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litz
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Dec 19, 2018 8:49 pm

This has been posted in this thread before, but it bears posting again.

for those claiming that MCAS was "hidden" ... it's right in the manual, covering differences between Max and previous iterations of the 737. Page 748.

Image

Now, whether pilots at a particular airline were exposed to this information ... that's not Boeing's problem, that's the airline's problem.

Apparently United shared this info, and WN/AA did not.

Or this picture is of a fictional training manual.
 
WIederling
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Dec 19, 2018 9:09 pm

N212R wrote:
WIederling wrote:
Did the MAX8 actually enter water still in one piece
or did it start to disassemble even before the final impact?

Why would someone ask a question to which they already know the answer?

Why do some posters make assumptions ( or was it an allegation ) that are wrong? :-)
Murphy is an optimist
 
Tristarsteve
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Dec 19, 2018 9:36 pm

litz wrote:
This has been posted in this thread before, but it bears posting again.

for those claiming that MCAS was "hidden" ... it's right in the manual, covering differences between Max and previous iterations of the 737. Page 748.

Image

Now, whether pilots at a particular airline were exposed to this information ... that's not Boeing's problem, that's the airline's problem.

Apparently United shared this info, and WN/AA did not.

Or this picture is of a fictional training manual.


This is from a maintenance training manual for technicians/mechanics.
Pilots do not see this. Maintenance do a two week difference course, pilots get a handout.
 
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scbriml
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Dec 19, 2018 9:58 pm

litz wrote:
This has been posted in this thread before, but it bears posting again.

for those claiming that MCAS was "hidden" ... it's right in the manual, covering differences between Max and previous iterations of the 737. Page 748.

Image

Now, whether pilots at a particular airline were exposed to this information ... that's not Boeing's problem, that's the airline's problem.

Apparently United shared this info, and WN/AA did not.

Or this picture is of a fictional training manual.


Which manual? Is it available online?

Someone claimed this was a maintenance manual, not something pilots are going to see.

Tristarsteve wrote:
This is from a maintenance training manual for technicians/mechanics.
Pilots do not see this. Maintenance do a two week difference course, pilots get a handout.


Ah, thanks. I thought I read that upthread.
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klkla
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 1:59 am

BEG2IAH wrote:
marcelh wrote:
@ BEG2IAH:
Good article, but IMHO it is a bit unbalanced. It lacks the answer at the question WHY Boeing told his customers/pilots nothing about the existence of MCAS.


How come UAL knew about MCAS?


Actually that is addressed in the article: "MCAS was not used in earlier 737 models. It was adopted for the MAX as a safety feature, to address stability issues related to the design changes necessitated by its larger engines. It was not mentioned in the aircraft manuals, nor was the possibility of uncommanded control inputs discussed. However, the aircraft manual gives pilots correct instructions on how to deal with such a situation, irrespective of its cause, by disconnecting the stabilizer trim system

In other words, they didn't need to know specifically about this feature. Irrespective of the cause of the behavior they were trained how to deal with it.
 
ikramerica
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 2:12 am

hivue wrote:
BEG2IAH wrote:
...In-flight stalls resulted in the loss of Air France Flight 447 in 2009 and Air Asia Flight 8501 in 2014. In each of these accidents, the automated flight control system failed...Both Air France 447 and Air Asia 8501 involved degradation of Airbus automated flight control systems which led the pilots to stall the airplanes and fail to regain control.


In the AF447 case the FCS did not "fail." It handed the airplane over to the pilots when it detected inaccurate sensor input -- as designed. This in turn did not "lead" the pilots to stall the airplane. They did that on their own.

The logic failed. Not the computer logic, but the human+computer logic.

The system as designed stopped warning pilots of stall once it well went past stall, so when they pulled it OUT of stall, the system screamed at them that they were entering stall. That is a logical problem. Should they have known this was a condition? Probably. But it was damn confusing in a panic.

There are plenty of systems that have defective user interfaces with dials that go "all the way around" and confuse people or stop providing input past a point because who on earth would get that far? Usually it's analog systems and not life and death situations. In some this confusion is even a feature, but you have to know about it.

