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PW100
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 5:28 pm

Polot wrote:
zoom321 wrote:
PixelFlight wrote:
The report has detailed explanations how the FAA certified (well, not anymore) Xtra Aerospace mis-calibrated the AoA sensor and certified it for operation.


Not the AoA sensor per se but the questions about the trouble shooting done by Lion mechanics and how they cleared the max for flight. Were the mechanics just following Boeing manual ?
Many say the max was not airworthy.

Even if Lionair completely follow approved procedures the severe problems encountered on the previous flight should have set off alarm bells that something was wrong and the aircraft should have been pulled from service to investigate. That is why many say it was not airworthy even before we learned the reasons behind the AOA issues.


Isn't that what they actually did?

KNKT Final Report PK-LQP wrote:
The AFML entry stated the engineer in Denpasar intended to replace the AOA sensor for trouble shooting due to repetitive problem.
Because a spare AOA sensor was not available in Denpasar, the engineer coordinated with Maintenance Control Centre (MCC) to order an AOA sensor from Batam Aero Technique (BAT) located in Batam.
While waiting for the AOA sensor to arrive in Denpasar, the aircraft was grounded [to replace the suspect AoA sensor].
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 5:34 pm

Revelation wrote:
mjoelnir wrote:
You just have to read the Reuters article. Boeing new that MCAS could activate several times. Boeing new that MCAS could activate while a Christmas tree of errors could confuse the pilots. Do you need to be hit with a four by two over the head, to get a clue.

In other words, you have no evidence that Boeing knowingly knew the design would kill people.

At best we have evidence of individuals at Boeing giving their company the benefit of the doubt on things that reduce the amount of change MAX needed.

We don't have documented evidence of a collective decision to accept a design that would kill people.

Safety is about to ensure that the product would not kill people. Consequently if the safety work is not done correctly, this could kill people.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
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PW100
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Re: Indonesia report on 737 MAX crash faults Boeing design, says Lion Air made mistakes

Sun Oct 27, 2019 5:37 pm

Revelation wrote:
dtw2hyd wrote:
Finn350 wrote:
Part of the correct procedure is to record the test values. The engineer didn't record the values. The engineer showed photos purportedly showing the test, but they were determined to be from a different aircraft (see p. 36).


I agree with you AMT did a sloppy job of documenting the work. It doesn't prove that the engineer didn't check the values.

We have no proof that he did record the values, and that's what the procedure demands the engineer does!


Do we have that procedure demanding to actually write down / record the values?

Reason I ask is a) the procedure is not shown in the report, and 2) since this test is a rather crude test, it seems not logical to actually write down values.
Accept (or Pass) / Reject would seem more natural write up for such procedure.

Thanks.
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Revelation
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 5:43 pm

PixelFlight wrote:
Revelation wrote:
mjoelnir wrote:
You just have to read the Reuters article. Boeing new that MCAS could activate several times. Boeing new that MCAS could activate while a Christmas tree of errors could confuse the pilots. Do you need to be hit with a four by two over the head, to get a clue.

In other words, you have no evidence that Boeing knowingly knew the design would kill people.

At best we have evidence of individuals at Boeing giving their company the benefit of the doubt on things that reduce the amount of change MAX needed.

We don't have documented evidence of a collective decision to accept a design that would kill people.

Safety is about to ensure that the product would not kill people. Consequently if the safety work is not done correctly, this could kill people.

True, but "this could kill people" is a different proposition than "Boeing knowingly knew the design would kill people".

There's a big difference between what you know is a possibility versus something you know as a fact.

There's also a big difference between what you suspect to be true, what you know to be true, and what you can prove to be true.

Boeing is still maintaining the plausible deniability defense in terms of legal proof, no "smoking gun" has emerged to break that defense.

Still, we very well could still yet see FBI/DoJ or someone else drop the hammer, time will tell.
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 5:58 pm

Revelation wrote:
PixelFlight wrote:
Revelation wrote:
In other words, you have no evidence that Boeing knowingly knew the design would kill people.

At best we have evidence of individuals at Boeing giving their company the benefit of the doubt on things that reduce the amount of change MAX needed.

We don't have documented evidence of a collective decision to accept a design that would kill people.

Safety is about to ensure that the product would not kill people. Consequently if the safety work is not done correctly, this could kill people.

True, but "this could kill people" is a different proposition than "Boeing knowingly knew the design would kill people".

While doing a functional hazard assessment (FHA) of a safety certified product, "could kill" == "would kill". It's just a matter to add a probability to it.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
mjoelnir
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 5:58 pm

Revelation wrote:
mjoelnir wrote:
Revelation wrote:
In other words, you have no evidence that Boeing knowingly knew the design would kill people.

At best we have evidence of individuals at Boeing giving their company the benefit of the doubt on things that reduce the amount of change MAX needed.

We don't have documented evidence of a collective decision to accept a design that would kill people.

Boeing knowingly accepted a automation that they new could bring the aircraft into trouble. You have to lean far out of the window to not call that knowingly accepting that people get killed.

In other words, you still have no evidence that Boeing knowingly knew the design would kill people.

There's a difference between "bring the aircraft into trouble" and "knowingly knew the design would kill people".

mjoelnir wrote:
What you not seem to understand, that you do not need intent, negligence goes quite far enough.

It depends on the forum: criminal court, civil court, or this forum.

In US criminal court you do need intent, in civil court you do not.

In this forum, you keep answering a question different than the one being asked and pretend that no one sees the difference.


In my country negligently killing somebody is enough in a criminal court. You do not intent to kill somebody, but you accept that you could kill somebody.
 
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Finn350
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Re: Indonesia report on 737 MAX crash faults Boeing design, says Lion Air made mistakes

Sun Oct 27, 2019 6:14 pm

PW100 wrote:
Revelation wrote:
dtw2hyd wrote:
I agree with you AMT did a sloppy job of documenting the work. It doesn't prove that the engineer didn't check the values.

We have no proof that he did record the values, and that's what the procedure demands the engineer does!


Do we have that procedure demanding to actually write down / record the values?

Reason I ask is a) the procedure is not shown in the report, and 2) since this test is a rather crude test, it seems not logical to actually write down values.
Accept (or Pass) / Reject would seem more natural write up for such procedure.

Thanks.


The procedure demands to actually record the values. See for example p. 185 of the report (emphasis added):

The alternative method was performed by deflecting the AOA vane to fully up, center, and fully down while observing the indication on the SMYD computer for each position. The AOA values indicated on the SMYD computer during the test were not recorded even though BAT procedures required it, however the engineer in Denpasar stated that the test result was satisfactory. The rectification was completed about 1230 UTC (2030 LT).


This fact has been stated several times in this thread, but for some reason even seasoned members find it difficult to grasp.
 
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PixelFlight
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Re: Indonesia report on 737 MAX crash faults Boeing design, says Lion Air made mistakes

Sun Oct 27, 2019 6:57 pm

Finn350 wrote:
PW100 wrote:
Revelation wrote:
We have no proof that he did record the values, and that's what the procedure demands the engineer does!


Do we have that procedure demanding to actually write down / record the values?

Reason I ask is a) the procedure is not shown in the report, and 2) since this test is a rather crude test, it seems not logical to actually write down values.
Accept (or Pass) / Reject would seem more natural write up for such procedure.

Thanks.


The procedure demands to actually record the values. See for example p. 185 of the report (emphasis added):

The alternative method was performed by deflecting the AOA vane to fully up, center, and fully down while observing the indication on the SMYD computer for each position. The AOA values indicated on the SMYD computer during the test were not recorded even though BAT procedures required it, however the engineer in Denpasar stated that the test result was satisfactory. The rectification was completed about 1230 UTC (2030 LT).


