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Old 8th November 2018, 16:58   #31
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Does that mean Boeing acknowledges that there is some serious problem in 737 MAX 8 series planes ?
If so why no one is talking about taking actions against the manufacturer ?
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Old 8th November 2018, 17:54   #32
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

This Emergency Airworthiness Directive was issued by FAA on 7th November.

Lion Air Boeing 737 MAX crashes in Jakarta-img_20181108_175607.jpg

https://twitter.com/AviationSafety/s...916329991?s=19

This was issued by Boeing itself.

Lion Air Boeing 737 MAX crashes in Jakarta-img_20181108_175808.jpg

https://twitter.com/theaircurrent/st...315278336?s=19


Quote:
Originally Posted by balenoed_ View Post
Is MAX there with any of the domestic operators in India? I would be anxious to get into one for the time being.
Jet Airways and SpiceJet have 1 737 Max each.

Last edited by BoneCollector : 8th November 2018 at 18:22.
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Old 8th November 2018, 18:13   #33
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

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Originally Posted by Foxbat View Post
Boeing Co. is preparing to send a bulletin to operators of its new 737 Max models warning that erroneous readings from a flight-monitoring system can cause the planes to aggressively dive, said a person familiar with the matter.
Is MAX there with any of the domestic operators in India? I would be anxious to get into one for the time being.

Last edited by balenoed_ : 8th November 2018 at 18:15.
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Old 9th November 2018, 10:48   #34
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

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Originally Posted by BoneCollector View Post
Jet Airways and SpiceJet have 1 737 Max each.
There are a total of six Boeing 737 Max 8s in service with Indian carriers today.
Jet Airways has five (VT-JXA/B/C/D/E) and Spicejet has one (VT-MAX).

Its Ironical that a system that was designed to save the aircraft in event of a stall, probably made the aircraft go into a nose dive and led to its crash.

Last edited by skanchan95 : 9th November 2018 at 11:09.
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Old 9th November 2018, 14:50   #35
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

We do not know yet what caused this particular crash. Of course the Boeing bulletin certainly seems to be pointing towards a possible cause of this tragic incident.

Basically what the bulletin implies, is that a faulty Angle of Attack sensor can lead to a runaway stabiliser trim. This will cause the aircraft to pitch down. The pilot will pull back on the yoke and most likely also use the trim stab switch to pull up. However, in this particular case as soon as the pilot releases the trim stab switch the faulty stabiliser system will again start to pitch down.

So you will get a sort of yo-yo effect where the pilot is trying to regain control and overtime he thinks he has the wonky stabiliser pushes the nose down again! Speeds builds up rapidly on the descent.

This wonky stabiliser is an intermittent fault in the sense that when the pilot pushes the trim stabs everything seems to work fine and the aircraft starts to pitch up again. But a few seconds after they release the trim stab switch the wonky stabiliser starts putting the nose down again.

Note, this particular error occurs only when flying manually (no autopilot engaged). An Angle of Attack error is likely to throw out a whole bunch of other alarms as you can read in the bulletin.

Whilst the crew is trying to regain control they are also trying to make sense of all these different alarms/indicators. This particular flight was still quite low, so if they were facing this scenario, they simply did not have a lot of time to sort out all of this.

I don’t have any insights on what the exact procedures are on this particular Boeing or how they are taught to deal with these sort of emergencies. Again, we will need to wait for the full accident report.

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Old 13th November 2018, 18:18   #36
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

An interesting video on this particular accident



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Old 13th November 2018, 20:13   #37
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Quote:
Originally Posted by suresh_gs View Post
Does that mean Boeing acknowledges that there is some serious problem in 737 MAX 8 series planes ?
If so why no one is talking about taking actions against the manufacturer ?
What actions ? I have never seen any action against aircraft makers or for that matter against car makers when they have not done anything intentionally. Ofcourse they have to acknowledge and investigate the issue quickly.
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Old 13th November 2018, 22:50   #38
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

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Originally Posted by Jeroen View Post
An interesting video on this particular accident
Great video. Reading the dry bulletin does not bring out what a complex situation the pilots were faced with. Even after reading the bulletin and watching the video, I wouldn’t know what to do if this happens (and more importantly how do you know this is what has happened and not something else). We find it hard enough to manage sensors on cars. Also tells you why human pilots will be needed for the foreseeable future.
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Old 13th November 2018, 23:44   #39
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

https://www.bloomberg.com/news/artic...ected-in-crash

Quote:
Two U.S. pilots’ unions say the potential risks of a safety feature on Boeing Co.’s 737 Max aircraft that has been linked to a deadly crash in Indonesia weren’t sufficiently spelled out in their manuals or training.