The logic of MCAS doesn't really matter. What matters is that like ALL systems, it can fail, and like ALL critical systems, there should be a way to disable it, and disabling it was no different than disabling other ways the trim could runaway. The previous crew knew this, and did it. The last crew, didn't do it.

The MECHANIC was on board and should have known it. It was in HIS manuals. And one would assume that if you put a mechanic on the flight to monitor a system, he should, I don't know, maybe, UNDERSTAND THE DAMN SYSTEM!

I can understand the pilots screwing up, but in this case, Lion had a mechanic on board to specifically monitor this and he should have been versed in the systems and how to disable them.
Of all the things to worry about... the Wookie has no pants.
 
LDRA
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 2:29 am

klkla wrote:
BEG2IAH wrote:
marcelh wrote:
@ BEG2IAH:
Good article, but IMHO it is a bit unbalanced. It lacks the answer at the question WHY Boeing told his customers/pilots nothing about the existence of MCAS.


How come UAL knew about MCAS?


Actually that is addressed in the article: "MCAS was not used in earlier 737 models. It was adopted for the MAX as a safety feature, to address stability issues related to the design changes necessitated by its larger engines. It was not mentioned in the aircraft manuals, nor was the possibility of uncommanded control inputs discussed. However, the aircraft manual gives pilots correct instructions on how to deal with such a situation, irrespective of its cause, by disconnecting the stabilizer trim system

In other words, they didn't need to know specifically about this feature. Irrespective of the cause of the behavior they were trained how to deal with it.


Thanks for the clarification from the article.

Even though the article clarifies what was actually known to the pilot before the mishap, there is still quite a bit of Boeing lawyering being slipped into it unfortunately.

The article implies there is procedure to handle MCAS failure. That is a lie. A procedure consists of DETECTION CRITERIA for pilot to properly diagnose condition, then RESPONSE ACTION(S) for pilot to execute to counteract the failure condition. Boeing existing procedure in FCOM only contains RESPONSE ACTION(S) for pilot to execute. The actual DETECTION CRITERIA for MCAS failure is not there, and only came out in the FAA AD

Below is the laundry list of potential symptoms to detect and diagnose MCAS failure, that only came out with the AD


Continuous or intermittent stick shaker on the affected side only.

Minimum speed bar (red and black) on the aff
ected 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.

Autopilot may disengage.

Inability to engage autopilot.
 
markno
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 4:23 am

What I don't get about the stability topic is why Boeing added a new "anti-something" system at all. If it's just a little stability issue, isn't it enough to change some values in the old logic that prevents stalls? Or did Boeing replace an old system with the MCAS system and it's like source code refactoring?

I know very little about planes and I would always agree and try to judge a plane as it is, with all systems added, and as they are meant to work, without defects. But when I try to understand this stability topic, I get lost in it. I'd rather pay more for a flight in a plane that needs more fuel, in a 737 NG or an Airbus like that, than thinking about fuel saving, even though it's only part of the airlines calculation. It's just that getting an advantage without any disadvantage never seems possible in my everyday life. At least that MCAS article a few pages earlier made me think so.
 
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scbriml
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 8:46 am

klkla wrote:
BEG2IAH wrote:
marcelh wrote:
@ BEG2IAH:
Good article, but IMHO it is a bit unbalanced. It lacks the answer at the question WHY Boeing told his customers/pilots nothing about the existence of MCAS.


How come UAL knew about MCAS?


Actually that is addressed in the article: "MCAS was not used in earlier 737 models. It was adopted for the MAX as a safety feature, to address stability issues related to the design changes necessitated by its larger engines. It was not mentioned in the aircraft manuals, nor was the possibility of uncommanded control inputs discussed. However, the aircraft manual gives pilots correct instructions on how to deal with such a situation, irrespective of its cause, by disconnecting the stabilizer trim system

In other words, they didn't need to know specifically about this feature. Irrespective of the cause of the behavior they were trained how to deal with it.


I think you're mistaken - that's for stabiliser trim runaway, no? A situation that this flight didn't experience.

