you land on the numbers and don't float down the runway if the throttle does something unexpected.

A great explanantion on Auto-throttle here - for reference I believe ET302 never left TOGA mode http://www.flaps2approach.com/journal/2 ... tions.html


There are only two options available: MANUAL electric TRIM and MANUAL TRIM wheel.

the Captain asked the First-Officer if the TRIM is functional. The First-Officer has replied that the TRIM was not working and asked if he could try it MANUALly. The Captain told him to try the First-Officer replied that it is not working.

I think it is unlikely that the F/O would use two different terms for the same function in the same sentence and would not asking the Capt. to confirm trying the same function is checked for a second time using two terms. But two terms are used. The only satisfactory conclusion is that the F/O is referring to both functions. The question is which term refers to which function.

My suggestion is that, remembering that it was FO that offered STAB TRIM CUT-OUT ~1 min. before hand and the Capt. seemed unsure in his response, that the Capt. was asking for confirmation that manual electric TRIM was not available, that the FO confirmed not working, because it was in cut-out, and then suggested to try MANUAL trim wheel -also not working.

Ray
 
kalvado
Posts: 1612
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 3:48 pm

spinotter wrote:
SEU wrote:
AABusDrvr wrote:

Let me start by saying I don't lay blame on the crews in either of these incidents. I've flown both A and B airplanes, not a "fan boy" for either, it just happens I currently fly the 737. IMHO, Boeing (and the FAA) dropped the ball bad with the design, and implementation of the MCAS. I do however, scratch my head at some of the actions of both crews. The full CVR transcripts would help understand things tremendously.

I won't even speculate on an answer to why the crews acted as they did, other than their training and experience led them to believe the actions they took, were correct at the time.

I'd like to know why the Lion Air captain was able to maintain control of the airplane for several minutes, and many MCAS trim command cycles, but when he passed control to the first officer, he wasn't able to keep the airplane flying.

Or why the ET crew couldn't, or didn't get the airplane back in trim with the normal stab trim. The Lion air captain at least, was seemingly able to do this several times.

I will never understand why the ET crew tried to engage the autopilot three times with an active stick shaker. Or why they never got the power back from the takeoff thrust setting. Pitch+Power=Performance is as true in a 737, as it is in a Cub.

There isn't any real procedural guidance about retracting the flaps, but I don't believe in a similar situation I would. Two reasons here, first is I know with flaps 1 or 5, I have more maneuver margin than if the wing is clean. Second would be that if I had a continuous, false stick shaker right after takeoff, I'm going to go right back and land. No reason to clean up, and accelerate, as long as I can assure terrain clearance, and it would appear the ET crew did climb high enough to do that.

I don't understand why any of these crews didn't do the "RUNAWAY STABILIZER" NNC, when the stab trim kept doing something other than what they told it to do. Maybe the check list needs to be renamed "UNCOMMANDED STABILIZER MOTION" or something like that.

When everything is working properly, the MAX is a great airplane to fly. I do hope they get this mess sorted out, and the airplanes resume flying before long.


Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


From someone who knows nothing about a flying a plane, but after reading many comments on the MAX accident threads, it seems to me that the measures which needed to be taken to save JT and ET were just too complicated for ordinary human beings. Does it have to be so extremely complex? You'd like to think that a pilot is the equivalent of the sensory/motor activities of a bird in flight? Do birds have MCAS?

You know the story about old guy who fixes machine by a single stroke of the hammer, and then bills owner as "hammer stroke $1, diagnostics $999"?
My impression is that cockpit situation was similar: fixes were not that complicated, but realization of how to do things right took days and weeks of discussion. Human nature is such that even well-trained procedures can be - and do - get messed up; something that was just read before has little chance of being recalled correctly in a high stress situation. Hindsight is 20/20 or better, so now we know how to act in those situations.
Birds are somewhat different; I would compare MCAS with some things people do while loosing balance on slippery ice. Which is trying to react to a non-normal situation with crude and barely efficient balancing moves.
 
FluidFlow
Posts: 94
Joined: Wed Apr 10, 2019 6:39 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:08 pm

morrisond wrote:

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.



