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ACCS300
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 3:32 pm

Extremely well produced visual account of the crash on YouTube now by Avinations, like jollo so brilliantly stated.. 'creepy, and sobering'.

https://www.youtube.com/watch?v=fIunpQQpzs0
 
Etheereal
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 3:40 pm

Paolo18 wrote:
And so it begins....

Garuda Indonesia is seeking to scrap its multi-billion dollar order for 49 Boeing 737 Max 8 jets after the plane was involved in two fatal crashes.


https://www.bbc.com/news/business-47662967

They've been trying that since october, so i dont see how this is news?
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 4:02 pm

ikramerica wrote:
Because despite Ethiopias long and documented storied history of government corruption including very recent events, they are beyond reproach, because racism.


I've neither blamed nor absolved anyone and certainly not claimed that anyone is "beyond reproach". Blame is not the purpose of the exercise, but you knew that.

There will be many factors that contribute to both these tragic accidents, some may be unique, some might be common between them. The pilots may have made poor choices under the most extreme pressure.

Whether or not those pilots did make errors, nothing excuses the casual and blatant racism that has been seen in these threads. How different would the Atlas Air 3591 thread be if it had been Ethiopian Airlines pilots that had flown a perfectly serviceable 767 into the ground?
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BEG2IAH
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 4:22 pm

scbriml wrote:
Whether or not those pilots did make errors, nothing excuses the casual and blatant racism that has been seen in these threads. How different would the Atlas Air 3591 thread be if it had been Ethiopian Airlines pilots that had flown a perfectly serviceable 767 into the ground?


If your racism argument was correct, someone would have found a way to blame a tragically deceased African American pilot of the Atlas Air flight 3591. The Western world has no confidence in anything that's not of the "first-world-country" origin and that's a very sad fact. I don't think it's racism, call it ignorance, lack of education, spacial/global surroundings "unawareness"...
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tjcab
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 4:50 pm

scbriml wrote:
ikramerica wrote:
Because despite Ethiopias long and documented storied history of government corruption including very recent events, they are beyond reproach, because racism.


I've neither blamed nor absolved anyone and certainly not claimed that anyone is "beyond reproach". Blame is not the purpose of the exercise, but you knew that.

There will be many factors that contribute to both these tragic accidents, some may be unique, some might be common between them. The pilots may have made poor choices under the most extreme pressure.

Whether or not those pilots did make errors, nothing excuses the casual and blatant racism that has been seen in these threads. How different would the Atlas Air 3591 thread be if it had been Ethiopian Airlines pilots that had flown a perfectly serviceable 767 into the ground?


Well Said!. Or the AA A300 crash (rudder situation)
 
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JetBuddy
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 5:06 pm

This racism accusation is quite the meta-debate. But here are my thoughts:

I think "racism" is too strong a word here. Nobody wants to be labeled a racist - unintended or not. And it's not fruitful to call people out for it either. It just poisons the debate and then figuratively put yourself on a pedistal.

People think in stereotypes and generalizations. Sometimes they're correct, sometimes they're not. Sometimes it can be helpful to understand something, sometimes it's not helpful. It doesn't mean people who think like that are bad people.

However, it would be good for the debate to look at Ethiopian aviation for what it is, not put them in the same category as the rest of Africa. Or even worse - put them in a basket of "everything outside the USA or Europe".

So let's just get back to the topic.
 
ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 6:31 pm

JetBuddy wrote:
This racism accusation is quite the meta-debate. But here are my thoughts:

I think "racism" is too strong a word here. Nobody wants to be labeled a racist - unintended or not. And it's not fruitful to call people out for it either. It just poisons the debate and then figuratively put yourself on a pedistal.

People think in stereotypes and generalizations. Sometimes they're correct, sometimes they're not. Sometimes it can be helpful to understand something, sometimes it's not helpful. It doesn't mean people who think like that are bad people.

However, it would be good for the debate to look at Ethiopian aviation for what it is, not put them in the same category as the rest of Africa. Or even worse - put them in a basket of "everything outside the USA or Europe".

So let's just get back to the topic.

Personally I dont care about being labeled anything because in my experience those doing the labeling are the worst offenders.

My point was that there has been a very obvioys attempt by many to tip toe around any hint that Ethiopia isnt run by saints because it would open those peopke up to cries of racism.

Read about Ethiopian history and of course its quite obvious that, JUST LIKE MOST OTHER COUNTRIES, they have political hacks corrupting most agencies.

Add to that election fraud, multiple states of emergency in the last few years, political prosecutions and chronyism, and the fact that the airline is state run and basically investigating themselves, and its not an outlandish demand that the investigation to be run by a third party.

Edit: and no i dont think the Usa should run it. Are we much better, when the secretary of transportation is a hack married to the corrupt senate majority leader?
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Saintor
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 6:49 pm

Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?
 
nyarlathotep
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:24 pm

jollo wrote:
* you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option


You mean for example United Airlines, whose "pilots use other data to fly the plane"?

https://www.nytimes.com/2019/03/21/business/boeing-safety-features-charge.html
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:35 pm

scbriml wrote:
ikramerica wrote:
Because despite Ethiopias long and documented storied history of government corruption including very recent events, they are beyond reproach, because racism.


I've neither blamed nor absolved anyone and certainly not claimed that anyone is "beyond reproach". Blame is not the purpose of the exercise, but you knew that.

There will be many factors that contribute to both these tragic accidents, some may be unique, some might be common between them. The pilots may have made poor choices under the most extreme pressure.

Whether or not those pilots did make errors, nothing excuses the casual and blatant racism that has been seen in these threads. How different would the Atlas Air 3591 thread be if it had been Ethiopian Airlines pilots that had flown a perfectly serviceable 767 into the ground?


