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ikramerica
Posts: 15231
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:51 pm

hivue wrote:
trnswrld wrote:
danj555 wrote:
Couldn't the pilots in any case of malfunction just turn off all electronic bs? Like you're a pilot. You know how to fly a plane. You have flown thousands of take-offs. You know the right speed, right angle, right altitude. You know how to do it without electronic interference if need be.

So why not hit the kill switch if the computer is having a fit?


I asked this exact question many pages ago. It got pretty much no response. Big problems in IMC is one thing, but to not be able to fly an airplane in clear blue VMC daylight conditions just baffles me....computer issues or not. How does this happen? Look out the window.....fly the airplane FIRST, then figure what the heck is going on. I know easier said than done.


Killing all computers operating on an airplane would have the same effect as killing all computer chips that are operating in your car while you're driving (assuming you are not driving a Stone Age car).

My car would shut off, the steering would lock, the brakes would not work (other than the parking brake) and I'd be in trouble. My wife's car, even the e-brake wouldn't work.
 
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monomojo
Posts: 87
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:55 pm

WIederling wrote:
dtw2hyd wrote:
This is a case of computer thinks it knows better than humans, which is historical with stall handing,

Also, everyone claims pilots need to flip two cut-off switches and they are good. Did anyone test this theory with MAX/MCAS (or) just based on runaway stab procedures?


There is no AI in safety critical computers.( at least not yet.)
Even heuristics are probably frowned on.
AI would result in action from stimulus being unpredictable.

MCAS acting on false input is not stab runaway.
Stab runaway is defined as continuous activation of trim in one direction
going by what has been posted here. like stuck contacts on a relay.


If you're a 737 pilot, and the stab trim starts running such that it's trying to fly you into the terrain, and your thought is "the runaway stab checklist doesn't apply here because, technically, this isn't acting like the most narrow definition of a runaway stab", then you haven't been trained very well.
 
osiris30
Posts: 2681
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 4:58 pm

Interested wrote:
osiris30 wrote:
Interested wrote:

Until this week I would have blindly trusted every new Boeing plane in operation to be perfectly safe. I would only be worried about bird strikes and terrorists. Now if I was on a max plane I would want to sit near the front ready to remind the pilots of lion and Ethiopia issues if anything weird happened on takeoff!


Well, there is no reason for you to change your behavior. Even as a fan of Boeing's products I will be the first to admit there have been some critical flaws (every aircraft ever has had them, sometimes they manifest in accidents, other times incidents) and they get worked out over time. Remember the jackscrew issue with the 737. Fuel tank inerting problems (all types). Wiring issues leading to fires (all types at that time period), Dc 10 issues. More than a few gremlins in Airbus's computers over the years. 99% of the time the pilots flying deal with these issues and they get reported and fixed. Sometimes things go wrong. Even Concorde it could be argued had critical flaws (despite being an absolute marvel of engineering ESPECIALLY given when it was built). Dash 8s had wonky landing gear issues for a while. I mean the list is pretty much endless and that is the stuff we KNOW was fixed. All the stuff that was fixed silently would likely fill volumes.

People acting like this is a unique thing are forgetting their history.


It's a different world in 2019 though don't you think?

Health and safety rules. Any of my staff have any kind of accident at work I have to report it and do something to stop it happening again. I can't have them carry on working with the same risk in place? Whikst I spend 4 months trying to figure out what to do different?

I could get prosecuted and lose my business if if I did.

And that's me a small business owner. This is Boeing in 2019.


While I get it, but also; what is your point? It is 2019, yes. Mistakes will still happen and things will have unintended consequences. We can think we have somehow gotten magically better and things don't go wrong anymore and people and processes don't miss things but guess what; aerospace is f***ing hard, and things ARE going to be missed. All the legislation, whatif'ing, wishing, etc., will not change that things will go wrong. Physics itself says you cannot possibly have a perfect system. Not that any of this replaces the lives lost or is in any way an excuse for the loss of life, but I won't delude myself into thinking we are somehow less fallible than we were 20-30 years ago. The only difference is the level of arrogance has increased many-fold to the point where we THINK we are so much better than we used to be.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:00 pm

Interested wrote:
osiris30 wrote:
ikramerica wrote:
Are they retracting flaps with net elevation less than 1000 feet? So the initial loss of control isn't MCAS.

