Author Topic: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'  (Read 63280 times)

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Offline floobydust

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #250 on: March 10, 2019, 06:10:35 pm »
Boeing's MCAS software update, as an emergency measure by the FAA and Boeing, deployment delayed for months. It was due January but now maybe after April 2019.
"...Boeing is examining whether the anti-stall system should also check data from the second probe before engaging"
 

Offline raptor1956

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #251 on: March 11, 2019, 06:22:37 am »
Too soon to say what happened for sure, but the similarities with the Lionair crash has to point a finger at MCAS as a logical place to look at.  The FDR will be revealing but as with the Lionair crash I think the CVR may well be more revealing if crew response to a problem played a role.  If it turns out that this is another case of MCAS taking over and the pilots not knowing what to do then Ethiopian Air has some explaining to do on the pilot training program.  If the pilots fought the MCAS system for 5 minutes and didn't turn off the Stab Trim then whatever blame Boeing gets, and probably deserves, should be shared equally with the pilots and the airline.  Can there be a 737 Max pilot that does not know about MCAS and how to respond when it acts up anywhere in the world at this point?


Brian
 

Offline sleemanj

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #252 on: March 11, 2019, 06:36:22 am »
At this point, if it's a Boeing (737 MAX) I ain't going.
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Offline Berni

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #253 on: March 11, 2019, 06:49:07 am »
When i saw the news i quickly remembered this very thread. The similarities between the crashes are quite striking.

Id imagine things are getting quite tense among the upper management at Boeing now.
 

Offline GeorgeOfTheJungle

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« Last Edit: March 11, 2019, 07:31:18 am by GeorgeOfTheJungle »
Even when the experts all agree, they may well be mistaken.
 

Offline FlyingHacker

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #255 on: March 11, 2019, 07:33:51 am »
As a pilot I can say an Angle of Attack (AOA) indicator is a suitable safety measure for when the pitot tube is clogged and you have no airspeed indication. The main thing a pilot is using the airspeed indicator for is to set the Angle of Attack to a safe measure to avoid a stall (lots of other stuff, too, but that is the one that usually kills you).

The 737 MAX has had bulletins on its AOA indicator. So perhaps it was multiple sensor failure.

A pilot is trained to cross check data from multiple sensors during IFR flight. We learn how to identify various failures. I can tell you from various in-flight failures (instrumentation as well as single engine loss of power) that this does take a moment to identify the issue, but the first thing I do is pitch forward (nose down) to decrease my AOA when diagnosing issues. If this means you can't hold your altitude immediately declare and emergency and work from there. Rule one of being a pilot is FLY THE AIRPLANE.

I feel like a lot of commercial pilots are so concerned about ATC deviations and possible career ramifications that they hesitate to declare emergencies or take emergency action prior to declaring.
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Online soldar

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #256 on: March 11, 2019, 08:56:02 am »
Flightradar24 data regarding the crash of Ethiopian Airlines flight 302:
https://www.flightradar24.com/blog/flightradar24-data-regarding-the-crash-of-ethiopian-airlines-flight-302/
I do not understand the graphs and they seem contradictory to me.

Compare altitude with rate of climb. When the aircraft is climbing it should be gaining altitude and yet at first it gains altitude while not climbing and later it climbs without gaining altitude.  Maybe the two lines are shifted with respect to each other? Or am I misunderstanding anything?
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Offline GeorgeOfTheJungle

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #257 on: March 11, 2019, 10:07:18 am »
I do not understand the graphs and they seem contradictory to me.

Yes, and I don't know what's going on:



Here's the chart of the previous 737-MAX crash https://www.flightradar24.com/blog/flightradar24-data-regarding-lion-air-flight-jt610/ It says "derived Vertical speed", I don't know in what sense is the word derived used. Most of it makes sense but in a few spots the data is contradictory too.
Even when the experts all agree, they may well be mistaken.
 

Online Gyro

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #258 on: March 11, 2019, 10:51:28 am »
The CVR has been found. Hopefully it's not too damaged.
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Offline AndyC_772

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #259 on: March 11, 2019, 11:01:10 am »
Slightly OT, but is it the case that one recorder only logs voice, while the other only logs data?

Is there a compelling reason why a single recorder can't log both? Or why both recorders don't each log everything?

Online Gyro

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #260 on: March 11, 2019, 11:18:55 am »
Some level of redundancy I guess. I'm not sure if modern CVRs still use tape rather than the Flash used in the FDR.  You'd hope that, with advancing technology, they'd move to two recorders, each recording both voice and data.