Scbriml:

We've both been here for... well forever, so while I appreciate you feel there may be a 'racial' tinge to some of the things being posted here (I would as an aside argue you may be better off accusing people of cultural bias rather than racial, because I have no idea what race any of these pilots were personally and I doubt anyone else does), can I ask that if you want to discuss the racial/cultural slant people have to these accident causes we do it in another thread. I think the topic itself warrants discussion, but the biases (or lack thereof) of posters in this thread has no direct impact on the causes or data for this crash. Less so does the bias of any media warrant discussion here. Until such time as an investigating body finds a 'lack of proper procedures that are endemic to an airline' any cultural/racial biases has no basis what ACTUALLY happened to their of these planes.

Cheers and hope you take this as intended.
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osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:39 pm

Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?


With flaps out MCAS is in inactive, correct.

We don't know if MCAS did anything in this flight. There has been no hard data to indicate MCAS did anything (yet). Media speculation yes, but not even semi-official leaks have directly said MCAS went active at any time. We don't know, but after 67 pages of people saying it did, it has become instant a.net myth (said myth may end up being correct, but right now it is unproven).

edit: inactive read active.. MCAS is inactive with flaps deployed.
Last edited by osiris30 on Fri Mar 22, 2019 7:47 pm, edited 1 time in total.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:43 pm

jollo wrote:
dare100em wrote:
It was the final nail to the coffin when the airspeed got to high and therefore the elevators, which would normally be capable of countering the (MCAS) down inertia of the tail by pilot upward force of the elevators lost its function (due to the higher and higher airspeed with the nose down). That seems very logical to me.


I'm beginning to picture this scenario:
    * you have a malfunctioning AOA sensor, which basically by random misfortune happens to be the one feeding STS and MCAS for this flight (the other one works just fine, but is being ignored)
    * you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option
    * instead, you get stick shaker and stall warning
    * so you push a bit of nose down (and perhaps add a little thrust) to build a safety speed margin above an airspeed you're suddenly no longer sure about
    * MCAS - which you may or may not know about, certainly not through reading the FCOM - silently kicks in and gives you 2.5°/sec of nose down trim for 10 seconds - speed increases quickly
    * you may have noticed - amid the cacophony of alarms, perhaps while trying to run an unreliable airspeed checklist - the uncommanded trim movement, but then it stops on its own - so no, this is not a runaway stab trim occurence
    * you pull back on the yoke to avoid overspeeding, and probably trim nose up to alleviate the effort - but not for a full 10 seconds: stab trim is still nose down and speed is not back down to where it started
    * after 10 seconds MCAS is back in action, and gives you another 10 seconds of nose down trim - speed increases further
    * you're now pulling back on the yoke with all your might, but blowback kicks in and despite your best efforts the elevator looses authority

At this point you have just one chance of living through the day by executing this exact sequence of actions:
1) do not heed the backseater pilot deadheading on the jump seat behind you, yelling to cutoff stab trim! At least not yet: if you do, you will not have enough elevator authority to climb out of the dive you're currently in; you need electric trim because hand cranking the manual trim wheel will not be fast enough, and you need both hands to apply as much nose up elevator as you can in the meanwhile
2) use electric trim switch to trim nose up and continue to pull back on the yoke (something they taught you since PPL should not be done: first stick, then trim)
3) if you aren't a smoking hole in the ground by now, get speed under control and back to level flight eventually
4) NOW you must cutoff the stab trim to avoid riding the rollercoaster again

Creepy, and sobering.


You have included MCAS where it didn't need to be included. The AC was overspeed before we saw any hard evidence of MCAS doing anything. The AC was overspeed before the FR data even ends! MCAS isn't required for this flight to end in disaster, it may have helped, but the assumption it is a vital piece of the puzzle *for this crash* is a reach IMHO. vMax for the frame is 340kts. KIAS based on FR data and winds was ~350kts, at the end of the FR data and 3+ minutes before the end of the flight.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
Interested
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:43 pm

osiris30 wrote:
Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?


With flaps out MCAS is in active, correct.

We don't know if MCAS did anything in this flight. There has been no hard data to indicate MCAS did anything (yet). Media speculation yes, but not even semi-official leaks have directly said MCAS went active at any time. We don't know, but after 67 pages of people saying it did, it has become instant a.net myth (said myth may end up being correct, but right now it is unproven).


But surely that is because Boeing have said the same software fix they are working on since Lion will work to make Ethiopia safe as well?

Alongside promising to put MCAS training into the flight manual?

Haven't they?

Doesn't that suggest MCAS is the problem?
Last edited by Interested on Fri Mar 22, 2019 7:45 pm, edited 2 times in total.
 
PlanesNTrains
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:43 pm

Interested wrote:
RickNRoll wrote:
Interested wrote:
A question that is going to actually become very relevant is:

If other airlines start following suit (which must be likely) and cancel their orders for 737 Max does it actually not solve a HUGE problem for the industry long term?

With all the bad news - A very possible scenario is nobody wants the plane now they know more about it - so lets not fix or certify something that nobody wants to buy into anymore

Basically we are just left with 350 existing planes to worry about. Can the industry handle that?

Cut the losses now

Clearly would be catastrophic financially short term for Boeing but at least we can move forward at some stage. Boeing or some form of Boeing will survive at least and learn from the whole sorry episode

Whilst Boeing create a new plane that is safe can they not focus on their other versions that are proven to be safe. Including the old 737 if needed
Boeing is going to deliver thousands of MAX planes to customers and few customers will cancel their orders. It will, however, have this scandal tainting it's reputation for many years.


Ok for the next few weeks each week I will google and post every cancelled order

You predict few will cancel I will predict many will cancel


1. Please do so, but can you do it in a thread that isn't about a specific crash? We have like a dozen MAX-related threads - find one about orders and post it there.
2. Garuda may be happy to get rid of the MAX orders, but that might not be because of the MAX.
-Dave


MAX’d out on MAX threads. If you are starting a thread, and it’s about the MAX - stop. There’s already a thread that covers it.
 
