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SomebodyInTLS
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:47 am

Aviation737 wrote:
Did the investigators of the lion air crash confirmed that the crash was caused by the MCAS malfunctioning?


MCAS didn't malfunction! It worked as designed but was fed bad data. The issues there are why the design was so poor and why the aircraft kept getting bad data despite several corrective actions by maintenance over the preceding days.
"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."
 
Bobloblaw
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:50 am

LTC8K6 wrote:
MikeAlpha95 wrote:
According to CNN

"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."

All 157 people on board the flight died in the accident."


Not sure what it's worth, but it's certainly a specific description.

It means if the eye witness is right and that is a big if since eyewitness are not all that reliable, the crash wasn’t caused by MCAS.
 
jumbojet
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:53 am

StreetF117 wrote:
Accidents are usually caused by a series of chain events and are usually prevented by an action breaking that chain. The main cause may be a technical failure or issue which is prevented by training.

The cause of this accident MAY be related to the MCAS system and may have be prevented on other occasions by training highlighted by the Emergency AD issued by the authorities. But these have not been widely reported by pilots flying the MAX. (Maybe because they cannot do so unless it is through a confidential reporting system)

Everything we do in life involves a calculated risk. If you are in control of that risk then people are usually happy but when you are NOT in control of that risk we hand that responsibility to better informed and knowledgable people.


While everything you said might be true, you have to remember that these are brand new planes, two within a 6 month period. Sorry, but something is not right with the MAX-8. You don't see brand new Airbus 320's falling out of the sky, or any other brand new planes falling out of the sky.
Last edited by jumbojet on Mon Mar 11, 2019 11:56 am, edited 1 time in total.
 
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Carlos01
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:54 am

edu2703 wrote:
In any air accident, there is always an eyewitness who reports having seen fire or smoke from the aircraft.

Of course we should not disregard it completely, but reports of fire or smoke are something that air crash investigators are already expecting to hear from eyewitnesses and usually are not true.


For sure, I can imagine a plane fighting for her life, and then hitting the terrain at several hundreds mph, there will for sure be some vaportrail coming off the plane, and wouldn't even be surprised if the wings will start to rip off just before impact, which would of course create a fire just before impact.

Has anyone found any pictures of the data recorders yet? I am really curious about their condition. The plane did hit the ground apparently in an almost perfect vertical dive, nose first, causing majority of it to be buried in the ground. As the recorders are in the tail, I would presume them to be almost at the top of the debris, but their condition can only be guessed. Could be in perfect condition, or completely destroyed, which I guess has not really happened ever before?

Such a sad day for aviation, and all involved of course. And the Boeing execs must be in a very unhappy place right now, the global media is ready to publicly lynch them should it turn out that the plane's design was at fault here. Even if it would turn out that one of Boeing's suppliers produced a part that led to this directly or indirectly, it would not change the public or media opinion.
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:59 am

Bobloblaw wrote:
It means if the eye witness is right and that is a big if since eyewitness are not all that reliable


I'd go as far as saying that eyewitnesses of disasters like this are notoriously unreliable.
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edu2703
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 11:59 am

Royal Air Maroc has grounded 737 MAX fleet
 
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Starlionblue
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:14 pm

trnswrld wrote:
Starlionblue wrote:
trnswrld wrote:
I still fail to see how an airplane can be flown into the ground in perfect VMC conditions....even IF there was unreliable speed, MCAS causing all sorts of issues...throw all that stuff in there. How in the heck can all that compile to an issue so bad that the airplane is completely uncontrollable? Do these systems literally take over the airplane the these pilots cant do anything to fly the airplane and they are sitting there just trying to diagnose computer issues?


That's not even remotely how it works. In all modern airliners, mode awareness is key. Know what the aircraft is doing, and what it means.


Ok understood, but I guess what is throwing me off is what is stopping the pilots from literally just flying the aircraft? they have all the visual references in the world....its day light, its clear. Will the aircraft not respond to control column inputs?


In general, yes. The first rule is to fly the aircraft.

However, there are exceptions. In a FBW Airbus, if you're in Normal Law pulling back further will lead to a stall, the aircraft will not pitch up further. Note that this is not a bad thing...

MartijnNL wrote:
Starlionblue wrote:
Frankly, you could fly any aircraft on the least safe airline operating within the dodgiest regulatory regime in the world and you'd still be safer than on the drive to the airport.

Not true. Fake news. Debunked up thread.


You're saying that flying for some reputedly dodgy airline is less safe than driving a car?
Last edited by Starlionblue on Mon Mar 11, 2019 12:44 pm, edited 1 time in total.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
theaviator380
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:16 pm

CVR and FDR both have been found...

RIP to all perished in this tragic accident.

https://edition.cnn.com/2019/03/10/afri ... index.html

Some details about Boeing MCAS system, explained in nice and easy way.

https://theaircurrent.com/aviation-safe ... cas-jt610/
 
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capshandler
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:17 pm

edu2703 wrote:
MikeAlpha95 wrote:
According to CNN

"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

"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."


In any air accident, there is always an eyewitness who reports having seen fire or smoke from the aircraft.

Of course we should not disregard it completely, but reports of fire or smoke are something that air crash investigators are already expecting to hear from eyewitnesses and usually are not true.