I suppose there is a huge amount of testing, not to mention backward compatibility involved in bringing new black boxes into service.


EDIT: It looks as if they are made http://www.aircpa.com/product/combined-cvr-fdr-wembedded-rips-cvfdr-145r/ I found some reference to them being used on the 787 too.
« Last Edit: March 11, 2019, 11:36:10 am by Gyro »
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Offline Berni

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #261 on: March 11, 2019, 11:40:42 am »
I'm guessing the reason for separate black box recorders is historical

Back when these things ware analog and used magnetic tape meant it was likely easier to build one optimized for mono audio while another box was designed for lower bandwidth sensor data but with many channels, Perhaps using multitrack heads or stuffing all the channels into one track using modulation and multiplexing.

Now that its all flash it doesn't really make a difference, but yeah id imagine its not easy to change it due to all the paperwork needed to do so. All existing aircraft also have wiring harnesses prepared for this kind of dual black box setup and likely couldn't very easily be upgraded to the new standard.
 

Offline GeorgeOfTheJungle

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #262 on: March 11, 2019, 11:52:56 am »
Quote
Gebeyehu Fikadu, an eyewitness to Sunday's fatal crash about two-hour drive south of the Ethiopian capital of Addis Ababa, told CNN that the plane was "swerving and dipping" and belching smoke as it came down. 

"I was in the mountain nearby when I saw the plane reach the mountain before turning around with a lot of smoke coming from the back and then crashed at this site," said the 25-year-old, who was collecting firewood on the mountain with three other locals when it happened.

"It crashed with a large boom. When it crashed luggage and clothes came burning down.

"Before it crashed the plane was swerving and dipping with a lot of smoke coming from the back and also making a very loud unpleasant sound before hitting the ground."
https://edition.cnn.com/world/live-news/ethiopian-airlines-plane-crash/index.html#h_f2affeaf6e5854fe7c4236c32490db45
« Last Edit: March 12, 2019, 04:27:16 pm by GeorgeOfTheJungle »
Even when the experts all agree, they may well be mistaken.
 

Online Gyro

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #263 on: March 11, 2019, 04:04:50 pm »
FDR now also found.
Chris

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Offline tooki

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #264 on: March 11, 2019, 05:28:40 pm »
I'm guessing the reason for separate black box recorders is historical

Back when these things ware analog and used magnetic tape meant it was likely easier to build one optimized for mono audio while another box was designed for lower bandwidth sensor data but with many channels, Perhaps using multitrack heads or stuffing all the channels into one track using modulation and multiplexing.

Now that its all flash it doesn't really make a difference, but yeah id imagine its not easy to change it due to all the paperwork needed to do so. All existing aircraft also have wiring harnesses prepared for this kind of dual black box setup and likely couldn't very easily be upgraded to the new standard.
What's kinda crazy is that, due to magnetic tape (and paper) being too sensitive to heat, pre-Flash CVRs and FDRs used metal tape (and in some really old ones, wire) as the magnetic recording medium. Older FDR models didn't even do it magnetically, but rather used styluses that engraved the data onto wide metal tape -- just like a polygraph or seismograph, except with a stylus instead of a pen.

I'm actually kinda surprised that we even still rely on CVRs and FDRs, since satellite-based, real-time, server-side logging is available. It is used by some airlines. Streaming all that means that you have it instantly, and it doesn't matter whether you find the black boxes. (I'm sure there are occasions where streaming fails, so I wouldn't say to get rid of black boxes entirely, but just to relegate them to being backups.)
 

Offline raptor1956

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #265 on: March 11, 2019, 06:40:03 pm »
Quote
Gebeyehu Fikadu, an eyewitness to Sunday's fatal crash about two-hour drive south of the Ethiopian capital of Addis Ababa, told CNN that the plane was "swerving and dipping" and belching smoke as it came down. 

"I was in the mountain nearby when I saw the plane reach the mountain before turning around with a lot of smoke coming from the back and then crashed at this site," said the 25-year-old, who was collecting firewood on the mountain with three other locals when it happened.

"It crashed with a large boom. When it crashed luggage and clothes came burning down.