Now, after a minute or two, the pilot asks to continue "normal" (not sure who's words) climb out to 14,000. One might assume he has flaps retracted then? So maybe it's then that MCAS comes on? But he's very low and something is preventing climb. He's also very fast because all the high thrust setting is going forward (and down when they pitch down) rather than into the climb.

Still want a commercial jet pilot's take on this:

If you are below 1000 feet from the ground, is it safe to bank a fully functioning aircraft for a 180 return to the airfield? Is it safe when your aircraft is acting like a petulant child and you don't know why?


The aircraft wasn't climbing despite more than enough airspeed, ostensibly flaps and everything else. This tells me the AC was out of trim before it left the ground. It makes me think that the previous crew disabled auto-trim and this crew never even turned it on, until possibly way too late.

As time has gone on I have continued to flesh out what *I* feel the chain of events is and to my mind now it starts before the take-off roll:

1) Either on prior flight or before commencing this flight; pilots of last flight or this flight disable MCAS as a precatuion (stab cut-off)
2) PIlots of this flight miss (or knew it was off), but fail to trim plane correctly.
3) Take off roll starts. IAS is broken.
4) Pilots attempt to rotate too early based on broken IAS. Nose comes off by AC doesn't unstick from the ground until 160kts (FR24 data). This is pretty high for a max IIRC.
5) Aircraft won't climb (bad trim). Pilots apply more pressure.
6a) Pilots fight with AC while continuing to increase speed to dangerous levels (no one watching the GPS ground speed). Cockpit is FULL of alarms at this point.
6b) Someone withdraws flaps during this time (or they come clean off depending on the extent of deployment, but probably the first option)
7) More time passes
8a) Someone in the cockpit notices the auto-trim is off and flips it on. Manual trim should have been used but for whatever reason wasn't (pilot may have thought they were fighting MCAS the entire time and they weren't).
8b) MCAS or autotrim (it could be either) kick in
(OR)
8a) Pilots notice trim is out and trim the AC the wrong way in error. At that altitude and speed it does not take much to cause really bad things to happen.

everything up to 7 is pretty solid in my mind based on the data we have (1/2 are obvious extrapolations of how it starts). 8 is obviously conjecture.


Which of the above (if any) are caused by software failings?


Possibly:
8b and airspeed/aoa errors.
2 one could argue should have alarmed and may be an opportunity for improvement or may be a bug.
 
rideforever
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:01 pm

On wikipedia it said that Boeing had originally had process to select either a 66in or 68in fan. 68in won.
But few months later this was bumped up to 69.6in.
Too much ? Too greedy ? Was it done without the careful process in the original selection ?
Was it done in response to the engine manufacturer or in response to a press release by Airbus about their own future improvements ?
 
osiris30
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Joined: Sat Sep 30, 2006 10:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:02 pm

CO953 wrote:
osiris30 wrote:
[...snip......]

People acting like this is a unique thing are forgetting their history.


I would respectfully submit that this is the first new aircraft type that repeatedly tries to commit suicide by diving toward the ground at low altitude.


I would respectfully counter that many new types have had flaws as bad or worse:

We all know the comet issues, and then there was the dc10 problems. Other types have had serious problems on introduction that didn't mainfest until later.. 737 jack screws for example. Problem was there from the get go, we just got lucky.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:20 pm

ikramerica wrote:
osiris30 wrote:
ikramerica wrote:
Are they retracting flaps with net elevation less than 1000 feet? So the initial loss of control isn't MCAS.

Now, after a minute or two, the pilot asks to continue "normal" (not sure who's words) climb out to 14,000. One might assume he has flaps retracted then? So maybe it's then that MCAS comes on? But he's very low and something is preventing climb. He's also very fast because all the high thrust setting is going forward (and down when they pitch down) rather than into the climb.

Still want a commercial jet pilot's take on this:

If you are below 1000 feet from the ground, is it safe to bank a fully functioning aircraft for a 180 return to the airfield? Is it safe when your aircraft is acting like a petulant child and you don't know why?


The aircraft wasn't climbing despite more than enough airspeed, ostensibly flaps and everything else. This tells me the AC was out of trim before it left the ground. It makes me think that the previous crew disabled auto-trim and this crew never even turned it on, until possibly way too late.

