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LU9092
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:45 pm

SimonL wrote:
LU9092 wrote:
People keep going on and on about the MCAS, but if the FR24 data is reasonably accurate, this aircraft had barely reached 1000' AGL in the first 3 minutes of the flight. If the plane wasn't climbing, would the pilots retract the flaps? I guess maybe if they couldn't get the nose up and they still had takeoff thrust selected, they'd quickly be overspeed for flaps down and decide to retract them, but this indicates that their control problems began before MCAS would even activate. To me it seems very likely that MCAS wasn't involved in this crash at all. ET has said the plane had just undergone a maintenance check. This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion.


Depends on what you mean with just undergone maintenance. The plane was in traffic and had just return from South Africa so it seems highly unlikely that anything was done to the aircraft prior to the flight that could jam the elevators.


Fair enough. The main point that the MCAS wouldn't have been active until after the data shows evidence of control issues stands.
 
Pyrex
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:47 pm

osiris30 wrote:
Trin wrote:
estorilm wrote:


One of the most pointed and impressively simple questions I've seen so far on here. My thoughts EXACTLY. It is high time that we got some answers as to the basic handling characteristics of this airframe, and what was discovered ruing testing/modeling that made the need for MCAS (or, if you are being pedantic - 'enhanced MCAS' on the MAX) to be implemented/allowed such aggressive and exclusive/recurring control of certain situations.


Geeze guys. You have your answer! The fact MCAS is there tells you as much. In high AOA high thrust situations the engines are forward enough of the cog to exacerbate the AOA situation. It is a situation that can be perfect cancelled with corrective actions on the flight controls but hands off the plane will flip itself over in theory.

The same may be true on the NEO with all protection controls disabled. Airbus's FBW system provides a lot of aircraft "feel" and behaviour enhancements for the pilots too. Airbus has had high alpha protection for decades now. This is, in effect the same thing.

The one thing I will agree with is MCAS should have a lower authority limit. Boeing agrees as well and is working on the software update already. As to why it isn't out yet, I would simply say that aircraft software takes FOREVER to validate due to regulatory oversight and requirements.

Boeing was (as I understand it) originally targeting this month for the change but it has apparently slipped a bit. Embedded QA is hard. Embedded QA in a highly regulated industry is infinitely harder (one of our old posters Astuteman had horror stories from back in the day as it related to software on nuclear subs).

And before anyone sounds off about "Boeing knew this or that":

1). Mcas if working properly is a perfectly acceptable solution to the CoG issue. Lots of frames use software compensation these days. It is not "new" and is totally acceptable.
2) sometimes when you design a system or certify one things happen that no one foresaw or could reasonably foresee. There is an old saying and hindsight being 20/20. This applies in all directions. Things are plainly obvious AFTER they happen but how many times have all of us done something that had an outcome we did not expect until we experienced that outcome. It happens. Welcome to humans.
3) there is still no evidence mcas had anything to do with this accident
4) ET's CEO just said the pilot had MCAS training recently.

I still think something very unrelated happened between the two crashes and I still maintain the grounding is in response to media and social media pressure and not facts. Others can disagree but again this isn't really the thread for grounding talk anyway (there is one elsewhere on this site).

I want to get the data from this crash. There could be any number of things at play from basic pilot error to mechanical failure to systems failure (mcas), etc. ANY of those can be made to fit the circumstances of this crash. And we can safely guess that some COMBINATION of those apply to Lion Air. Yet all anyone wants to talk about is MCAS and that is likely leading people down a very wrong path (anyone who has studied any aviation accident knows it is rarely as simple as "my first guess was right and the sole contributer")


Very good post. The reactions of many people here remind me of that South Park episode about Captain Hindsight - expected a lot better in an aviation website, frankly, but I guess at a time where "corporations = bad" is being drilled so incessantly in the minds of impressionable young people by college professors and politicians who never worked a proper job in their lives, perhaps I am just too optimistic. Heck, we even have people on this forum praising Soviet aircraft certification procedures (because everybody knows Soviets cared a lot about safety, as their wonderful airline safety record attests to).
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Moose135
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:49 pm

gr09 wrote:
Btw. isn't the whole reason for MCAS the more forward installed engines causing significant change in CoG and affecting stall speed?

No, as I understand it, at high AOA, the location and design of the nacelles causes additional lift, wanting to raise the nose even further. MCAS adds nose down trim to counteract this. As a stand-alone design, it probably wouldn't be needed, as pilot training would highlight this. MCAS allows the Max to handle more like the NG, so they can be flown under the same type certificate.
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rayfound
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:50 pm

Superboi wrote:

If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?



Right - Garbage in, garbage out - But one wouldn't expect "ALL" data to be bad. ie: if it is a bad AoA reading, or bad airspeed reading, you should still expect elevation to be correct, since these aren't reported from dead reckoning. So while data should be considered Suspect, it shouldn't be ignored completely.
 
ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:51 pm

gr09 wrote:
B777LRF wrote:
If you're flying a NG, the engines are mounted lower and further back thus a) securing natural stability and b) cause much less of a nose-up momentum in high thrust situations.

Lower mounted engine will be further from the CoG and so creating bigger nose-up momentum (with the same thrust).
Btw. isn't the whole reason for MCAS the more forward installed engines causing significant change in CoG and affecting stall speed?

I thought it was that the engines themselves (the structural shape and placement in front of the wing) create a lifting force as the AoA increases, and MCAS combats this when the AoA passes a critical point where stall might occur. It's envelope protection. It's also why it won't activate during flaps operation, because in that situation, the flaps have already increased the surface area of the bottom of the wing so that even at a higher AoA, the engines are within the path of the flaps and aren't adding lift.

In general, if you get to the point of MCAS activation, you have gone to far on AoA and should back off, just like a stick shaker would tell you when you approached stall. In the Lion situation, the aircraft was mistakenly thinking it got to that point even though they were attempting a standard climb, or even trying to stay level. But the crew didn't' know what was happening or how to turn it off.