This fact has been stated several times in this thread, but for some reason even seasoned members find it difficult to grasp.

I don't think this is about "difficult to grasp".
If the procedure require the values to be recorder, there should be possible to read the document of that procedure and to read in what document the values are required to be recorded. Fact is that the report did not show the actual procedure nor where the values are required to be recorded. It just only say that there is a procedure.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
RogerMurdock
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 7:07 pm

airtechy wrote:
Unless I missed it (entirely possible), I also saw nothing that said that the force at trim extremes would require more force on the manual trim wheel than could be managed by the pilots.


It doesn't appear to be mentioned in this report, but it may show up in the ET findings. It was certainly a known concern in the 737-200 days, hence the "roller coaster" technique.
 
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par13del
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Re: Indonesia report on 737 MAX crash faults Boeing design, says Lion Air made mistakes

Sun Oct 27, 2019 7:09 pm

PixelFlight wrote:
I don't think this is about "difficult to grasp".
If the procedure require the values to be recorder, there should be possible to read the document of that procedure and to read in what document the values are required to be recorded. Fact is that the report did not show the actual procedure nor where the values are required to be recorded. It just only say that there is a procedure.

Is this equivalent to what Boeing did with MCAS and its documentation and notifications?
 
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aerolimani
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 7:52 pm

morrisond wrote:
aerolimani wrote:
morrisond wrote:

I'm not familiar with it but I believe Airbus has a button you can push to put it into Direct Law. No idea if that turns off AT but I assume it would turn off AP.

That wouldn't be a bad idea on the MAX - really all it needs is a switch to turn off anything that can affect the electric trim just like the NG has - then you have a AP switch and an AT switch.

However one big red button would be simpler and wouldn't be a bad idea on all aircraft. It would probably be a lot simpler to understand under stress and you would now what you had vs trying to remember what systems were still working.

Hit the big red button - take manual control and then have maintenance remote diagnose the problem with you and run you through how to fix it.

Lufthansa 1829 is a great example of this.

Actually, no. I’m pretty damned sure you can’t just put an A320 into direct law by pressing a button. If you want to choose to go all the way into direct law, you have to actively disable functional parts of the system to force the plane into direct law. Considering there is no direct human to machine control of the plane, there must always be a computer between you and the controls. Things have to go very, very wrong before you’re in that situation, and the plane already knows you’re in that situation, and takes care of moving you into alternate law, or if things get really bad, direct law.

Anyhow… comparing an FBW aircraft to the MAX is so apples and oranges, it’s really a waste of time. Only the MAX could possibly benefit from a “big red button” because only the MAX is a Frankenstein which needs to marry automation with non-FBW.

Anyhow… that’s enough ridiculous off-topic pollution of this thread. If somebody reported and erased this entire conversation, I would not be upset. I would leave AirlineCritic’s reasonable post, but your cherry-picked “red button” response, and everything after it, is a waste of words on here.



It's not off topic at all - we are discussing the how things could have/should have been done better after seeing the Final Report from Lion Air.

See above - sorry on Airbus's its a Rotary switch. I'm quite aware that the Computer is still involved in Direct Law. Even in an Airbus ( or Boeing FBW) things can go wrong like on Lufthansa 1829 - where if they had gone straight to Direct Law they would have solved their control issues sooner. They did do a great job though of saving the plane - however it was almost a case of another co-pilot putting it into the ground.

Machines are not perfect. In addition to design issues parts do break (or two sensors can freeze).

The topic was general triage. What to do when things go wrong.

In triage the first thing is to Stabilize the patient. Then figure out what to do. It's a great suggestion by AirlineCritic.

I'm trying to suggest Cockpit procedures that would make it simpler for crews in highly stressed situations to save the plane by calming things down and have time to sort through things.

When you think back through almost all the fatals due to aircraft control issues - as planes have grown so Complex - what do you think is a better first reaction?

Option A - something goes weird and you try to instantly diagnose what has gone wrong with one of the Sensors/Control Systems/Computers and recall which of the 10 memory procedures (I'm exaggerating but maybe not) is the right one or what page of the QRH to go to (Even the A320's is 238 pages) while making sure the plane doesn't crash.

or

Option B - Something happens you don't understand - turn off anything that can affect the flight path/ speed of the aircraft without your direct control and put the plane in straight and level flight (How to fly an plane straight and level is Lesson #1 when you are taking your Pilots license) within the normal operating speed range - Boeing and Airbuses 4 Degree nose up 75% thrust Airspeed Unreliable Procedure (it might be slightly different between the two) - facilitated by one button to make things simpler.

If Lion Air had option B - the big red button do you not think that the Co-pilot could at least remember that simple procedure if it was drilled and made mantra? Even the Pilot in his incapacitated state should have been able to remember that.

Sorry for trying to offer a suggestion that might make things safer so we don't repeat these tragedies and help account for design failures/parts failures and failure to train crews properly failures.

This probably would have produced different results on AF447 as well and definitely on ET302.

A big red button approach is just not wise. Removing, all at once, all the automated systems, is antithetical to safety. For the MAX, we’re talking auto-spoilers, speedbrakes, STS, Mach trim, yaw damper, MCAS, stall management, and so on. Where should we stop? Furthermore, the MAX, after all the generational changes, is even further from being a directly controllable manually flyable aircraft than the original. It needs its digital nannies. Or, are you going to start advocating for the return of the flight engineer now too?

The proper approach is first to design systems with redundancies so that risk of failure is limited to the maximum degree possible. Next is to give pilots the ability to disable things as needed. In fact, the MAX already has that ability.

Triage is assessing the symptoms, determining the cause, and finding the solution. It’s not giving the patient every antiviral, antibiotic, and pain killer known to man, and hoping for the best.

As regards doing proper triage, what the MAX really needs, and the NG too for that matter, is EICAS! Not the big red button approach.

The first thing to do properly was the aircraft design. That failed to happen. The second thing to do was document the changes properly, and recommend training regimes. Failure #2. The third thing to do was for the regulator to catch these issues during certification. Failure #3. The next failures go on to maintenance (at Xtra and Lion), and finally to the poor training of the FO and the poor choices of the Captain. Absolutely, action needs be taken on all these fronts, but priorities say it starts at Boeing, then FAA, and so on. The first layer of Swiss cheese that appeared was the plane, and it is the first one that needs fixing.

Even with the best pilots, bad days can happen. A pilot can become suddenly incapacitated during flight. It’s happened before. The plane needs to be as safe as possible first, and a big red button is not going to do that.

A question for you… with all the aircraft designed with any level of digitally controlled flight systems, why is it that no designers have put in your “big red button?” You seem to think this is some sort of obvious solution. You can’t even get anyone here to agree with you. The lack of the big red button’a existence would seem to suggest that the engineering minds, who’ve actually created successful and safe designs, don’t agree with you either.

There… I tried to make this relevant to this thread.
 
travelhound
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 8:09 pm

mjoelnir wrote:
morrisond wrote:
mjoelnir wrote:

Nice rant and than we get to the Boeing 737MAX.

It´s pilot machine interface is that old, it needs exceptions from current FARs to get certified. No accommodation for Boeing developments in this area since the 757/767 something called EICAS. A more modern interface used on all Boeing frames, but the commercial 737, since. Even the P-8, a military 737, got EICAS.

The designers at Boeing designing MCAS, gave the pilots exactly 3 seconds to diagnose the problem of MCAS failure and react with the right action. They actually discussed the danger of multible activation of MCAS and the problem of overload through multible error alarms and they decided to leave it as they designed it.
Boeing designers accepted the possibility, that if you did not react very fast, averting the catastrophic events would be difficult.