MrBretz
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:44 pm

osiris30, you mean with flaps out MCAS is inactive, not active, right?

If so, he's flying real fast so the flaps are probably not extended. So the MCAS was probably active.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:47 pm

MrBretz wrote:
osiris30, you mean with flaps out MCAS is inactive, not active, right?

If so, he's flying real fast so the flaps are probably not extended. So the MCAS was probably active.


Yes I will edit that, thank you!
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
XRAYretired
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 7:52 pm

Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?



First question -yes, but speed considerable beyong 250kts limit for flaps as I understand it.

Last question - wrong, no data has been released at all. Suspect you are referring to FR24 data, the unreliability of which, is covered in detail in this thread. suggest you review it.

In the middle you rightly suggest objectivity should be the watchword but then but go on to push the 'it dint happen here' button? (just wondering)

Ray
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:09 pm

Interested wrote:
osiris30 wrote:
Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?


With flaps out MCAS is in active, correct.

We don't know if MCAS did anything in this flight. There has been no hard data to indicate MCAS did anything (yet). Media speculation yes, but not even semi-official leaks have directly said MCAS went active at any time. We don't know, but after 67 pages of people saying it did, it has become instant a.net myth (said myth may end up being correct, but right now it is unproven).


But surely that is because Boeing have said the same software fix they are working on since Lion will work to make Ethiopia safe as well?

Alongside promising to put MCAS training into the flight manual?

Haven't they?

Doesn't that suggest MCAS is the problem?


Ermmm...

Boeing have said the same software fix they are working on since Lion will work to make Ethiopia safe as well?


Can you please find me the quote where Boeing said the Lion Air fix was relevant to Ethiopia? I'd love to see a statement from them to that effect. Without that statement (that I would be STUNNED if it exists);

Doesn't that suggest MCAS is the problem?
becomes a false statement.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:11 pm

XRAYretired wrote:
Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?



First question -yes, but speed considerable beyong 250kts limit for flaps as I understand it.

Last question - wrong, no data has been released at all. Suspect you are referring to FR24 data, the unreliability of which, is covered in detail in this thread. suggest you review it.

In the middle you rightly suggest objectivity should be the watchword but then but go on to push the 'it dint happen here' button? (just wondering)

Ray


FR's speed data is reliable (as reliable as any other source of speed data). Is there a discussion you can point me to that definitively disproves this (FR has explained on their page/tweets what their data is and where it comes from, this shouldn't be a debate item unless something has changed I missed).
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
MarcoT
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:11 pm

Saintor wrote:
Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.


On which planet?

You DO realize that, out of 350 MAX out there, only less than one third flies for North American carriers?
Talk about facts...

Oh, and MAX belonging to Western carriers account for less than 40% of the total: acting surprised because both crashes happened to non Western carriers prove only one thing...
Too short space for my favorite hopelessly long winded one liner
 
kq747
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:27 pm

jollo wrote:


* you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option
* instead, you get stick shaker and stall warning


Not sure where you live mate but only AA opted to buy both right off the bat. Southwest installed one of them after the Lion Air crash (or both, cant recall) and United still doesn't have either...
 
CO953
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:42 pm

jollo wrote:
dare100em wrote:
It was the final nail to the coffin when the airspeed got to high and therefore the elevators, which would normally be capable of countering the (MCAS) down inertia of the tail by pilot upward force of the elevators lost its function (due to the higher and higher airspeed with the nose down). That seems very logical to me.


I'm beginning to picture this scenario:
    * you have a malfunctioning AOA sensor, which basically by random misfortune happens to be the one feeding STS and MCAS for this flight (the other one works just fine, but is being ignored)
    * you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option
    * instead, you get stick shaker and stall warning
    * so you push a bit of nose down (and perhaps add a little thrust) to build a safety speed margin above an airspeed you're suddenly no longer sure about
    * MCAS - which you may or may not know about, certainly not through reading the FCOM - silently kicks in and gives you 2.5°/sec of nose down trim for 10 seconds - speed increases quickly
    * you may have noticed - amid the cacophony of alarms, perhaps while trying to run an unreliable airspeed checklist - the uncommanded trim movement, but then it stops on its own - so no, this is not a runaway stab trim occurence
    * you pull back on the yoke to avoid overspeeding, and probably trim nose up to alleviate the effort - but not for a full 10 seconds: stab trim is still nose down and speed is not back down to where it started
    * after 10 seconds MCAS is back in action, and gives you another 10 seconds of nose down trim - speed increases further
    * you're now pulling back on the yoke with all your might, but blowback kicks in and despite your best efforts the elevator looses authority

At this point you have just one chance of living through the day by executing this exact sequence of actions:
1) do not heed the backseater pilot deadheading on the jump seat behind you, yelling to cutoff stab trim! At least not yet: if you do, you will not have enough elevator authority to climb out of the dive you're currently in; you need electric trim because hand cranking the manual trim wheel will not be fast enough, and you need both hands to apply as much nose up elevator as you can in the meanwhile
2) use electric trim switch to trim nose up and continue to pull back on the yoke (something they taught you since PPL should not be done: first stick, then trim)
3) if you aren't a smoking hole in the ground by now, get speed under control and back to level flight eventually
4) NOW you must cutoff the stab trim to avoid riding the rollercoaster again

Creepy, and sobering.


Now try nailing this diagnostic sequence while climbing out of a hot and high airfield, with a mountain in the way.
 
XRAYretired
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:42 pm

osiris30 wrote:
XRAYretired wrote:
Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?



First question -yes, but speed considerable beyong 250kts limit for flaps as I understand it.

Last question - wrong, no data has been released at all. Suspect you are referring to FR24 data, the unreliability of which, is covered in detail in this thread. suggest you review it.

In the middle you rightly suggest objectivity should be the watchword but then but go on to push the 'it dint happen here' button? (just wondering)

Ray


FR's speed data is reliable (as reliable as any other source of speed data). Is there a discussion you can point me to that definitively disproves this (FR has explained on their page/tweets what their data is and where it comes from, this shouldn't be a debate item unless something has changed I missed).