We don't know enough of the details of Ethiopian.
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Pyrex
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:53 pm

ELBOB wrote:
ikramerica wrote:
You can't flight test for 20 years to make sure that they didn't miss anything over the useful life of the aircraft. There is no complex piece of mechanical and or computer equipment that doesn't need some corrections after release to customers.


Why not? That's the magnitude of deveopment period typical for military platforms. 15 years for the F-35, 17 for the V-22, 11 to 13 for the Typhoon.

Why are airliners, into which we entrust the lives of hundreds, tested for just over a year?


By the time the LionAir crash happened you had hundreds of 737 MAXs in operation flying thousands of flights a week. Probably more flights in a month than the entire Typhoon certification process. Just how much more do you think would be necessary, since in your own "expert" opinion the plane was not ready to be flown by passengers?
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ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:54 pm

Moose135 wrote:
gr09 wrote:
Btw. isn't the whole reason for MCAS the more forward installed engines causing significant change in CoG and affecting stall speed?

No, as I understand it, at high AOA, the location and design of the nacelles causes additional lift, wanting to raise the nose even further. MCAS adds nose down trim to counteract this. As a stand-alone design, it probably wouldn't be needed, as pilot training would highlight this. MCAS allows the Max to handle more like the NG, so they can be flown under the same type certificate.

And this is what I still don't get. How does every MAX pilot on the globe not know of this now? If it's your job and a matter of your own safety, and the incident is current, public knowledge and actively in the news, how do you not know?

That's why I wonder if the ET crash was related to something else. If ET has good training, how would the pilots not know?
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LU9092
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:55 pm

Superboi wrote:
LU9092 wrote:
People keep going on and on about the MCAS, but if the FR24 data is reasonably accurate, this aircraft had barely reached 1000' AGL in the first 3 minutes of the flight. If the plane wasn't climbing, would the pilots retract the flaps? I guess maybe if they couldn't get the nose up and they still had takeoff thrust selected, they'd quickly be overspeed for flaps down and decide to retract them, but this indicates that their control problems began before MCAS would even activate. To me it seems very likely that MCAS wasn't involved in this crash at all. ET has said the plane had just undergone a maintenance check. This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion.


If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?


You're making an incorrect assumption about my imagination. Anyway, if the FR24 data is wrong, and it's the data the pilots had, then that ALSO suggests a scenario inconsistent with the Lion Air accident.
 
trex8
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:56 pm

ikramerica wrote:
[

A look at the 767 accident in Houston and the latest information, it looks like the pilots were fighting a perceived uncommanded upward trajectory at full thrust, and then crashed it into the ground. We have no absolute cause yet. All of them should be grounded around the world...


I must have missed all those 767s diving into the ground in vaguely similar situations the last few years. You got any links to those I missed because I literally read AWST and FI cover to cover weekly. Maybe its because Im AARP age and my memory isnt so good these days.
 
ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:56 pm

Superboi wrote:
LU9092 wrote:
People keep going on and on about the MCAS, but if the FR24 data is reasonably accurate, this aircraft had barely reached 1000' AGL in the first 3 minutes of the flight. If the plane wasn't climbing, would the pilots retract the flaps? I guess maybe if they couldn't get the nose up and they still had takeoff thrust selected, they'd quickly be overspeed for flaps down and decide to retract them, but this indicates that their control problems began before MCAS would even activate. To me it seems very likely that MCAS wasn't involved in this crash at all. ET has said the plane had just undergone a maintenance check. This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion.


If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?

Especially because people are commenting on FR24 airspeed issues and the pilots were claiming they also had airspeed indication issues.

Maybe the FR24 isn't pulling data from the plane here? But everyone is saying it does.
Of all the things to worry about... the Wookie has no pants.
 
OlafW
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 5:56 pm

ikramerica wrote:
It could be fuel contamination...

quite unlikely as that would cause the engines to fail, and even if both fail simultaneously, there would be no reason for the plane to drop like stone. It would rather glide for some time in a rather shallow angle. That doesn't match the scene of the crash. Also, contaminated fuel wouldn't be a cause for the reported "flight control issues"
 
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Jouhou
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:03 pm

Pyrex wrote:
osiris30 wrote:
Trin wrote:

One of the most pointed and impressively simple questions I've seen so far on here. My thoughts EXACTLY. It is high time that we got some answers as to the basic handling characteristics of this airframe, and what was discovered ruing testing/modeling that made the need for MCAS (or, if you are being pedantic - 'enhanced MCAS' on the MAX) to be implemented/allowed such aggressive and exclusive/recurring control of certain situations.


Geeze guys. You have your answer! The fact MCAS is there tells you as much. In high AOA high thrust situations the engines are forward enough of the cog to exacerbate the AOA situation. It is a situation that can be perfect cancelled with corrective actions on the flight controls but hands off the plane will flip itself over in theory.

The same may be true on the NEO with all protection controls disabled. Airbus's FBW system provides a lot of aircraft "feel" and behaviour enhancements for the pilots too. Airbus has had high alpha protection for decades now. This is, in effect the same thing.

The one thing I will agree with is MCAS should have a lower authority limit. Boeing agrees as well and is working on the software update already. As to why it isn't out yet, I would simply say that aircraft software takes FOREVER to validate due to regulatory oversight and requirements.

Boeing was (as I understand it) originally targeting this month for the change but it has apparently slipped a bit. Embedded QA is hard. Embedded QA in a highly regulated industry is infinitely harder (one of our old posters Astuteman had horror stories from back in the day as it related to software on nuclear subs).

And before anyone sounds off about "Boeing knew this or that":

1). Mcas if working properly is a perfectly acceptable solution to the CoG issue. Lots of frames use software compensation these days. It is not "new" and is totally acceptable.
2) sometimes when you design a system or certify one things happen that no one foresaw or could reasonably foresee. There is an old saying and hindsight being 20/20. This applies in all directions. Things are plainly obvious AFTER they happen but how many times have all of us done something that had an outcome we did not expect until we experienced that outcome. It happens. Welcome to humans.
3) there is still no evidence mcas had anything to do with this accident
4) ET's CEO just said the pilot had MCAS training recently.