Furthermore Boeing designed MCAS so that all usual ways for a pilot to stop it from working were excluded. No turn off button, but disabling all electrical trim. No turning off by pulling heavily on the column, like in the KC-46.

But Boeing´s care for pilots and their passengers did not end there. Boeing made sure that no pilot would know about MCAS, that nobody could train for MCAS if by chance they got wind of it, going so far as to exclude MCAS and its failure modes from the commercial available 737MAX simulators.


Yes we know Boeing is evil I don't think anyone on here is refuting that - and you call mine a rant?

So what is your solution for making sure Lion Air 610's, Lufthansa 1829's, AF447 and Et302's don't happen again?

More bells and whistles going off in the cockpit and more automation, including more memory items and a 300 page QRH?

Please provide a solution vs just ranting. At least I'm trying - mine applies to all aircraft types and if made a core training could have prevented most of the air disasters of the past 20 years.


If you point to one comment I made about Boeing and the 737MAX that is not a fact, you can call my post a rant.

How dare you compare the other accidents with the terrible death trap Boeing produced knowingly with the 737MAX? Can you point to me where another air framer discussed possible catastrophic failures of an automation and decides to hide the automation?
This disaster is so far out of everything I once believed the airline industry to be about. Once upon a time Boeing was a beacon for safety conscious design of airplanes, but that was perhaps always a misconception.


If I understand correctly, the module that controls the MCAS system was designed, manufactured and programmed by Rockwell Collins, a reputable company in the aerospace industry.

Flight Control Systems are used on almost all aircraft including commercial passenger aircraft, freighters, business jets and military aircraft. There is nothing sinister about using a Flight Control System like MCAS.

I think it is fair to say design flaws within the MCAS system contributed to the Lion Air accident, but with the caveat being there were systemic maintenance, pilot training and operational procedural inadequacies that were significant factors in the chain of events that led to the demise of the aircraft.

As such, I am not convinced we can place blame solely on MCAS or Boeing. At a guess Boeing and their supporting contractors would have designed, programmed and certified 1000's of Flight Control Systems. The Accident report states certification of the system was in accordance to current regulations and as a consequence acceptable industry practice.

As can be seen in the news articles relating to the design and certification of MCAS, there were mitigating circumstances that resulted in the design of MCAS not being ideal. A fair assessment would not place blame on Boeing for these circumstances.

From where I sit a global view of the lion air and ET accidents will add more value to the discussion. Aircraft are extremely complex pieces of equipment designed by extremely talented people. Every day these talented people have passengers lives in their hand. Let's not unfairly load these people up with blame.

Ultimately, the ET crash investigation report will give us a greater understanding of the role of MCAS. I suspect we will have a different set of circumstances which will broaden the scope of the discussion.

It could be the case that there is mismatch in the ability of airlines to adapt to the rate of change in aircraft designs from the OEM's where even small subtle changes to an aircraft design are not being properly understood in an operational environment.
 
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 8:57 pm

travelhound wrote:
If I understand correctly, the module that controls the MCAS system was designed, manufactured and programmed by Rockwell Collins, a reputable company in the aerospace industry.
Right. The NTSB report detail all of the Rockwell Collins work into the "E.1.1 Requirements Generation and Traceability":
"An NTSB review of a December 09, 2016 Rockwell Collins document titled
“EDFCS FCC-730 P10.0 Requirement Verification Matrix” was conducted. This
document included a “traceability matrix” table that identified the incremental
requirements that were changed/added/deleted for the EDFCS FCC-730 P10.0
software development. The document indicated that the traceability matrix had
been reviewed by Rockwell and their review found that the requirements affected
by the EDFCS FCC-730 P10.0 software development have been correctly allocated,
implemented, and verified. The NTSB review of the “traceability matrix” table
found that it included all of the safety requirements that were added to the SCD per
Boeing document “B-1740, including the MCAS safety requirement 3.1.1.5.3.1.1-
A. According to Boeing, the safety requirement would be covered in the EDFCS
system safety assessment. A review on the Boeing EDFCS system safety
assessment found that the MCAS safety requirement 3.1.1.5.3.1.1-A was addressed."

travelhound wrote:
I think it is fair to say design flaws within the MCAS system contributed to the Lion Air accident, but with the caveat being there were systemic maintenance, pilot training and operational procedural inadequacies that were significant factors in the chain of events that led to the demise of the aircraft.
The MCAS was not safe enough. Of course an unsafe design will first hit the less experimented pilots. As the EASA have emphasis:
"Pilot training requirements are not meant to compensate for non-acceptable design on the compliance and safety standpoint."

travelhound wrote:
As such, I am not convinced we can place blame solely on MCAS or Boeing. At a guess Boeing and their supporting contractors would have designed, programmed and certified 1000's of Flight Control Systems. The Accident report states certification of the system was in accordance to current regulations and as a consequence acceptable industry practice.
This is not exactly what is on the JT610 report:
"During the design and certification of the Boeing 737-8 (MAX),
assumptions were made about flight crew response to malfunctions which,
even though consistent with current industry guidelines, turned out to be
incorrect."
And if you read the details, it's clear that the 737-8/9 MAX was not "in accordance to current regulations" due to a flawed Functional Hazard Analysis (FHA).

travelhound wrote:
As can be seen in the news articles relating to the design and certification of MCAS, there were mitigating circumstances that resulted in the design of MCAS not being ideal. A fair assessment would not place blame on Boeing for these circumstances.
The report did not blame, and did not limit the contributing factors only on Boeing.

travelhound wrote:
From where I sit a global view of the lion air and ET accidents will add more value to the discussion. Aircraft are extremely complex pieces of equipment designed by extremely talented people. Every day these talented people have passengers lives in their hand. Let's not unfairly load these people up with blame.

Ultimately, the ET crash investigation report will give us a greater understanding of the role of MCAS. I suspect we will have a different set of circumstances which will broaden the scope of the discussion.
I don't see how the ET302 final report will change anything substantial to the already existing NTSB report and JATR review.

travelhound wrote:
It could be the case that there is mismatch in the ability of airlines to adapt to the rate of change in aircraft designs from the OEM's where even small subtle changes to an aircraft design are not being properly understood in an operational environment.
Boeing was selling the 737-8/9 MAX with the big marketing point "MAX == NG, no pilots training required". This was obviously a very strong requirement to the 737-8/9 MAX design.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
RogerMurdock
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 9:12 pm

PixelFlight wrote:
I don't see how the ET302 final report will change anything substantial to the already existing NTSB report and JATR review.


ET302 situation points to even broader and more fundamental issues with the entire 737 line in regards inability to manually adjust trim once it the stabilizer has reached a certain loading. (See "roller coaster" technique mentioned above.)
 
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 9:18 pm

RogerMurdock wrote:
PixelFlight wrote:
I don't see how the ET302 final report will change anything substantial to the already existing NTSB report and JATR review.


ET302 situation points to even broader and more fundamental issues with the entire 737 line in regards inability to manually adjust trim once it the stabilizer has reached a certain loading. (See "roller coaster" technique mentioned above.)
:checkmark: :thumbsup:
Right ! I missed that one.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
travelhound
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 10:56 pm

If I am correct, when the 737MAX returns to service it will still have the same Functional Hazard Analysis grading of "Major". As such, the original assumptions made by Boeing may be found to be correct.

From what I understand, the issues with MCAS revolve around pilot control when MCAS engages. As such, if Boeing can address this issue through the reprograming of the existing system there may not be a need for substantial changes required by a different classification.
 