Boeing and the Federal Aviation Administration issued directives last week telling flight crews about the system, which is designed to provide extra protection against pilots losing control. That prompted aviators, unions and training departments to realize that none of the documentation for the Max aircraft included an explanation of the system, the union leaders said.
Quote:
Few details have been released about the underlying causes of the Lion Air crash Oct. 29 in the sea near Jakarta, but Indonesian investigators say that an erroneous sensor prompted the plane’s computers to push the aircraft into a steep dive. A new safety measure added on the Max models to prevent pilots from losing control is what caused the plane to point downward, according to the FAA and Boeing.
Quote:
When Boeing designed its latest version of the 737, it added the new safety feature to combat a loss of lift, which is a leading contributor to the loss-of-control accidents that by far cause the most crash deaths around the world.

Known as the Maneuvering Characteristics Augmentation System, it was added “to compensate for some unique aircraft handling characteristics,” according to a bulletin sent by Southwest’s flight operations division to its pilots on Nov. 10.

When the system senses the plane is close to losing lift on the wings, it automatically commands a lowering of the nose to counteract the risk. However, the chief sensor used to predict a loss of lift -- known as an angle-of-attack vane -- was malfunctioning on the Lion Air flight. It essentially tricked the system into ordering a sharp dive.
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Old 14th November 2018, 00:28   #40
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Quote:
Originally Posted by Hayek View Post
Reading the dry bulletin does not bring out what a complex situation the pilots were faced with. Even after reading the bulletin and watching the video, I wouldn’t know what to do if this happens (and more importantly how do you know this is what has happened and not something else). We find it hard enough to manage sensors on cars. Also tells you why human pilots will be needed for the foreseeable future.
As I said before, I don’t know what happened, in fact nobody does. All we have is the Boeing bulletin. Based on what it says and just knowledge of the B738 system it is not that difficult to piece together what a likely scenario could look like, if this particular problem with the AoA sensor occurs. Again, nobody knows for sure whether this is what happened.

Check out the real pilot forums and you will find much more eloborate en depth stories how this scenario is likely to play out in the cockpit. But again, we don’t know if this happened, although from what we know it is definitely a very likely possibility. But let’s not speculate.

At the heart of the Boeing bulletin is how Boeing implemented some of it’s control system. For those that like some more details that might not be so apparent from the Boeing bulletin. This is from one of my pilot forums:

Quote:
737 MAX8 Emergency Airworthiness Directive
The recently released Emergency Airworthiness Directive directs pilots how to deal with a known issue, but it does nothing to address the systems issues with the AOA system, which may be the causal system in the Lion Air accident. This is significant. The positive takeaway is that we are advised, as pilots, that once we recognize the issue, we can stop the negative impacts by taking the trim system out of the loop.

At the heart of this investigation is the MCAS system (description from Boeing):

MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aislestand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.
If pilots are faced with this problem of a wonky AoA it might be very difficult and counterintuitive for them to respond. Very likely the wonky AoA also means the stall warning is going and the stick shaker is telling you the plane is in a stall.

The standard recovery procedure is push the nose down, firewall the throttles and build up air speed. But in this particular scenario they would need to haul back on the stick, trim back the stab to a normal position and throw the cut out switches.

All (commercial) pilots train regularly on their simulator check rides AoA faults. But nobody knew of this particular problem apparently.

We will just have to wait for more information from the accident investigation to see whether such a scenario was indeed the cause of this tragedy.

I am not sure your conclusion is correct. There were two human pilots up front. Did not make a difference, they still crashed.

Automation in aviation has played an incredible important role in the ever increasing safety. To a large extend you can say that a lot of aviation automation addressed all sorts of human issues. So automation has done away with a lot of the pilot error of the past. But as always, it also introduces some new problems and error. If you don’t have a angle of attack sensor, you can’t have a false angle of attack reading obviously! Still, having incorporated AoA sensor and automation in the flight controls has saved thousands and thousand of lives.

Loss of control (i.e. stalling a plane) as it is called by the FAA is still the number one cause for fatal accidents in General Aviation. And guess what General Aviation has a lot less of automation than your typical commercial jet liner. Few GA aircrafts have AoA sensors. Thus they often fall out of the sky close to airport.

None of the planes I pilot have AoA sensors. So they can’t go wonky on my. But then again, statistically I do have a much higher chance of stalling it and falling out of the sky.

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Old 14th November 2018, 00:37   #41
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Quote:
Originally Posted by Jeroen View Post
Automation in aviation has played an incredible important role in the ever increasing safety. To a large extend you can say that a lot of aviation automation addressed all sorts of human issues. So automation has done away with a lot of the pilot error of the past. But as always, it also introduces some new problems and error.
Perhaps commercial aircraft should always be in manual mode by default. Computers should takeover only when:

Pilots are confused, sense some danger and request computer assistance by pressing a big red HELP button

OR

Computers sense an imminent crash based on flying behavior (rapid altitude loss, aircraft going into stall etc) and automatically takeover controls from the pilot after warning a couple of times.
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Old 14th November 2018, 01:32   #42
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

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Originally Posted by smartcat View Post
Perhaps commercial aircraft should always be in manual mode by default. Computers should takeover only when:

Pilots are confused, sense some danger and request computer assistance by pressing a big red HELP button

OR

Computers sense an imminent crash based on flying behavior (rapid altitude loss, aircraft going into stall etc) and automatically takeover controls from the pilot after warning a couple of times.
Sure, I agree completely; this whole "fly by wire / Glass cockpit thing" is just utter nonsense. It is just a conspiracy so pilots can talk all sort of crap that nobody understands. Gets them those big salaries! They are just glorified bus drivers. And they don’t even have to deal with the passengers these days. They keep the cockpit door locked!