Absolutely agree on that. I remember that the whitnesses report on JK5022 gave unvoluntarely a false hint to investigators as they reported that they had one engine on fire. I’d say that things happen quite quick and you might get confused on a sub conscious level by the inmediate aftermath fire and explosion. However is valuable information in how the aircraft behaved on the last minute of the crash.

Regarding the endless debate of grounding/no grounding I will recuse myself as I could give an aviator perspective but not an aviation safety expert which is IMHO the people we should give the time to work on those tough decisions.

I’d jump in any airplane right now maybe driven by passion or maybe by admirarion of what aviation pioneers including both Airbus and Boeing have achieved. I remember when in GA fiber airplanes started popping up, a huge innovation with sad losses on its path. Some would say its a price to innovation and some (myself included) would say y it’s destiny and agree with a comment stated before, maybe someday numbers and fate will decide it’s going to be my last flight. I hope not and train myself to avoid that, but still is a fantastic result of human engineering, human above all, thus prone to error.

I do really hope the victims didn’t suffer much, and as aviation enthusiasts today is time to pay them tribute by toning and calming down on those posts. My prayers to the families as nothing else can be made but to respect their mourning and hoping that this will never happen again.

Best
 
A3801000
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:29 pm

Image

Supposed to be one of the 'Blackboxes' , unconfirmed.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:31 pm

scbriml wrote:
Bobloblaw wrote:
It means if the eye witness is right and that is a big if since eyewitness are not all that reliable


I'd go as far as saying that eyewitnesses of disasters like this are notoriously unreliable.


Which ever way. It is a data point sitting pretty together with the remaining dirty dozend. :-)
synthesis is the way to go forward.
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THS214
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:43 pm

Starlionblue wrote:
trnswrld wrote:
Starlionblue wrote:

That's not even remotely how it works. In all modern airliners, mode awareness is key. Know what the aircraft is doing, and what it means.


Ok understood, but I guess what is throwing me off is what is stopping the pilots from literally just flying the aircraft? they have all the visual references in the world....its day light, its clear. Will the aircraft not respond to control column inputs?


In general, yes. The first rule is to fly the aircraft.

However, there are exceptions. In a FBW Airbus, if you're in Normal Law pulling back further will lead to a stall, the aircraft will not pitch up further. Note that this is not a bad thing...

MartijnNL wrote:
Starlionblue wrote:
Frankly, you could fly any aircraft on the least safe airline operating within the dodgiest regulatory regime in the world and you'd still be safer than on the drive to the airport.

Not true. Fake news. Debunked up thread.


Wait. It has been debunked that air travel is safer than driving?


Air travel is safer than driving. But when you limit driving only to the airport things change.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:46 pm

Starlionblue wrote:
Frankly, you could fly any aircraft on the least safe airline operating within the dodgiest regulatory regime in the world and you'd still be safer than on the drive to the airport

Wait. It has been debunked that air travel is safer than driving?


I'm not sure I read that it was either proved, or debunked within this thread, and that is after reading all 1012 posts within this thread (unlike many others and ask the same question again and again :banghead: ). I admit I may have missed some points of detail in amongst all the chaff.

The (inadvertent) mistake made by yourself and the other post up thread, was to equate safety on a 5km drive to the airport with safety on a 1500km flight.

Civil aviation is much safer per km travelled.

I am 100% sure that is what you intended to say.
Nothing to see here; move along please.
 
aaexecplat
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:53 pm

kalvado wrote:
hivue wrote:
flyer737sw wrote:
I can see Boeing completely deal away with the MCAS.


In that case the airplane would lose its certification. To regain certification, Boeing would have to come up with a fix for the problem that MCAS currently addresses.

SOmeone else mentioned that solution is being developed, without extra details. I don't see a simple one here, but Boeing definitely has more skill and data than entire forum combined.


I suspect the only good option is to add another AOA sensor and develop a software solution similar to what Airbus has on its planes to allow the onboard computer to discern bad data from good data. CLEARLY, repositioning the engines or modifying the size of the horizontal stabilizers seems impossible at this point.
 
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CLTRampRat
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:53 pm

Hello everyone,
I do not have time to dig through the thread at this time, would anyone be willing to post the last recorded FPM descent rate?

Admittedly it’s for my own curiosity.
Thank you.
 
mcogator
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:54 pm

Wow, Boeing Corp stock is down over 11% in premarket open.
“Traveling – it leaves you speechless, then turns you into a storyteller.” – Ibn Battuta
 
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Gonzalo
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:55 pm

I think probably most bigger airlines will ground the MAX in a precautionary way and trying to avoid a PR nightmare.
Today, with the social networks going viral for the most insignificant thing, a MAX suffering a moderate turbulence, a bird strike or a flat tire will be used by media to get clickbites from the mass, and any minor incident could be a PR nightmare. Grounding the MAX sub-fleet can make them look as very worried about safety, a safe and trustable airline caring for the passengers.
I don’t know if there is some airline where the MAX sub-fleet is a significant part of the total fleet, those could choose to continue operations because grounding a big part of the fleet could be a mess, but the big airlines with 100+ aircraft and just a few MAX in service will ground the sub fleet just out of PR issues.
Just my 2 cents.

Rgds.
G.
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musicrab
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:56 pm

A3801000 wrote:
Supposed to be one of the 'Blackboxes' , unconfirmed.

