OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 8:13 pm

kalvado wrote:
OldAeroGuy wrote:
kalvado wrote:
What you're showing in this example is the rate of force decrease, d^2F/da^2.
I am referring to fig. 7.2 in AC 25-7D where "acceptable" curve (vs speed) shows that exact behavior - decrease of derivative to zero at the edge. You interpret such behavior (vs AoA) as unacceptable.
So where does that come from?


It comes from this:

"8.1.5.3.3 During the approach to the stall, the longitudinal control pull force should
increase continuously as speed is reduced from the trimmed speed to the
onset of stall warning. Below that speed some reduction in longitudinal
control force is acceptable, provided it is not sudden or excessive."

Fig 7.2 addresses an overall airplane speed stability requirement. For small portions of overall speed stability, small slope reversals are acceptable. This is distinct from the stall handling requirements of FAR 25.203 that are quoted above. For stall handling, a reduction in stick force gradient (dV/dF or dAoA/dF) is not acceptable prior to stall warning. As an aside, stall warning is based on AoA, not speed due to stall speed variation with airplane weight.

As a point of reference, AC25-7C was applicable for 737 MAX flight test. AC25-7D was not adopted until 05/04/2018, after 737 MAX certification.

This particular graph is the same in -7C and -7D, so we're good.
I understand what you say, but I fail to see reversal in your numbers. POssibly just a typo?
Again, here is the dataset:
OldAeroGuy wrote:
Case 2 - Fails 25.203
AoA - Stick Force - lbs
4 - 0 (trimmed)
5 - 5
6 - 10
7 - 15
8 - 20
9 - 25
10 - 28
11 - 30 (stall warning)
12 - 32 (stall)
A stall of this type would be indicative of stall starting on the outboard wing. The configuration is stable throughout the stall as stick force must be increased to stall the airplane. The change in gradient after 9 deg AoA causes the airplane to fail 25.203. This is the type of stall handling is typically called "stick lightening". The 737 MAX probably has this type of stall approach behavior and is why MCAS was added.

Force numbers increase across the range of AoA values. What is decreasing, is the slope of change, but not the sign of slope which FAA interprets as acceptable.

Or my eyes are not doing a good job, can you point specific range where you see the problem? 9-10-11-12 is still increase of force situation.

Nothing wrong with your eyes or your analysis of the stick force situation in my example. As I said above: The change in gradient after 9 deg AoA causes the airplane to fail 25.203. The FAA wants a continuous (or increasing) force gradient. The force gradient cannot decrease as my example shows.

The kicker is in this Section:

8.1.5.3.1 The airplane should be trimmed for hands-off flight at a speed 13 percent
to 30 percent above the reference stall speed, with the appropriate power
or thrust setting and configuration. Then, using only the primary
longitudinal control, establish and maintain a deceleration (stall entry rate)
consistent with that specified in § 25.201(c)(1) or (c)(2), as appropriate,
until the airplane is stalled.
Both power/thrust and pilot selectable trim
should remain constant throughout the stall and recovery (to where the
angle-of-attack has decreased to the point of no stall warning).

To maintain a steady deceleration rate, dAoA/dF must remain relatively constant. Otherwise, as the stick force gradient changes, the deceleration rate will not be steady.
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 8:26 pm

kalvado wrote:
I would assume Boeing should be able to get repositioning flight permits for MAX - or not really?
Some MAX flights were mentioned in this thread, and I suspect there should be some room in the desert...

Yes, they can get ferry permits.

Yes, they can move 737s to the desert, or even better yet, https://en.wikipedia.org/wiki/Port_San_Antonio ( SKF ) which has a lot of land that Boeing already leases.

Some have moved to SKF already as noted in this thread.

But it seems Boeing is finding it more effective to move the larger aircraft (787s) rather than smaller ones.

Who knows, maybe they can even accomplish some of the 787 flight test stuff on the trip across to CHS.
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7BOEING7
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 8:59 pm

XRAYretired wrote:

Bear in mind that AOA DISAGREE would have been displayed from 05:39:00 at the latest and in presence of single side stick shaker may have helped conclude that stick shaker was erroneous more quickly. With IAS and ALT DISGREE also probably present, the crew may have been alerted to the possibility of the MCAS problem, looking out for it and acting more quickly when it engaged. They may even have elected to CUT-OUT stab trim prior to MCAS engaging at a push.They may have elected to keep flaps extended and pulled back the thrust. (Although may they still have retracted flaps because it was still not communicated as a condition of MCAS activation in the documents).

The point is that they were not given the chance because the display was not available.

Ray


With IAS DISAGREE and possibly ALT DISAGREE (amber alerts) visible to the flight crew if they were "familiar" with the bulletin, that would have been more than enough to alert them to an MCAS issue -- IMHO the lack of an AOA DISAGREE amber alert has always been a non-event and blown way out of proportion especially if you don't have AOA indicators which most carriers don't have.

As for the AOA DISAGREE being of any value to the LIon AIr maintenance if it was present on the prior flight, IMHO that would have made no difference to their troubleshooting.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 9:17 pm

planecane wrote:
PW100 wrote:
morrisond wrote:

Actually I did point out all the 737 runway excursions as a problem - probably due to over reliance on auto throttle and not knowing what the plane was doing. I've also said about 500 times that this is worldwide problem not just an ET one.
The attempts in the sim were at the point way after the proper procedure should have been applied as has been discussed many times.

Find me a Sim where they put the plane in trim, had control of the airplane and hit the cut off switches and still crashed.


Apparently, the plane somehow did not allow them [ET crew] to put the plane in trim before hitting the cut off switches


This is your theory, not a fact. Please don't present it as a fact. Just as you say it would be a coincidence that the trim always stopped at 2.3 units , I can say it would be a hell of a coincidence that they moved the switches exactly at the moment that it reached 2.3 units so that the stabilizer would move linearly right to that moment but it would have stopped abruptly if they didn't move the switches. Nothing in any schematic shows that the thumb switch command can go away with anything but releasing the thumb switch or moving the cutout switches.


You are absolutely right.

However, This was not aimed at you. Please take into consideration that my post was a reply to (an)other poster(s) who present the opposite as fact: as they state that the crew did not follow proper procedures - by hitting the cut-off switches before the stabilizer was in trim. That also cannot be presented as fact, However, they continue to bring this line over and over and over. And until such time that evidence has been presented for that, I will follow up with the same reply.
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par13del
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 9:22 pm

Revelation wrote:
Yes, they can get ferry permits.

Yes, they can move 737s to the desert, or even better yet, https://en.wikipedia.org/wiki/Port_San_Antonio ( SKF ) which has a lot of land that Boeing already leases.