My understanding is that pre-MAX if the plane was trimming nose down, pulling back on the yoke stopped it. Without telling pilots Boeing added MCAS to the MAX which behaves similarly, except it will start to trim nose down again a few seconds later (assuming condition causing it to activate remain). This is different to trim runaway and something that pilots were not aware of.
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PixelFlight
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 9:41 am

ikramerica wrote:
hivue wrote:
In the AF447 case the FCS did not "fail." It handed the airplane over to the pilots when it detected inaccurate sensor input -- as designed. This in turn did not "lead" the pilots to stall the airplane. They did that on their own.

The logic failed. Not the computer logic, but the human+computer logic.

The system as designed stopped warning pilots of stall once it well went past stall, so when they pulled it OUT of stall, the system screamed at them that they were entering stall. That is a logical problem. Should they have known this was a condition? Probably. But it was damn confusing in a panic.

There are plenty of systems that have defective user interfaces with dials that go "all the way around" and confuse people or stop providing input past a point because who on earth would get that far? Usually it's analog systems and not life and death situations. In some this confusion is even a feature, but you have to know about it.

For the AF447 case, Airbus identified the human/machine interface as one point of improvement.

ikramerica wrote:
The logic of MCAS doesn't really matter. What matters is that like ALL systems, it can fail, and like ALL critical systems, there should be a way to disable it, and disabling it was no different than disabling other ways the trim could runaway. The previous crew knew this, and did it. The last crew, didn't do it.

Disabling is the last possible action. But there are two important points that can't be avoided in case of a certification required safety system like MCAS:
1) It must be designed with redundancy and to avoid dangerous action on important control surface.
2) It must be well know to the pilot and regularly trained in case of failure.

ikramerica wrote:
The MECHANIC was on board and should have known it. It was in HIS manuals. And one would assume that if you put a mechanic on the flight to monitor a system, he should, I don't know, maybe, UNDERSTAND THE DAMN SYSTEM!

I can understand the pilots screwing up, but in this case, Lion had a mechanic on board to specifically monitor this and he should have been versed in the systems and how to disable them.

The crew received no specific indication of a AoA error, nor of a FCC/MCAS error, nor stab trim error, as required by part 25 certification. There received many indirectly related errors, and the document that explain the relation to the MCAS and stab trim was issued only after there death. So don't blame them on this.
 
WIederling
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 10:26 am

klkla wrote:
In other words, they didn't need to know specifically about this feature.
Irrespective of the cause of the behavior they were trained how to deal with it.


issue is that runaway behaviour has changed too. Strongly.
Makes detection more difficult without further explanations.
Then, in that referenced document MCAS is assigned to counter high speed excessive pitch up.
Not a strong indication that it can entangle you at lower speeds in a bog standard flight situation.

Over all MCAS is quite the U-BOATing addition to flight augmentation.
Murphy is an optimist
 
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PW100
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 1:27 pm

ikramerica wrote:
The MECHANIC was on board and should have known it. It was in HIS manuals. And one would assume that if you put a mechanic on the flight to monitor a system, he should, I don't know, maybe, UNDERSTAND THE DAMN SYSTEM!

I can understand the pilots screwing up, but in this case, Lion had a mechanic on board to specifically monitor this and he should have been versed in the systems and how to disable them.


I suspect that, even in the USA, it would be highly illegal for a licensed-mechanic, to interfere (or even interact) with licensed air line pilots in the cockpit while in-flight. Wonder what/how CRM protocol would handle such . . .
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
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litz
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 20, 2018 6:42 pm

The two points that still bother me about this whole mess ...

1) the crew on the previous flight obviously handled the issue and were able to successfully disable the system, and were able to successfully fly a (later determined to be) un-airworthy aircraft safely to its destination ... however wise/unwise that ended up being.

2) the crew on the accident flight apparently went between flaps 0 and flaps 5 several times ... and the plane pitched down each time they went to flaps 0. What on earth kind of logic makes them keep doing an action that makes the plane do something unexpected? Once, twice ... by the third time you gotta wonder what was going through their minds .... all they had to do was leave flaps 5, and none of this likely would have ever happened.