My memory of understanding. Suggest we all wait for the FDR to appear and the clarity it will bring for all.
 
dakota123
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:49 pm

SheikhDjibouti wrote:
OlafW wrote:
Another question as I don't know too much about flight physics and systems: How would the AoA sensor behave during a turn? I seem to remember that flying a curve usually correlates with changing altitude, but I'm not sure about that.
And what would happen if you move the stabilizer during a turn? Is that something a pilot would normally do?
Leading up to my main question: MCAS can be somewhat counteracted during straight flight, as it seems. But what if the MCAS-induced stabilizer trim kicks in during a turn? I get the impression that both the Lion and the Ethiopian flights were in the process of turning back when they crashed. Could a stabilizer movement during a turn leave the aircraft completely uncontrollable?

I've posted this before.
Boeing MOM -18-0664-01B dated 11 Nov 2018
The MCAS functions commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall

In addition to both crash flights seemingly losing control whilst attempting a turn, both occurred after take-off with "elevated load factors"(assuming it applies to aircraft weight, not aerodynamic loading)

Beyond that, I'm still waiting for a 737 jockey to explain the full significance of those words.


Aerodynamic load. Load factors and hence stall speed increase with increasing bank angle, to the extent altitude is maintained. With a standard 30* bank, stall speed increases 15%, with a 45* bank, stall speed increases 41%, with a 60* bank, it’s doubled (1/COS bank angle) — it’s a hockey stick. Load factor also increases as you transition from one regime to another, say straight-and-level to establishing a climb, or increasing climb rate.
“And If I claim to be a wise man, well surely it means that I don’t know”
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 8:55 pm

BEG2IAH wrote:
If your racism argument was correct, someone would have found a way to blame a tragically deceased African American pilot of the Atlas Air flight 3591.


Racism isn't just about skin colour and the Atlas situation supports my view - no criticism of pilot because he's one of those American pilots with lots of hours. Would have been very different if he was from "one of those crappy third-world airlines".

BEG2IAH wrote:
The Western world has no confidence in anything that's not of the "first-world-country" origin and that's a very sad fact. I don't think it's racism, call it ignorance, lack of education, spacial/global surroundings "unawareness"...


Good point and I certainly don't disagree.

JetBuddy wrote:
I think "racism" is too strong a word here.


OK.

JetBuddy wrote:
It just poisons the debate and then figuratively put yourself on a pedistal.


Well, I have no intention of that but I've never been on a pedestal before! ;)

ikramerica wrote:
Personally I dont care about being labeled anything because in my experience those doing the labeling are the worst offenders.


Well, for clarity, I wan't accusing you of racism.

But we do see posts like this:
jollo wrote:
* you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option


osiris30 wrote:
Scbriml:

We've both been here for... well forever, so while I appreciate you feel there may be a 'racial' tinge to some of the things being posted here (I would as an aside argue you may be better off accusing people of cultural bias rather than racial, because I have no idea what race any of these pilots were personally and I doubt anyone else does)


Fair point.

osiris30 wrote:
Cheers and hope you take this as intended.


No problem.
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:02 pm

Saintor wrote:
Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.


Maybe an objective person would produce stats to support their claim? Then again, maybe the stats don't actually support their position? :scratchchin:
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mila
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:06 pm

I have a few queustion regarding MCAS and AoA sensor that I hope someone can answer.

- Is MCAS redundant, that means atleast two of them?
- And the AoS sensor, since MCAS only uses one of the two AoA, which one of the two does it use?

/m
 
Exeiowa
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:09 pm

It seems a little odd for people to opt to buy a safety indicating system for something you do not know exists
 
PixelPilot
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:11 pm

Exeiowa wrote:
It seems a little odd for people to opt to buy a safety indicating system for something you do not know exists


!!!!!!!!!!!
Which leads us to believe that all max buyers knew about the extra option but choose not to install/buy it.
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:12 pm

osiris30 wrote:
XRAYretired wrote:
Saintor wrote:
Is that correct that if the pilot would have extended the flaps minimally, the MCAS couldn't have kicked in?

Some people just loves to push the r*ce button. Not the way to stay objective. It is a fact that those two crashes happened out of western world. Most the MAX flights happened in North America by a large margin and there was no drama.

Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?



First question -yes, but speed considerable beyong 250kts limit for flaps as I understand it.

Last question - wrong, no data has been released at all. Suspect you are referring to FR24 data, the unreliability of which, is covered in detail in this thread. suggest you review it.

In the middle you rightly suggest objectivity should be the watchword but then but go on to push the 'it dint happen here' button? (just wondering)

Ray


FR's speed data is reliable (as reliable as any other source of speed data). Is there a discussion you can point me to that definitively disproves this (FR has explained on their page/tweets what their data is and where it comes from, this shouldn't be a debate item unless something has changed I missed).


Yes there was a discussion, and the very person who originally noted the 'low speed' rotation corrected themselves and noted the runway there has a significant elevation gain in the middle. That's probably what FR24 picked up, and the point their vertical speed becomes positive again is in line with a normal takeoff speed.

So no it probably isn't a debate item.

As for the racism point. It comes up because there are people still writing nonsense like 'well most Max''s are in the US and none crashed there' as if it means anything. In only one country in the world did a pilot snap the tail off a plane because they didnt know how to use the rudder. By some of the 'logic' some geniuses here use, that means US pilots are the worst in the world.
 
MarcoT
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:19 pm

scbriml wrote:

But we do see posts like this:
jollo wrote:
* you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option


Well, I _think_ that he was being sarcastic, in a dryly, wry mode: think "A Modest Proposals"... but I can be wrong...
Too short space for my favorite hopelessly long winded one liner
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:28 pm

MarcoT wrote:
Well, I _think_ that he was being sarcastic, in a dryly, wry mode: think "A Modest Proposals"... but I can be wrong...