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Sun Oct 27, 2019 11:28 pm

travelhound wrote:
If I am correct, when the 737MAX returns to service it will still have the same Functional Hazard Analysis grading of "Major". As such, the original assumptions made by Boeing may be found to be correct.

From what I understand, the issues with MCAS revolve around pilot control when MCAS engages. As such, if Boeing can address this issue through the reprograming of the existing system there may not be a need for substantial changes required by a different classification.

I don't see any possibility that the flawed Functional Hazard Analysis of the MCAS will not be fixed and classified as "Catastrophic", since it was flawed precisely because the Boeing assumptions was incorrect. That new classification require a lot more Fault Tree Analysis (FTA) and consequently design changes to ensure risks control.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
Saintor
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 12:28 am

At page 91 of the final report, they mention 4 simulations with some variations of parameters. I read it many times, yet there is one point unclear to me. Do I understand it right that all of them didn't crash?
 
rheinwaldner
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 10:04 am

morrisond wrote:
It's revealing after the report has been released how quiet it's gotten in here.

We were waiting on your damning elaborations about the other 98% of the accident report (= on the real root cause) of the accident.

To no avail, as it seems...

morrisond wrote:
These are my main three takeaways in regards to the pilots actions:

#1 The Pilot did not review the issues from the Previous Flight - that is a huge No-no. If he had he probably would have had the knowledge that would have saved everyone on board.

#2 The Co-Pilot was cited as basically being incompetent and did not even have a mastery over the basics of Manual flight (did not know how to even use Manual Electric Trim properly) therefore should not have even be licensed as a pilot but kept getting passes through the Lion Air system.

#3 While the Pilot missed the review of the previous flight and showed relatively okay skills in the cockpit - it's one thing to look at the traces and see him counteracting MCAS activation 22 times - it's another thing to read about it in the timeline and say - why the hell didn't he throw the switches?

If these are you main takeaways, you are demonstrating an incredible bias.

Starting on page 204 the report lists 89 findings and 9 contributional factors. I have categorized these in the following categories:
1. Findings blaming Boeing, the FAA or Xtra
2. Findings blaming Maintenance deficiencies
3. Findings blaming the crew
4. Findings explicitly exonerating the crew (this kind of: "This would lead to the inability of the flight crew to predict and be prepared ….")
(findings were possible to belong to multiple categories)

This is the result:
Total: 98
Number of findings category 1: 42
Number of findings category 2: 10
Number of findings category 3: 7
Number of findings category 4: 25

So Boeing and FAA findings prevails over pilot error findings with a 6:1 ratio. There goes your unbalanced commenting on these crashes.

The 7 findings of pilot errors are diminished by 25 findings, which explicitly come to defend the pilots!!!

So were are your balanced comments that focus on the big issues mentioned in the report? Where are your comments that take into considerations the much higher number of findings, that take away blame from the pilots for their mistakes?

Please elaborate about the huge no-nos Boeing did. The accident gives you much more material to do that than for rants about pilot proficiency.
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planecane
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 10:54 am

PixelFlight wrote:
travelhound wrote:
If I am correct, when the 737MAX returns to service it will still have the same Functional Hazard Analysis grading of "Major". As such, the original assumptions made by Boeing may be found to be correct.

From what I understand, the issues with MCAS revolve around pilot control when MCAS engages. As such, if Boeing can address this issue through the reprograming of the existing system there may not be a need for substantial changes required by a different classification.

I don't see any possibility that the flawed Functional Hazard Analysis of the MCAS will not be fixed and classified as "Catastrophic", since it was flawed precisely because the Boeing assumptions was incorrect. That new classification require a lot more Fault Tree Analysis (FTA) and consequently design changes to ensure risks control.


The reason MCAS 1.0 should have been classified as catastrophic is that it could create the full nose down runaway scenario that led to the crashes. MCAS 2.0 will not be able to do that so therefore is no longer catastrophic.
 
planecane
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 10:57 am

RogerMurdock wrote:
airtechy wrote:
Unless I missed it (entirely possible), I also saw nothing that said that the force at trim extremes would require more force on the manual trim wheel than could be managed by the pilots.


It doesn't appear to be mentioned in this report, but it may show up in the ET findings. It was certainly a known concern in the 737-200 days, hence the "roller coaster" technique.


The manual wheel did not come into play at all in the JT610 crash. That's why it isn't mentioned. It wasn't a contributing factor to the crash which the report is investigating.
 
travelhound
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 11:48 am

rheinwaldner wrote:
morrisond wrote:
It's revealing after the report has been released how quiet it's gotten in here.

We were waiting on your damning elaborations about the other 98% of the accident report (= on the real root cause) of the accident.

To no avail, as it seems...

morrisond wrote:
These are my main three takeaways in regards to the pilots actions:

#1 The Pilot did not review the issues from the Previous Flight - that is a huge No-no. If he had he probably would have had the knowledge that would have saved everyone on board.

#2 The Co-Pilot was cited as basically being incompetent and did not even have a mastery over the basics of Manual flight (did not know how to even use Manual Electric Trim properly) therefore should not have even be licensed as a pilot but kept getting passes through the Lion Air system.

#3 While the Pilot missed the review of the previous flight and showed relatively okay skills in the cockpit - it's one thing to look at the traces and see him counteracting MCAS activation 22 times - it's another thing to read about it in the timeline and say - why the hell didn't he throw the switches?

If these are you main takeaways, you are demonstrating an incredible bias.

Starting on page 204 the report lists 89 findings and 9 contributional factors. I have categorized these in the following categories:
1. Findings blaming Boeing, the FAA or Xtra
2. Findings blaming Maintenance deficiencies
3. Findings blaming the crew
4. Findings explicitly exonerating the crew (this kind of: "This would lead to the inability of the flight crew to predict and be prepared ….")
(findings were possible to belong to multiple categories)

This is the result:
Total: 98
Number of findings category 1: 42
Number of findings category 2: 10
Number of findings category 3: 7
Number of findings category 4: 25

So Boeing and FAA findings prevails over pilot error findings with a 6:1 ratio. There goes your unbalanced commenting on these crashes.

The 7 findings of pilot errors are diminished by 25 findings, which explicitly come to defend the pilots!!!

So were are your balanced comments that focus on the big issues mentioned in the report? Where are your comments that take into considerations the much higher number of findings, that take away blame from the pilots for their mistakes?

Please elaborate about the huge no-nos Boeing did. The accident gives you much more material to do that than for rants about pilot proficiency.


If we are going to be fair, each one of those findings should have a rating (i.e. each finding has a value greater or less than one).

I don't think anyone is disputing there were fundamental flaws with the way MCAS operates.

What we are disputing is that the aircraft should have been deemed unairworthy prior to the fatal flight; and that this was a consequence of systemic pilot training and maintenance deficiencies.

Reporting of the continued stick shaker nose downs commands on the prior flight could have resulted in a more detailed investigation of the MCAS system by Boeing and the ruling governing bodies.

From what I understand the repeated nose downs commands from MCAS was not properly understood and tested during the certification process.

From the report the base assumptions for MCAS were defined in 2012 and as such there should have been plenty of time to rectify MCAS issues if they had been known at that time or were highlighted during the design and certification process.

Recent news articles suggest the repeated nose downs commands of MCAS surfaced during flight testing, but was latter deemed to be a flight simulator and not a MCAS issue.

As such there were a few opportunities missed to identify the MCAS problems.

Moves by Boeing to improve governance and oversight should be seen as a welcomed sign.

Similarly, LionAir should acknowledge their role in flight safety and make similar commitments.
 
Thorkel
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 12:08 pm

planecane wrote:
PixelFlight wrote:
travelhound wrote:
If I am correct, when the 737MAX returns to service it will still have the same Functional Hazard Analysis grading of "Major". As such, the original assumptions made by Boeing may be found to be correct.