Some have moved to SKF already as noted in this thread.

But it seems Boeing is finding it more effective to move the larger aircraft (787s) rather than smaller ones.

Who knows, maybe they can even accomplish some of the 787 flight test stuff on the trip across to CHS.

It is known that whatever fix is agreed has to be implemented, keeping as many 737's close should make those a/c easier to fix, I would assume that those flown away are birds to be delivered later, once all cler is given, clear the site of frames first then bring back the others.
It does show the benefit of having 787 production in two locations, now they just have to kick test flights up at the alternate.
 
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 9:25 pm

morrisond wrote:
PW100 wrote:
morrisond wrote:

Actually I did point out all the 737 runway excursions as a problem - probably due to over reliance on auto throttle and not knowing what the plane was doing. I've also said about 500 times that this is worldwide problem not just an ET one.
The attempts in the sim were at the point way after the proper procedure should have been applied as has been discussed many times.

Find me a Sim where they put the plane in trim, had control of the airplane and hit the cut off switches and still crashed.


Apparently, the plane somehow did not allow them [ET crew] to put the plane in trim before hitting the cut off switches


Yes as they left the Thrust levers in TOGA - there was not much they could do until they fixed that.

It reminds me of the 1995 Darwin Award

"The Arizona Highway Patrol were mystified when they came upon a pile of smoldering wreckage embedded in the side of a cliff rising above the road at the apex of a curve. The metal debris resembled the site of an airplane crash, but it turned out to be the vaporized remains of an automobile. The make of the vehicle was unidentifiable at the scene.
The folks in the lab finally figured out what it was, and pieced together the events that led up to its demise.

It seems that a former Air Force sergeant had somehow got hold of a JATO (Jet Assisted Take-Off) unit. JATO units are solid fuel rockets used to give heavy military transport airplanes an extra push for take-off from short airfields.

Dried desert lakebeds are the location of choice for breaking the world ground vehicle speed record. The sergeant took the JATO unit into the Arizona desert and found a long, straight stretch of road. He attached the JATO unit to his car, jumped in, accelerated to a high speed, and fired off the rocket.

The facts, as best as could be determined, are as follows:

The operator was driving a 1967 Chevy Impala. He ignited the JATO unit approximately 3.9 miles from the crash site. This was established by the location of a prominently scorched and melted strip of asphalt. The vehicle quickly reached a speed of between 250 and 300 mph and continued at that speed, under full power, for an additional 20-25 seconds. The soon-to-be pilot experienced G-forces usually reserved for dog-fighting F-14 jocks under full afterburners.

The Chevy remained on the straight highway for approximately 2.6 miles (15-20 seconds) before the driver applied the brakes, completely melting them, blowing the tires, and leaving thick rubber marks on the road surface. The vehicle then became airborne for an additional 1.3 miles, impacted the cliff face at a height of 125 feet, and left a blackened crater 3 feet deep in the rock."


Nice story. I Always like the Darwin award storeys.

However you seem to have missed the fact that the first time MCAS became active, their speed (around 250 kts IAS) was nowhere near Vmo. So I fail to see the relevance to the nice story.

I may be mistaken, perhaps your flight experience can help us out here: would 250 kts IAS be an airspeed where you lose control over a 737 in the same sense as a JATO-powered 1967 Chevy Impala?
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PW100
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sat Jun 08, 2019 9:42 pm

7BOEING7 wrote:
XRAYretired wrote:
. . .


With IAS DISAGREE and possibly ALT DISAGREE (amber alerts) visible to the flight crew if they were "familiar" with the bulletin, that would have been more than enough to alert them to an MCAS issue -- IMHO the lack of an AOA DISAGREE amber alert has always been a non-event and blown way out of proportion especially if you don't have AOA indicators which most carriers don't have.

As for the AOA DISAGREE being of any value to the LIon AIr maintenance if it was present on the prior flight, IMHO that would have made no difference to their troubleshooting.


I agree with you here. I see the AoA thing basically as a red herring. However due to the direct relationship between AoA and MCAS, it is not helping Boeing's case. The press will use anything at this moment. But again, I don't think that would have made a fundamental difference to both accidents. Perhaps circumstantially, but certainly not causal.

Also, in the gazillion pages of this these Anet threads and numerous newspaper articles, we have learned a great deal on MCAS system specifics, background and behaviour. Most of that information was not available to the accident crews, and certainly not learned to them in their MAX training and Flight Operating Manual(s).

And lastly, there were already quite some warnings, alerts, stick shaker etc going off. Throwing yet another alert/warning at them would probably not do much good in helping them in prioritizing their actions.
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OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 1:05 am

DenverTed wrote:

So, 10 - 25.01, 11 - 25.02, 12 -25.03 is within spec?


No, an FAA or OEM AR pilot would consider this as neutrally stable and flunk the configuration per 25.203.

DenverTed wrote:
Or is there some minimum increase in force?


No, this one of the areas in the FAR's that is subject to pilot evaluation. The airplane has to feel "right" in terms of stick force based on its size, control responsiveness, mission requirements, etc.

An Embraer ERJ 170 doesn't to have the same control forces and responses as a 747-8I even though both are certified to FAR Part 25.
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OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 1:09 am

PW100 wrote:
7BOEING7 wrote:
XRAYretired wrote:
. . .


With IAS DISAGREE and possibly ALT DISAGREE (amber alerts) visible to the flight crew if they were "familiar" with the bulletin, that would have been more than enough to alert them to an MCAS issue -- IMHO the lack of an AOA DISAGREE amber alert has always been a non-event and blown way out of proportion especially if you don't have AOA indicators which most carriers don't have.

As for the AOA DISAGREE being of any value to the LIon AIr maintenance if it was present on the prior flight, IMHO that would have made no difference to their troubleshooting.


I agree with you here. I see the AoA thing basically as a red herring. However due to the direct relationship between AoA and MCAS, it is not helping Boeing's case. The press will use anything at this moment. But again, I don't think that would have made a fundamental difference to both accidents. Perhaps circumstantially, but certainly not causal.

Also, in the gazillion pages of this these Anet threads and numerous newspaper articles, we have learned a great deal on MCAS system specifics, background and behaviour. Most of that information was not available to the accident crews, and certainly not learned to them in their MAX training and Flight Operating Manual(s).

And lastly, there were already quite some warnings, alerts, stick shaker etc going off. Throwing yet another alert/warning at them would probably not do much good in helping them in prioritizing their actions.

Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.
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zippy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:24 am

OldAeroGuy wrote:
Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.