As time has gone on I have continued to flesh out what *I* feel the chain of events is and to my mind now it starts before the take-off roll:

1) Either on prior flight or before commencing this flight; pilots of last flight or this flight disable MCAS as a precatuion (stab cut-off)
2) PIlots of this flight miss (or knew it was off), but fail to trim plane correctly.
3) Take off roll starts. IAS is broken.
4) Pilots attempt to rotate too early based on broken IAS. Nose comes off by AC doesn't unstick from the ground until 160kts (FR24 data). This is pretty high for a max IIRC.
5) Aircraft won't climb (bad trim). Pilots apply more pressure.
6a) Pilots fight with AC while continuing to increase speed to dangerous levels (no one watching the GPS ground speed). Cockpit is FULL of alarms at this point.
6b) Someone withdraws flaps during this time (or they come clean off depending on the extent of deployment, but probably the first option)
7) More time passes
8a) Someone in the cockpit notices the auto-trim is off and flips it on. Manual trim should have been used but for whatever reason wasn't (pilot may have thought they were fighting MCAS the entire time and they weren't).
8b) MCAS or autotrim (it could be either) kick in
(OR)
8a) Pilots notice trim is out and trim the AC the wrong way in error. At that altitude and speed it does not take much to cause really bad things to happen.

everything up to 7 is pretty solid in my mind based on the data we have (1/2 are obvious extrapolations of how it starts). 8 is obviously conjecture.


I hope that's not the cause. It would, however, match with what I think two of the main failure modes of the Lion air crash was:
1. lack of transfer of knowledge from the previous flight crew to the next. Not informing the fateful crew what the previous crew turned on/off and why.
2. lack of information provided by Boeing/Aircraft that something isn't working right, a safety mechanism is activating, something is disable, etc.

And number 2 seems to me is a broader issue of the 737NG as well, just not showing itself because the implications have YET to lead to a crash. I'm sure in the history of the 737NG there have been many incidents where the crew was not aware of some issues with the aircraft that were impacting flight control, and the aircraft wasn't designed to make them aware, but crashes didn't ensue, just white knuckles and dirty knickers.


We will have to wait and see, but that is the closest fit we have so far to what the data shows. Again, I have no data folks here do not have. Just trying to fit it all together.
 
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airkas1
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:21 pm

 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:22 pm

rideforever wrote:
Too much ? Too greedy ? Was it done without the careful process in the original selection ?


Too simplistic a view of it. Engineers looked at it and felt they could go larger. MAYBE the made an error, maybe they didn't. Maybe whatever is plaguing the Max right now will be fixed and the plane will go 20 years and 1000s of copies without another incident.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:23 pm

airkas1 wrote:



Also note the attendees are EXACTLY as predicted they would be for all the people worrying about governmental interference ... sigh... luckily the industry is far more professional than our posters.
 
Interested
Posts: 890
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:31 pm

osiris30 wrote:
Interested wrote:
osiris30 wrote:

Well, there is no reason for you to change your behavior. Even as a fan of Boeing's products I will be the first to admit there have been some critical flaws (every aircraft ever has had them, sometimes they manifest in accidents, other times incidents) and they get worked out over time. Remember the jackscrew issue with the 737. Fuel tank inerting problems (all types). Wiring issues leading to fires (all types at that time period), Dc 10 issues. More than a few gremlins in Airbus's computers over the years. 99% of the time the pilots flying deal with these issues and they get reported and fixed. Sometimes things go wrong. Even Concorde it could be argued had critical flaws (despite being an absolute marvel of engineering ESPECIALLY given when it was built). Dash 8s had wonky landing gear issues for a while. I mean the list is pretty much endless and that is the stuff we KNOW was fixed. All the stuff that was fixed silently would likely fill volumes.

People acting like this is a unique thing are forgetting their history.


It's a different world in 2019 though don't you think?

Health and safety rules. Any of my staff have any kind of accident at work I have to report it and do something to stop it happening again. I can't have them carry on working with the same risk in place? Whikst I spend 4 months trying to figure out what to do different?

I could get prosecuted and lose my business if if I did.

And that's me a small business owner. This is Boeing in 2019.