Lets get some proper mechanical stuff back into the cockpit, proper yoke with mechanical wires and pulleys and a flight engineer that needs to grease them. So they break now and then, at least we have a real pilot in control.

Who needs a flight management system with a GPS? I mean what is wrong with a magnetic compass, a sextant and a chart?

ABS and autobraking, phew, just for wussies. Just stomp your feet on those two pedals with all your might and see what happens

Rip out those glass displays and let’s have those proper steam gauges back! The ones you could not read properly because the needles were all over the place or they were broken to start with.

This is how we like our cockpits. Minimum of at least a thousand instruments

https://imgur.com/gallery/Fi5oE

Who needs a cockpit like this, no flight engineer station and just a couple of pieces of glass: Less than 300 instruments. any idiot can fly this thing

https://www.flickr.com/photos/rohanp...hy/27434627839

Angle of Attack sensor; throw it out of the window. Any real pilot should be able to fly by the seat of his/her pants. This whole AoA is just a complex theory thought up by flight schools so they can fail you on your check ride and you need to buy twenty more hours with your flight instructor.

Yaw dampers; I mean come on, did the Wright boys have a yaw damper?

Oh wait, that means we are likely to see aviation fatalities rising to what they were in the 60/70s.

Jeroen

Last edited by Jeroen : 14th November 2018 at 01:47.
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Old 14th November 2018, 08:51   #43
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Quote:
Originally Posted by Jeroen View Post
Check out the real pilot forums and you will find much more eloborate en depth stories how this scenario is likely to play out in the cockpit. But again, we don’t know if this happened, although from what we know it is definitely a very likely possibility.

At the heart of the Boeing bulletin is how Boeing implemented some of it’s control system.

All (commercial) pilots train regularly on their simulator check rides AoA faults. But nobody knew of this particular problem apparently.

I am not sure your conclusion is correct. There were two human pilots up front. Did not make a difference, they still crashed.

Automation has done away with a lot of the pilot error of the past. But as always, it also introduces some new problems and error. None of the planes I pilot have AoA sensors. So they can’t go wonky on my. But then again, statistically I do have a much higher chance of stalling it and falling out of the sky.

Agree fully that automation helps - that has been statistically proven. And agree we need to wait for the final results of the investigation. But what’s the point of a forum if you don’t speculate?

To me, this does seem to be a case of faulty automation implementation, and even worse improper training. Am sure that there would have been instances of faulty AoA sensors in 737 NGs, which are one of the two most flown aircraft in the world. Can’t recall any crash in good conditions on a new plane due to that. Perhaps this is just the case of a very low probability event happening early in the life cycle of the Max. But the odds of that are low - the more likely scenario is that the control system design here makes the plane prone to a feedback loop with disastrous consequences - in short the automation system here has increased the probability of a crash. What made things worse is that pilots were not trained for this - Boeing indicated that there is no new training needed for the Max and Indian pilots for example have continued to train on NG simulators where this scenario would not occur.

Finally to my point on pilots - let’s draw an analogy with self driving cars. We have over 30000 deaths and 2 million injuries a year from cars accidents in the US. Let’s assume self driving cars are 100x better - they cause only 300 deaths and 20000 injuries a year. Is that good enough to introduce self driving cars? Statistically, yes. Commercially, no. A defective product that kills even 300 people and injures 20000 a year would drive its makers bankrupt. It’s only if self driving cars are 10000x better (3 deaths and 200 injuries a year) that they can be introduced without new laws that protect manufacturers from tort claims. The same applies to pilotless planes.
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Old 14th November 2018, 09:20   #44
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Quote:
Originally Posted by Hayek View Post
To me, this does seem to be a case of faulty automation implementation, and even worse improper training.
No its a new implementation of a system which was not discussed in the manual not a faulty implementation. A shocking lapse as far as Boeing is concerned. If it was America and American citizen's were killed, you would have a big fat lawsuit coming in no time.
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Old 14th November 2018, 10:19   #45
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Re: Lion Air Boeing 737 MAX crashes in Jakarta

Why is it taking so much time to find the CVR? Considering it is not one of the remotest ocean on the earth like where MH370 was doomed. Also there is a location transmitter beacon which is active for 30 days which might help to narrow down the search area.

Also read the news that the authorities have stopped searching for victims. I thought they would continue it for days until they find majority of the bodies and major parts of the fuselage.
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