Maybe the CVR, when it's found (and make no mistake, it WILL be found) will shed light on the decision making.
 
maint123
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 4:39 am

Using software to stabilise a plane is not a new concept. Its common in fighter jets which are inherently unstable to improve response.
The issue is keeping the feature hidden in manual mode, just to rush through the certification.
Give the pilots the tools to handle emergencies and the changes are manageable but to spring a new system on pilots struggling to stabilize a plane at low heights is not forgivable.
That's my summary.
 
ryanov
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 5:40 am

Are mechanics permitted on the flight deck during a flight?
 
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AirlineCritic
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 7:28 am

litz wrote:
2) the crew on the accident flight apparently went between flaps 0 and flaps 5 several times ... and the plane pitched down each time they went to flaps 0. What on earth kind of logic makes them keep doing an action that makes the plane do something unexpected? Once, twice ... by the third time you gotta wonder what was going through their minds .... all they had to do was leave flaps 5, and none of this likely would have ever happened.


I don't think this is complicated. They were confused and unaware of the full logic behind MCAS. This wasn't one clear set of symptoms, but rather a set of problems, a set of *changing* problems and they had minutes to figure out the algorithms behind and determine what's wrong. They didn't know flaps was part of the logic... might be apparent to us now in perfect hindsight, but we were not in the cockpit.

You try this in your mind: half of your important instruments are showing non-sensical values, your yoke is fighting you, you feel like you are losing the battle with your hand strength starting to not be enough. At seemingly random times some adjustments are made to the way the aircraft is balanced. You're close to the ground and the plane wants to put the nose straight down. The situation keeps changing. You have a minute to live if you don't solve this puzzle: what component(s) failed and what do you do you save the situation? Now figure it out...
 
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Finn350
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 8:06 am

litz wrote:
This has been posted in this thread before, but it bears posting again.

for those claiming that MCAS was "hidden" ... it's right in the manual, covering differences between Max and previous iterations of the 737. Page 748.

Image

Now, whether pilots at a particular airline were exposed to this information ... that's not Boeing's problem, that's the airline's problem.

Apparently United shared this info, and WN/AA did not.

Or this picture is of a fictional training manual.


You are correct that the MCAS is described in SYSTEMS DIFFERENCES VOLUME I. The question is that should the MCAS have been described in the pilot training material and manuals or not. It was not described, and pilots were unaware of the MCAS.

United pilots were not any more aware of the MCAS than the other airlines pilots.
 
marcelh
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 11:35 am

ikramerica wrote:

The MECHANIC was on board and should have known it. It was in HIS manuals. And one would assume that if you put a mechanic on the flight to monitor a system, he should, I don't know, maybe, UNDERSTAND THE DAMN SYSTEM!

I can understand the pilots screwing up, but in this case, Lion had a mechanic on board to specifically monitor this and he should have been versed in the systems and how to disable them.


IIRC the mecanic wasn’t on board because of those specific problems. As mentioned earlier in this thread, Lion Air does send a mecanic on flights to remote locations because there is inadequate MC support on those locations.
But correct me if I’m wrong
 
Tristarsteve
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 2:22 pm

marcelh wrote:
ikramerica wrote:

The MECHANIC was on board and should have known it. It was in HIS manuals. And one would assume that if you put a mechanic on the flight to monitor a system, he should, I don't know, maybe, UNDERSTAND THE DAMN SYSTEM!

I can understand the pilots screwing up, but in this case, Lion had a mechanic on board to specifically monitor this and he should have been versed in the systems and how to disable them.


IIRC the mecanic wasn’t on board because of those specific problems. As mentioned earlier in this thread, Lion Air does send a mecanic on flights to remote locations because there is inadequate MC support on those locations.
But correct me if I’m wrong


This was a new type for Lion Air. The mechanics have to take a two week training course, a couple of days practical experience, and apply for the licence extension, just to convert from the NG. This takes time, so for the first few weeks the mechanics that are qualified on the new aircraft will travel with it to clear it for service at its destination. This is common to all airlines. As the mechanics on the stations are trained, then they can take over.
 
wingman
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 21, 2018 4:27 pm

maint123 wrote:
Using software to stabilise a plane is not a new concept. Its common in fighter jets which are inherently unstable to improve response.
The issue is keeping the feature hidden in manual mode, just to rush through the certification.
Give the pilots the tools to handle emergencies and the changes are manageable but to spring a new system on pilots struggling to stabilize a plane at low heights is not forgivable.
That's my summary.