I still think something very unrelated happened between the two crashes and I still maintain the grounding is in response to media and social media pressure and not facts. Others can disagree but again this isn't really the thread for grounding talk anyway (there is one elsewhere on this site).

I want to get the data from this crash. There could be any number of things at play from basic pilot error to mechanical failure to systems failure (mcas), etc. ANY of those can be made to fit the circumstances of this crash. And we can safely guess that some COMBINATION of those apply to Lion Air. Yet all anyone wants to talk about is MCAS and that is likely leading people down a very wrong path (anyone who has studied any aviation accident knows it is rarely as simple as "my first guess was right and the sole contributer")


Very good post. The reactions of many people here remind me of that South Park episode about Captain Hindsight - expected a lot better in an aviation website, frankly, but I guess at a time where "corporations = bad" is being drilled so incessantly in the minds of impressionable young people by college professors and politicians who never worked a proper job in their lives, perhaps I am just too optimistic. Heck, we even have people on this forum praising Soviet aircraft certification procedures (because everybody knows Soviets cared a lot about safety, as their wonderful airline safety record attests to).


Could you not inject politics into this? Your statement is not true, my college professors (state university) were ideologically mostly libertarian aka corporations = good. You're using this as an opportunity to inject an unfounded political opinion in here- those of us who went to college know it is false.

Basically, your statement is epitomizes the thing you're complaining about.

Also, even the president is jumping on the MCAS hate train, even though to our knowledge we don't know the cause yet.
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WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:05 pm

gr09 wrote:
Btw. isn't the whole reason for MCAS the more forward installed engines causing significant change in CoG and affecting stall speed?

The nacelles as drag source are apparently the primary culprit. increased AoA increases drag that creates further AoA increasing moment ....ad nauseam.
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osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:10 pm

Superboi wrote:
LU9092 wrote:
People keep going on and on about the MCAS, but if the FR24 data is reasonably accurate, this aircraft had barely reached 1000' AGL in the first 3 minutes of the flight. If the plane wasn't climbing, would the pilots retract the flaps? I guess maybe if they couldn't get the nose up and they still had takeoff thrust selected, they'd quickly be overspeed for flaps down and decide to retract them, but this indicates that their control problems began before MCAS would even activate. To me it seems very likely that MCAS wasn't involved in this crash at all. ET has said the plane had just undergone a maintenance check. This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion.


If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?


Pick your poision.. that same FR24 data is what people are using to blame MCAS...
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osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:12 pm

trex8 wrote:
osiris30 wrote:
[ This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion


What sort of check on a almost new plane would likely leave a tool in some important space? Isnt it mostly a visual check?I have no idea and thats why Im asking.
On the other hand USAF just grounded and stopped taking KC46 deliveries after FO left in important spaces!
https://www.military.com/defensetech/20 ... craft.html


No clue.. just like everything else on this flight, but if everyone is jumping to conclusions I wouldn't want to feel left out!!!
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:13 pm

JAAlbert wrote:
frmrCapCadet wrote:
A number of assumptions in this thread are simply wrong.

Boeing did not do the MAX because they were short of money. They in fact wanted to do an all new plane - airlines would not wait after the 320neo came out.


I recall reading back at the time that Boeing did approach airlines re: a clean sheet design, but the airlines didn't want to wait that long. Boeing did the MAX as a result. I'm sure money was an issue as well - it always is. Does anyone else recall this?


Airbus basically forced Boeing's hand by introducing A320neo which American Airlines was prepared to order in a huge quantity. Boeing had no other alternative than launch 737MAX, as getting a clean sheet to the market would have given Airbus huge competitive advantage for at least 5 years. In the end Boeing got half of the American Airlines narrowbody order.
 
rayfound
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:16 pm

osiris30 wrote:
Pick your poision.. that same FR24 data is what people are using to blame MCAS...


Right, but again there's no reason to assume ALL of the FR24 data is wrong. So airspeed could be wrong and we could be seeing MCAS trying to prevent stall based on bad data, or something entirely different...
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:23 pm

rayfound wrote:
osiris30 wrote:
Pick your poision.. that same FR24 data is what people are using to blame MCAS...


Right, but again there's no reason to assume ALL of the FR24 data is wrong. So airspeed could be wrong and we could be seeing MCAS trying to prevent stall based on bad data, or something entirely different...


MCAS shouldn't have been active when the issues with control started or flaps were withdrawn VERY early, which would be really weird out of an H&H airport.
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Jouhou
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:23 pm

trex8 wrote:
osiris30 wrote:
[ This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion


What sort of check on a almost new plane would likely leave a tool in some important space? Isnt it mostly a visual check?I have no idea and thats why Im asking.
On the other hand USAF just grounded and stopped taking KC46 deliveries after FO left in important spaces!
https://www.military.com/defensetech/20 ... craft.html


Yeah, leaving foreign material in a system would cause heads to roll internally. For some reason the private sector doesn't seem to understand the importance of this.
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:25 pm

ikramerica wrote:
Superboi wrote:
LU9092 wrote:
People keep going on and on about the MCAS, but if the FR24 data is reasonably accurate, this aircraft had barely reached 1000' AGL in the first 3 minutes of the flight. If the plane wasn't climbing, would the pilots retract the flaps? I guess maybe if they couldn't get the nose up and they still had takeoff thrust selected, they'd quickly be overspeed for flaps down and decide to retract them, but this indicates that their control problems began before MCAS would even activate. To me it seems very likely that MCAS wasn't involved in this crash at all. ET has said the plane had just undergone a maintenance check. This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion.


If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?

Especially because people are commenting on FR24 airspeed issues and the pilots were claiming they also had airspeed indication issues.

Maybe the FR24 isn't pulling data from the plane here? But everyone is saying it does.


FR24 speed is ground speed derived from the GPS signal. The pilots fly by the indicated airspeed unrelated to the GPS signal.
 