While I get it, but also; what is your point? It is 2019, yes. Mistakes will still happen and things will have unintended consequences. We can think we have somehow gotten magically better and things don't go wrong anymore and people and processes don't miss things but guess what; aerospace is f***ing hard, and things ARE going to be missed. All the legislation, whatif'ing, wishing, etc., will not change that things will go wrong. Physics itself says you cannot possibly have a perfect system. Not that any of this replaces the lives lost or is in any way an excuse for the loss of life, but I won't delude myself into thinking we are somehow less fallible than we were 20-30 years ago. The only difference is the level of arrogance has increased many-fold to the point where we THINK we are so much better than we used to be.


My point is once the first accident happened and that Boeing knew the plane wasn't safe and they needed to upgrade the software they should have not flown again until it was fixed

I accept there will always be faults even in this day and age. But once you identify the risks with health and safety you HAVE to address them. This wasn't a minor fault with minor consequences they identified in November.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:37 pm

Interested wrote:
osiris30 wrote:
Interested wrote:

It's a different world in 2019 though don't you think?

Health and safety rules. Any of my staff have any kind of accident at work I have to report it and do something to stop it happening again. I can't have them carry on working with the same risk in place? Whikst I spend 4 months trying to figure out what to do different?

I could get prosecuted and lose my business if if I did.

And that's me a small business owner. This is Boeing in 2019.


While I get it, but also; what is your point? It is 2019, yes. Mistakes will still happen and things will have unintended consequences. We can think we have somehow gotten magically better and things don't go wrong anymore and people and processes don't miss things but guess what; aerospace is f***ing hard, and things ARE going to be missed. All the legislation, whatif'ing, wishing, etc., will not change that things will go wrong. Physics itself says you cannot possibly have a perfect system. Not that any of this replaces the lives lost or is in any way an excuse for the loss of life, but I won't delude myself into thinking we are somehow less fallible than we were 20-30 years ago. The only difference is the level of arrogance has increased many-fold to the point where we THINK we are so much better than we used to be.


My point is once the first accident happened and that Boeing knew the plane wasn't safe and they needed to upgrade the software they should have not flown again until it was fixed

I accept there will always be faults even in this day and age. But once you identify the risks with health and safety you HAVE to address them. This wasn't a minor fault with minor consequences they identified in November.


False assumption there; you are assuming Boeing "knew the plane wasn't safe". That is a false statement. Boeing knew there could be IMPROVEMENTS made. Just because something isn't perfect doesn't mean it is unsafe. That is a false equivalency and would not hold up remotely in a court of law, especially when the FAA felt the same way based on the AD.
 
Trin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:41 pm

osiris30 wrote:
rideforever wrote:
Too much ? Too greedy ? Was it done without the careful process in the original selection ?


Too simplistic a view of it. Engineers looked at it and felt they could go larger. MAYBE the made an error, maybe they didn't. Maybe whatever is plaguing the Max right now will be fixed and the plane will go 20 years and 1000s of copies without another incident.


I think we're all guilty of occasionally taking a simplistic view of it from time to time. The facts however do speak for themselves. The MAX was designed with one purpose in mind and that was to provide maximum profit to airlines by offering fuel saving. That fuel saving came mostly from the new LEAP engines. The new LEAP engines were so huge and had such a large nacelle that they had to be mounted to the plane in such a way that rendered it (at least somewhat) unstable in flight due to increased life/drag......which is why the MCAS system was included on the new type.

Anybody who believes that the MAX has engines that large just because the engineers "decided it would be OK" is, IMHO, also looking at things too simplistically. Boeing was under massive pressure to come up with a new model that saves massive amounts of fuel because that is the bottom line that the airlines operate on. The MAX was engineered because of that - not the other way around. It's not like they made the MAX the way they did, and then someone in a cubicle at Boeing suddenly found out that it ALSO saved $$$$$$$$ on fuel and decided to include that in the marketing materials.
Last edited by Trin on Fri Mar 15, 2019 5:45 pm, edited 1 time in total.
 
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BaconButty
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:42 pm

osiris30 wrote:
airkas1 wrote:



Also note the attendees are EXACTLY as predicted they would be for all the people worrying about governmental interference ... sigh... luckily the industry is far more professional than our posters.