CVR - looks ok or are those holes in the side?
 
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smittythepirate
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:56 pm

mcogator wrote:
Wow, Boeing Corp stock is down over 11% in premarket open.


Not sure if this is actually a surprise to anybody
www.jbweather.com
 
kalvado
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 12:57 pm

aaexecplat wrote:
kalvado wrote:
hivue wrote:

In that case the airplane would lose its certification. To regain certification, Boeing would have to come up with a fix for the problem that MCAS currently addresses.

SOmeone else mentioned that solution is being developed, without extra details. I don't see a simple one here, but Boeing definitely has more skill and data than entire forum combined.


I suspect the only good option is to add another AOA sensor and develop a software solution similar to what Airbus has on its planes to allow the onboard computer to discern bad data from good data. CLEARLY, repositioning the engines or modifying the size of the horizontal stabilizers seems impossible at this point.

I would hope the solution is aerodynamic, it definitely sounded like the person was hinting that way. Maybe something along the line of modifying engine nacelle to reduce extra lift. Hopefully, we will know in a few months..
 
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Aesma
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:00 pm

A3801000 wrote:
Image

Supposed to be one of the 'Blackboxes' , unconfirmed.


Well the photo definitely is of a recorder. The cylinder contains the data card, doesn't seem too damaged.
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
 
aaexecplat
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:01 pm

kalvado wrote:
aaexecplat wrote:
kalvado wrote:
SOmeone else mentioned that solution is being developed, without extra details. I don't see a simple one here, but Boeing definitely has more skill and data than entire forum combined.


I suspect the only good option is to add another AOA sensor and develop a software solution similar to what Airbus has on its planes to allow the onboard computer to discern bad data from good data. CLEARLY, repositioning the engines or modifying the size of the horizontal stabilizers seems impossible at this point.

I would hope the solution is aerodynamic, it definitely sounded like the person was hinting that way. Maybe something along the line of modifying engine nacelle to reduce extra lift. Hopefully, we will know in a few months..


That is a solution that may be far more difficult to implement than the added AOA+ software option? I assume that if this had been easy, Boeing would have done so when they designed the MAX in the first place. I am less hopeful that this is possible, but I hope you are right.
 
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keesje
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:04 pm

A3801000 wrote:
Image

Supposed to be one of the 'Blackboxes' , unconfirmed.


Looks like it. http://www.mro-network.com/sites/mro-network.com/files/MR-FDR_2_L3.jpg

mcogator wrote:
Wow, Boeing Corp stock is down over 11% in premarket open.


For Boeing it is now imporatnt to show passenger safety is more important than stock value.

Thinking about it a little longer, sends out a clear message too. Leadership pls.

https://www.washingtontimes.com/news/2019/mar/10/boeing-737-max-8-planes-grounded-china-after-ethio/
"Never mistake motion for action." Ernest Hemingway
 
Comyn
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:09 pm

350 plus dead, same aircraft, similar circumstances can hardly be called jumping the gun! Should we wait for a few more aircraft to go down!
 
trnswrld
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:24 pm

I always wonder how and why witnesses are so unreliable. I know not everyone knows about aircraft, but how hard is it to fully understand and comprehend what you’re seeing? Just weird how so many people claim to see fire and smoke when they really didn’t. I know I know it would be a very intense situation to see an aircraft crash in front of you, but still.
Now I will say IF this witness is right and there was smoke, then that changes things a lot here.
 
estorilm
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:28 pm

AviationBob wrote:
WIederling wrote:
For the A320 it is integral in the FBW system and highly redundant including a fall back path on (sensor) fault.
For the 737MAX it is a stuck on wart relying on a single input, no fault check, no fall back, no documentation.


The way you talk in such glowing terms about the A320 and then in such clearly disparaging terms about the 737 leads me to think you have an inherent bias and your overall statement can’t be trusted as rational or objective.

It's not a matter of bias, it would take someone unfamiliar days to understand the sensor flow and computer processing paths, decision-making programming, error-detection and correction, as well as overall redundancy built into Airbus FBW architecture. It's probably one of the single largest investments in commercial aviation history (as a whole) and totally defines how Airbus products operate to the core. They developed this in the '80's and it's allowed all of their products to scale up seamlessly. Any type of system like MCAS is not only pointless due to speed and alpha prot programs, but any inherent instabilities or handling characteristics can be augmented in the basic FBW programming.

It's not a matter of one being better than the other, but if you're talking systems-integration and the overall "elegance" and simplicity of work-flow in the cockpit, one is absolutely better. This is exponentially more true when we're talking about updating products that are decades old.

acechip wrote:
I feel that this zeal to ensure backward compatibility for cost considerations is one of the problems. Regulators must take a call on what constitutes a new aircraft type. The A320neo PW issue is also an equally uncomfortable situation to have, frankly.

This is something that's become more and more frustrating for me lately. Regardless of what happened with this flight, it's annoying that a supplemental type certificate can be issued for an aircraft which clearly handles different enough to require an augmentation system. Likewise - if said system is so important, it's frustrating that it has no capacity to self-check its data before performing a physical action on the aircraft's controls. I'm not a conspiracy theorist in the slightest, but I've GOT to assume the FAA/EASA looked the other way on this one. I understand they claim it's just like speed trim, with two ways of disabling.. but, eh.