And the counterpoint to this from everything I've distilled on this thread is that when a system on the 737 or any other plane doesn't work properly and actually prevents you from flying a stable flight path you shut it off and fly manually. Up to three prior crews and for certain the one prior crew did exactly this in accordance with this fundamental directive. The final crew fought it instead. We'll surely find out their thought process assuming they were clearly communicating in the cockpit as they were trying to save the plane.

The two positions above are likely to form the basis of all forthcoming lawsuits.."they should've known like the prior crew as a basic scenario procedure" vs. "Boeing should have disclosed the new system and forced additional training on it or at minimum called it out in the conversion differences document". And this leaves out maintenance practice at Lion which may well tip the blame scale in their direction. But Boeing will be paying out billions on this, I don't doubt that one bit. We can only hope that in the end this accident improves safety on all sides of the business (+ government).
 
AVLnative
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sun Dec 23, 2018 8:58 pm

Looks like CVR search resumed last Thursday:

http://www.xinhuanet.com/english/2018-1 ... 689363.htm
 
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SomebodyInTLS
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 27, 2018 12:51 pm

Don't think was posted yet... the inevitable US lawsuit:

https://www.channelnewsasia.com/news/wo ... l-11064640
"As with most things related to aircraft design, it's all about the trade-offs and much more nuanced than A.net likes to make out."
 
olddominion727
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 27, 2018 2:32 pm

how does this airline stay in business? I am not mocking, I am serious. Praying the souls and their family. Isn't that the second Max8? They have the same safety record as KE and CI had in the 80's 90's. I remember the Buddhist Monks praying of the CI planes from the tarmac, at TSA and TPE as they pushed back to keep them from crashing. I also remember DL & AF were putting KE on notice that if they didn't stop crashing and improve their safety record, they would be booted from SkyTeam. I knew the US had put them on probation from flying to US destinations because their record was so awful. They both cleaned it up. I still wouldn't fly CI.
 
mxaxai
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Dec 27, 2018 6:19 pm

olddominion727 wrote:
how does this airline stay in business? I am not mocking, I am serious. Praying the souls and their family. Isn't that the second Max8? They have the same safety record as KE and CI had in the 80's 90's. I remember the Buddhist Monks praying of the CI planes from the tarmac, at TSA and TPE as they pushed back to keep them from crashing. I also remember DL & AF were putting KE on notice that if they didn't stop crashing and improve their safety record, they would be booted from SkyTeam. I knew the US had put them on probation from flying to US destinations because their record was so awful. They both cleaned it up. I still wouldn't fly CI.

Well first of all this is the first Max8 to crash. Secondly their record is actually pretty decent for an Indonesian airline, although clearly less than ideal. They were on the EU black list (like all Indonesian airlines) and got removed since they satisfied the necessary criteria. Third, they are a large carrier that provides service to many places where Garuda doesn't fly and offers fares cheap enough to allow the large not-so-wealthy population to fly. The government probably won't shut them down nor can customers really opt to fly a competitor.
 
LDRA
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 12:24 am

https://www.wsj.com/articles/maintenanc ... 4?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.
 
pugman211
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 12:29 am

Maintenance instructions or maintenance actions????
 
MaksFly
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 12:36 am

... and there starts the chain of events.

If not for that unfortunate screwup... the world at large and pilots would not know that a single faulty AoA sensor can plunge an aircraft.

Safe to assume that if this happened on an NG... pilots would figure out the issue and plane would land safely?
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 2:52 am

LDRA wrote:
https://www.wsj.com/articles/maintenance-lapse-identified-as-initial-problem-leading-to-lion-air-crash-11545739204?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.


I read the full article, none of this information came from the investigators, the investigators, NTSB, and Boeing all declined to comment.