Of course - that's all set out by ICAO annex 13. But by sending the FDR to France, it enabled another party to be present. Dress it up how you like, but this was a symptom of distrust in the US authorities - whether warranted or not.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:46 pm

VS11 wrote:
MCAS may have its issues and like all software it is work in progress



Outch, Outch, Outch.
This is not "beta test by user" stuff from Microsoft.
This is a qualitycontrolled certfied piece of software. ( at least that is the requirement.)

and small chance that this is due to bad production sensors.
much higher chance this is from bad design software.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:46 pm

mcdu wrote:
You won’t see pilots operating at those speeds normally. First of all in the USA and many other places the limit is 250kts below 10k.

SheikhDjibouti wrote:
That is an ATC restriction, and nothing to do with aircraft structural issues.
The 250kt limit would apply to a Piper Malibu just as it would apply to Concorde (if it was still flying)
..
Is there nobody here with actual verifiable figures from Boeing?

mcdu wrote:
But no one flies around at the barber pole even when allowed (offshore). If you are on the barber pole there is no margin if you hit a bump and causes a momentary overspeed. That is a required maintenance inspection when you land. Also it is terrible inefficient to fly on like that.

Absolutely correct. But that wasn't my point, so your reply whilst mildly interesting, is irrelevant.

In your haste to show my logic as faulty, you have somehow managed to isolate my response, totally ignoring the context and the original comment.
Here it is one more time.
osiris30 wrote:
At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

Neither Osiris30 nor myself were suggesting flying at (or near, or beyond) Vmo was a smart thing to do. Or "normal" procedure.
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

I still, after all this time, would like some source to confirm that.
Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

And it should be a simple matter to confirm, except here we are still dancing around.

Perhaps the actual answer doesn't suit somebody's agenda... :scratchchin:
 
osiris30
Posts: 2681
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:49 pm

BaconButty wrote:
osiris30 wrote:
airkas1 wrote:



Also note the attendees are EXACTLY as predicted they would be for all the people worrying about governmental interference ... sigh... luckily the industry is far more professional than our posters.


Of course - that's all set out by ICAO annex 13. But by sending the FDR to France, it enabled another party to be present. Dress it up how you like, but this was a symptom of distrust in the US authorities - whether warranted or not.


I'm not arguing WHY it is in France. That is pretty evident. But there were folks on here saying that only the French and Ethiopians would be present. Had to defend a post saying no several times. Just pointing it out now that it's been said formally.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:51 pm

WIederling wrote:
VS11 wrote:
MCAS may have its issues and like all software it is work in progress



Outch, Outch, Outch.
This is not "beta test by user" stuff from Microsoft.
This is a qualitycontrolled certfied piece of software. ( at least that is the requirement.)

and small chance that this is due to bad production sensors.
much higher chance this is from bad design software.


For someone who is claiming to be an engineering guru in his posts you sure make a lot of (unnoted) assumptions. This is not badly designed software. You are highlighting software when it seems the single biggest part of engineering failure around this is actually UI/UX engineering. The interface with humans is what is broken. If MCAS just shouted 'I AM DOING STUFF' all this would be squarely pilot error.
 
osiris30
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Joined: Sat Sep 30, 2006 10:16 am

Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 5:52 pm

SheikhDjibouti wrote:
mcdu wrote:
You won’t see pilots operating at those speeds normally. First of all in the USA and many other places the limit is 250kts below 10k.

SheikhDjibouti wrote:
That is an ATC restriction, and nothing to do with aircraft structural issues.
The 250kt limit would apply to a Piper Malibu just as it would apply to Concorde (if it was still flying)
..
Is there nobody here with actual verifiable figures from Boeing?

mcdu wrote:
But no one flies around at the barber pole even when allowed (offshore). If you are on the barber pole there is no margin if you hit a bump and causes a momentary overspeed. That is a required maintenance inspection when you land. Also it is terrible inefficient to fly on like that.

Absolutely correct. But that wasn't my point, so your reply whilst mildly interesting, is irrelevant.

In your haste to show my logic as faulty, you have somehow managed to isolate my response, totally ignoring the context and the original comment.
Here it is one more time.
osiris30 wrote:
At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

Neither Osiris30 nor myself were suggesting flying at (or near, or beyond) Vmo was a smart thing to do. Or "normal" procedure.
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

I still, after all this time, would like some source to confirm that.
Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

And it should be a simple matter to confirm, except here we are still dancing around.