"Before it crashed the plane was swerving and dipping with a lot of smoke coming from the back and also making a very loud unpleasant sound before hitting the ground."
https://edition.cnn.com/world/live-news/ethiopian-airlines-plane-crash/index.html#h_f2affeaf6e5854fe7c4236c32490db45


If there was smoke coming from the plane, and particularly if it wasn't clearly identified with and engine, could completely change the picture of what happen and surely opens the door to something nefarious going on.  If there was an onboard fire or cabin or cargo hold explosion it's quite possible we would have seen a similar flight profile and ultimate crash.  But, as with so many cases, eye witness accounts are often the least trust worthy even when a competent person is involved and the average passer by is next to useless in these maters.

It's also possible that the pilots were jacking the throttles around as a consequence of an MCAS takeover and it is possible that could produce some smoke.

If the reports are true that both the CVR and FDR have been found and they are in decent shape we should get a preliminary report pretty soon given the stand-down ordered for more than 100 737 Max AC -- if there was evidence that the problem wasn't MCAS and was a cargo fire then that should permit the grounded AC to resume flying.


Brian
 

Offline edy

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #266 on: March 11, 2019, 09:48:07 pm »
I do not understand the graphs and they seem contradictory to me.

Yes, and I don't know what's going on:



Here's the chart of the previous 737-MAX crash https://www.flightradar24.com/blog/flightradar24-data-regarding-lion-air-flight-jt610/ It says "derived Vertical speed", I don't know in what sense is the word derived used. Most of it makes sense but in a few spots the data is contradictory too.


I don't know what measurements are actually being tracked by flightradar24 but if it is just GPS coordinates (or "pings") every once in a while, it would have a location in 3D space which includes coordinates and altitude. The "derived" part would be vertical speed, which would essentially be the derivative of the altitude measurement (i.e. the delta or slope of the altitude). So if you see your altitude changing by 100 feet every minute... 0, 100, 200, 300, 400... you have a gradual slope in altitude, during that time the "derived" vertical speed would be a constant 100 per minute. When it flattens to 400, 400, 400, 400... you would see vertical speed become 0 on that part of the altitude curve (i.e. flat or zero slope). The ground speed would therefore simply be the change in the X,Y (GPS) coordinates. Now since we are looking at 3D vectoring there would be more complex way to determine airspeed because you would then include the vertical in that as well with the ground speed, do XYZ vector and determine actual velocity through air. Then again, there is also wind that complicates things. I'm not sure how flightradar is tracking things but I'm sure the "blackbox" on the airplane has the detail they will need to determine what happened.

Not being a pilot, I am actually surprised at how much of the flight is "fly by wire" and relying on instruments. I guess at that level of airplane you need to... I can only imagine flying a Cessna, looking out the window, feeling the G-forces and wind and hearing the engine noise to determine whether I am properly flying the thing. Someone mentioned earlier in the thread that pilots want to stay in that flight path regardless as deviation may cause disciplinary actions, instead of just FLYING THE PLANE no matter where and how and at what speed and altitude.
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Offline Nusa

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #267 on: March 11, 2019, 10:34:53 pm »
Not being a pilot, I am actually surprised at how much of the flight is "fly by wire" and relying on instruments.

Let's not go down this rabbit hole again, like we did way earlier in this thread. The 737 is NOT a fly by wire aircraft, and uses hydraulic control systems. That includes the 737 MAX, with the exception of the spoiler system. The term "fly by wire" means that the interface between the pilots controls is interpreted and converted to electronic signals transmitted to the actuators for flight surfaces via signal wires.

As for paying attention to instruments, that's part of the job, but doesn't mean they aren't looking and feeling as well. If you're suggesting that the pilots were unaware they weren't climbing properly and had failed to notice they never got more than a few hundred feet off the ground before running into rising terrain, that is clearly not the case. Even passengers would notice that difference in "feel" from a normal takeoff, without looking out the windows.
 
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Offline edy

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #268 on: March 11, 2019, 10:59:43 pm »
Not being a pilot, I am actually surprised at how much of the flight is "fly by wire" and relying on instruments.

Let's not go down this rabbit hole again, like we did way earlier in this thread. The 737 is NOT a fly by wire aircraft, and uses hydraulic control systems.

Yes thank you for the correction and clarification, as I misspoke about the "fly by wire". I am not sure how the controls and the mechanics interconnect, so I used the term incorrectly to refer to this. What I was trying to get at was whether in the evolution of flight training from smaller aircraft to larger ones, we see a gradual diminishing in flying relying on feedback directly from what you see, hear and feel, and more reliance on instrumentation and indicators? Is this due to the level of experience needed by the pilot, the conditions (night time, no visibility) that is expected in training, the larger aircraft (versus a small one which perhaps may respond more quickly to external forces and changes)? Not being a pilot I am not sure why someone mentioned earlier in the thread that when something starts going "wrong" whether going off-road (so to speak) with the plane and just flying it based on basic principles and "gut" feedback and ignoring the instruments is practical or just not possible in a large modern airplane.
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Offline Berni

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #269 on: March 12, 2019, 06:33:57 am »
Flying by feel can become very misleading actually.