The article said this information came from people closely following the investigation (which could just be an a.netter), not the actual investigators.

It has zero credibility.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
fadecfault
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 3:52 am

LDRA wrote:
https://www.wsj.com/articles/maintenance-lapse-identified-as-initial-problem-leading-to-lion-air-crash-11545739204?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.

Misleading article because aircraft technicians do not calibrate the aoa sensor, we only verify it's working correctly.
Calibration is done by the manufacturer or repair station. The aoa is not line adjustable.
The views and opinions written here are my own and do not reflect those of my employer.
 
PlanesNTrains
Posts: 8924
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 6:08 am

fadecfault wrote:
LDRA wrote:
https://www.wsj.com/articles/maintenance-lapse-identified-as-initial-problem-leading-to-lion-air-crash-11545739204?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.

Misleading article because aircraft technicians do not calibrate the aoa sensor, we only verify it's working correctly.
Calibration is done by the manufacturer or repair station. The aoa is not line adjustable.


I suppose they mean “failed to verify the calibration” or some such?
-Dave


”Yet somewhere in Iceland a great anger stirred in the soul of a troubled individual...” - Revelation
 
luv2cattlecall
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 6:29 am

PlanesNTrains wrote:
fadecfault wrote:
LDRA wrote:
https://www.wsj.com/articles/maintenance-lapse-identified-as-initial-problem-leading-to-lion-air-crash-11545739204?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.

Misleading article because aircraft technicians do not calibrate the aoa sensor, we only verify it's working correctly.
Calibration is done by the manufacturer or repair station. The aoa is not line adjustable.


I suppose they mean “failed to verify the calibration” or some such?



If that were the case, couldn't the blame extend even further up - such as the source of the sensor for shipping a defective unit, or heck, even Boeing for having such a sensor failure on such a young frame?
 
fadecfault
Posts: 141
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 6:36 am

PlanesNTrains wrote:
fadecfault wrote:
LDRA wrote:
https://www.wsj.com/articles/maintenance-lapse-identified-as-initial-problem-leading-to-lion-air-crash-11545739204?mod=e2tw

Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash

Crash investigators have concluded preliminarily that improper calibration of an airspeed (AoA?) sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.

The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board.

Two days before Lion Air Flight 610’s early morning takeoff from Jakarta on Oct. 29, according to these people, mechanics installed but failed to properly calibrate a replacement airspeed sensor called an angle-of-attack indicator.

Based on information downloaded from the flight-data recorder, last month’s interim report revealed a constant 20-degree difference between signals from the angle-of attack sensor on the captain’s side—which had been replaced—and those from the co-pilot’s-side sensor.

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

People closely tracking the probe said that after U.S. air-safety experts re-enacted the tasks of installing, calibrating and verifying operation of the sensor, they deemed current maintenance instructions appropriate.

Misleading article because aircraft technicians do not calibrate the aoa sensor, we only verify it's working correctly.
Calibration is done by the manufacturer or repair station. The aoa is not line adjustable.


I suppose they mean “failed to verify the calibration” or some such?


That's the way it should be but the way it's written absolves the aoa repair station from any blame. There's too little information given to tell what happened to it.
The views and opinions written here are my own and do not reflect those of my employer.
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 7:34 am

luv2cattlecall wrote:
If that were the case, couldn't the blame extend even further up - such as the source of the sensor for shipping a defective unit, or heck, even Boeing for having such a sensor failure on such a young frame?


I am aware of no evidence to suggest the sensor that was removed or the one replaced was defective. The sensor that was removed and I assume installed during manufacture is being sent back to the manufacturer for testing. I would not be surprised to learn that that sensor removed had no problems with it. As these sensors output electrical signals, there are other ways for a constant change in resistance, impedance, or voltage to enter the signal such as a screw through a wire, or chafing against the airframe which can create apparent offsets.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
WIederling
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 8:42 am

PlanesNTrains wrote:
I suppose they mean “failed to verify the calibration” or some such?


The text in discussion here is hearsay and supposition. irrelevant what was meant or not. fiction.
Murphy is an optimist
 
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Finn350
Posts: 1343
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 8:54 am

The chain of events leading to the accident began in the MCAS design phase, especially the MCAS operation under certain malfunctions.
 