Well, if he was, I apologise. But it's easy to remove all doubt by using :sarcastic: or :wink2: . Just sayin'.
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ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:31 pm

CO953 wrote:
jollo wrote:
dare100em wrote:
It was the final nail to the coffin when the airspeed got to high and therefore the elevators, which would normally be capable of countering the (MCAS) down inertia of the tail by pilot upward force of the elevators lost its function (due to the higher and higher airspeed with the nose down). That seems very logical to me.


I'm beginning to picture this scenario:
    * you have a malfunctioning AOA sensor, which basically by random misfortune happens to be the one feeding STS and MCAS for this flight (the other one works just fine, but is being ignored)
    * you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option
    * instead, you get stick shaker and stall warning
    * so you push a bit of nose down (and perhaps add a little thrust) to build a safety speed margin above an airspeed you're suddenly no longer sure about
    * MCAS - which you may or may not know about, certainly not through reading the FCOM - silently kicks in and gives you 2.5°/sec of nose down trim for 10 seconds - speed increases quickly
    * you may have noticed - amid the cacophony of alarms, perhaps while trying to run an unreliable airspeed checklist - the uncommanded trim movement, but then it stops on its own - so no, this is not a runaway stab trim occurence
    * you pull back on the yoke to avoid overspeeding, and probably trim nose up to alleviate the effort - but not for a full 10 seconds: stab trim is still nose down and speed is not back down to where it started
    * after 10 seconds MCAS is back in action, and gives you another 10 seconds of nose down trim - speed increases further
    * you're now pulling back on the yoke with all your might, but blowback kicks in and despite your best efforts the elevator looses authority

At this point you have just one chance of living through the day by executing this exact sequence of actions:
1) do not heed the backseater pilot deadheading on the jump seat behind you, yelling to cutoff stab trim! At least not yet: if you do, you will not have enough elevator authority to climb out of the dive you're currently in; you need electric trim because hand cranking the manual trim wheel will not be fast enough, and you need both hands to apply as much nose up elevator as you can in the meanwhile
2) use electric trim switch to trim nose up and continue to pull back on the yoke (something they taught you since PPL should not be done: first stick, then trim)
3) if you aren't a smoking hole in the ground by now, get speed under control and back to level flight eventually
4) NOW you must cutoff the stab trim to avoid riding the rollercoaster again

Creepy, and sobering.


Now try nailing this diagnostic sequence while climbing out of a hot and high airfield, with a mountain in the way.

Well if his summary were actually accurate and the timeline correct, you are right.

Except its not.

We dont know yet about ET, but at Lion the captain correctly countered MCAS fault 21 times, and then by what can only be classified as a complete failure of cockpit communication, transferred flying tk tbe FO to look up a solution without telling him what he had been fighting and what he was doing to stop it.

21 times, but no communication. FO crashes the plane in short order.

Then you have the issue of the changing story about the previous flight. The current story is that the jumpseater told them to turn off stab trim, and when they landed nobody wrote it up! WTF?

My guess is we will find out that MCAS wasn’t even the issue on this crash until it was actually kicking in to counteract what this crew had done to get unti this jam. MCAS is a safety feature designed to help prevent pilots from over doing a climb. MCAS activating doesnt mean its the thing malfunctioning. It might be the fight crew that is malfunctioning and MCAS is desperately trying to stop them.
Of all the things to worry about... the Wookie has no pants.
 
flybucky
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 9:35 pm

journeyperson wrote:
dare100em wrote:
Bjorn has an article on LH which I foun very enlithening at least:

https://leehamnews.com/2019/03/22/bjorn ... sh-part-2/


"Blowback". Just when you thought it couldn't get any more complicated!

Great article, thanks for posting the link.

At the end of the day, though, I don't think it made a difference in the outcome. Beforehand, the general thought was that the elevator at full extension could not overcome the stabilizer at full nose down. That's why pulling the yoke back could not overcome stabilizer at full nose down, and doomed JT610.

Now, according to the article, it would have been possible for elevator to overcome stabilizer at full nose down. Except when the speed is too high, then the elevator cannot extend fully because the airflow pushes it back down. So basically, the same end result. Elevator cannot overcome stabilizer. (Of course, the difference will matter for investigators and the fix/solution.)
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:08 pm

PixelPilot wrote:
Exeiowa wrote:
It seems a little odd for people to opt to buy a safety indicating system for something you do not know exists


!!!!!!!!!!!
Which leads us to believe that all max buyers knew about the extra option but choose not to install/buy it.


Oh good lord... guys the SAME SYSTEM and OPTION was on the NG. If you can't figure out why AoA disagree is helpful on an airframe as an airline you need to fire some people!
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:11 pm

flybucky wrote:
journeyperson wrote:
dare100em wrote:
Bjorn has an article on LH which I foun very enlithening at least:

https://leehamnews.com/2019/03/22/bjorn ... sh-part-2/


"Blowback". Just when you thought it couldn't get any more complicated!

Great article, thanks for posting the link.

At the end of the day, though, I don't think it made a difference in the outcome. Beforehand, the general thought was that the elevator at full extension could not overcome the stabilizer at full nose down. That's why pulling the yoke back could not overcome stabilizer at full nose down, and doomed JT610.

Now, according to the article, it would have been possible for elevator to overcome stabilizer at full nose down. Except when the speed is too high, then the elevator cannot extend fully because the airflow pushes it back down. So basically, the same end result. Elevator cannot overcome stabilizer. (Of course, the difference will matter for investigators and the fix/solution.)


So basically, the same end result. Elevator cannot overcome stabilizer.


Untrue statement. Correct Statement: Elevator cannot overcome stabilizer once airspeed has exceeded design limits for the elevator system.