From what I understand, the issues with MCAS revolve around pilot control when MCAS engages. As such, if Boeing can address this issue through the reprograming of the existing system there may not be a need for substantial changes required by a different classification.

I don't see any possibility that the flawed Functional Hazard Analysis of the MCAS will not be fixed and classified as "Catastrophic", since it was flawed precisely because the Boeing assumptions was incorrect. That new classification require a lot more Fault Tree Analysis (FTA) and consequently design changes to ensure risks control.


The reason MCAS 1.0 should have been classified as catastrophic is that it could create the full nose down runaway scenario that led to the crashes. MCAS 2.0 will not be able to do that so therefore is no longer catastrophic.


This is backwards. We conduct this types of assessments, and categorise severity of hazard given a failure on demand, in order to ensure something is built sufficiently well to mitigate the risk. i.e. if a failure of MCAS has a high potential of leading to a catastrophic failure, then it needs to be engineered to a higher build standard to minimise that chance of failure.

In other words, the classification dictates how MCAS is engineered. A better engineered MCAS does not change the classification. To change the classification, you need something else that is independent from MCAS. I.e. an MCAS failure by itself isn’t catastrophic because something else will potentially stop an initiating event converting to a hazard - another system, well trained, pilots, etc will reliably intervene to prevent the catastrophic effect. Given the evidence of what can happen due to the impact of MCAS failure, this to me seems like a tricky argument to make.

I’d also be very reticent to say MCAS 2.0 will not be able to do something. It may be designed or intended not to do something, but stating as fact that it cannot happen in any circumstance is also a tricky argument to make.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 12:48 pm

Finn350 wrote:
The installed left AOA sensor had a 21° bias which was undetected during the installation test in Denpasar.


Actually the bias was variable, it jumped around on the ground during taxi compared to the other side and was erratic when on the ground at low speed, and had a near constant value in flight. Analysis of similar events in the past have found this was due to the mass balance inside the AOA vane not being fixed tight enough on the shaft allowing it to move independently of the shaft.

There are other plausible explanations ranging from mechanical tightness of grub screws inside the AOA vane which has happened before, to damage similar to what was found on the probe that was removed in DPS on one coil of either the SIN or COS which could have resulted in a output voltage offset.

Finn350 wrote:
The on-aircraft test prodedure allows ± 5° bias.


Actually these are tolerances, and the tolerance is not a fixed 5 degrees across the range of movement.

Finn350 wrote:
If the test was done correctly at Denpasar, it would have shown the miscalibration.


Not at all. The AOA vane has two resolver outputs, one output goes to the SYMD, the other to the ADIRU. Just testing the SYMD input only tests half of the vanes outputs, however either resolver output can active MCAS.

This is my fundamental problem I have with this report, the test they suggest should have uncovered the problem has failed in the past on other aircraft to detect internal problems in the AOA sensor, and it only tests half of the sensor output.

The other issue I have is the on aircraft demonstration of the test procedures is they did had a known bad probe with a known 33 degree bias. That was 57% larger than what was seen on the accident aircraft.

They should have done a double blind experiment with a pool of normal line mechanics and a bunch of known good probes, one of each resolver bad and one with a both resolvers bad and get a statistically valid experiment. Going in there with the manufacturer and a known bad problem with both resolvers with a predetermined outcome does nothing to reassure me there procedure is robust. We know it is not robust as the SYMD only sees one of the two resolvers from the probe.

Additionally a previous event which has happened after a AOA probe came from overhaul had the internal grub screws not torqued to the correct value allowing the shaft, resolvers, and counter weight to rotate independently when subjected to the vibration during operation, however tight enough to pass a post installation static test. The AMM task will not detect that sort of issue.

Finn350 wrote:
If Lion Air AMM Task 34-21-05-400-801 somehow deviated from the Boeing recommendation, it surely would have been mentioned in the final report.


The Boeing AMM task from what I read says nothing about recording values, the element of recording values from what I have seen in the report comes not from the AMM task, it comes from the investigators interpenetration of Section 3.5 of the line maintenance procedures manual (top of page 138). The report states on page 185 "The AOA values indicated on the SYMD computer during the test were not recorded even though the BAT procedures required it", similar comment was repeated again on page 188, it does not say the AMM task requires it.

However looking at the LMPM on the top of page 138 it says to record the values "if applicable", I would suggest any line maintenance engineer would not consider it to be applicable unless the AMM task requires it. For example I have not seen any line maintenance engineer record the torque values or tyre pressures after replacing a wheel, however these are checked as part of the AMM procedure. I have never seen any line maintenance engineer record the inlet fuel pressure during refueling, however that also has a limit and tolerance in the AMM.
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SwissCanuck
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 2:00 pm

The way I understand it is the instrument was not outputting correct values, and that two steps should have caught this - during the calibration when the part was on a bench, and then after installation on the aircraft. Just playing devil's advocate, but in the sections of the report I've read I haven't seen anything that rules out a problem even if these two tests were performed correctly. Of course they debated it - I guess I'd just love a transcript of that conversation.
 
BEG2IAH
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 5:57 pm

MSPNWA wrote:
You're certainly entitled to your opinion, but I think an economist should know more than most that everything has a price--safety/life included. It isn't automatically greed. It's not downplaying the value of life. It's the reality of the life we face. Saying Boeing doesn't care is a slanderous exaggeration. Getting it wrong =/= not caring. I expect better from a fellow economist.


Oh I agree, we can do a pure cold blood economic analysis with price tags on everything, but I can't help but feel the way I feel about this whole tragedy. Maybe it's not greed, we can debate that, but it's not a naive "getting it wrong" either. This was much worse.
Flying at the cruising altitude is (mostly) boring. I wish all flights were nothing but endless take offs and landings every 10 minutes or so.
 
dtw2hyd
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 6:43 pm

There is so much news on MAX and MCAS, but I couldn't figure out who developed MCAS v1 software?

1) Boeing's inhouse software development team.
2) Unpaid interns
3) Rockwell Collins (HW supplier)
4) Contractors in India
All posts are just opinions.
 
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Finn350
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 6:59 pm

zeke wrote:
Finn350 wrote:
The installed left AOA sensor had a 21° bias which was undetected during the installation test in Denpasar.


Actually the bias was variable, it jumped around on the ground during taxi compared to the other side and was erratic when on the ground at low speed, and had a near constant value in flight. Analysis of similar events in the past have found this was due to the mass balance inside the AOA vane not being fixed tight enough on the shaft allowing it to move independently of the shaft.

There are other plausible explanations ranging from mechanical tightness of grub screws inside the AOA vane which has happened before, to damage similar to what was found on the probe that was removed in DPS on one coil of either the SIN or COS which could have resulted in a output voltage offset.


As you very well know, AOA sensors are designed to function only with sufficient airflow. Therefore the ground values are really not meaningful. In the flight the bias was constant 21°, and the report comes to the conclusion that the AOA sensor was most likely improperly calibrated at Xtra Aerospace introducing an equal bias into both resolvers.

Are you now suggesting that the bias might have been caused due to a defect or damage to the sensor and not miscalibration?
 
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PixelFlight
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 8:26 pm

dtw2hyd wrote:
There is so much news on MAX and MCAS, but I couldn't figure out who developed MCAS v1 software?

1) Boeing's inhouse software development team.
2) Unpaid interns
3) Rockwell Collins (HW supplier)
4) Contractors in India


Boeing did the (flawed) safety analysis and the (bad) specification.
Rockwell Collins did the implementation and compliance verification to the (bad) Boeing specification.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Mon Oct 28, 2019 10:29 pm

Finn350 wrote:
As you very well know, AOA sensors are designed to function only with sufficient airflow.


if that was the case any post installation static test could not be valid, you cannot have it both ways.