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PixelFlight
Posts: 125
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 9:01 am

zeke wrote:
luv2cattlecall wrote:
If that were the case, couldn't the blame extend even further up - such as the source of the sensor for shipping a defective unit, or heck, even Boeing for having such a sensor failure on such a young frame?


I am aware of no evidence to suggest the sensor that was removed or the one replaced was defective. The sensor that was removed and I assume installed during manufacture is being sent back to the manufacturer for testing. I would not be surprised to learn that that sensor removed had no problems with it..

Exactly. And in fact the text admit to have nothing to put on the table:

Until now, the precise cause of the improper signals from the captain’s-side sensor hasn’t been clear.

All the sames questions remains, in particular:
1) The AoA data from all others flights.
2) Failure analysis of the removed AoA.
3) Failure scenario of the installed AoA.
4) Design decision on the MCAS function with a single AoA.
5) Safety assessment activity on the MCAS.
6) Certification of the MCAS.
It's official that investigators have 1) and manufacturer started 2), both since several weeks already. At least 5) and 6) should be part of the required paperwork and meetings minutes.

zeke wrote:
As these sensors output electrical signals, there are other ways for a constant change in resistance, impedance, or voltage to enter the signal such as a screw through a wire, or chafing against the airframe which can create apparent offsets.

This is the hard part. The destruction of the aircraft give little chance on finding a common cause of failure of both the removed and installed AoA sensors. But if it's not a common cause, there have to explain how two consecutive AoA sensors failed. The removed AoA was probably originally installed by Boeing.
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Dec 28, 2018 9:30 am

PixelFlight wrote:
This is the hard part. The destruction of the aircraft give little chance on finding a common cause of failure of both the removed and installed AoA sensors. But if it's not a common cause, there have to explain how two consecutive AoA sensors failed. The removed AoA was probably originally installed by Boeing.


I think the FDR will have something like the last 60 hrs of flight which should include before and after the sensor replacement.

They should also have the other QAR style data from previous flights.

They have only released a small snapshot of the data they have available.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
maint123
Posts: 89
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 1:42 am

https://www.reuters.com/article/us-boei ... SKCN1OR1MJ

"Family of Lion Air co-pilot sues Boeing in Chicago over fatal crash
FILE PHOTO: Families and colleagues of passengers and crew of Lion Air flight JT610 throw flowers and petals from the deck of Indonesia Navy ship KRI Banjarmasin as they visit the site of the crash to pay their tribute, at the north coast of Karawang, Indonesia, November 6, 2018. REUTERS/Beawiharta/File Photo
CHICAGO (Reuters) - The family of the Indonesian co-pilot of a Lion Air flight that crashed in October, killing all 189 on board, has filed a wrongful death lawsuit against Boeing Co in Chicago, adding to litigation piling up against the manufacturer in its hometown.

The lawsuit, filed on Friday in the Circuit Court of Cook County, Illinois, alleges that a Lion Air-operated Boeing 737 MAX 8 was unreasonably dangerous because its sensors provided inconsistent information to both the pilots and the aircraft.

Boeing declined to comment on pending litigation."

As per past record the US judge will throw out the suit saying its not in their jurisdiction. American judges typically support their countrymen and companies.
But if a American is effected abroad than then they lay claim to the whole world, like in the case of the American "student" who fell ill in a North Korean prison and died, and has been awarded half a billion in damages.
 
AvObserver
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 2:52 am

maint123 wrote:
As per past record the US judge will throw out the suit saying its not in their jurisdiction. American judges typically support their countrymen and companies.
But if a American is effected abroad than then they lay claim to the whole world, like in the case of the American "student" who fell ill in a North Korean prison and died, and has been awarded half a billion in damages.