The problem isn't so much that not having a working annunciator is a catastrophic problem. The problem is:

- Boeing documented the MAX as having a working AOA disagree annunciator. All of the documentation was written with the assumption that the annunciator would work. If there are situations where it's crucial to know whether or not the AOA data is good, this could easily result in pilots becoming fixated on something that never worked in the first place (a la Eastern). If there were pilots looking for "AOA disagree" as part of a differential diagnosis, you could easily run into pilots not recognizing a predatory MCAS engagement (much like the mixed interpretations of what runway stabilizer trim actually is).

- Boeing discovered the annunciator didn't work. This means they either didn't test the PFDs in every configuration they planned to sell them in or it means that Boeing QA is pretty terrible. I'm not intimately familiar with what processes are required in safety critical aerospace software, but this could be problematic for Boeing going forward as non-compliance reduces their credibility and raises the question of what other, more significant, things did Boeing overlook?

- Boeing explicitly hid the non-op annunciator from the FAA. Agreed that the annunciator on its own doesn't seem that important. So why lie about it? If Boeing is willing to lie about something seemingly so minor, what other big things will they go to the ends of the earth to hide?
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:50 am

zippy wrote:
OldAeroGuy wrote:
Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.


The problem isn't so much that not having a working annunciator is a catastrophic problem.

+1. The problem is that it is yet another thing that Boeing did that defies reason.
 
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7BOEING7
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 4:07 am

zippy wrote:
OldAeroGuy wrote:
Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.


The problem isn't so much that not having a working annunciator is a catastrophic problem. The problem is:

- Boeing documented the MAX as having a working AOA disagree annunciator. All of the documentation was written with the assumption that the annunciator would work. If there are situations where it's crucial to know whether or not the AOA data is good, this could easily result in pilots becoming fixated on something that never worked in the first place (a la Eastern). If there were pilots looking for "AOA disagree" as part of a differential diagnosis, you could easily run into pilots not recognizing a predatory MCAS engagement (much like the mixed interpretations of what runway stabilizer trim actually is).


There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't). When you go to the NNC there are no procedures to follow, it just advises you that you may have an IAS DISAGREE and /or an ALT DISAGREE amber alert. The IAS DISAGREE alert would have been immediately noticed by the pilot flying requiring execution of the AIRSPEED UNRELIABLE NNC and the appropriate memory items. You're not going to be looking for an AOA DISAGREE as part of a differential diagnosis.

zippy wrote:
- Boeing discovered the annunciator didn't work. This means they either didn't test the PFDs in every configuration they planned to sell them in or it means that Boeing QA is pretty terrible. I'm not intimately familiar with what processes are required in safety critical aerospace software, but this could be problematic for Boeing going forward as non-compliance reduces their credibility and raises the question of what other, more significant, things did Boeing overlook?


They screwed up and took a vendors word that it was park of he package -- no argument there.

zippy wrote:
- Boeing explicitly hid the non-op annunciator from the FAA. Agreed that the annunciator on its own doesn't seem that important. So why lie about it? If Boeing is willing to lie about something seemingly so minor, what other big things will they go to the ends of the earth to hide?


They didn't hide anything. They went thru the process and determined the airplane was perfectly safe without it -- which it is -- and planned on installing it at a later time. Probably with the next scheduled software roll.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 4:27 am

Add up all those little things that by themselves don't matter and you reach the threshold of a major problem
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:58 am

https://www.bbc.com/news/business-48461110

So Chris Brady (author of 737 technical guide and pilot) is wrong saying the disagree light would be first warning something is wrong and could have helped save the plane?

His view is wrong and can be discounted can it?

No point calling him as a witness in court?
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 8:21 am

https://www.thedailybeast.com/how-boein ... x-disaster

This article today highlights the irony that over the years no plane has made Boeing more money than 737 but now no plane has jeapordised Boeing's reputation more than 737
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 8:36 am

7BOEING7 wrote:
zippy wrote:
OldAeroGuy wrote:
Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.


The problem isn't so much that not having a working annunciator is a catastrophic problem. The problem is:

- Boeing documented the MAX as having a working AOA disagree annunciator. All of the documentation was written with the assumption that the annunciator would work. If there are situations where it's crucial to know whether or not the AOA data is good, this could easily result in pilots becoming fixated on something that never worked in the first place (a la Eastern). If there were pilots looking for "AOA disagree" as part of a differential diagnosis, you could easily run into pilots not recognizing a predatory MCAS engagement (much like the mixed interpretations of what runway stabilizer trim actually is).


There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't). When you go to the NNC there are no procedures to follow, it just advises you that you may have an IAS DISAGREE and /or an ALT DISAGREE amber alert. The IAS DISAGREE alert would have been immediately noticed by the pilot flying requiring execution of the AIRSPEED UNRELIABLE NNC and the appropriate memory items. You're not going to be looking for an AOA DISAGREE as part of a differential diagnosis.

zippy wrote:
- Boeing discovered the annunciator didn't work. This means they either didn't test the PFDs in every configuration they planned to sell them in or it means that Boeing QA is pretty terrible. I'm not intimately familiar with what processes are required in safety critical aerospace software, but this could be problematic for Boeing going forward as non-compliance reduces their credibility and raises the question of what other, more significant, things did Boeing overlook?


They screwed up and took a vendors word that it was park of he package -- no argument there.

zippy wrote:
- Boeing explicitly hid the non-op annunciator from the FAA. Agreed that the annunciator on its own doesn't seem that important. So why lie about it? If Boeing is willing to lie about something seemingly so minor, what other big things will they go to the ends of the earth to hide?


They didn't hide anything. They went thru the process and determined the airplane was perfectly safe without it -- which it is -- and planned on installing it at a later time. Probably with the next scheduled software roll.


The alarm that points out a failure in the sensor that triggers MCAS, is to be completely disregarded? It does not matter if this alarm is active or not? Tell more of this jokes.

What due process includes not telling the FAA and customers about a defect?

Knowing that the alarm, that is standard and described in the manuals, is inactive and not telling either the FAA nor the customers about it for 13 month, is not hiding the defect? The question is rather, why did Boeing hide that an alarm was not active. In what dream world are you operating?
 
sillystrings
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 12:16 pm

7BOEING7 wrote:
zippy wrote:
OldAeroGuy wrote:
Even CNN's Richard Quest has described not having the "AOA DISAGREE" Alert issue as a red herring.


The problem isn't so much that not having a working annunciator is a catastrophic problem. The problem is:

- Boeing documented the MAX as having a working AOA disagree annunciator. All of the documentation was written with the assumption that the annunciator would work. If there are situations where it's crucial to know whether or not the AOA data is good, this could easily result in pilots becoming fixated on something that never worked in the first place (a la Eastern). If there were pilots looking for "AOA disagree" as part of a differential diagnosis, you could easily run into pilots not recognizing a predatory MCAS engagement (much like the mixed interpretations of what runway stabilizer trim actually is).