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:29 pm

Could we please keep this thread about the crash, if you want to add information on the groundings please use the relevant thread
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osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:30 pm

Finn350 wrote:
ikramerica wrote:
Superboi wrote:

If the plane was giving the Pilots in it wrong information, why can't you imagine it was giving FR24 recivers wrong reading too?

Especially because people are commenting on FR24 airspeed issues and the pilots were claiming they also had airspeed indication issues.

Maybe the FR24 isn't pulling data from the plane here? But everyone is saying it does.


FR24 speed is ground speed derived from the GPS signal. The pilots fly by the indicated airspeed unrelated to the GPS signal.


IF this is true and IF the aircraft continued to accelerate, would that not have put the AC in a SEVERE overspeed situation that may have induced control surface failure?
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phugoid1982
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:38 pm

ikramerica wrote:
gr09 wrote:
B777LRF wrote:
If you're flying a NG, the engines are mounted lower and further back thus a) securing natural stability and b) cause much less of a nose-up momentum in high thrust situations.

Lower mounted engine will be further from the CoG and so creating bigger nose-up momentum (with the same thrust).
Btw. isn't the whole reason for MCAS the more forward installed engines causing significant change in CoG and affecting stall speed?

I thought it was that the engines themselves (the structural shape and placement in front of the wing) create a lifting force as the AoA increases, and MCAS combats this when the AoA passes a critical point where stall might occur. It's envelope protection. It's also why it won't activate during flaps operation, because in that situation, the flaps have already increased the surface area of the bottom of the wing so that even at a higher AoA, the engines are within the path of the flaps and aren't adding lift.

In general, if you get to the point of MCAS activation, you have gone to far on AoA and should back off, just like a stick shaker would tell you when you approached stall. In the Lion situation, the aircraft was mistakenly thinking it got to that point even though they were attempting a standard climb, or even trying to stay level. But the crew didn't' know what was happening or how to turn it off.

We don't know enough of the details of Ethiopian.


Mounting the engines lower will in general create a greater Pitch up moment. However, the weight of of the heavier bigger engines will also shift the the c.g. slightly lower so this increased pitch up moment is offset the shifting of the c.g. downwards which reduces the lever arm. However, the nacelle aerodynamics will generate a greater pitch up moment but with greater lift also comes drag and the induced drag from the nacelle will counteract this and produce a pitch down moment offsetting this effect although I would imagine this is quite a bit smaller. I'm sure this is all proprietary but I would love the know the difference between the static margin of the 737NG's and other variants compared to the max. In general 5%-15% is normal.

If I remember correctly, the MD-11 was designed to have a much smaller static margin and thus much less trim drag to improve fuel efficiency which made it a big more difficult to handle especially during landing hence the multiple landing accidents. It seem like the quest for greater and greater efficiency and increased automation in an attempt to remove pilots from the loop has come at a cost to safety.

Not a perfect example but I remember that when the Soviets designed the Tu-154 which was the workhorse of Aeroflot's fleet the Yaw damper designed was notoriously unreliable and i'm not sure production models even had one. Therefore, they just designed the aircraft with moderate anhedral to minimize Dutch Roll tendencies. I imagine it was an aircraft that kept its pilots on their toes but at least they had complete control of the aircraft systems and didn't have to worry about it secretly trying to countermand their inputs.
 
Elshad
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:46 pm

Isn’t the best solution to remove all the software etc. designed to make the MAX feel like the NG and get a new certification. Obviously there would be a lot of distruption and pilot training issues, and Boeing would probably lose a lot of money. But it’s better than this patchy solution where we’re stuck with this system which is a bit like trying to make a Bugatti handle like a WV Golf.
 
indcwby
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:51 pm

https://www.businessinsider.com/ethiopi ... ycF3_7rvE0

Thoughts on this angle of co-pilot having 200 flight hours?
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dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:54 pm

I wonder if the government shutdown earlier this year delayed certification of Boeings MCAS software improvements that were supposed to come out in December. The company I work for had a STC approval delayed by 6-7 weeks because of the shutdown.
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casinterest
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 6:56 pm

Let's look at the FR24 data again. They are in a leveled off climb with altitude increasing. The values to that point indicate they had issues with altitude, which may have involved issues with the Air Speed indicators.
Image


It seems they struggled, but had for the last minute of data gotten it under control .
We do not have the data from after this point to understand what happened till the crash minutes later and miles away. We need the FDR for that.

Image

Below is the lion air profile, and we do know from Prelim that they couldn't get reliable altitude or speed measurements, but there has been no report yet on what caused the final dive into the crash.
Image

It should be noted that Boeing's response to the initial Lion Air incident indicates that the previous flight had had the same issues and that crew had successfully disengaged the trim switches.


https://boeing.mediaroom.com/news-relea ... tem=130336


The report states that the flight crew of the Oct. 28 flight turned off the stabilizer trim switches within minutes of experiencing the automatic nose down trim, and continued with manual trim through the end of the flight. The report further notes that the pilot performed three non-normal checklist procedures, including the runaway stabilizer non-normal checklist, which is a memory item prescribed by the 737 MAX Flight Crew Operations Manual, and reaffirmed in Boeing Flight Crew Operations Manual Bulletin TBC-19 and FAA Emergency Airworthiness Directive (AD) Number 2018-23-51, as the appropriate procedure to address unintended horizontal stabilizer movement, regardless of source.

The report indicates that the remainder of the Oct. 28 flight was uneventful and that the flight continued to its destination. The report also states that, after landing, the pilot reported some of the experienced issues both on the aircraft maintenance log and to engineering. The report states that the pilot ran the runaway stabilizer non-normal check list, but it does not state that he communicated that fact in the maintenance documentation following that flight.

The following day, Oct. 29, shortly after taking off, the pilots experienced issues with altitude and airspeed data that the pilots had previously experienced on the earlier flights, due to erroneous AOA data. Data from the flight data recorder summarized in the report also makes clear that, as on the previous flight, the airplane experienced automatic nose down trim. In response, the flight crew repeatedly commanded nose up trim. This sequence repeated for the remainder of the flight, during which the flight crew was able to maintain control of the airplane for approximately ten minutes. Unlike as is stated with respect to the prior flight, the report does not state whether the pilots performed the runaway stabilizer procedure or cut out the stabilizer trim switches.