Changes the nature of the failure doesn't it?
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:25 pm

ikramerica wrote:
CO953 wrote:
jollo wrote:

I'm beginning to picture this scenario:
    * you have a malfunctioning AOA sensor, which basically by random misfortune happens to be the one feeding STS and MCAS for this flight (the other one works just fine, but is being ignored)
    * you get no warning of the failure, because your cheap-o third-world airline did not purchase the AOA disagree warning option
    * instead, you get stick shaker and stall warning
    * so you push a bit of nose down (and perhaps add a little thrust) to build a safety speed margin above an airspeed you're suddenly no longer sure about
    * MCAS - which you may or may not know about, certainly not through reading the FCOM - silently kicks in and gives you 2.5°/sec of nose down trim for 10 seconds - speed increases quickly
    * you may have noticed - amid the cacophony of alarms, perhaps while trying to run an unreliable airspeed checklist - the uncommanded trim movement, but then it stops on its own - so no, this is not a runaway stab trim occurence
    * you pull back on the yoke to avoid overspeeding, and probably trim nose up to alleviate the effort - but not for a full 10 seconds: stab trim is still nose down and speed is not back down to where it started
    * after 10 seconds MCAS is back in action, and gives you another 10 seconds of nose down trim - speed increases further
    * you're now pulling back on the yoke with all your might, but blowback kicks in and despite your best efforts the elevator looses authority

At this point you have just one chance of living through the day by executing this exact sequence of actions:
1) do not heed the backseater pilot deadheading on the jump seat behind you, yelling to cutoff stab trim! At least not yet: if you do, you will not have enough elevator authority to climb out of the dive you're currently in; you need electric trim because hand cranking the manual trim wheel will not be fast enough, and you need both hands to apply as much nose up elevator as you can in the meanwhile
2) use electric trim switch to trim nose up and continue to pull back on the yoke (something they taught you since PPL should not be done: first stick, then trim)
3) if you aren't a smoking hole in the ground by now, get speed under control and back to level flight eventually
4) NOW you must cutoff the stab trim to avoid riding the rollercoaster again

Creepy, and sobering.


Now try nailing this diagnostic sequence while climbing out of a hot and high airfield, with a mountain in the way.

Well if his summary were actually accurate and the timeline correct, you are right.

Except its not.

We dont know yet about ET, but at Lion the captain correctly countered MCAS fault 21 times, and then by what can only be classified as a complete failure of cockpit communication, transferred flying tk tbe FO to look up a solution without telling him what he had been fighting and what he was doing to stop it.

21 times, but no communication. FO crashes the plane in short order.

Then you have the issue of the changing story about the previous flight. The current story is that the jumpseater told them to turn off stab trim, and when they landed nobody wrote it up! WTF?

My guess is we will find out that MCAS wasn’t even the issue on this crash until it was actually kicking in to counteract what this crew had done to get unti this jam. MCAS is a safety feature designed to help prevent pilots from over doing a climb. MCAS activating doesnt mean its the thing malfunctioning. It might be the fight crew that is malfunctioning and MCAS is desperately trying to stop them.


You better tell Boeing fast to stop work on their 'fix' if MCAS was actually trying to save the crew. You think Boeing are actually trying to make a safe plane less age?

Where did you see the CVR transcript by the way, since apparently you know well enough what happened to put your view forward as fact and tell others that their theories are wrong?
 
flybucky
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:27 pm

Saintor wrote:
Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?

That was according to FR24's Airborne/Ground data. At that data point, the plane had only travelled ~1,900 ft down the 12,467 ft runway, and its ground speed was 93 kts. I am doubtful that the plane tried to take off or rotate at that point. I attributed it to the rise in runway elevation profile (see this post). My opinion is that the plane rotated at the 174 kts ground speed data point, which is ~7000 ft down the runway (see this chart).

Others have said that the ADS-B airborne/ground data comes from a sensor in the nose gear. That could definitely be true. There are some possible explanations for that:
  • Perhaps the nose of the plane lightened enough to trigger the sensor that it was "airborne", without actually having taken off. (But then why didn't the sensor go back to "ground" later?)
  • It could be that the FR24 source did not use the ADS-B airborne/ground data, and used the Pressure Altitude increase to determine when it was airborne.
  • Or maybe the pilots really did rotate that early based on a faulty airspeed indicator.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:47 pm

Planetalk wrote:
ikramerica wrote:
CO953 wrote:

Now try nailing this diagnostic sequence while climbing out of a hot and high airfield, with a mountain in the way.

Well if his summary were actually accurate and the timeline correct, you are right.

Except its not.

We dont know yet about ET, but at Lion the captain correctly countered MCAS fault 21 times, and then by what can only be classified as a complete failure of cockpit communication, transferred flying tk tbe FO to look up a solution without telling him what he had been fighting and what he was doing to stop it.

21 times, but no communication. FO crashes the plane in short order.

Then you have the issue of the changing story about the previous flight. The current story is that the jumpseater told them to turn off stab trim, and when they landed nobody wrote it up! WTF?

My guess is we will find out that MCAS wasn’t even the issue on this crash until it was actually kicking in to counteract what this crew had done to get unti this jam. MCAS is a safety feature designed to help prevent pilots from over doing a climb. MCAS activating doesnt mean its the thing malfunctioning. It might be the fight crew that is malfunctioning and MCAS is desperately trying to stop them.


You better tell Boeing fast to stop work on their 'fix' if MCAS was actually trying to save the crew. You think Boeing are actually trying to make a safe plane less age?

Where did you see the CVR transcript by the way, since apparently you know well enough what happened to put your view forward as fact and tell others that their theories are wrong?