Is it not a bit scary that you last line of defense, if you want to call it that way, when everything else fails, is not working in every scenario?

In general it should be that the less complicated the system the broader it should be usable?

The fact that the back up system is heavily limited is kind of a really bad design because in general when you need the back up system you are already in a bad situation.

If your electirc supply in a hospital fails and the back up generator only works wednesdays its not a great design.

Same should go for manual trim, it should work always no matter how fast you are, it should never fail except you have a structural failure. That should be the design limit and not overspeed.
 
planecane
Posts: 559
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:35 pm

PW100 wrote:
planecane wrote:
AirBoat wrote:
The MCAS software update does not make sense.
The logic of disabling MCAS if the two sensors disagree by more than 5 deg, assumes that the faulty sensor is the high value. What if the low value is the faulty one. You are then approaching the edge of your flight envelope with no protection.(According to the Boeing information , the critical AOA is lower at higher speeds. So climbing hard at max. speed can possibly get you in to trouble)
I would hope that Boeing puts a minimum of 3 sensors on the thing.
The word MCAS is also misleading, There is no constant protection through the whole flight envelope. Only edge of envelope protection. (Is there some really bad behaviour during a full stall?)
The manual trim that can not be used at high speed is unacceptable. This needs to be placarded on the speed tape.
FXL


The manual trim wheel can be used at high speed. The problem is when severely out of trim where high speed makes it even harder.
To your point about the software. I'm sure (well, I'd hope) there will be an AoA disagree checklist. I'm sure this checklist will include parameters to stay away from the part of the flight envelope where MCAS is needed.
In reality, SOP should be doing that anyway in normal flight. Your concern about not having MCAS protection if the high AoA value is the correct one is not an issue in normal flight.
No transport aircraft should ever be approaching a stall especially with passengers on board. MCAS is needed because it is possible to put the 737MAX into that part of the flight envelope, not because it is normal to do so.


Best post so far. Really, this is the heart of the MCAS thing and how to recover the situation.

Then there is also such thing as root casue: how did we arrive at MCAS 1.0 being accepted (and certified), and how do we know there aren't other gremlins that slipped thropugh the mazes of the same net . . . ?


I assume (hope) that part of the current reveiw process for ungrounding is for Boeing to disclose every single thing that was changed from the NG to the MAX so that third parties can review the changes and perform an independent fault tree analysis.

MCAS 1.0 was accepted because of the very bad assumption that a failure would lead to the runaway stabilizer NNC. When presented that way in the submission to the FAA, it doesn't really sound like a big deal.

What should have been done is that Boeing should have programmed an NG simulator to simulate an MCAS failure, put some randomly selected NG pilots in the simulator and determined if they recognized it as runaway stabilizer.

With respect to all 737s, I think some investigation should also be done on worldwide training for "real" runaway stablizer. I am not confident that either crew would have responded properly to a continuous runaway stabilizer. We won't know for sure until the full CVR transcript is released, but I just don't see a conversation between the captain and FO where they discussed runaway stabilizer and then determined that it wasn't because the trim movement wasn't continuous.

I don't have any way to find the statistics, but I am assuming that runaway stabilizer on an NG is an extremely rare event. The reason no NG has crashed because of it may be luck in that it almost never happens and, if it has, it was lucky that the crews for those flights did recognize it. My though is that MCAS just made it an order of magnitude or more higher chance to have a runaway stabilizer but that there may be an underlying training issue for all runaway stabilizer situations (possibly in all countries).
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:43 pm

XRAYretired wrote:
morrisond wrote:
PW100 wrote:

That certainly won't help. But then again, the FDR traces suggest the same thing going on before they were approaching overspeed territory.

TBH, from the ET crew performance point of view I find the (over)speed discussion, much more intersting then your manual trim wheel thing, which seems to be a bit of a red herring to me. I surely hope the investigation team will spend a lot of time trying to figure out and understand how/why their air speed was (mis-)managed. I'm very curious to know if that is in any way related to (your) "declining pilot standards world wide", or that their were other factors in play that made their decision profile somewhat more understandable.