For this crash, I'm actually starting to wonder if it wasn't MCAS at all, but rather the reason MCAS exists (the nose-up / sketchy power-on stall characteristics). It's entirely possible that we're seeing a MAX that stalled (due to unreliable airspeed issues) in a manner that was nothing like the NG/Classic and MCAS wasn't enough and/or didn't work fast enough.

Just something to think about that I haven't heard mentioned yet. Kinda fits.

sandyb123 wrote:

Yes this is correct, however the A320 has three sensors whereas the 737MAX has only two. If one starts to give erroneous data then the A320 has two others to fall back on whereas the 737MAX FMC has to decide which one to believe. I understand that the problem potentially here is that the system may 'fight back' on corrective pilot inputs on the 737MAX whereas the A320 will switch to 'alternate law' if it doesn't understand the data it is getting, effectively handing full control to the pilots.

Conjecture alert... Boeing, I am sure in good faith, has tried to retrofit automation within the physical limitations of an older design, but this has potentially created an Achilles Heal. That, compounded with a 'systems know best' approach to the logic is dangerous if true, in my opinion.

In summary it's a subtle but potentially significant difference in the coding of the systems.
Sandyb123

A single pitot / ADR failure is a non-issue on an Airbus, in fact it should isolate it automatically and tell you. The plane can still perform a CATIII auto land actually. Even two failures isn't much of an issue from a systems point of view. Also such failures would NOT degrade FBW into ALT LAW, you should still retain all flight protections. In the newer 330/340 and all 380 you can lose ALL THREE pitot/ADR systems and still fly on the BUSS speed tape on PFD using extrapolated AoA data. Losing primary and stby pitot in a Boeing (minus 787) = big trouble. Losing even one can be very confusing and dangerous (ie. Birgenair 301 757 crash).

The additional (and fundamental) problem here is that, eventually (if we're talking sensor/computer failures) an Airbus (and AFAIK, every other Boeing) hands controls to you - with no actions being taken at any point. In the case of the MAX, sensor or data/computer failures can result in ACTION being taken. From an aviation systems engineering standpoint, that should never happen in my opinion - it shouldn't even be able to be certified. The issue here is that fixing it basically requires Boeing to develop an integrated computer system with redundant inputs that can check for data integrity - and poof, now look where we are. ;)
 
nachopants
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:28 pm

I think journalists ask "everyone" and someone wants to get on TV saying "something" a lot of the time.
 
planecane
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:28 pm

If this turns out to be a similar MCAS event as Lion Air and the pilots didn't follow the cutout procedure doesn't that place the blame on the training or retention more than the flaw itself? I'm not a trained pilot (I did spend a couple of hours in a 738 simulator) and I would know what to do in a MAX that kept commanding nose down trim against my control column inputs after reading so much about it. How can a trained 737 pilot not know what to do at this point?
 
smokeybandit
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:31 pm

mcogator wrote:
Wow, Boeing Corp stock is down over 11% in premarket open.


Doesn't take much for Wall Street to be affected. Actually seems like a great time to buy Boeing stock
 
smokeybandit
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:33 pm

trnswrld wrote:
I always wonder how and why witnesses are so unreliable. I know not everyone knows about aircraft, but how hard is it to fully understand and comprehend what you’re seeing? Just weird how so many people claim to see fire and smoke when they really didn’t. I know I know it would be a very intense situation to see an aircraft crash in front of you, but still.
Now I will say IF this witness is right and there was smoke, then that changes things a lot here.


Eye witnesses are actually quite unreliable.

https://www.washingtonpost.com/opinions ... 7794f57f0f
 
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william
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:40 pm

estorilm wrote:
AviationBob wrote:
WIederling wrote:
For the A320 it is integral in the FBW system and highly redundant including a fall back path on (sensor) fault.
For the 737MAX it is a stuck on wart relying on a single input, no fault check, no fall back, no documentation.


The way you talk in such glowing terms about the A320 and then in such clearly disparaging terms about the 737 leads me to think you have an inherent bias and your overall statement can’t be trusted as rational or objective.

It's not a matter of bias, it would take someone unfamiliar days to understand the sensor flow and computer processing paths, decision-making programming, error-detection and correction, as well as overall redundancy built into Airbus FBW architecture. It's probably one of the single largest investments in commercial aviation history (as a whole) and totally defines how Airbus products operate to the core. They developed this in the '80's and it's allowed all of their products to scale up seamlessly. Any type of system like MCAS is not only pointless due to speed and alpha prot programs, but any inherent instabilities or handling characteristics can be augmented in the basic FBW programming.

It's not a matter of one being better than the other, but if you're talking systems-integration and the overall "elegance" and simplicity of work-flow in the cockpit, one is absolutely better. This is exponentially more true when we're talking about updating products that are decades old.

acechip wrote:
I feel that this zeal to ensure backward compatibility for cost considerations is one of the problems. Regulators must take a call on what constitutes a new aircraft type. The A320neo PW issue is also an equally uncomfortable situation to have, frankly.