This too is an outrageous claim without foundation unless you prefixed with "In my opinion". Otherwise you come off as just another U.S. hating troll of the sort we seem to have too many of on this forum. As for the lawsuit itself, it's on shaky ground anyway until at least the specific cause of the crash is pinpointed. Nothing unusual about courts entertaining a premature lawsuit but if it's going to go anywhere, it needs to be grounded in some basis of fact and as of yet, there aren't enough hard facts to support it's contention. More likely the judge will throw it out as lacking in merit, at least until the crash investigation is complete.
 
787SIN
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 2:56 am

What I noted from the reported is that the PIC of the flight from DPS-CGK picked up the automatic trim inputs nose down and also stated that by the third trim input the control column became too heavy for the SIC. Fortunately, a decision was made at that point to cut off the electric trim which probably saved the aircraft.

Could unfortunately the crew of the incident flight have realised what they needed to do but by the fourth/fifth trim input, but it was already too late as the control forces were such that both had to compensate by holding on to the column with neither of them wanting to/or being able to let go of the column as that's all that was keeping the nose up to reach for the trim cut out switches.

So what could ohave caused the increased forces, as we all know aerodynamic forces should not really be felt even on a 737 through the column unless the hyds are off, so could the Elevator Feel Shift that occurs when a stall is detected (I believe based on AoA input to the SMYD) be the cause of the increase of column forces, as this applies forces to the feel and centering unit to resist elevator up movement which could have effectively compounded the situation.

So perhaps the same AoA fault that caused the MCAS inputs also caused effectively a counter issue in that full elevator authourity was not readily available.
 
N212R
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 3:31 am

Any updates on the hunt for the CVR? Don't all speak up at once....
 
ikramerica
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 7:14 am

N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....

If the copilots family is already filing a lawsuit they must be confident it won’t be found.
Of all the things to worry about... the Wookie has no pants.
 
StTim
Posts: 3119
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 7:51 am

ikramerica wrote:
N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....

If the copilots family is already filing a lawsuit they must be confident it won’t be found.

Please explain your rationale for that statement.
 
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AirlineCritic
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 8:03 am

Folks, whether or not the WSJ article has any grains of truth in it, please remember the Swiss cheese model. A failed component is not the only cause of an accident. For instance, in the AF 447 case, we can improve the sensors but can't make the never fail; the rest of the system (incl. pilots) must deal with the situations.

So, lets just wait...

...and also, can we stop the fanboy attacks? Thanks :-)
 
airnorth
Posts: 281
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 8:07 am

N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....

Look up thread at reply#2231, sounds like the search should have started a few days ago, scheduled to search for 10 days.
 
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scbriml
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 8:42 am

N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....


My last hourly update said the search was continuing. Did you not sign up for hourly updates?
Time flies like an arrow. Fruit flies like a banana!
There are 10 types of people in the World - those that understand binary and those that don't.
 
peterinlisbon
Posts: 1292
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 9:42 am

If this turns out to be another problem with the pitot tube or static system, surely they should have some kind of procedure to put aircraft into a special emergency mode that disables the stall warning and overspeed alarm and instead flies based on throttle and attitude settings with an estimated airspeed. Either that or their should be a totally separate backup system that can be deployed like the RAT. It's stupid that so many aircraft are lost just because one indicator isn't working.
 
marcelh
Posts: 295
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 11:51 am

airnorth wrote:
N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....

Look up thread at reply#2231, sounds like the search should have started a few days ago, scheduled to search for 10 days.


Just checked “FR24 for ships” and the MPV Everest is positioned at the crash site.
 
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PixelFlight
Posts: 125
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 12:59 pm

787SIN wrote:
So perhaps the same AoA fault that caused the MCAS inputs also caused effectively a counter issue in that full elevator authourity was not readily available.

Interesting. Can this be validated on a 737 MAX simulator ? From my understanding there exists programming interface to add a specific failure mode. Adding +20° to a single AoA sensor should be easy for someone that already worked on a such system.
 
PlanesNTrains
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Dec 29, 2018 4:31 pm

scbriml wrote:
N212R wrote:
Any updates on the hunt for the CVR? Don't all speak up at once....


My last hourly update said the search was continuing. Did you not sign up for hourly updates?


Touché.
-Dave


”Yet somewhere in Iceland a great anger stirred in the soul of a troubled individual...” - Revelation

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