There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't). When you go to the NNC there are no procedures to follow, it just advises you that you may have an IAS DISAGREE and /or an ALT DISAGREE amber alert. The IAS DISAGREE alert would have been immediately noticed by the pilot flying requiring execution of the AIRSPEED UNRELIABLE NNC and the appropriate memory items. You're not going to be looking for an AOA DISAGREE as part of a differential diagnosis.

zippy wrote:
- Boeing discovered the annunciator didn't work. This means they either didn't test the PFDs in every configuration they planned to sell them in or it means that Boeing QA is pretty terrible. I'm not intimately familiar with what processes are required in safety critical aerospace software, but this could be problematic for Boeing going forward as non-compliance reduces their credibility and raises the question of what other, more significant, things did Boeing overlook?


They screwed up and took a vendors word that it was park of he package -- no argument there.

zippy wrote:
- Boeing explicitly hid the non-op annunciator from the FAA. Agreed that the annunciator on its own doesn't seem that important. So why lie about it? If Boeing is willing to lie about something seemingly so minor, what other big things will they go to the ends of the earth to hide?


They didn't hide anything. They went thru the process and determined the airplane was perfectly safe without it -- which it is -- and planned on installing it at a later time. Probably with the next scheduled software roll.


The TBC-19 NNC subject line states: "Uncommanded Nose Down Stabilizer Trim Due to Erroneous Angle of Attack (AOA) During Manual Flight Only".

Wouldn't it be logical to look for AOA DISAGREE if one suspects MCAS is misfiring?
 
sillystrings
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 12:51 pm

7BOEING7 wrote:
There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't). When you go to the NNC there are no procedures to follow, it just advises you that you may have an IAS DISAGREE and /or an ALT DISAGREE amber alert. The IAS DISAGREE alert would have been immediately noticed by the pilot flying requiring execution of the AIRSPEED UNRELIABLE NNC and the appropriate memory items. You're not going to be looking for an AOA DISAGREE as part of a differential diagnosis.

This certainly is valid for NG. If a birds strike takes out an AOA vane on NG, nothing much happens and 737 pilots know that. That's not the case with the MAX. I think this was the blind spot for Boeing.
 
sillystrings
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 12:59 pm

7BOEING7 wrote:
They didn't hide anything. They went thru the process and determined the airplane was perfectly safe without it -- which it is -- and planned on installing it at a later time. Probably with the next scheduled software roll.

And one final point. Boeing also determined at one point that a trust reverser deployment in flight was recoverable. Until it wasn't. So much for determinations...
 
OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 1:01 pm

Interested wrote:
https://www.bbc.com/news/business-48461110

So Chris Brady (author of 737 technical guide and pilot) is wrong saying the disagree light would be first warning something is wrong and could have helped save the plane?

His view is wrong and can be discounted can it?

No point calling him as a witness in court?


Mr Brady is very knowledgeable on the 737 but he publishes his 737 technical guide as a private citizen, not associated with Boeing. If he testifies in court, there is a counter argument to the statement you attribute to him.

Mr Brady appears to be incorrect when he says an AOA Disagree alert would have been the first indication that something was wrong. There were several other indications something was amiss with AoA indication.

737 MAX AD 2018-23-51 lists these symptoms for potential erroneous MCAS operation:

    Continuous or intermittent stick shaker on the affected side only
    Minimum speed bar (red and black) on the affected side only
    Increasing nose down control forces
    IAS DISAGREE alert
    ALT DISAGREE alert
    AOA DISAGREE alert (if the option is installed)
    FEEL DIFF PRESS light
    Auto pilot may disengage
    Inability to engage the autopilot

From the ET302 preliminary report, we know at least 3 or 4 (shown in bold) of these symptoms were present at Flaps 5, before erroneous MCAS operation began. Only the ALT DISAGREE alert is in doubt. Others may have been present but are not apparent in the report.

It is difficult to see how adding the AOA DISAGREE alert would have been of material value. As 7BOEING7 says, there is no NNC associated with AOA DISAGREE, it only refers you to NNC's that the other symptoms would have also lead you to. There is no evidence to date that these NNC's were correctly performed by the ET302 crew.

PS I didn't find any statement from Mr Brady in the video link you posted.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Interested
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 2:55 pm

And Boeing have admitted their mistakes above

Yes you can have people disagree and agree with Mr Brady but as author of a technical guide for 737s and as a pilot then he's going to have plenty of credibility in a court

Any help the indicator could give has to be a factor in whether the pilots could have dealt better with the situation they were in

Surely that's a given?


I'm still waiting for someone to tell me why the max 737 before it was grounded wasn't the very definition of a deathtrap?
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:07 pm

Interested wrote:
And Boeing have admitted their mistakes above

Yes you can have people disagree and agree with Mr Brady but as author of a technical guide for 737s and as a pilot then he's going to have plenty of credibility in a court

Any help the indicator could give has to be a factor in whether the pilots could have dealt better with the situation they were in

Surely that's a given?


I'm still waiting for someone to tell me why the max 737 before it was grounded wasn't the very definition of a deathtrap?

It wasn't a death trap because, as evidenced by Lion Air 043, it was possible to save the aircraft. Spare me the "it needed a 3rd pilot" stuff. It needed a pilot that recognized the situation and knew what to do. That same 3rd pilot would likely have had the same recognition if he was one of two pilots.

A plane that is a death trap would have a design issue that causes an unrecoverable failure. If MCAS commanded full nose down trim and also caused the jackscrew to seize in that position, then it would be a death trap.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:08 pm

7BOEING7 wrote:
XRAYretired wrote:

Bear in mind that AOA DISAGREE would have been displayed from 05:39:00 at the latest and in presence of single side stick shaker may have helped conclude that stick shaker was erroneous more quickly. With IAS and ALT DISGREE also probably present, the crew may have been alerted to the possibility of the MCAS problem, looking out for it and acting more quickly when it engaged. They may even have elected to CUT-OUT stab trim prior to MCAS engaging at a push.They may have elected to keep flaps extended and pulled back the thrust. (Although may they still have retracted flaps because it was still not communicated as a condition of MCAS activation in the documents).

The point is that they were not given the chance because the display was not available.

Ray


With IAS DISAGREE and possibly ALT DISAGREE (amber alerts) visible to the flight crew if they were "familiar" with the bulletin, that would have been more than enough to alert them to an MCAS issue -- IMHO the lack of an AOA DISAGREE amber alert has always been a non-event and blown way out of proportion especially if you don't have AOA indicators which most carriers don't have.