This is something that's become more and more frustrating for me lately. Regardless of what happened with this flight, it's annoying that a supplemental type certificate can be issued for an aircraft which clearly handles different enough to require an augmentation system. Likewise - if said system is so important, it's frustrating that it has no capacity to self-check its data before performing a physical action on the aircraft's controls. I'm not a conspiracy theorist in the slightest, but I've GOT to assume the FAA/EASA looked the other way on this one. I understand they claim it's just like speed trim, with two ways of disabling.. but, eh.

For this crash, I'm actually starting to wonder if it wasn't MCAS at all, but rather the reason MCAS exists (the nose-up / sketchy power-on stall characteristics). It's entirely possible that we're seeing a MAX that stalled (due to unreliable airspeed issues) in a manner that was nothing like the NG/Classic and MCAS wasn't enough and/or didn't work fast enough.

Just something to think about that I haven't heard mentioned yet. Kinda fits.

sandyb123 wrote:

Yes this is correct, however the A320 has three sensors whereas the 737MAX has only two. If one starts to give erroneous data then the A320 has two others to fall back on whereas the 737MAX FMC has to decide which one to believe. I understand that the problem potentially here is that the system may 'fight back' on corrective pilot inputs on the 737MAX whereas the A320 will switch to 'alternate law' if it doesn't understand the data it is getting, effectively handing full control to the pilots.

Conjecture alert... Boeing, I am sure in good faith, has tried to retrofit automation within the physical limitations of an older design, but this has potentially created an Achilles Heal. That, compounded with a 'systems know best' approach to the logic is dangerous if true, in my opinion.

In summary it's a subtle but potentially significant difference in the coding of the systems.
Sandyb123

A single pitot / ADR failure is a non-issue on an Airbus, in fact it should isolate it automatically and tell you. The plane can still perform a CATIII auto land actually. Even two failures isn't much of an issue from a systems point of view. Also such failures would NOT degrade FBW into ALT LAW, you should still retain all flight protections. In the newer 330/340 and all 380 you can lose ALL THREE pitot/ADR systems and still fly on the BUSS speed tape on PFD using extrapolated AoA data. Losing primary and stby pitot in a Boeing (minus 787) = big trouble. Losing even one can be very confusing and dangerous (ie. Birgenair 301 757 crash).

The additional (and fundamental) problem here is that, eventually (if we're talking sensor/computer failures) an Airbus (and AFAIK, every other Boeing) hands controls to you - with no actions being taken at any point. In the case of the MAX, sensor or data/computer failures can result in ACTION being taken. From an aviation systems engineering standpoint, that should never happen in my opinion - it shouldn't even be able to be certified. The issue here is that fixing it basically requires Boeing to develop an integrated computer system with redundant inputs that can check for data integrity - and poof, now look where we are. ;)


Good post.

Ironic in that we will never know how many lives the A320's FBW have saved.
 
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flyingturtle
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:43 pm

trnswrld wrote:
I always wonder how and why witnesses are so unreliable. I know not everyone knows about aircraft, but how hard is it to fully understand and comprehend what you’re seeing? Just weird how so many people claim to see fire and smoke when they really didn’t. I know I know it would be a very intense situation to see an aircraft crash in front of you, but still.
Now I will say IF this witness is right and there was smoke, then that changes things a lot here.


One problem is that people try to interpret things and give it a meaning. Consciously and subconsciously.

In an interview, the leader of the Swiss accident investigation board has said that the most reliable witnesses are children, because they don't have a good concept of *how* a plane should fly, which parts of the airplane are the engines, how a plane should be configured for landing...


David
Reading accident reports is what calms me down
 
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:45 pm

william wrote:

Ironic in that we will never know how many lives the A320's FBW have saved.


The Habsheim air show crash. And the Hudson miracle. In both cases, the airplane fought the pilots and didn't allow them to stall the aircraft.


David
Reading accident reports is what calms me down
 
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:46 pm

flyingturtle wrote:
william wrote:

Ironic in that we will never know how many lives the A320's FBW have saved.


The Habsheim air show crash. And the Hudson miracle. In both cases, the airplane fought the pilots and didn't allow them to stall the aircraft.


David


How so in the USAirways case?
 
HaulSudson
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:50 pm

estorilm wrote:
AviationBob wrote:
WIederling wrote:
For the A320 it is integral in the FBW system and highly redundant including a fall back path on (sensor) fault.
For the 737MAX it is a stuck on wart relying on a single input, no fault check, no fall back, no documentation.


The way you talk in such glowing terms about the A320 and then in such clearly disparaging terms about the 737 leads me to think you have an inherent bias and your overall statement can’t be trusted as rational or objective.

It's not a matter of bias, it would take someone unfamiliar days to understand the sensor flow and computer processing paths, decision-making programming, error-detection and correction, as well as overall redundancy built into Airbus FBW architecture. It's probably one of the single largest investments in commercial aviation history (as a whole) and totally defines how Airbus products operate to the core. They developed this in the '80's and it's allowed all of their products to scale up seamlessly. Any type of system like MCAS is not only pointless due to speed and alpha prot programs, but any inherent instabilities or handling characteristics can be augmented in the basic FBW programming.

It's not a matter of one being better than the other, but if you're talking systems-integration and the overall "elegance" and simplicity of work-flow in the cockpit, one is absolutely better. This is exponentially more true when we're talking about updating products that are decades old.

acechip wrote:
I feel that this zeal to ensure backward compatibility for cost considerations is one of the problems. Regulators must take a call on what constitutes a new aircraft type. The A320neo PW issue is also an equally uncomfortable situation to have, frankly.