You are conflating two things (potentially erroneously). MCAS behaviour in the instance of the Lion Air crash was found to be problematic, to the point where a fix is being deployed. NOWHERE has ANY actual EVIDENCE been presented that MCAS did anything wrong on ET. Everyone has made assumptions, that may well end up being true, but are currently 100% unsupported by an official or semi-official released data. The extent of what has been seen are 'similarities' between the two crashes. Similarities is vague enough to mean anything; both were maxes... check. Both crashed after take-off, check. Both had a stab at nose down detent, check. Nowhere have I seen definitive information that the stab on ET was at max travel. I have only seen CONFIRMATION that it was deflected down. That would be an EXPECTED ACTION of STS if the aircraft was overspeed.... so...
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 10:48 pm

flybucky wrote:
Saintor wrote:
Finally it was duly noted that the aircraft took off at an anormal low speed (many points confirmed that by the released i fo). Even worse at 7600ft altitude. Was that explained?

That was according to FR24's Airborne/Ground data. At that data point, the plane had only travelled ~1,900 ft down the 12,467 ft runway, and its ground speed was 93 kts. I am doubtful that the plane tried to take off or rotate at that point. I attributed it to the rise in runway elevation profile (see this post). My opinion is that the plane rotated at the 174 kts ground speed data point, which is ~7000 ft down the runway (see this chart).

Others have said that the ADS-B airborne/ground data comes from a sensor in the nose gear. That could definitely be true. There are some possible explanations for that:
  • Perhaps the nose of the plane lightened enough to trigger the sensor that it was "airborne", without actually having taken off. (But then why didn't the sensor go back to "ground" later?)
  • It could be that the FR24 source did not use the ADS-B airborne/ground data, and used the Pressure Altitude increase to determine when it was airborne.
  • Or maybe the pilots really did rotate that early based on a faulty airspeed indicator.


My money has been on #3 for a while, assuming incorrect airspeed (Which is the only thing that can also explain the dangerous overspeed condition the crew found themselves in just minutes after lift-off.)
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
jollo
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 11:12 pm

scbriml wrote:
MarcoT wrote:
Well, I _think_ that he was being sarcastic, in a dryly, wry mode: think "A Modest Proposals"... but I can be wrong...


Well, if he was, I apologise. But it's easy to remove all doubt by using :sarcastic: or :wink2: . Just sayin'.


Gentlemen, *of course* this was sarcarm, poking at some posters here trying to leverage on nationality at all costs. The point being that it's not at all relevant where the affected airline might be based, but rather than an essential situational awareness item was being offered as an option. Sorry if (and a litle surprised that) my intent wasn't obvious to all: I'm just not very comfortable to pour on the emoticons in a post about an accident (potentially two accidents) with hundreds of victims: just shows my age, I suppose :old:
 
flybucky
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 11:13 pm

ikramerica wrote:
at Lion the captain correctly countered MCAS fault 21 times, and then by what can only be classified as a complete failure of cockpit communication, transferred flying tk tbe FO to look up a solution without telling him what he had been fighting and what he was doing to stop it.
21 times, but no communication. FO crashes the plane in short order.

Most of us had been assuming that the Captain did not tell the FO to trim when he handed it off, since the stabilizer trim went to full nose down shortly after the Captain handed it off to the FO. However, Bjorn Fehrm astutely noted that the FO did do the electric trim. He just was not doing it enough to fully counteract the MCAS trim. The FDR data shows electric trim being used all the way to the end. So the nose pitch went from something like: 0, -2.5, -2.0, -4.0, -3.5, -5.

Image

Then you have the issue of the changing story about the previous flight. The current story is that the jumpseater told them to turn off stab trim, and when they landed nobody wrote it up! WTF?

I was also pretty shocked when I heard about the jumpseater. I thought they were trying to hide something. But after that news leaked, the Indonesian investigators held a press conference and said that they didn't mention the jumpseater in the Preliminary Report because they had not interviewed him at that time yet. I think that is a reasonable explanation.

"Investigators on Thursday confirmed there was a third, off-duty pilot in the cockpit that evening. That was not mentioned in the preliminary report because they had not interviewed the pilot at that stage as they worked to get the report out fast, Utomo said." https://www.reuters.com/article/us-indo ... SKCN1R20XH
 
afgeneral
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 22, 2019 11:42 pm

XRAYretired wrote:
glideslope900 wrote:
scbriml wrote:

More casual racism in the article.

The last para finishes:
"We don’t know how many other pilots may share these feelings … however when you look at these against the potential training problems with the 737 Max, training that the FAA said could be done through an iPad course, and the lack of 737 Max simulators, these don’t paint a very rosy picture of how Ethiopian Airlines views safety,” he said.

The issues listed there apply to just about every airline flying 737MAX in the World.


Except no other airline in the world crashed a 737MAX (except Indonesia). Why does everyone immediately resort to crying “racism” over any critisizm of a non-western country?


The PIC of the Indonesian aircraft was an Indian and the PIC of the Ethiopian aircraft was an Indonesian.The Plot thickens!


The Ethiopian PIC of an Indian MAX is thankful of the grounding
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 12:16 am

dakota123 wrote:
SheikhDjibouti wrote:
The MCAS functions commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall

Beyond that, I'm still waiting for a 737 jockey to explain the full significance of those words.

Aerodynamic load. Load factors and hence stall speed increase with increasing bank angle, to the extent altitude is maintained. With a standard 30* bank, stall speed increases 15%, with a 45* bank, stall speed increases 41%, with a 60* bank, it’s doubled (1/COS bank angle) — it’s a hockey stick. Load factor also increases as you transition from one regime to another, say straight-and-level to establishing a climb, or increasing climb rate.

Got it now - I was sort of aware of the basic physics, but for some reason I hadn't associated it with that specific term.
There is even a nice page on Wikipedia that explains it to idiots like myself.

https://en.wikipedia.org/wiki/Load_factor_(aeronautics)

Thank you dakota123 :bigthumbsup:
Nothing to see here; move along please.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 12:32 am

ikramerica wrote:
We dont know yet about ET, but at Lion the captain correctly countered MCAS fault 21 times, and then by what can only be classified as a complete failure of cockpit communication, transferred flying tk tbe FO to look up a solution without telling him what he had been fighting and what he was doing to stop it.
And you know this for a fact because.....?