I keep reading this excerpt from the Preliminary report.

At 05:41:20, the right overspeed clacker was recorded on CVR. It remained active until the end of
the recording.
At 05:41:21, the selected altitude was changed from 32000 ft to 14000 ft.
At 05:41:30, the Captain requested the First-Officer to pitch up with him and the First-Officer
acknowledged.
At 05:41:32, the left overspeed warning activated and was active intermittently until the end of the
recording.
At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied
that the trim was not working and asked if he could try it manually. The Captain told him to try. At
05:41:54, the First-Officer replied that it is not working.


They were overspeed on both sides of the cockpit at his point in the flight where even if Electric Trim was functional may not have worked that well either. Overspeed is as bad as being Underspeed in terms of the aircraft staying in the air and the controls being functional.

The debatable part is whether or not the Co-Pilot took the Pilots order as "try the Electric Trim manually" or "try the trim wheel".

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.

We need the cockpit voice recorders to know the full story.

I think the biggest contributor to the Overspeed is over reliance on Auto-Throttle. Crews are trained to rely on it heavily so they don't have that much experience hand flying without it - it was big contributor to the Asiana 214 crash in SFO.

I think it was also help to explain a lot of the runway overruns - if you don't have manual control of the thrust it's hard to balance pitch so that you land on the numbers and don't float down the runway if the throttle does something unexpected.

A great explanantion on Auto-throttle here - for reference I believe ET302 never left TOGA mode http://www.flaps2approach.com/journal/2 ... tions.html


There are only two options available: MANUAL electric TRIM and MANUAL TRIM wheel.

the Captain asked the First-Officer if the TRIM is functional. The First-Officer has replied that the TRIM was not working and asked if he could try it MANUALly. The Captain told him to try the First-Officer replied that it is not working.

I think it is unlikely that the F/O would use two different terms for the same function in the same sentence and would not asking the Capt. to confirm trying the same function is checked for a second time using two terms. But two terms are used. The only satisfactory conclusion is that the F/O is referring to both functions. The question is which term refers to which function.

My suggestion is that, remembering that it was FO that offered STAB TRIM CUT-OUT ~1 min. before hand and the Capt. seemed unsure in his response, that the Capt. was asking for confirmation that manual electric TRIM was not available, that the FO confirmed not working, because it was in cut-out, and then suggested to try MANUAL trim wheel -also not working.

Ray


Totally possible - and as I mentioned above as they were in Overspeed the manual trim wheel was not going to be that effective(impossible to turn) anyways even if they did try it.

We have got to hear the cockpit traces to be sure. We should be able to hear if he extended the Helper Handles as well.
 
morrisond
Posts: 1012
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:46 pm

FluidFlow wrote:
morrisond wrote:

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.



Is it not a bit scary that you last line of defense, if you want to call it that way, when everything else fails, is not working in every scenario?

In general it should be that the less complicated the system the broader it should be usable?

The fact that the back up system is heavily limited is kind of a really bad design because in general when you need the back up system you are already in a bad situation.

If your electirc supply in a hospital fails and the back up generator only works wednesdays its not a great design.

Same should go for manual trim, it should work always no matter how fast you are, it should never fail except you have a structural failure. That should be the design limit and not overspeed.


Well then you would have to redesign most of the control surfaces on all Commercial Aircraft - not many of them are going to be that effective beyond Vmo. There is a reason there is a Vmo limit.
 
marcelh
Posts: 510
Joined: Wed Jun 19, 2013 12:43 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 4:56 pm

morrisond wrote:
FluidFlow wrote:
morrisond wrote:

Only 9 seconds elapsed between the Captains request and the Co-Pilot coming back and saying it didn't work. That doesn't seem like he gave it much of an effort if he was trying the manual wheel. He may have tried just spinning the wheel by hand and not knowing that there was a fold out handle to assist - or why didn't he ask the Pilot to help if he couldn't budge it by himself. In any case even if he tried it properly the overspeed at that point probably made it impossible to use.



Is it not a bit scary that you last line of defense, if you want to call it that way, when everything else fails, is not working in every scenario?