The end of all of this, is that if you don't trust the data, fly the plane manually.
Where ever you go, there you are.
 
Z88
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:05 pm

This thread contains much explanation and speculation about MCAS and whether it aligns with the limited amount of available information.

MCAS aside, is there another plausible malfunction that fits what is known, including the Flightradar24 data and the condition of the impact site?
 
michi
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:14 pm

casinterest wrote:
...
We do not have the data from after this point to understand what happened till the crash minutes later and miles away. We need the FDR for that.

Image




The crash location on this map is not correct.
 
FlyingElvii
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:15 pm

Elshad wrote:
Isn’t the best solution to remove all the software etc. designed to make the MAX feel like the NG and get a new certification. Obviously there would be a lot of distruption and pilot training issues, and Boeing would probably lose a lot of money. But it’s better than this patchy solution where we’re stuck with this system which is a bit like trying to make a Bugatti handle like a WV Golf.

As I noted above, adding a new fleet type, especially in the US, is insanely expensive. This was supposed to be a “Plug-and-play” airplane to operators already flying 737’s, not requiring extension retraining programs, or a new type certificate.
 
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trpmb6
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:16 pm

dragon6172 wrote:
I wonder if the government shutdown earlier this year delayed certification of Boeings MCAS software improvements that were supposed to come out in December. The company I work for had a STC approval delayed by 6-7 weeks because of the shutdown.


No. Airworthiness issues would not have been impacted by the shutdown. STC's would have yes because they would not impact aircraft already flying.
 
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casinterest
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:19 pm

michi wrote:
casinterest wrote:
...
We do not have the data from after this point to understand what happened till the crash minutes later and miles away. We need the FDR for that.

Image




The crash location on this map is not correct.



Do you have an updated one ?
Where ever you go, there you are.
 
ikramerica
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:20 pm

FlyingElvii wrote:
Elshad wrote:
Isn’t the best solution to remove all the software etc. designed to make the MAX feel like the NG and get a new certification. Obviously there would be a lot of distruption and pilot training issues, and Boeing would probably lose a lot of money. But it’s better than this patchy solution where we’re stuck with this system which is a bit like trying to make a Bugatti handle like a WV Golf.

As I noted above, adding a new fleet type, especially in the US, is insanely expensive. This was supposed to be a “Plug-and-play” airplane to operators already flying 737’s, not requiring extension retraining programs, or a new type certificate.

If anything, there would be (will be?) more difference training required.
Of all the things to worry about... the Wookie has no pants.
 
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caoimhin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:20 pm

ikramerica wrote:
How does every MAX pilot on the globe not know of this now? If it's your job and a matter of your own safety, and the incident is current, public knowledge and actively in the news, how do you not know?

That's why I wonder if the ET crash was related to something else. If ET has good training, how would the pilots not know?


My thoughts as well. That was a high profile crash that prompted significant discussion among aviation stakeholders (be they regulators, airlines, crew members, maintenance technicians, or otherwise) about MCAS specifically. I cannot imagine a MAX pilot, post-JT610, being unaware of how to identify and manage unexpected MCAS activity. So, I agree with you that my suspicions aren't fixated on MCAS, and I would expect a different cause.

On the other hand, with nothing ruled out, if MCAS is involved in this incident, even if they were aware and trained how to handle the JT610-type circumstance, there is always the possibility that the crew did not have sufficient time to react and recover given their altitude.

As a final comment, shame on those of you who all but celebrate these tragedies when they happen on an aircraft not produced by your preferred vendor. There is an almost gleeful smugness among two or three (famously partisan) posters, which mirrors the same attitude they expressed after JT610.
 
hamiltondaniel
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:20 pm

phugoid1982 wrote:

If I remember correctly, the MD-11 was designed to have a much smaller static margin and thus much less trim drag to improve fuel efficiency which made it a big more difficult to handle especially during landing hence the multiple landing accidents. It seem like the quest for greater and greater efficiency and increased automation in an attempt to remove pilots from the loop has come at a cost to safety.



Unfairly quoting you specifically when it's no less than 50% of the posters on this thread making the same argument that "too much automation is coming at a cost to safety" Even so.

Enough. It's simply not statistically accurate to say that. Automation is the reason that airplanes are as safe as they are. Human factors are still, by far, the most common reason for accidents.

Is automation perfect? Of course not. It must and can be improved. But it's already vastly better than the alternative. The Back-to-the-Stone-Age dialogue developing around this aircraft is absurd as it is entirely unrelated to the evidence; the evidence tells us that automation improves safety.
 
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trpmb6
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:21 pm

Jouhou wrote:
trex8 wrote:
osiris30 wrote:
[ This makes me wonder if maybe something like a tool left behind or a fastener left undone led to the elevators being jammed or having limited range of motion


What sort of check on a almost new plane would likely leave a tool in some important space? Isnt it mostly a visual check?I have no idea and thats why Im asking.
On the other hand USAF just grounded and stopped taking KC46 deliveries after FO left in important spaces!
https://www.military.com/defensetech/20 ... craft.html


Yeah, leaving foreign material in a system would cause heads to roll internally. For some reason the private sector doesn't seem to understand the importance of this.


They do. And everyone gets FOD training. The problem is how fast these get rolled out and the fact that they are having to do extra work down stream because suppliers can't keep up - doing work at other work stations that should have been completed earlier.

I know that's not an excuse, just pointing out it's a well known issue that is monitored and mitigated. I've left tools in places while doing work in my own home - I know it's not excusable but it's also not malice.

That being said... A tool wouldn't jam the elevator. And a single fastener wouldn't be a problem either - you could probably lose half the elevator and be fine.
 
JoeCanuck
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:23 pm

Carlos01 wrote:

This is the part I still don't understand. Everyone keeps saying "safety first", "safety is our top priority" and all that crap, and yet actions are the complete opposite. You want to save the faux horror, and keep on flying until we know more. Fine. But what if there will be another deadly crash while we wait? Is that seriously "ok"? Shit happens? Human life really means that little to you and other likeminded people?