As for the AOA DISAGREE being of any value to the LIon AIr maintenance if it was present on the prior flight, IMHO that would have made no difference to their troubleshooting.


Well, since you mention Lion AIr.

Maintenance Log has
:
28 October 2018 Denpasar to Jakarta (JT043)

IAS and ALT Disagree shown after take off
(Refer to IFIM task 34-20-00810-801 REV 15 June 2018). Performed flushing Left Pitot Air Data Module (ADM) and static ADM. Operation test on ground found satisfied.

feel diff press light illuminate
Refer IFIM 27-31-00-810-803 Rev 15 June 2018, performed cleaned electrical connector plug of elevator feel computer carried out. test on ground found OK.

So, if the next line was AOA DIAGREE after take off, the MX response would be - Did nowt cos this is a pointless and irrelevant alert message and has nothing to do with the other alerts mentioned above?

Ray
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:10 pm

mjoelnir wrote:
7BOEING7 wrote:
There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't). When you go to the NNC there are no procedures to follow, it just advises you that you may have an IAS DISAGREE and /or an ALT DISAGREE amber alert. The IAS DISAGREE alert would have been immediately noticed by the pilot flying requiring execution of the AIRSPEED UNRELIABLE NNC and the appropriate memory items. You're not going to be looking for an AOA DISAGREE as part of a differential diagnosis.

The alarm that points out a failure in the sensor that triggers MCAS, is to be completely disregarded? It does not matter if this alarm is active or not? Tell more of this jokes.

What is the logical path that translated "it is not crucial" into "it is to be completely disregarded"?

Maybe a statement such as "AOA DISAGREE" is redundant considering the presence of "IAS DISAGREE" and "ALT DISAGREE" are present would sink in better?

Maybe this post should be read more carefully, considering it comes from someone who has a lot of 737 time which most of us here do not.

mjoelnir wrote:
7BOEING7 wrote:
They didn't hide anything. They went thru the process and determined the airplane was perfectly safe without it -- which it is -- and planned on installing it at a later time. Probably with the next scheduled software roll.

What due process includes not telling the FAA and customers about a defect?

Clearly you don't work in engineering. Defects get prioritized all the time based on professional judgement. Some things get fixed immediately, others get deferred to the next software roll. It would be very unusual for a customer or even a regulator to have full access to the engineering bug reporting system.
Last edited by Revelation on Sun Jun 09, 2019 3:13 pm, edited 1 time in total.
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OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:12 pm

Interested wrote:
Any help the indicator could give has to be a factor in whether the pilots could have dealt better with the situation they were in

Surely that's a given?


Not necessarily.

The ET302 crew appears to have been overloaded by the indications that were available on the flight deck. Another indication that leads you back to the indications that were already present may have only increased the overload.
Last edited by OldAeroGuy on Sun Jun 09, 2019 3:16 pm, edited 1 time in total.
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Interested
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:13 pm

planecane wrote:
Interested wrote:
And Boeing have admitted their mistakes above

Yes you can have people disagree and agree with Mr Brady but as author of a technical guide for 737s and as a pilot then he's going to have plenty of credibility in a court

Any help the indicator could give has to be a factor in whether the pilots could have dealt better with the situation they were in

Surely that's a given?


I'm still waiting for someone to tell me why the max 737 before it was grounded wasn't the very definition of a deathtrap?

It wasn't a death trap because, as evidenced by Lion Air 043, it was possible to save the aircraft. Spare me the "it needed a 3rd pilot" stuff. It needed a pilot that recognized the situation and knew what to do. That same 3rd pilot would likely have had the same recognition if he was one of two pilots.

A plane that is a death trap would have a design issue that causes an unrecoverable failure. If MCAS commanded full nose down trim and also caused the jackscrew to seize in that position, then it would be a death trap.


Deathtrap is an object/vehicle with the potential to be very dangerous

Let's not pretend the Max 737 wasnt a vehicle with the potential to be very dangerous

It's caught out two sets of pilots with disastrous results

And that's why it's grounded now and for some time to come

It doesn't have to crash every time to be a deathtrap

It' didn't "trap" the first lion pilots (albeit they needed help from a third pilot)
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:15 pm

In some actual news, AA has extended MAX cancellations from 8/19 to 9/3, 2 additional weeks.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:17 pm

OldAeroGuy wrote:
Interested wrote:
Any help the indicator could give has to be a factor in whether the pilots could have dealt better with the situation they were in

Surely that's a given?


Not necessarily.

The ET302 crew appears to have been overloaded by the indications that where available on the flight deck. Another indication that leads you back to the indications that were already present may have only increased the overload.


They deliberately created a defective sensor to prevent pilot overload. Same reason they didn't tell the test pilots who were writing the manual for Max about MCAS

Both things they've since admitted they were at fault for

Why are you defending and excusing something Boeing now accept was a failing on their part?
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:20 pm

7BOEING7 wrote:
There are no situations where the AOA DISAGREE amber alert is crucial even if you have purchased the optional AOA indicator (which the majority of airlines haven't).


So Boeing put it on the display for no reason, right?
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:44 pm

planecane wrote:
In some actual news, AA has extended MAX cancellations from 8/19 to 9/3, 2 additional weeks.

I'm not sure if it's news, but it is relevant to the legal investigations kicked off based on the MCAS tragic failures:


In addition to describing the lawyers and their "high powered" nature, it describes a lot of the challenges they face.

The part I found most interesting was:

“As a general rule, the issue in a white-collar case, unlike a traditional street-crime case, is whether a crime was committed as opposed to who committed the crime,” said John Wolfe, a longtime criminal defense attorney in Seattle.

“As such, a primary goal of a white-collar criminal defense lawyer is persuading the government that her client did not commit a crime, in order to avoid an indictment,” Wolfe said. “Generally speaking, once an indictment is returned, it becomes very difficult for defense counsel to persuade the government to dismiss.”

Defense lawyers must conduct an investigation that “mirrors or nearly parallels the investigation being conducted by the government,” he said, calling it a “race against time to develop the necessary facts and law which demonstrate that no crime was committed.”

I have to wonder if Boeing is just hiring these "high powered" assets if they aren't way behind the curve in kicking off their own fact gathering and case building, especially since the article makes it clear that it's important for Boeing to nip this in the bud and try to avoid indictment altogether.

Yet the article says "the investigation is only in its early stages" which I find kind of surprising.

And:

In the 737 investigation, prosecutors in the Justice Department’s Fraud Section will be looking for any evidence of the “hallmarks of classic fraud” — misrepresentation to federal regulators and customers, said a person familiar with their work who asked not to be named.