This is something that's become more and more frustrating for me lately. Regardless of what happened with this flight, it's annoying that a supplemental type certificate can be issued for an aircraft which clearly handles different enough to require an augmentation system. Likewise - if said system is so important, it's frustrating that it has no capacity to self-check its data before performing a physical action on the aircraft's controls. I'm not a conspiracy theorist in the slightest, but I've GOT to assume the FAA/EASA looked the other way on this one. I understand they claim it's just like speed trim, with two ways of disabling.. but, eh.

For this crash, I'm actually starting to wonder if it wasn't MCAS at all, but rather the reason MCAS exists (the nose-up / sketchy power-on stall characteristics). It's entirely possible that we're seeing a MAX that stalled (due to unreliable airspeed issues) in a manner that was nothing like the NG/Classic and MCAS wasn't enough and/or didn't work fast enough.

Just something to think about that I haven't heard mentioned yet. Kinda fits.

sandyb123 wrote:

Yes this is correct, however the A320 has three sensors whereas the 737MAX has only two. If one starts to give erroneous data then the A320 has two others to fall back on whereas the 737MAX FMC has to decide which one to believe. I understand that the problem potentially here is that the system may 'fight back' on corrective pilot inputs on the 737MAX whereas the A320 will switch to 'alternate law' if it doesn't understand the data it is getting, effectively handing full control to the pilots.

Conjecture alert... Boeing, I am sure in good faith, has tried to retrofit automation within the physical limitations of an older design, but this has potentially created an Achilles Heal. That, compounded with a 'systems know best' approach to the logic is dangerous if true, in my opinion.

In summary it's a subtle but potentially significant difference in the coding of the systems.
Sandyb123

A single pitot / ADR failure is a non-issue on an Airbus, in fact it should isolate it automatically and tell you. The plane can still perform a CATIII auto land actually. Even two failures isn't much of an issue from a systems point of view. Also such failures would NOT degrade FBW into ALT LAW, you should still retain all flight protections. In the newer 330/340 and all 380 you can lose ALL THREE pitot/ADR systems and still fly on the BUSS speed tape on PFD using extrapolated AoA data. Losing primary and stby pitot in a Boeing (minus 787) = big trouble. Losing even one can be very confusing and dangerous (ie. Birgenair 301 757 crash).

The additional (and fundamental) problem here is that, eventually (if we're talking sensor/computer failures) an Airbus (and AFAIK, every other Boeing) hands controls to you - with no actions being taken at any point. In the case of the MAX, sensor or data/computer failures can result in ACTION being taken. From an aviation systems engineering standpoint, that should never happen in my opinion - it shouldn't even be able to be certified. The issue here is that fixing it basically requires Boeing to develop an integrated computer system with redundant inputs that can check for data integrity - and poof, now look where we are. ;)


Thanks for explaining this.
 
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Erebus
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:57 pm

SomebodyInTLS wrote:
AFAIK there is no evidence of a "botched repair" in the Lion Air case. Two things still need to be answered there: 1) why MCAS was designed and implemented in a way that could cause trouble under certain circumstances and 2) what was actually behind the spurious air data which kicked MCAS into action in the first place.

No one here seems to have considered that you don't need to have MCAS be a common factor between Lion Air and Ethiopian if the root cause of both is actually avionics issues producing faulty air data...


100% agree with this. Almost everyone seems to be too fixated on the MCAS, maintenance and pilot training regarding the Lion Air crash. The MCAS worked as designed albeit with a faulty logic, and whatever the output it was giving was just a symptom and not likely the root cause.

My real concern has been with what was giving it such bad information and whether it could also potentially affect other systems. From what it appears, the 'fix' has been targeted at the symptom, i.e. reinforce pilot training on runaway stab and a software fix for the MCAS.

People have debated here that the JT610 aircraft was not flight-worthy and should not have taken off if there was a persistent sensor issue that remained improperly resolved. But still, there's always a first time for everything and unfortunately, it appears that ET302 didn't make it to the ground for maintenance to have a look.
 
Reason077
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 1:57 pm

sandyb123 wrote:
akb88 wrote:
If (and it is an if at this stage) EASA decides to ground the Boeing 737 MAX aircraft then this will be a tough gig for Norwegian. I have noted a number of public concerns posted to Norwegian over the weekend about the MAX aircraft. They only have 8 in service, but given their already tough trading it could hit their operations and financials hard if they have to ground 15% of their short haul fleet.


Wouldn't Boeing be on the hook for compensation if a grounding was ordered due to a safety issue with the MAX? Rolls-Royce have certainly paid out a lot to airlines affected by the 787 grounding.
 
estorilm
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:00 pm

planecane wrote:
If this turns out to be a similar MCAS event as Lion Air and the pilots didn't follow the cutout procedure doesn't that place the blame on the training or retention more than the flaw itself? I'm not a trained pilot (I did spend a couple of hours in a 738 simulator) and I would know what to do in a MAX that kept commanding nose down trim against my control column inputs after reading so much about it. How can a trained 737 pilot not know what to do at this point?