21 times, but no communication.
Repeating it doesn't equate to having any evidence whatsoever.
In fact, the evidence on file suggests the opposite.
I suggest you read the Preliminary Accident Report, paying particular attention to Fig 5 (The significant parameters from the accident flight)

Then you have the issue of the changing story about the previous flight. The current story is that the jumpseater told them to turn off stab trim, and when they landed nobody wrote it up! WTF?
Another red herring. :roll:
Again, you should read the Preliminary Accident Report section 1.18.1 "PK-LQP Previous Flight"
Please stop repeating stories that you have made up.
Nothing to see here; move along please.
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 12:49 am

ikramerica wrote:
My guess is we will find out that MCAS wasn’t even the issue on this crash until it was actually kicking in to counteract what this crew had done to get unti this jam. MCAS is a safety feature designed to help prevent pilots from over doing a climb. MCAS activating doesnt mean its the thing malfunctioning. It might be the fight crew that is malfunctioning and MCAS is desperately trying to stop them.

I doubt you could say MCAS was functioning properly and have the same porpoising flight profile as the Lion Air crash, as the investigators have said was the case. Remember that with valid inputs that MCAS is only going to trim enough to reduce AoA to below threshold. The interval between those climbs and descents would be much different.
Phrogs Phorever
 
berari
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 1:13 am

glideslope900 wrote:
Except no other airline in the world crashed a 737MAX (except Indonesia). Why does everyone immediately resort to crying “racism” over any critisizm of a non-western country?


It's because every claim that is being raised re: Ethiopian also applies to airlines in western countries that fly the MAX: training on an iPad, lack of knowledge about the MCAS, having to deal with notices from Boeing post Indonesian crash. While I won't call it racism, the judgement and scrutiny is greater on Ethiopian while the same elements and approaches existed in North America and elsewhere in the western world. Maybe we will have to wait for a western airline MAX to crash to give you an apples to apples comparison so you would get it.
 
Chemist
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 1:42 am

ACCS300 wrote:
Extremely well produced visual account of the crash on YouTube now by Avinations, like jollo so brilliantly stated.. 'creepy, and sobering'.

https://www.youtube.com/watch?v=fIunpQQpzs0


Also, YouTuber Mentour Pilot is an active 737 Pilot, and he's made a very good video explaining trim, the trim system in the 737, and the use of the cutoff switches and memory items. Includes a video of the jackscrew operation:

https://www.youtube.com/watch?v=xixM_cwSLcQ
 
speedbird52
Posts: 1013
Joined: Sat Nov 26, 2016 5:30 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 2:06 am

sierrakilo44 wrote:
And further to my last post, don’t forget Ethiopian lost a 737-800 as recently as 2010 due to pilot error. Let’s not jump to conclusions:

https://en.m.wikipedia.org/wiki/Ethiopi ... Flight_409

Wasn't this the only pilot error crash in around 40 years?
 
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SheikhDjibouti
Posts: 2113
Joined: Sat Sep 30, 2017 4:59 pm

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Sat Mar 23, 2019 2:08 am

flybucky wrote:
Most of us had been assuming that the Captain did not tell the FO to trim when he handed it off, since the stabilizer trim went to full nose down shortly after the Captain handed it off to the FO. However, Bjorn Fehrm astutely noted that the FO did do the electric trim. He just was not doing it enough to fully counteract the MCAS trim. The FDR data shows electric trim being used all the way to the end. So the nose pitch went from something like: 0, -2.5, -2.0, -4.0, -3.5, -5.


Image
I am one of the minority that always understood that to be the case, so I'm happy to agree with you and [email protected]

I have my own theory as to what precisely happened when control was handed off to the FO. (it is only a theory...)

1) Firstly, I assume English was not the first language of either pilot (one Indian, one Indonesian), so the potential for misunderstanding is already there. It would be useful to know how often this crew combination had worked together before?

2) I believe that the 10 second MCAS cycle can be interrupted with a simple flick (blip) of the trim switch.

Hence, if you are lucky enough to notice the trim starting to move early in this MCAS cycle, a short burst of counter-trim would be enough to set things straight.
Conversely, if you wait until the MCAS cycle ends, presumably you need to apply corrective trim for an equal length of time.

At various points during the doomed flight, both methodologies were applied by the Captain, though I would be reluctant to assume he necessarily understood exactly what he was achieving on each occasion. Sometimes he held it continuously, and sometimes he blipped it three or even four times in quick succession.

Now we move on to the final minute; I propose this scenario -
The Captain hands over to the FO, instructing him to operate the trim switch whenever he sees the trim moving the wrong way.
He doesn't elaborate exactly how long to operate the trim switch, because that depends on the factors outlined above.

Significantly, the final two iterations by the Captain (before handover) are shown as two quick blips. This detail might have lodged in the FO's mind.

Either way, the FO copies this action, blipping the trim switch four more times in response to MCAS
Twice he is "correct" in this action, because he interrupted MCAS early in it's 10 second cycle.
However on two other iterations the FO blips to interrupt MCAS, when in fact he should have operated the trim switch for longer.

By the time the Captain looks up from reading the FCOM, he realises his handover instruction was ambiguous (or lost in translation...), but it is already too late.

This is pure conjecture and would require very careful analysis of the CVR.

The obvious comment to make here is that the FO should have applied enough corrective trim to bring the aircraft back to level flight regardless of how quickly he interrupted the MCAS cycle (that he presumably knew nothing about).

I cannot answer why that wouldn't he didn't do this, except to note that even the Captain with his more successful strategy only managed to get the 737 approximately level on each occasion. The absence of an AoA display they could trust means they were flying VFR whilst heading towards a low morning sun. Not exactly ideal, although it could have been worse.

If I have got any of the facts wrong, please advise.
Nothing to see here; move along please.

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