It seems to me that Boeing, their fanboys, and the FAA are completely indifferent to the fact that hundreds of people have been killed, and it could be their fault! Well ok, not the fanboys, but the other two. Seriously, this so-what attitude is just unbelievable, even racist.


Almost very aircraft accident is treated like this. It's not just Boeing and the FAA. Grounding is the exception, not the rule, for everybody.

Making this a Boeing vs everyone else thing, is ridiculous.
What the...?
 
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trpmb6
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:23 pm

casinterest wrote:
michi wrote:
casinterest wrote:
...
We do not have the data from after this point to understand what happened till the crash minutes later and miles away. We need the FDR for that.

Image




The crash location on this map is not correct.



Do you have an updated one ?


Cas, the correct crash location is N8.8772 E39.2512. it's further east along the line of action the FR24 plot follows. Not much deviation from it. Avherald has a picture I believe.
 
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trpmb6
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:26 pm

JoeCanuck wrote:
Carlos01 wrote:

This is the part I still don't understand. Everyone keeps saying "safety first", "safety is our top priority" and all that crap, and yet actions are the complete opposite. You want to save the faux horror, and keep on flying until we know more. Fine. But what if there will be another deadly crash while we wait? Is that seriously "ok"? Shit happens? Human life really means that little to you and other likeminded people?

It seems to me that Boeing, their fanboys, and the FAA are completely indifferent to the fact that hundreds of people have been killed, and it could be their fault! Well ok, not the fanboys, but the other two. Seriously, this so-what attitude is just unbelievable, even racist.


Almost very aircraft accident is treated like this. It's not just Boeing and the FAA. Grounding is the exception, not the rule, for everybody.

Making this a Boeing vs everyone else thing, is ridiculous.



I'll be pretty blunt. Quite certain Boeing and the FAA believe the previous AD released is adequate for safety. Follow the checklist and hit the trim cutoff switch.

Also.. how the hell is that racist?
 
pugman211
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:28 pm

casinterest wrote:

The end of all of this, is that if you don't trust the data, fly the plane manually.


If you fly manually, I believe MCAS can engage without warning or prompting if triggered.
 
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Moose135
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:28 pm

indcwby wrote:
https://www.businessinsider.com/ethiopian-airlines-flight-302-co-pilot-200-flight-hours-2019-3?utm_content=bufferd80ac&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer-bi&fbclid=IwAR16nl2PczIeb6fK09_3VJLHkLh0AGD_SKI54nUvn2-EmdHpCycF3_7rvE0

Thoughts on this angle of co-pilot having 200 flight hours?

I guess you are just jumping into the discussion at this point. It was thoroughly hashed out, with arguments on both sides of the issue, over a number of pages in this thread.
KC-135 - Passing gas and taking names!
 
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giosue61
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:33 pm

If I remember correctly the stick pusher was developed after the BAC 1-11 protoypes could not recover form deep stall because of the new T tail design. Something that nobody had ever exeprienced before, simply because no jet liner had T tail. I think it was later installed in the DC9 family for the same reason. Was the old system working on a single sensor as well? Or since it belonged to the analogic era it was completely different from the current MCAS?
Last edited by giosue61 on Tue Mar 12, 2019 7:34 pm, edited 1 time in total.
 
michi
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:34 pm

As nobody answered before, I would like to repost some observations and questions.

There is a lot of focus on the MCAS. Still, there are other questions not answered yet.

Those questions came up after reading all the information in the news (and this thread). This information might not be reliable, incomplete (as FR24 coverage is poor in that area) and even fake. But still, there are question that should be asked. They might even help in looking somewhere else for clues.

The pilots apparently did notice something is wrong after being airborne. They apparently declared emergency and told ATC that they have unreliable airspeed. This is quite good, as the most difficult part with unreliable airspeed is the detection of unreliable air data. The pilots obviously did detect it.

But what caused the unreliable airspeed? (Remark: no tech history is known so far!)

Did they climb normal or not?
Despite the discussion wether the FR24 data is reliable or not, it is still not known for sure which altitude they have reached. The FR24 data and the eyewitness suggest a low altitude flight. Did they have an energy problem of some sort?

In case they did not climb that much, as it is being interpreted by the data available so far, what caused the degraded climb performance?
When having unreliable air data, pilots fly pitch and power. With specific pitch and power values, climb performance should be a no factor, even in ADD.

The pilots apparently reported difficulties in controlling the aircraft.
During unreliable speed scenarios controlling the aircraft is not the main task or issue, as all the controls should work normal. Something was obviously wrong. Is there a combination of events making control of the aircraft difficult and leaves you with unreliable air data and less than normal power?
Flock of birds hitting the aircraft at Radom, Engines and Pitots?

MCAS is using AOA. This sensor does not affect IAS. But the pilots apparently had unreliable airspeed, as noted above.

Since the pilots apparently knew (at wich timespan after takeoff is unclear as far as I am aware) that they had unreliable airspeed, they should have followed the respective procedure. This normally includes the instruction to not move the flaps until you have stabilized the aircraft and did troubleshoot the problem.
When does the Boeing FCOM procedure for unreliable air speed ask for cleaning up the aircraft? Any B737 driver around?
Also not cleaning up the aircraft prevents MCAS kicking in, as it only activates when the flaps are up (plus all the other engagement conditions).

Just by asking a few questions I think there is more to the story than MCAS kicking in. The trouble started way earlier during the flight.

The MCAS is a "tool" preventing the real bad, when everything else already went south. Apparently the trouble started earlier at stage where MCAS should not kick in per design (Flaps extended). The problems they had might have caused a situation where MCAS ultimately kicked in. But in this case it is way to early to claim MCAS as the root cause for this crash.

To me it does not look like Lionair with what is known so far.


Edit: a little n was missing somewhere
Last edited by michi on Tue Mar 12, 2019 7:39 pm, edited 1 time in total.
 
michi
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:37 pm

casinterest wrote:
Do you have an updated one ?