I don't think it would be pilot error at all - it's a new plane and wasn't listed in the FCOM at all initially, it's type certificate implies minimal training differences - this was just added recently.
You have to think worse-case scenario here. Shortly after takeoff they have an airspeed disagree with an inexperienced FO, probably running the checklists and trying to maintain a safe speed. You don't want to throw any fuel on the fire at that point and have a new system kick in, regardless of training.

Personally I'm leaning away from MCAS and more towards perhaps a nasty power-on pre-stall high-AoA behavior (like I said before, they stuck MCAS in there for a reason). Only Boeing engineers know just how nasty / different the MAX behaves vs. NG.

william wrote:
Oh, you must not had been old enough to remember the A320 debut.

Ehhh still, they're flying low and slow maneuvers in an AIR SHOW and the pilot clearly screwed up, and part of the procedure was specifically disabling flight protections including alpha floor. They also did it at 30' not 100'. Not normal ops.

Regardless though, 3 deaths during an air show in 1988 is not the same as two crashes 4 months apart in 2018/19 killing 339. :(
Last edited by estorilm on Mon Mar 11, 2019 2:18 pm, edited 1 time in total.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:02 pm

AviationBob wrote:
The way you talk in such glowing terms about the A320 and then in such clearly disparaging terms about the 737 leads me to think you have an inherent bias and your overall statement can’t be trusted as rational or objective.


The terms I use reflect hard product design quality. it is your interpretation that they are "glowing" partisan.
Ask around.
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kruiseri
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:03 pm

william wrote:
flyingturtle wrote:
william wrote:

Ironic in that we will never know how many lives the A320's FBW have saved.


The Habsheim air show crash. And the Hudson miracle. In both cases, the airplane fought the pilots and didn't allow them to stall the aircraft.


David


How so in the USAirways case?


In that case, didn't Sullivan state that since he knew that the plane would not stall it helped him a lot as he could pull the stick all the way, ie make the plane fly at the lowest possible safe speed to the impact.

So yes, the A320 FBW saved 150+ lives.
 
flyingbird
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:07 pm

benjjk wrote:
Sorry but the FR24 data is not anywhere near accurate enough for that kind of analysis. They show a runway overrun for nearly every takeoff at my local airport. And no 737 can get airborne at 95kts of groundspeed, especially at that density altitude.


Why are people questioning the ADS-B data?
It's not data that FR24 is guessing or making up.
It's data transmitted by the transponder.
Instead of complaining about the data source, try to understand it!

At 93 knots, the ground flag changed to airborne. The trigger for this is the front gear. So it indicated that the front wheels went off from ground at that point.
Why? We don't know. Maybe it doesn't make sense, but once again, it's not FR24 guessing, it's what the transponder was transmitting. There must be a reason why the transponder transmitted this data!
Last edited by flyingbird on Mon Mar 11, 2019 2:09 pm, edited 1 time in total.
 
Trin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:08 pm

trnswrld wrote:
I always wonder how and why witnesses are so unreliable. I know not everyone knows about aircraft, but how hard is it to fully understand and comprehend what you’re seeing? Just weird how so many people claim to see fire and smoke when they really didn’t. I know I know it would be a very intense situation to see an aircraft crash in front of you, but still.
Now I will say IF this witness is right and there was smoke, then that changes things a lot here.



That's a really narrow-minded outlook. Commercial airplanes travel over sparsely populated, unconnected, zero-infrastructure areas of the world every single day. Not every country in the world is like the US. There are people in rural areas that get flown over who have never even BEEN to the city that the flight originated from, let alone ever flown before. People who lead simple lives and to whom the internet does not even feature in their daily lives. I would imagine the sight of a low-flying, fast-moving airplane with standard engine omissions and noises coming from the power plants would be an alarming thing to many onlookers. Criticizing people for not understanding what they are seeing is fairly pointless.

I could not believe the new yesterday when I heard about this tragedy. Sincerely hoping the investigators expedite the investigations of this crash AND the Lion Air crash.
 
estorilm
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:14 pm

flyingturtle wrote:
The Habsheim air show crash. And the Hudson miracle. In both cases, the airplane fought the pilots and didn't allow them to stall the aircraft.
David

This is absurd - it is widely known that one of Sullenberger's primary reasons for starting the APU was specifically to retain full flight protections including alpha floor. It didn't fight him - he knew the system would prevent a stall.

You're totally wrong about the air show crash by the way; the pilots specifically stated that part of the routine was to "disable alpha floor". They flew the pass 3x lower than they were supposed to as well. Seems obvious.
 
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:16 pm

kruiseri wrote:
william wrote:

How so in the USAirways case?


In that case, didn't Sullivan state that since he knew that the plane would not stall it helped him a lot as he could pull the stick all the way, ie make the plane fly at the lowest possible safe speed to the impact.

So yes, the A320 FBW saved 150+ lives.


Yep. Airbus FBW lets the pilots focus on flying. They don't have to think about whether their inputs are safe.

In several near-collision events, Airbus FBW lets the pilots jerk the airplane out of the way. Nobody has to care about whether the inputs are, in itself, another cause for danger.
Reading accident reports is what calms me down
 
flyingbird
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:21 pm

SDFspectator wrote:
A couple of remarks before the rest of this. I'm not a pilot. I'm not an engineer. I'm not a role model. This is pure speculation. The field elevation is listed as 7656 feet, not 7200 that flightradar has. .