Finn350 wrote:
In the flight the bias was constant 21°, and the report comes to the conclusion that the AOA sensor was most likely improperly calibrated at Xtra Aerospace introducing an equal bias into both resolvers.


Actually we dont know that for certainty, only the output of one of the resolver outputs is on the FDR, the SMYD sends the on side AOA data to the Flight Data Acquisition Unit for data recording, the output of the other resolver is not recorded. There is other plausible known reasons for similar behavior to do with the grub screws inside ( http://www.smartcockpit.com/docs/Boeing ... akeoff.pdf ) and partial intermittent failure of a single coil winding like the probe that was removed in DPS.

Without the probe from the accident aircraft, no absolute reason can be stated.

Finn350 wrote:
Are you now suggesting that the bias might have been caused due to a defect or damage to the sensor and not miscalibration?


I am saying without the senor it is inconclusive, incorrect calibration is just one of many hypothesis.
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Finn350
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 7:04 am

zeke wrote:
Finn350 wrote:
As you very well know, AOA sensors are designed to function only with sufficient airflow.


if that was the case any post installation static test could not be valid, you cannot have it both ways.


As explained in the report, the post-installation test in the alternative method is performed by deflecting the AOA vane to the fully up, center, and fully down positions while verifying the indication on the SMYD computer for each position. The different positions are to simulate the airflow.

zeke wrote:
Finn350 wrote:
In the flight the bias was constant 21°, and the report comes to the conclusion that the AOA sensor was most likely improperly calibrated at Xtra Aerospace introducing an equal bias into both resolvers.


Actually we dont know that for certainty, only the output of one of the resolver outputs is on the FDR, the SMYD sends the on side AOA data to the Flight Data Acquisition Unit for data recording, the output of the other resolver is not recorded. There is other plausible known reasons for similar behavior to do with the grub screws inside ( http://www.smartcockpit.com/docs/Boeing ... akeoff.pdf ) and partial intermittent failure of a single coil winding like the probe that was removed in DPS.

Without the probe from the accident aircraft, no absolute reason can be stated.


The report states the most likely reason, and no alternative reasons are presented or even speculated.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 7:54 am

Finn350 wrote:
As explained in the report, the post-installation test in the alternative method is performed by deflecting the AOA vane to the fully up, center, and fully down positions while verifying the indication on the SMYD computer for each position. The different positions are to simulate the airflow.


The report does not actually state that is the AMM task. Nor does it answer the clear problem with such a test in that it only sees one of the two resolvers. The other resolver is not connected to the SYMD.

Finn350 wrote:

The report states the most likely reason, and no alternative reasons are presented or even speculated.


It does not however rule out the other potential issues I stated. And the other reasons I stated have happened.

What is missing from the report is another probe that had the same outcome from that repair facility they suggested.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
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Finn350
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 8:41 am

zeke wrote:
Finn350 wrote:
As explained in the report, the post-installation test in the alternative method is performed by deflecting the AOA vane to the fully up, center, and fully down positions while verifying the indication on the SMYD computer for each position. The different positions are to simulate the airflow.


The report does not actually state that is the AMM task.


It does state that, see p.62 (and also p. 36 which has been quoted previously):

The initial evaluation of the IFIM task 34-21-00-810-828 requires the test of AOA sensor referring to the AMM TASK 34-21-05-400-801 which contains measurement of the AOA vane angle value via SMYD.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 11:20 am

Finn350 wrote:
It does state that, see p.62 (and also p. 36 which has been quoted previously):


That is not the AMM task, other times they have produced the document in the raw source like the emergency AD.

They haven’t actually produced any of the maintenance procedures as they were at the time of the different maintenance events.

Just providing a reference is useless as the procedures change all the time. As the system has been modified, the AMM task will have changed.

I don’t think the report does justice to the people who lost their lives in the accident. Far too many holes in it. Questions still unanswered.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
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flyingturtle
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 6:50 pm

zeke wrote:

I don’t think the report does justice to the people who lost their lives in the accident. Far too many holes in it. Questions still unanswered.


Do you hint at a criminal investigation against Boeing? Or a civil lawsuit, with depositions and discovery?
Reading accident reports is what calms me down
 
ILNFlyer
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 8:06 pm

Man, there appears to be lots of blame to go around.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 8:18 pm

flyingturtle wrote:

Do you hint at a criminal investigation against Boeing? Or a civil lawsuit, with depositions and discovery?


No, I don’t see the point in that. The idea behind accident investigations is to learn from the past to make the future safer.

The report in my view still has open questions, open questions in my view are learning opportunities to make things safer, not litigation opportunities.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
Saintor
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 10:50 pm

rheinwaldner wrote:
Starting on page 204 the report lists 89 findings and 9 contributional factors. I have categorized these in the following categories:
1. Findings blaming Boeing, the FAA or Xtra
2. Findings blaming Maintenance deficiencies
3. Findings blaming the crew
4. Findings explicitly exonerating the crew (this kind of: "This would lead to the inability of the flight crew to predict and be prepared ….")
(findings were possible to belong to multiple categories)

This is the result:
Total: 98
Number of findings category 1: 42
Number of findings category 2: 10
Number of findings category 3: 7
Number of findings category 4: 25


This doesn't hold water at all.

The only resource who could change everything and save the day AT THAT MOMENT was your category #3 - the crew.

AFAIK, no simulation proved that it wasn't recoverable, because with a competent crew *it was*.

I agree however that there is no excuse that Boeing didn't provide more info. For example if the flaps were all in, it was not possible for the MCAS to act.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Tue Oct 29, 2019 11:47 pm

Saintor wrote:
AFAIK, no simulation proved that it wasn't recoverable, because with a competent crew *it was*.


My understanding is that is is recoverable from above 8000 ft, but not at the level they had.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
morrisond
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 12:53 am

zeke wrote:
Saintor wrote:
AFAIK, no simulation proved that it wasn't recoverable, because with a competent crew *it was*.


My understanding is that is is recoverable from above 8000 ft, but not at the level they had.


Yes it would have been very hard to recover with less than 8,000’ of elevation above ground when the elevator was already at full stop. If that was the point in time when a competent crew took over.

However in both crashes the competent crew would have had minutes to figure things after first MCAS activation and if they had followed proper procedures they would never had gotten to that point.

None of the SIM recreations that I am aware of started the accident at first MCAS activation. At that point LA counteracted MCAS 22 times before the co-pilot lost the battle and ET was doing fine until they switched the Electric trim back on and MCAS started up again which was a specific No-No in the FCOM bulletin released after LA.

A competent crew who read the FCOM and had it in the cockpit should have easily identified the problem as MCAS as the accident was almost as exactly described in the FCOM bulletin.

There was nothing wrong with the revised procedure - it would have saved the plane.

Normal Runaway stabilizer would have saved the Lion Air flight.
 
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zeke
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 1:22 am

morrisond wrote:
competent crew would have had minutes to figure things after first MCAS activation


How is a crew supposed to work out something in a few minutes that was deliberately left out of the manuals ?

morrisond wrote:
At that point LA


LA is LATAM, JT is Lion Air

morrisond wrote:
ET was doing fine.


No they were not, both pilots were pulling and they were unable to move the trim, they turned on the trim switches to get electric trim assistance, not to turn on MCAS. Using electric trim momentary disables MCAS.

morrisond wrote:
A competent crew who read the FCOM and had it in the cockpit should have easily identified the problem as MCAS as the accident was almost as exactly described in the FCOM bulletin.