I suggest to use the map on avherald.

http://avherald.com/h?article=4c534c4a&opt=0
 
slvrblt
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:42 pm

Mortyman wrote:
So is it only US airlines that has not grounded it's Max's now ?


Yes. I said it before upthread, but everyone is so intent on harping over grounding the airplanes no one seems to notice that fact. Again...........does EVERYONE here think all the AA, UA, and WN pilots are dumb, suicide-intent fools? Really? And those militant pilot unions? Unions that are still silent, happy to let their members fly dangerous diving, plunging tubes??? I'm not for or against grounding but I do think the CVR and FDR data needs to be revealed first. I talk to those flyguys all the time. None of them seem particularly worried about this 737. I'm going to guess the US airlines' pilots know how to handle the planes, making them no more dangerous than the NG's. If the AA, UA, WN guys/gals had also had narrow escapes from wildly bucking airplanes, we'd know it by now.

It's been mentioned before also, but I'm guessing the older, more experienced guys DO have an edge (I'm talking seniority here, trained the old-fashioned way, fly the plane your damn-self) instead of having an over-reliance on instruments.
..everything works out in the end.
 
Curiousflyer
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:56 pm

A big difference in this crash is that the Lion Air plane was apparently not airworthy, it had major issues on its earlier flight and should not have been sent on this suicide mission. Of course it would be good to see a CVR transcript and anyone can now tell that it is being held from the public at a time where major questions are raising. Horrible attitude from the Lion Air crash investigators. They might have blood on their hands.
The Ethiopian aircraft on the other hand seemed to be in good shape when it left for its last flight, had been recently checked, and Ethiopian at least have a better reputation (and although some people would question the first officer's lack of experience, the captain at least had plenty). So this is a much more significant crash, it is less likely to be blamed on the airline and its pilots, and we meed to understand more about it.
I think grounding those planes will also kick Boeing's and and the FAA's butts, they seem to need this. Because they might have blood on their hands too, maybe because of the government shutdown, which leaves blood on Trump's hands too, the monster. Including eight Americans.
Last edited by Curiousflyer on Tue Mar 12, 2019 8:00 pm, edited 2 times in total.
 
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casinterest
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 7:58 pm

pugman211 wrote:
casinterest wrote:

The end of all of this, is that if you don't trust the data, fly the plane manually.


If you fly manually, I believe MCAS can engage without warning or prompting if triggered.


Per the below article,. it will reengage if you use the electric trim.

That is why there is a procedure for turning the Trim off Manually.

Image

https://theaircurrent.com/aviation-safe ... cas-jt610/
Where ever you go, there you are.
 
estorilm
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 8:02 pm

Curiousflyer wrote:
A big difference in this crash is that the Lion Air plane was apparently not airworthy, it had major issues on its earlier flight and should not have been sent on this suicide mission. Of course it would be good to see a CVR transcript and anyone can now tell that it is being held from the public at a time where major questions are raising. Horrible attitude from the Lion Air crash investigators.
The Ethiopian aircraft on the other hand seemed to be in good shape when it left for its last flight, had been recently checked, and Ethiopian at least have a better reputation (and although some people would question the first officer's lack of experience, the captain at least had plenty). So this is a much more significant crash, it is less likely to be blamed on the airline and its pilots, and we meed to understand more about it.
I think grounding those planes will also kick Boeing's and and the FAA's butts, they seem to need this.

I don't know why people fixate on this so much (Lion Air's MX).

Parts break on aircraft constantly, usually in the air. The issue is if said part, sensor, or system failing can lead to a dangerous situation or crash. The grounding isn't just about the Lion Air crash, it's about the systems in the aircraft at this point.

If that same inop part failed in flight on another aircraft, who the hell cares about Lion Air's mx issues - now they're a couple miles in the air in the exact same potentially dangerous situation. Their mx is literally completely irrelevant. Sure slap them with a fine, and it'll hurt their reputation - but as far as the MAX's safety is concerned, you can't have single-point failures like that.

Just my $.02
 
Z88
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 8:02 pm

If it is of use to anyone, I have made a new map that includes the FR24 KML data along with the verified location of the site at 8.876944, 39.251111.

Image

As there was some confusion about the site location, these coordinates can be manually confirmed by comparing the bend in the road shown on the map versus aerial photos of the site.

Image

Image
 
rheinwaldner
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Tue Mar 12, 2019 8:04 pm

gloom wrote:
Not sure, where you're trying to go, but the numbers seem non adequate:
(i did some cut from quote to show my case)

A320FlyGuy wrote:
their safety records were downright abysmal:
Boeing 707:
1962:
4 crashes in 8 months with a total of 435 fatalities

Boeing 727:
1965 (First Year of Service)
3 crashes in 87 days with a total of 131 fatalities


Judging by:
https://www.icao.int/safety/iStars/Page ... stics.aspx
and rate going down more than twice those 10 past years (anyone has a reliable source to judge past 10 years?), it's extremely rare to have two planes of the type going down so fast after EIS.

Correct, the last one, which crashed two times in two years after EIS was the DC-9.

osiris30 wrote:
Using your logic every time there is a crash we should ground the type until the report. So right now 767s and 737maxes would be grounded. The 777 would be grounded (mh370). The 330s would have been out of the air for quite a while. And do we stop there or do we ground for near crashes and severe failures after all "safety first". In which case the NEOs and done and the a220 can stay right where it is too.

There is a difference between crashes shortly after EIS and crashes of aircraft with a long term safety record.

Cdydatzigs wrote:
Other than the fact the fuselage of a MAX is shaped like a plane from 1958, all of the other components of the aircraft are state-of-the art.

Boeings reaction comes after 300 people have died. AFAIK no other design ever required bandaid bugfixes under such circumstances. Are you sure, calling that state-of-the-art is appropriate?

osiris30 wrote:
Does it make you just as mad to know mcas was on the NG BUT CALLED SOMETHING DIFFERENT? The auto trim system has been on the AC for decades. They just changed the name and tweaked the parameters.