Then it goes on to mirror this investigation to the infamous VW Dieselgate investigation.

This mirrors some of my earlier posts: things can be dealt with if they were honest engineering miscalculations or bad engineering judgements or even excessive influence by management, but God help them if the FBI/DoJ finds the kind of outright fraud that they found in the VW Dieselgate case.
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:50 pm

planecane wrote:
In some actual news, AA has extended MAX cancellations from 8/19 to 9/3, 2 additional weeks.


Can you provide a link?
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:53 pm

SQ22 wrote:
planecane wrote:
In some actual news, AA has extended MAX cancellations from 8/19 to 9/3, 2 additional weeks.


Can you provide a link?


https://www.foxbusiness.com/industrials/american-airlines-extends-boeing-737-max-flight-cancellations-through-early-september
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 3:56 pm

Revelation wrote:
In the 737 investigation, prosecutors in the Justice Department’s Fraud Section will be looking for any evidence of the “hallmarks of classic fraud” — misrepresentation to federal regulators and customers, said a person familiar with their work who asked not to be named.

Then it goes on to mirror this investigation to the infamous VW Dieselgate investigation.

This mirrors some of my earlier posts: things can be dealt with if they were honest engineering miscalculations or bad engineering judgements or even excessive influence by management, but God help them if the FBI/DoJ finds the kind of outright fraud that they found in the VW Dieselgate case.


I hope some over the top posters take notice that the investigation is about FRAUD, not murder.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 4:35 pm

planecane wrote:
I hope some over the top posters take notice that the investigation is about FRAUD, not murder.

With the result of the fraud leading to deaths. No one has an idea of what avenues the feds are investigating related to Boeing's actions. The media reports if what Boeing knew, when they knew it, and more importantly the lack of actions opens up Boeing to several avenues of possibly illegal and criminal activity at multiple levels of the firm. They knew systems they sold as working (cockpit warning lights) were not working yet they didn't alert feds nor their customers about not fulfilling contractual requirements.

This leads me to the question I do have with international regulators stating they will approve Max operations on their own timeframe. Usually FAA and EASA accept each others certifications. If FAA approves flights before international regulators, can code share partners sell flights that connect to flights on a Max while Max is awaiting certifications in home market? Ie can Lufthansa sell a code share on a United flight that has Max operating it even though EASA has not certified the Max? First time the lack of a coordinated certification would come into play in international aviation.
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 5:06 pm

Revelation wrote:
Defects get prioritized all the time based on professional judgement. Some things get fixed immediately, others get deferred to the next software roll. It would be very unusual for a customer or even a regulator to have full access to the engineering bug reporting system.


This is more of a missing feature than defect. I think this is big enough to warrant immediate notification of customers, so that THEY could prioritize the fix. Just because some minor flaws here and their can be deem unimportant, does not mean this was handled properly. The mere fact that they notified FAA now and moved to rectify the problem now, indicates they are reconsidering their own decision to delay the fix.

For gods sake, the CEO admitted it was a mistake. And you still insist that all is kosher.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 5:09 pm

planecane wrote:
I hope some over the top posters take notice that the investigation is about FRAUD, not murder.

Indeed, killing/murdering is about as serious a charge as we have, and it's pathetic how casually some throw it around when there is no proof of it, nor even a formal charge of it.

Personally I wish the mods would ban such serious charges made without any proof nor even formal charges as they serve no purpose other than to incite other members and/or inflame the discussion.

jh380 wrote:
With the result of the fraud leading to deaths. No one has an idea of what avenues the feds are investigating related to Boeing's actions. The media reports if what Boeing knew, when they knew it, and more importantly the lack of actions opens up Boeing to several avenues of possibly illegal and criminal activity at multiple levels of the firm. They knew systems they sold as working (cockpit warning lights) were not working yet they didn't alert feds nor their customers about not fulfilling contractual requirements.

I don't know what point you are trying to make, but it reads to me as if you are saying serious criminal charges can be made due to accidentally not providing largely redundant warning text.

ArgentoSystems wrote:
Revelation wrote:
Defects get prioritized all the time based on professional judgement. Some things get fixed immediately, others get deferred to the next software roll. It would be very unusual for a customer or even a regulator to have full access to the engineering bug reporting system.


This is more of a missing feature than defect. I think this is big enough to warrant immediate notification of customers, so that THEY could prioritize the fix. Just because some minor flaws here and their can be deem unimportant, does not mean this was handled properly. The mere fact that they notified FAA now and moved to rectify the problem now, indicates they are reconsidering their own decision to delay the fix.

For gods sake, the CEO admitted it was a mistake. And you still insist that all is kosher.

Context, my friend.

The other member accused Boeing of "hiding" i.e. intentional concealment, when we are being told it was a misjudgement that they now regret:

A Boeing spokesman said that based on a safety review, the company had originally planned to fix the cockpit warning when it began delivering a new, larger model of the Max to airlines in 2020.

We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again,” said the spokesman, Gordon Johndroe.

Ref: https://www.latimes.com/business/la-fi- ... story.html

... and no one has offered evidence of intentional concealment.

Yet if you read the reference:

Boeing and the head of the FAA both say the alert is not critical for safety. Boeing says all its planes, including the Max, give pilots all the flight information — including speed, altitude and engine performance — that they need to fly safely.

(Edit: fix redundant post, add reference...)
Last edited by Revelation on Sun Jun 09, 2019 5:27 pm, edited 2 times in total.
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 5:37 pm

jh380 wrote:
planecane wrote:
I hope some over the top posters take notice that the investigation is about FRAUD, not murder.

With the result of the fraud leading to deaths. No one has an idea of what avenues the feds are investigating related to Boeing's actions. The media reports if what Boeing knew, when they knew it, and more importantly the lack of actions opens up Boeing to several avenues of possibly illegal and criminal activity at multiple levels of the firm. They knew systems they sold as working (cockpit warning lights) were not working yet they didn't alert feds nor their customers about not fulfilling contractual requirements.

This leads me to the question I do have with international regulators stating they will approve Max operations on their own timeframe. Usually FAA and EASA accept each others certifications. If FAA approves flights before international regulators, can code share partners sell flights that connect to flights on a Max while Max is awaiting certifications in home market? Ie can Lufthansa sell a code share on a United flight that has Max operating it even though EASA has not certified the Max? First time the lack of a coordinated certification would come into play in international aviation.


I don’t think it would be beneficial to anyone to deviate now from past practices of the FAA and EASA accepting each other’s certifications. Not with Captain tariffs in the White House. Airbus depends heavily on the US market.