How could the JT crew have read the "FCOM bulletin" if it was only published after their crash ?

morrisond wrote:
Normal Runaway stabilizer would have saved the Lion Air flight.


It did not present as a runaway stab, https://youtu.be/UD4-8MlEy44

They were able to move it and control it with the electric trim, and with the timer involved the trim does not move for 5 seconds after using eclectic trim. A runaway stab goes in one direction to the stop, and is uncontrollable.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
airtechy
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 2:41 am

A runaway trim is controllable. You stop it with the kill switches on the console. I was warned about this in the 70's when I first flew a plane with electric trim .
 
VV
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 7:56 am

airtechy wrote:
A runaway trim is controllable. You stop it with the kill switches on the console. I was warned about this in the 70's when I first flew a plane with electric trim .


I agree with you.

It is also the reason of my repeated question as whether there has been any indication the pilots had seen the trim wheel turning in an excessive manner without their input. I did not get any answer.

The only reason I asked the question is that it seems
  1. the different crew had not identified the trim as the issue
  2. they had not applied the trim runaway procedure properly

If someone does not recognize the issue then I do not think he/she would apply the right procedure. Problem not identified, no right solution applied.

This said, I do not know what exactly happened in the cockpit, but after reading the final report, I still do not understand why they failed to identify the issue because they had several minutes before the final plunge.

The initial attempts to use the electrical trim switch on the control column seems to indicate they tried to do something about the stabilizer, but they did not seem to have cut the kill switches as required in the trim runaway procedure. Why? I do not know.

For the record, I have never piloted a transport aircraft.

Is that correct to say that elevator and/or horizontal stabilizer movement is the main cause of pitch change?
 
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SheikhDjibouti
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 12:19 pm

There is so much to read in the report, and I feel I need to read it at least three times over before I can fully appreciate it.

Meanwhile, here is one section I have cherry-picked because it disturbs me in several ways.

JT610 Final; section 2.5.1.2.4 wrote:
During the Functional Hazard Analysis (FHA), unintended MCAS-commanded stabilizer movement was considered a failure condition with Major effect in the normal flight envelope. Boeing reasoned that such a failure could be countered by using elevator alone. In addition, stabilizer trim is available to offload column forces, and stabilizer cutouts is also available but not required to counter failure.

"Boeing reasoned..." - so they tossed the idea around in a meeting but it wasn't verified by any test flying?
"could be countered by using elevator alone" - yeah, how did that work out in practice?
"and stabilizer cutouts is also available but not required to counter failure." ...not required :rotfl:

Now I realize most (probably all) of the above have been raised at some point here on a.net, but to see them stated so plainly in black-and-white shook me.
Am I mis-interpreting anything here?

But it gets worse...
JT610 Final; section 2.5.1.2.4 wrote:
(continued) With an MCAS command due to an erroneous high AOA signal, and flight crew inputs that do not fully return the aircraft to a trimmed state, subsequent MCAS commands can result in the aircraft becoming significantly miss-trimmed.
To recover, the flight crew could:
1) stop making manual electric trim inputs (which would stop resetting MCAS),
or
2) make sufficient (long duration) manual electric trim inputs to return the aircraft to a trimmed state
or
3) use the stabilizer trim cutout procedure to stop all electric trim commands and control trim using the manual trim wheels.

I'm ok with 2) and 3), but I have a problem with the first solution. Until now I didn't realise it was the Lion Air crews fault for provoking MCAS by using manual electric trim inputs (22 times)
They should have just stopped making manual electric inputs, and allowed MCAS to go back to sleep.
It would leave them with an aircraft that was out-of-trim, but not lethally so. And over time they could ask some of the well-fed first class passengers to move to the back of the plane to help keep the aircraft level.
After twelve months of careful deliberation, has the report got it right? Does simply keeping your thumbs away from the thumb switches prevent MCAS firing off again (reminder - there are still erroneous high AOA signals)? This is the first I have heard.

Zeke - you have the knowledge of an encyclopedia, and the patience of a saint (and boy do you need that whilst you are dealing with Captain Hindsight!) - please help us out here. :white:
Nothing to see here; move along please.
 
XRAYretired
Posts: 870
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 12:32 pm

SheikhDjibouti wrote:
There is so much to read in the report, and I feel I need to read it at least three times over before I can fully appreciate it.

Meanwhile, here is one section I have cherry-picked because it disturbs me in several ways.

JT610 Final; section 2.5.1.2.4 wrote:
During the Functional Hazard Analysis (FHA), unintended MCAS-commanded stabilizer movement was considered a failure condition with Major effect in the normal flight envelope. Boeing reasoned that such a failure could be countered by using elevator alone. In addition, stabilizer trim is available to offload column forces, and stabilizer cutouts is also available but not required to counter failure.

"Boeing reasoned..." - so they tossed the idea around in a meeting but it wasn't verified by any test flying?
"could be countered by using elevator alone" - yeah, how did that work out in practice?
"and stabilizer cutouts is also available but not required to counter failure." ...not required :rotfl:

Now I realize most (probably all) of the above have been raised at some point here on a.net, but to see them stated so plainly in black-and-white shook me.
Am I mis-interpreting anything here?

But it gets worse...
JT610 Final; section 2.5.1.2.4 wrote:
(continued) With an MCAS command due to an erroneous high AOA signal, and flight crew inputs that do not fully return the aircraft to a trimmed state, subsequent MCAS commands can result in the aircraft becoming significantly miss-trimmed.
To recover, the flight crew could:
1) stop making manual electric trim inputs (which would stop resetting MCAS),
or
2) make sufficient (long duration) manual electric trim inputs to return the aircraft to a trimmed state
or
3) use the stabilizer trim cutout procedure to stop all electric trim commands and control trim using the manual trim wheels.

I'm ok with 2) and 3), but I have a problem with the first solution. Until now I didn't realise it was the Lion Air crews fault for provoking MCAS by using manual electric trim inputs (22 times)
They should have just stopped making manual electric inputs, and allowed MCAS to go back to sleep.
It would leave them with an aircraft that was out-of-trim, but not lethally so. And over time they could ask some of the well-fed first class passengers to move to the back of the plane to help keep the aircraft level.
After twelve months of careful deliberation, has the report got it right? Does simply keeping your thumbs away from the thumb switches prevent MCAS firing off again (reminder - there are still erroneous high AOA signals)? This is the first I have heard.

Zeke - you have the knowledge of an encyclopedia, and the patience of a saint (and boy do you need that whilst you are dealing with Captain Hindsight!) - please help us out here. :white:


You have miss-interpreted. MCAS (in AoA failed high fault condition) will operate for in 9.26 sec cycles repetitively, with a 5 sec delay between each cycle, if you do not touch the manual electrical trim switch (or hit the cut-out). You will just get to full nose down quicker.

Ray
 
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Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 1:38 pm

SheikhDjibouti wrote:
There is so much to read in the report, and I feel I need to read it at least three times over before I can fully appreciate it.

Meanwhile, here is one section I have cherry-picked because it disturbs me in several ways.

JT610 Final; section 2.5.1.2.4 wrote:
During the Functional Hazard Analysis (FHA), unintended MCAS-commanded stabilizer movement was considered a failure condition with Major effect in the normal flight envelope. Boeing reasoned that such a failure could be countered by using elevator alone. In addition, stabilizer trim is available to offload column forces, and stabilizer cutouts is also available but not required to counter failure.

"Boeing reasoned..." - so they tossed the idea around in a meeting but it wasn't verified by any test flying?
"could be countered by using elevator alone" - yeah, how did that work out in practice?
"and stabilizer cutouts is also available but not required to counter failure." ...not required :rotfl:

Now I realize most (probably all) of the above have been raised at some point here on a.net, but to see them stated so plainly in black-and-white shook me.
Am I mis-interpreting anything here?