Sorry, this is only true, if you look at MCAS with close to zero background knowledge. Are you a manager?

buzzard302 wrote:
Ground an airplane is a big deal. Most likely someone knows something that is not public. These decisions don't come lightly.

That's correct and warranted. On the other hand even worse would be an increase of the blood toll in the coming months.

ikramerica wrote:
A look at the 767 accident in Houston and the latest information, it looks like the pilots were fighting a perceived uncommanded upward trajectory at full thrust, and then crashed it into the ground. We have no absolute cause yet. All of them should be grounded around the world...

It gets boring that people fail to understand the difference between crashes shortly after EIS and crashes of aircraft with a long term safety record.

osiris30 wrote:
"ramming the nose down every 10 seconds" isn't what it remotely does. It will try to re-enage after being disengaged in 10 seconds unless disabled, so long as the condition exists. Otherwise it pushes the nose forward. The only 'ramming the nose down' that happened (ostensibly) in Lion Air was due to a faulty AOA sensor. If you think it just rams the nose forward you don't understand the system or its operation.

It drives the stabilizer into the locks in about two or three cycles. A situation not recoverable using the yokes.

osiris30 wrote:
MCAS shouldn't have been active when the issues with control started or flaps were withdrawn VERY early, which would be really weird out of an H&H airport.

Addis Ababa is not hot. Most European Capitals are hotter.

ikramerica wrote:
In general, if you get to the point of MCAS activation, you have gone to far on AoA and should back off, just like a stick shaker would tell you when you approached stall.

I keep hearing, that the intention of MCAS is to handle situations with high speeds and high altitudes, where the span between stall and overspeed becomes quite narrow. Flying a turn in manual flight up there might already be sufficient to see MCAS becoming effective as it was intended (because the geometry of the MAX would pitch up the aircraft more than wished by the pilot otherwise).

ikramerica wrote:
We don't know enough of the details of Ethiopian.

We do have a vertical flight profile with frequent climb rate changes. If we exclude MCAS or any other source of malfunctioning automatic pitch input, I have a hard time to imagine any reason, why the climb out could be so fluctuating. Does anybody have another (even if theoretical) explanation?

Also the time pattern of the ups and downs (of the climb rate) is very similar to the Lionair case. For more details please refer to my earlier post about that:
rheinwaldner wrote:
maui19 wrote:
FR24's blog (https://www.flightradar24.com/blog/flig ... light-302/) is really interesting. The AC appeared to have no problem gaining speed, but plenty of trouble gaining altitude. Every time they started to climb, they would quickly level off or descend (I think this happened 5 times). Finally they were able to achieve a fairly constant rate of climb (2,900 FPM?) before the flight data ended. Given that they were approaching higher terrain surrounding the airport (and "long" nature of the impact crater shown in the earlier picture of the crash site), I think it is entirely plausible that this is a recurrence of the MCAS problem...

I downloaded the data from the blog and I would say it is an MCAS case.

See how the normal positive climb rate drops from time to time:
Image

If these vspd drops would be induced by MCAS, we would be able find the find 10s periods, after which MCAS would kick in again in absence of trim input. Now, see the timestamps to the dots on the chart:
1 2019-03-10 05:38:14Z.070
2 2019-03-10 05:38:17Z.172
3 2019-03-10 05:38:18Z.994
4 2019-03-10 05:38:23Z.998
5 2019-03-10 05:38:26Z.454
6 2019-03-10 05:38:29Z.534
7 2019-03-10 05:38:32Z.970
8 2019-03-10 05:38:34Z.314
9 2019-03-10 05:38:39Z.688
10 2019-03-10 05:38:43Z.408
11 2019-03-10 05:38:45Z.798
12 2019-03-10 05:38:47Z.714
13 2019-03-10 05:38:50Z.200
14 2019-03-10 05:38:53Z.774
15 2019-03-10 05:38:56Z.266
16 2019-03-10 05:38:59Z.102
17 2019-03-10 05:39:04Z.028
18 2019-03-10 05:39:06Z.656
19 2019-03-10 05:39:11Z.250
20 2019-03-10 05:39:14Z.836
21 2019-03-10 05:39:16Z.590
22 2019-03-10 05:39:21Z.570
23 2019-03-10 05:39:22Z.172
24 2019-03-10 05:39:26Z.100
25 2019-03-10 05:39:28Z.258
26 2019-03-10 05:39:32Z.026
27 2019-03-10 05:39:34Z.706
28 2019-03-10 05:39:39Z.288
29 2019-03-10 05:39:43Z.262
30 2019-03-10 05:39:44Z.314
31 2019-03-10 05:39:48Z.288
32 2019-03-10 05:39:50Z.428
33 2019-03-10 05:39:55Z.632
34 2019-03-10 05:39:56Z.928
35 2019-03-10 05:40:00Z.398
36 2019-03-10 05:40:03Z.598
37 2019-03-10 05:40:06Z.660
38 2019-03-10 05:40:09Z.518
39 2019-03-10 05:40:14Z.384
40 2019-03-10 05:40:16Z.124
41 2019-03-10 05:40:18Z.734
42 2019-03-10 05:40:22Z.734
43 2019-03-10 05:40:26Z.040
44 2019-03-10 05:40:28Z.784
45 2019-03-10 05:40:35Z.868
46 2019-03-10 05:40:35Z.928
47 2019-03-10 05:40:45Z.714
48 2019-03-10 05:40:47Z.724
49 2019-03-10 05:40:51Z.618
50 2019-03-10 05:40:52Z.474
51 2019-03-10 05:40:55Z.720
52 2019-03-10 05:41:02Z.242
53 2019-03-10 05:41:02Z.286
54 2019-03-10 05:41:02Z.286

This gives me the following chart, where at the yellow arrows the VSpd curve indicates with some probability that nose-up trim input was applied. The green bars are 10 second intervals, during which MCAS slept after the nose-up input. And right after these MCAS idle times, each time you can see a nose down moment coming into effect (red arrows):
Image

It seems I was wrong, when I said in the Lionair thread, that after the crash last year no 737 pilot would ever fall in that trap again...
Many things are difficult, all things are possible!

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