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OldAeroGuy
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 5:49 pm

Interested wrote:

They deliberately created a defective sensor to prevent pilot overload. Same reason they didn't tell the test pilots who were writing the manual for Max about MCAS


No, Boeing did not create a defective sensor to prevent pilot overload.

Your logic path strains a rational thought process.
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Interested
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 5:56 pm

OldAeroGuy wrote:
Interested wrote:

They deliberately created a defective sensor to prevent pilot overload. Same reason they didn't tell the test pilots who were writing the manual for Max about MCAS


No, Boeing did not create a defective sensor to prevent pilot overload.

Your logic path strains a rational thought process.


I was being sarcastic.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:03 pm

STT757 wrote:

I don’t think it would be beneficial to anyone to deviate now from past practices of the FAA and EASA accepting each other’s certifications. Not with Captain tariffs in the White House. Airbus depends heavily on the US market.


This seriously sounds like a threat - Do as the US says or we will cause problems. Not the way to resolve this situation.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:19 pm

Interested wrote:
https://www.bbc.com/news/business-48461110

So Chris Brady (author of 737 technical guide and pilot) is wrong saying the disagree light would be first warning something is wrong and could have helped save the plane?

His view is wrong and can be discounted can it?

No point calling him as a witness in court?


Chris Brady is providing his opinion, that's all it is. His opinion is just as valid as any of the other thousands of 737 rated pilots out there but that doesn't make him an expert. He's got a side job selling a book called "The Boeing 737 Technical Guide" which is compiled of information he has taken from Boeing 737 publications and other information provided by people in the field but that doesn't make him an expert either. IMHO no attorney with any intelligence would call him to testify in court relative to the AOA DISAGREE amber alert message. He sells more books with headlines which IMHO he wouldn't get if he felt the missing AOA DISAGREE alert was no big deal.
Last edited by 7BOEING7 on Sun Jun 09, 2019 6:46 pm, edited 1 time in total.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:42 pm

planecane wrote:
SQ22 wrote:
planecane wrote:
In some actual news, AA has extended MAX cancellations from 8/19 to 9/3, 2 additional weeks.


Can you provide a link?


https://www.foxbusiness.com/industrials/american-airlines-extends-boeing-737-max-flight-cancellations-through-early-september


The recertification seem to drag on forever. So much for this magical "quick fix".
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:48 pm

7BOEING7 wrote:
Interested wrote:
https://www.bbc.com/news/business-48461110

So Chris Brady (author of 737 technical guide and pilot) is wrong saying the disagree light would be first warning something is wrong and could have helped save the plane?

His view is wrong and can be discounted can it?

No point calling him as a witness in court?


Chris Brady is providing his opinion, that's all it is. His opinion is just as valid as any of the other thousands of 737 rated pilots out there but that doesn't make him an expert. He's got a side job selling a book called "The Boeing 737 Technical Guide" which is compiled of information he has taken from Boeing 737 publications and other information provided by people in the field but that doesn't make him an ext either. IMHO no attorney with any intelligence would call him to testify in court relative to the AOA DISAGREE amber alert message. He sells more books with headlines which IMHO he wouldn't get if he felt the missing AOA DISAGREE alert was no big deal.


My point is that the Boeing defenders on here have all said the disagree lights would have made no difference to the safety of the plane

As an outsider looking in I find that hard to believe

The fact a pilot and author of a 737 tech guide says he believes the disagree light would likely have prevented the crashes is very telling for me

He's disagreeing with Boeing and disagreeing with posters on here

And so I'm pointing it out.

So we get a balanced argument on here and not just the one Boeing would like us to read
 
morrisond
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 6:57 pm

Interested wrote:
7BOEING7 wrote:
Interested wrote:
https://www.bbc.com/news/business-48461110

So Chris Brady (author of 737 technical guide and pilot) is wrong saying the disagree light would be first warning something is wrong and could have helped save the plane?

His view is wrong and can be discounted can it?

No point calling him as a witness in court?


Chris Brady is providing his opinion, that's all it is. His opinion is just as valid as any of the other thousands of 737 rated pilots out there but that doesn't make him an expert. He's got a side job selling a book called "The Boeing 737 Technical Guide" which is compiled of information he has taken from Boeing 737 publications and other information provided by people in the field but that doesn't make him an ext either. IMHO no attorney with any intelligence would call him to testify in court relative to the AOA DISAGREE amber alert message. He sells more books with headlines which IMHO he wouldn't get if he felt the missing AOA DISAGREE alert was no big deal.


My point is that the Boeing defenders on here have all said the disagree lights would have made no difference to the safety of the plane

As an outsider looking in I find that hard to believe

The fact a pilot and author of a 737 tech guide says he believes the disagree light would likely have prevented the crashes is very telling for me

He's disagreeing with Boeing and disagreeing with posters on here

And so I'm pointing it out.

So we get a balanced argument on here and not just the one Boeing would like us to read


He did not say likely - he said "Might have" there is a big difference. Then on ET you have the perpetual problem of TOGA thrust.

If ET had the light - how would that have changed what they did?
 
jh380
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 7:29 pm

STT757 wrote:

I don’t think it would be beneficial to anyone to deviate now from past practices of the FAA and EASA accepting each other’s certifications. Not with Captain tariffs in the White House. Airbus depends heavily on the US market.



Agreed, but before the Max issues it was unknown the amount of self certification that Boeing was allowed to do. with the Max there will be changes ongoing for sure to ensure a 3rd party reviews independently plans changes.
With the Max though, we have already heard EASA and CAA state they will independently review the air worthiness of the Max and can institute their own requirements.
Behind the scenes I FAA will balance Boeing and their "its good with no other changes" and other regulators demands to be in sync. But if timelines are off by months would FAA hold off certification to ensure continuity of the certification system that you exists?
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 7:37 pm

StTim wrote:
STT757 wrote:

I don’t think it would be beneficial to anyone to deviate now from past practices of the FAA and EASA accepting each other’s certifications. Not with Captain tariffs in the White House. Airbus depends heavily on the US market.


This seriously sounds like a threat - Do as the US says or we will cause problems. Not the way to resolve this situation.


That was my point. Look at how this administration deals with diplomacy.


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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 7:39 pm

Of course the disagree light fuss is a Red Herring.

You have to ask yourself why Boeing is so quick to accept blame for the non-functioning AoA disagree light. They know that they easily can prove that the light would have made little difference in the two crashes and hence they'd rather have people talking about that than the real problem.