I don't find the text shocking.

Boeing has always been saying they felt the pilots should be able to counter MCAS.

The now famous Mike Sinnett hidden mic recording with US pilot union reps said the same thing.

Overall I do find the apparent lack of end-to-end testing very disappointing.

I would have thought the test matrix would have had to have had a "take off with incorrectly calibrated AoA sensor" test case as a primary requirement given the reliance on one AoA sensor.

I've seen in my (non-aviation) engineering career many cases where lots of individual engineers put their changes into a system in isolation, and no one does end to end analysis or testing with real world scenarios.

I expect Boeing and FAA to be better than to allow such stuff to pass through their processes undetected.

I think that the CEO's testimony to the Senate that they were following long established aviation practices is a big cop out, a definite use of weasel words.

A weasel word, or anonymous authority, is an informal term for words and phrases aimed at creating an impression that something specific and meaningful has been said, when in fact only a vague or ambiguous claim has been communicated. Examples include the phrases "some people say", "most people think”, and "researchers believe". Using weasel words may allow the audience to later deny any specific meaning if the statement is challenged, because the statement was never specific in the first place. Weasel words can be a form of tergiversation, and may be used in advertising and political statements to mislead or disguise a biased view.

Ref: https://en.wikipedia.org/wiki/Weasel_word

Basically no one from Boeing or FAA chose to question those aviation practices where they were weak, in fact they seemed to have taken advantage of the weakness to avoid the cost of making a robust system and are now hiding behind the "anonymous authority" of "long established aviation practices".

Unfortunately the Senators were too focused on getting their sound bite on TV so no one called him on his weaseling.

Maybe if the US had more sensible liability laws the CEO would be able to be more forthcoming, but that's a topic for a different thread.
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morrisond
Posts: 2653
Joined: Thu Jan 07, 2010 12:22 am

Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 2:04 pm

zeke wrote:
morrisond wrote:
competent crew would have had minutes to figure things after first MCAS activation


How is a crew supposed to work out something in a few minutes that was deliberately left out of the manuals ?

morrisond wrote:
At that point LA


LA is LATAM, JT is Lion Air

morrisond wrote:
ET was doing fine.


No they were not, both pilots were pulling and they were unable to move the trim, they turned on the trim switches to get electric trim assistance, not to turn on MCAS. Using electric trim momentary disables MCAS.

morrisond wrote:
A competent crew who read the FCOM and had it in the cockpit should have easily identified the problem as MCAS as the accident was almost as exactly described in the FCOM bulletin.


How could the JT crew have read the "FCOM bulletin" if it was only published after their crash ?

morrisond wrote:
Normal Runaway stabilizer would have saved the Lion Air flight.


It did not present as a runaway stab, https://youtu.be/UD4-8MlEy44

They were able to move it and control it with the electric trim, and with the timer involved the trim does not move for 5 seconds after using eclectic trim. A runaway stab goes in one direction to the stop, and is uncontrollable.


Sorry on the LA acronym - I knew it wasn't right I was just being lazy - I figured you would know what I meant.

I'm quite aware that Lion Air did not have the FCOM bulletin. So what is ET's excuse?

Zeke - I've asked you this following one before - but you have never replied.

You are flying along with the AP engaged and it tries to put you into a 30 Degree bank without your input but you noticed the bank and corrected it with the controls but then it did it again.

How many times would that have to happen before you would consider it your fault for not turning off the offending system and flying using the manual controls?

2-3 times? 4-5 times? 22 times? or is 23 times the magic number - anything below that and the Pilot holds no responsibility for shutting off the bad system?
Last edited by morrisond on Wed Oct 30, 2019 2:18 pm, edited 1 time in total.
 
morrisond
Posts: 2653
Joined: Thu Jan 07, 2010 12:22 am

Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 2:09 pm

SheikhDjibouti wrote:
There is so much to read in the report, and I feel I need to read it at least three times over before I can fully appreciate it.

Meanwhile, here is one section I have cherry-picked because it disturbs me in several ways.

JT610 Final; section 2.5.1.2.4 wrote:
During the Functional Hazard Analysis (FHA), unintended MCAS-commanded stabilizer movement was considered a failure condition with Major effect in the normal flight envelope. Boeing reasoned that such a failure could be countered by using elevator alone. In addition, stabilizer trim is available to offload column forces, and stabilizer cutouts is also available but not required to counter failure.

"Boeing reasoned..." - so they tossed the idea around in a meeting but it wasn't verified by any test flying?
"could be countered by using elevator alone" - yeah, how did that work out in practice?
"and stabilizer cutouts is also available but not required to counter failure." ...not required :rotfl:

Now I realize most (probably all) of the above have been raised at some point here on a.net, but to see them stated so plainly in black-and-white shook me.
Am I mis-interpreting anything here?

But it gets worse...
JT610 Final; section 2.5.1.2.4 wrote:
(continued) With an MCAS command due to an erroneous high AOA signal, and flight crew inputs that do not fully return the aircraft to a trimmed state, subsequent MCAS commands can result in the aircraft becoming significantly miss-trimmed.
To recover, the flight crew could:
1) stop making manual electric trim inputs (which would stop resetting MCAS),
or
2) make sufficient (long duration) manual electric trim inputs to return the aircraft to a trimmed state
or
3) use the stabilizer trim cutout procedure to stop all electric trim commands and control trim using the manual trim wheels.

I'm ok with 2) and 3), but I have a problem with the first solution. Until now I didn't realise it was the Lion Air crews fault for provoking MCAS by using manual electric trim inputs (22 times)
They should have just stopped making manual electric inputs, and allowed MCAS to go back to sleep.
It would leave them with an aircraft that was out-of-trim, but not lethally so. And over time they could ask some of the well-fed first class passengers to move to the back of the plane to help keep the aircraft level.
After twelve months of careful deliberation, has the report got it right? Does simply keeping your thumbs away from the thumb switches prevent MCAS firing off again (reminder - there are still erroneous high AOA signals)? This is the first I have heard.

Zeke - you have the knowledge of an encyclopedia, and the patience of a saint (and boy do you need that whilst you are dealing with Captain Hindsight!) - please help us out here. :white:


I think #1 might have been a typo or misunderstanding - as long as the AOA read high - MCAS would have kept triggering as it had unlimited ability to do so. It just paused for 5 seconds before continuing again.

I don't think Boeing considered how effective the Elevator would be after multiple MCAS activations - it was good for one - so so with 2 - definitely not beyond that.
 
ryanov
Posts: 236
Joined: Sat Nov 03, 2012 4:38 am

Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 2:38 pm

BEG2IAH wrote:
I still can't wrap my mind around how many things went wrong and then some. We can definitely say that the root cause was Boeing's bad design, but why stop there? The actual root cause is greed and an utmost devaluation of the human life. And this applies to all the parties involved, not only Boeing. May all the victims rest in peace, I really hope lessons are learned.

I would include members of this board who mention how greedy labor unions are at every turn. The backstop against greed should not be loss of life from crashes.
 
frmrCapCadet
Posts: 4026
Joined: Thu May 29, 2008 8:24 pm

Re: Updated: Final report of Lion Air JT610 has been released

Wed Oct 30, 2019 2:48 pm

As I mentioned earlier, the Boeing CEO should have been questioned first in a private hearings by aides who were knowledgeable about aviation and FAA certification - witness is allowed to correct himself, ask for time to seek more information from other company experts. After that comes the public hearing, and having been called out in private about specific evasive answers, substantive answers will result.
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