Once again. FR24 does not have it as 7200. FR24 show the airport at 7625 feet.
The number 7200 comes from the ADS-B transponder of ET-AVJ. FR24 has published the raw and unprocessed data from flight ET302.
In this case the reason why the transponder was transmitting 7200 and not 7625 can be found on FR24 blog.

https://www.flightradar24.com/blog/flig ... light-302/

"Important note: altitude data reported by ADS-B is the pressure altitude at standard pressure and not the altitude above ground level. This is why some values may be below the ground altitude at Addis Ababa airport. Standard pressure is 1013 hPa, pressure reported at HAAB | ADD at the time of accident was 1029 hPa. Airport elevation is 7625 feet MSL. All altitude data when the aircraft is ‘on ground’ is reported as 0. Airborne altitude values are report as stated above."

Instead of blaming the messager, try to understand the data. It's not FR24 data, it data from the transponder of the crashed aircraft. FR24 just made it available to the public.
Last edited by flyingbird on Mon Mar 11, 2019 2:24 pm, edited 1 time in total.
 
ytz
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:23 pm

ACCS300 wrote:
Although I did admire the MAX I'd be a bit hesitant to fly one until I know more about this horrific crash. As a frequent Canadian domestic flyer, it's gonna be a challenge avoiding the MAX here soon with big orders from AC and Westjet and few if any new NEOs for Canadian carriers in the future.


I really hope AC is thinking of cancelling their MAX order and getting NEOs instead. A dozen and a half dead Canadians. And on the face of it, looks like something is wrong with the aircraft. Either it's build, how training was done by Boeing, manuals, whatever....

I know I am not going to feel comfortable putting myself or a family member on a 737 Max until they absolutely have figured out what's going on. And at the rate this is going, all but guaranteed, there will be another 737 Max crash within months.
 
MD80Ttail
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:23 pm

“”I will start my TR on the NG/MAX in a few months and so it would be nice if there was not a general problem with the Max.
First Job and also less than 250h.””

Shakes head. No one with this low of time should be flying pax in scheduled service or flying any type of mainline aircraft. I know that’s how it’s done everywhere but the USA.....there is a reason we have the safest air travel system in the world.
 
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flyingturtle
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:24 pm

estorilm wrote:
This is absurd - it is widely known that one of Sullenberger's primary reasons for starting the APU was specifically to retain full flight protections including alpha floor. It didn't fight him - he knew the system would prevent a stall.

You're totally wrong about the air show crash by the way; the pilots specifically stated that part of the routine was to "disable alpha floor". They flew the pass 3x lower than they were supposed to as well. Seems obvious.


1. You seem to have a different understanding of "fight the pilot". I want a safety system to fight me when I'm about to do something unsafe, whether it is intentional or unintentional.

2. Do you have a source for your statement that they disabled alpha prot?


David
Reading accident reports is what calms me down
 
BHM
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:25 pm

theaviator380 wrote:

Some details about Boeing MCAS system, explained in nice and easy way.

https://theaircurrent.com/aviation-safe ... cas-jt610/



Thanks for that info as it help a novice like myself understand how it works. I do have a question about the MCAS system. According to the explanation, it will kick in when...

1. Angle of attack is high.
2. Autopilot is off.
3. Flaps are up
4. Steeply turning.


Does this mean all four must be true for MCAS to adjust flight parameters? If so, if they just continued flying straight, the only item to troubleshoot would have been the inaccurate airspeed indication issue. Item 4 would have came into play perhaps when they made the turn to return to the airport and that is when MCAS kicked in and pushed the nose down resulting in a loss of control.

Am I understanding this correctly?
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 11, 2019 2:27 pm

CLTRampRat wrote:
Hello everyone,
I do not have time to dig through the thread at this time, would anyone be willing to post the last recorded FPM descent rate?
Thank you.

The FDR data is not available yet
The FR24 data ceased several minutes before the crash.

Some people have looked at the crash site and concluded the aircraft must have been higher than believed, after which it came down nearly vertical, and fast (e.g. 400 kts)

It seems as if only one person here believes the crater (positioned on a gently sloping hillside) could equally be due to a much shallower impact (say 30°) but at high speed (e.g 400 kts). Anything shallower than 25° could have resulted in a degree of bounce, or at the very least an elongated debris field.

Before data was lost, FR24 did suggest higher speeds had been reached during the flight, but if that data is generated by the same faulty sensors that befuddled the pilots, then trusting it might be a mistake. What is needed is someone to match up time stamps and physical co-ordinates, and calculate actual ground speed using fingers, thumbs, and Pythagoras' theorem. I'll confess I haven't quite got around to it yet.... (¹)

I recall having similar arguments over the impact angle of the An-148 about a year ago (albeit for different reasons).

Basically I am imagining a scenario where the 737MAX was flying at low level, high throttle, high speed (²), with the pilots fighting the controls as the ground crept closer and closer. "Pull Up, Pull Up!"
It's an ugly thought, and I apologise if sharing it here upsets anybody.

(¹) Unless FR24 already features true ground speed using GPS data ?
(²) High speed at low level is normally a no-no, except "low-level" in this case is around 8,000 feet where the air is already thinner.
Nothing to see here; move along please.

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