In general it should be that the less complicated the system the broader it should be usable?

The fact that the back up system is heavily limited is kind of a really bad design because in general when you need the back up system you are already in a bad situation.

If your electirc supply in a hospital fails and the back up generator only works wednesdays its not a great design.

Same should go for manual trim, it should work always no matter how fast you are, it should never fail except you have a structural failure. That should be the design limit and not overspeed.


Well then you would have to redesign most of the control surfaces on all Commercial Aircraft - not many of them are going to be that effective beyond Vmo. There is a reason there is a Vmo limit.

Still blaming the pilots?
 
XRAYretired
Posts: 313
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 5:00 pm

kalvado wrote:
spinotter wrote:
SEU wrote:

Great post.

Can I ask, as a 737 pilot. If you were piloting a 737-max simulator and had the exact same issues as the indonesian and ethiopian crash, with the paper manuals and not knowing about MCAS at all, would you be able to "save the plane" to a safe landing every single time? Edit - or do you think the pilots had an impossible chance to save it ?


From someone who knows nothing about a flying a plane, but after reading many comments on the MAX accident threads, it seems to me that the measures which needed to be taken to save JT and ET were just too complicated for ordinary human beings. Does it have to be so extremely complex? You'd like to think that a pilot is the equivalent of the sensory/motor activities of a bird in flight? Do birds have MCAS?

You know the story about old guy who fixes machine by a single stroke of the hammer, and then bills owner as "hammer stroke $1, diagnostics $999"?
My impression is that cockpit situation was similar: fixes were not that complicated, but realization of how to do things right took days and weeks of discussion. Human nature is such that even well-trained procedures can be - and do - get messed up; something that was just read before has little chance of being recalled correctly in a high stress situation. Hindsight is 20/20 or better, so now we know how to act in those situations.
Birds are somewhat different; I would compare MCAS with some things people do while loosing balance on slippery ice. Which is trying to react to a non-normal situation with crude and barely efficient balancing moves.


The picture of flayling arms and legs has cheered my day up. Anyway, birds would probably describes as fully FBW ('W' selection is entirely personal!) wouldn't they?

Ray
 
xmp125a
Posts: 175
Joined: Mon Mar 11, 2019 6:38 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 5:14 pm

bgm wrote:
To be fair, it's probably because a lot of the systems haven't been updated since 1967... I guess at this point we can call it great-grandfathering?


I think this is slowly becoming a problem on its own. Overspeed in ET flight notwithstanding, you do need certain amount of physical power to fly the 737 plane and to adjust the trim with the trim wheel. There have been barely any female pilots in 1967, but now the female pilots are something that has to be expected. Let's wait until someone finds out that the 737 would need different medical examination, which would make sure the pilots possess enough physical force to fly the plane.

As far as I know, the limits on pilot height and weight have never been an issue, and I am pretty sure that historically, the candidates who were too far from median simply were not selected to become pilots. But now there is a ton of regulations which prevent any kind of bias, as long as pilot fulfills the criteria. I am curious whether a very normal female of 1.6 cm and 50 kg would actually be able to handle 737 (MAX or NG). Medical standards only require that pilot comfortably reaches switches and controls, nothing about how much he/she has to bench...

Any thoughts or even data on this?
 
xmp125a
Posts: 175
Joined: Mon Mar 11, 2019 6:38 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Tue May 14, 2019 5:19 pm

7BOEING7 wrote:
14ccKemiskt wrote:
This i probably old news, but the claim that MCAS relied on only one AoA sensor was a deliberate design choice in order to avoid extra training for pilots, since new two-sensor features would require just that, is horrifying.

https://youtu.be/QytfYyHmxtc?t=35m23s


And doesn't make any sense, especially because the FAA doesn't appear to require any sim training for MCAS 2.0 -- see discussion going on around near the end of previous page.


There is no good way to explain away the botched MCAS 1.0. Either:

- Boeing engineers did not interpret the regulations properly or
- Boeing engineers did interpret the regulations properly, but instead of following them, tried to hide recertification-prone design.

Pick one. Both of them are disastrous for the reputation of Boeing's plane design process.

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