You can feel fast changes in speed or orientation very well because of feeling forces on your seat and the "biological gyroscope" in your ear. But both of these don't notice any slow long term change as you sort of get used to it along the slow change. Just like real gyroscope sensors our biological ones have trouble with long term drift.

Having no visibility and not looking at the instruments you can easily fly banked to the right 30 degrees but being absolutely certain you are perfectly level. If the bank angle builds up very slowly you just get used to it and take it as a new "zero reference" had someone corrected it back to level quickly you would swear that you are banking the other way rather than straightening out. What makes things worse with planes is that banks are used to steer left and right, because of this the acceleration from the turn is always pointing down. A bubble level in a plane would stay centered in the middle on a correctly executed turn. You don't feel yourself pulled to the side at all, the only clue is that looking out the window you can see the sky looks sideways.
 
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Offline tautech

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #270 on: March 12, 2019, 07:12:41 am »
Flying straight by eye is one thing, not as hard as flying level by eye.

The tall dashboard in the Cessna's I've had a play in are high for a reason when you're flying VFR so to help you keep a cockpit horizon to keep somewhere level.
First I thought the altimeter was the thing to watch all the time but no, you only check it from time to time to keep well in your allotted airspace and use the top of the dash to some distant point to keep yourself close to level flight.

Even when doing a 180 to line up for landing, if it was dark you'd have no idea you were both descending and turning without instruments, as the bodily feedback was so minimal unless you really cranked it over.
When my daughter did her initial IFR training they wore like a low brimmed hat so to not be able to see out the windscreen and so have to rely on instruments.
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Offline Kjelt

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #271 on: March 12, 2019, 04:08:22 pm »
Many countries (also ours) is closing their airspace for 737-max planes.
This is I think the first time this is going on in so many countries ?  :-//
 

Offline GeorgeOfTheJungle

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #272 on: March 12, 2019, 04:25:54 pm »
Boeing: UK joins wave of countries grounding the 737 Max
https://www.bbc.com/news/world-asia-47536502?intlink_from_url=https://www.bbc.com/news/topics/cv06837xl7lt/ethiopian-airlines-crash&link_location=live-reporting-story
Quote
The UK's Civil Aviation Authority (CAA) has banned the Boeing 737 MAX from operating in or over UK airspace "as a precautionary measure".
[...]
In the aftermath of the accident, Ethiopia, Singapore, China, France, Ireland, Germany, Australia, Indonesia and Malaysia have all temporarily suspended the 737 Max.
Even when the experts all agree, they may well be mistaken.
 
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Online macboy

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Re: Cockpit voice recorder recovered
« Reply #273 on: March 12, 2019, 05:45:24 pm »
(emphasis below is mine)
Update today , the CVR is recovered, ...

That is good news and hopefully this will clear up the actions the pilots made and provide an insight into the sequence of actions they took.  The great question is:  why did they not turn of the Stab Trim and did they talk about doing so.

The upside to the crash, if there is an upside, is that there can't be a single 737MAX pilot that does not now know what MCAS is and how and when to power off the Stab Trim.


Brian

Sigh. Apparently not yet.
 

Offline raptor1956

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Re: Lion Air crash: Jakarta Boeing 737 'had prior instrument error'
« Reply #274 on: March 12, 2019, 06:29:46 pm »
Well the heat on Boeing is being turned up to eleven.   The EU is suspending all 737 Max flights beginning at 3PM ET. 

Flight attendant union now calls for 737 MAX fleet to be grounded.

Senator asks American, Southwest and United to voluntarily to ground their Boeing 737 MAX 8s.

Austria, Poland and Italy are the latest to ground 737 MAX 8s.

Turkish Airlines grounds all Boeing 737 MAX aircraft.

Netherlands suspends Boeing 737 MAX 8 aircraft.

Iceland and Germany join list of countries deciding to ban 737 MAX 8 aircraft.

France's aviation authority bans Boeing 737 MAX aircraft from its airspace.

Meanwhile...

Boeing says it has "full confidence" in its 737 MAX jets and isn't issuing new guidance


Brian   :popcorn:
« Last Edit: March 12, 2019, 06:33:06 pm by raptor1956 »
 


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