And they kind of succed, both the media along with a big part of this thread is now focusing on that instead of what should really be focused on: Why they released MCAS only connected to a single AoA sensor. Why they did that might be the single most important part of this story and if the paper trail shows that it was because what the whistleblower in 60 minutes Australia claims, then Boeing could be in really big trouble.
 
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Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 7:55 pm

morrisond wrote:
Interested wrote:
7BOEING7 wrote:

Chris Brady is providing his opinion, that's all it is. His opinion is just as valid as any of the other thousands of 737 rated pilots out there but that doesn't make him an expert. He's got a side job selling a book called "The Boeing 737 Technical Guide" which is compiled of information he has taken from Boeing 737 publications and other information provided by people in the field but that doesn't make him an ext either. IMHO no attorney with any intelligence would call him to testify in court relative to the AOA DISAGREE amber alert message. He sells more books with headlines which IMHO he wouldn't get if he felt the missing AOA DISAGREE alert was no big deal.


My point is that the Boeing defenders on here have all said the disagree lights would have made no difference to the safety of the plane

As an outsider looking in I find that hard to believe

The fact a pilot and author of a 737 tech guide says he believes the disagree light would likely have prevented the crashes is very telling for me

He's disagreeing with Boeing and disagreeing with posters on here

And so I'm pointing it out.

So we get a balanced argument on here and not just the one Boeing would like us to read


He did not say likely - he said "Might have" there is a big difference. Then on ET you have the perpetual problem of TOGA thrust.

If ET had the light - how would that have changed what they did?


Why dispute what he is quoted as saying and then get it wrong when the quote is readily available?
https://www.bbc.co.uk/news/business-48461110

This is the Chris Brady Quote-
Chris Brady, a pilot and author of The Boeing 737 Technical Guide said: "I'm fairly confident that the Ethiopian Airlines flight probably would not have crashed if they had had the AOA disagree alert" on the aircraft.

This is the reporters appreciation of his interview-
Mr Brady believes that if there had been an alert warning light showing that the AOA sensors were giving different readings, then the pilots might have followed an emergency procedure at an earlier point in the doomed flight.

These are a few possibilities I posted earlier, perhaps you missed them-
AOA DISAGREE would have been displayed from 05:39:00 (a full minute before MCAS activation), at the latest, and in presence of single side stick shaker may have helped conclude that stick shaker was erroneous more quickly. With IAS and ALT DISGREE also probably present, the crew may have been alerted to the possibility of the MCAS problem, looking out for it and acting more quickly when it engaged. They may even have elected to CUT-OUT stab trim prior to MCAS engaging, at a push. They may have elected to keep flaps extended and pulled back the thrust. (Although may they still have retracted flaps because it was still not communicated as a condition of MCAS activation in the documents).

The point is that they were not given the chance because the display was not available.

Ray
 
User avatar
aerolimani
Posts: 1134
Joined: Tue Jun 18, 2013 5:46 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 8:02 pm

XRAYretired wrote:
morrisond wrote:
Interested wrote:

My point is that the Boeing defenders on here have all said the disagree lights would have made no difference to the safety of the plane

As an outsider looking in I find that hard to believe

The fact a pilot and author of a 737 tech guide says he believes the disagree light would likely have prevented the crashes is very telling for me

He's disagreeing with Boeing and disagreeing with posters on here

And so I'm pointing it out.

So we get a balanced argument on here and not just the one Boeing would like us to read


He did not say likely - he said "Might have" there is a big difference. Then on ET you have the perpetual problem of TOGA thrust.

If ET had the light - how would that have changed what they did?


Why dispute what he is quoted as saying and then get it wrong when the quote is readily available?
https://www.bbc.co.uk/news/business-48461110

This is the Chris Brady Quote-
Chris Brady, a pilot and author of The Boeing 737 Technical Guide said: "I'm fairly confident that the Ethiopian Airlines flight probably would not have crashed if they had had the AOA disagree alert" on the aircraft.

This is the reporters appreciation of his interview-
Mr Brady believes that if there had been an alert warning light showing that the AOA sensors were giving different readings, then the pilots might have followed an emergency procedure at an earlier point in the doomed flight.

These are a few possibilities I posted earlier, perhaps you missed them-
AOA DISAGREE would have been displayed from 05:39:00 (a full minute before MCAS activation), at the latest, and in presence of single side stick shaker may have helped conclude that stick shaker was erroneous more quickly. With IAS and ALT DISGREE also probably present, the crew may have been alerted to the possibility of the MCAS problem, looking out for it and acting more quickly when it engaged. They may even have elected to CUT-OUT stab trim prior to MCAS engaging, at a push. They may have elected to keep flaps extended and pulled back the thrust. (Although may they still have retracted flaps because it was still not communicated as a condition of MCAS activation in the documents).

The point is that they were not given the chance because the display was not available.

Ray

Short version: they might have hit stab trim cutout before MCAS activated, and before the aircraft was out of trim.
 
planecane
Posts: 1041
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounded Worldwide Q2 2019

Sun Jun 09, 2019 8:09 pm

aerolimani wrote:
XRAYretired wrote:
morrisond wrote:

He did not say likely - he said "Might have" there is a big difference. Then on ET you have the perpetual problem of TOGA thrust.

If ET had the light - how would that have changed what they did?


Why dispute what he is quoted as saying and then get it wrong when the quote is readily available?
https://www.bbc.co.uk/news/business-48461110

This is the Chris Brady Quote-
Chris Brady, a pilot and author of The Boeing 737 Technical Guide said: "I'm fairly confident that the Ethiopian Airlines flight probably would not have crashed if they had had the AOA disagree alert" on the aircraft.

This is the reporters appreciation of his interview-
Mr Brady believes that if there had been an alert warning light showing that the AOA sensors were giving different readings, then the pilots might have followed an emergency procedure at an earlier point in the doomed flight.

These are a few possibilities I posted earlier, perhaps you missed them-
AOA DISAGREE would have been displayed from 05:39:00 (a full minute before MCAS activation), at the latest, and in presence of single side stick shaker may have helped conclude that stick shaker was erroneous more quickly. With IAS and ALT DISGREE also probably present, the crew may have been alerted to the possibility of the MCAS problem, looking out for it and acting more quickly when it engaged. They may even have elected to CUT-OUT stab trim prior to MCAS engaging, at a push. They may have elected to keep flaps extended and pulled back the thrust. (Although may they still have retracted flaps because it was still not communicated as a condition of MCAS activation in the documents).

The point is that they were not given the chance because the display was not available.

Ray

Short version: they might have hit stab trim cutout before MCAS activated, and before the aircraft was out of trim.


Except there is no NNC procedure that said to do that on AoA disagree warning. Just an AoA disagree doesn't mean MCAS would cause runaway.

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