Perhaps the actual answer doesn't suit somebody's agenda... :scratchchin:


The maximum permitted speed of most models of B737 is 340 knots CAS (Calibrated Airspeed) or Mach 0.82, whichever is slower. (Ref: Detailed Technical Data ).

Edit: This flight was doing approximately: 350kias airspeed when the FR data cut out. based on 380kt ground speed, 1.12 scaling factor for air density and 10kt head wind.
 
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N14AZ
Posts: 4366
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:02 pm

osiris30 wrote:
Interested wrote:
osiris30 wrote:

While I get it, but also; what is your point? It is 2019, yes. Mistakes will still happen and things will have unintended consequences. We can think we have somehow gotten magically better and things don't go wrong anymore and people and processes don't miss things but guess what; aerospace is f***ing hard, and things ARE going to be missed. All the legislation, whatif'ing, wishing, etc., will not change that things will go wrong. Physics itself says you cannot possibly have a perfect system. Not that any of this replaces the lives lost or is in any way an excuse for the loss of life, but I won't delude myself into thinking we are somehow less fallible than we were 20-30 years ago. The only difference is the level of arrogance has increased many-fold to the point where we THINK we are so much better than we used to be.


My point is once the first accident happened and that Boeing knew the plane wasn't safe and they needed to upgrade the software they should have not flown again until it was fixed

I accept there will always be faults even in this day and age. But once you identify the risks with health and safety you HAVE to address them. This wasn't a minor fault with minor consequences they identified in November.


False assumption there; you are assuming Boeing "knew the plane wasn't safe". That is a false statement. Boeing knew there could be IMPROVEMENTS made. Just because something isn't perfect doesn't mean it is unsafe.

Wow, I really hope no one of the ET crash victim’s families will read this statement.
 
VS11
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:12 pm

WIederling wrote:
VS11 wrote:
MCAS may have its issues and like all software it is work in progress



Outch, Outch, Outch.
This is not "beta test by user" stuff from Microsoft.
This is a qualitycontrolled certfied piece of software. ( at least that is the requirement.)

and small chance that this is due to bad production sensors.
much higher chance this is from bad design software.


But the root cause for Lion jet was a faulty indicator that triggered MCAS, no? Where is the quality control in that? I am not downplaying the contributing factor of MCAS and all the associated shortcomings of it but let’s not forget it was not the root cause .
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:14 pm

N14AZ wrote:
osiris30 wrote:
Interested wrote:

My point is once the first accident happened and that Boeing knew the plane wasn't safe and they needed to upgrade the software they should have not flown again until it was fixed

I accept there will always be faults even in this day and age. But once you identify the risks with health and safety you HAVE to address them. This wasn't a minor fault with minor consequences they identified in November.


False assumption there; you are assuming Boeing "knew the plane wasn't safe". That is a false statement. Boeing knew there could be IMPROVEMENTS made. Just because something isn't perfect doesn't mean it is unsafe.

Wow, I really hope no one of the ET crash victim’s families will read this statement.


Why? Because it is logical. Good grief. Everyone is falling all over themselves. This thread is discussing an accident. Accidents need to be dissected in a logical manner, not an emotional one. Emotional dissections lead to biases. Biases lead to erroneous decisions and data favoring. The families of the people on BOTH ET and JT flights have my most sincere condolences, as do the families of the folks on the Atlas '67, as do the families of the folks in NZ this morning. Condolences don't do jack squat to make anything safer or better. Calling out a false assumption is not some horrible heartless act as much as people here like to think it is when they climb aboard their trusty tall steed of moral righteousness.

The statement is 100% true because: There is NOT ONE single piece of man-made equipment on the planet that is PERFECT. Every aircraft has errors, so does every car, building, bridge, toaster, fridge, stove, lightbulb, etc. It does NOT (in and of itself) make them unsafe. If you can't grasp that, perhaps this thread isn't the one for you. The poster I was replying to was conflating imperfection with unsafe. That was and still is a false assumption and I called them on it.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:16 pm

VS11 wrote:
WIederling wrote:
VS11 wrote:
MCAS may have its issues and like all software it is work in progress



Outch, Outch, Outch.
This is not "beta test by user" stuff from Microsoft.
This is a qualitycontrolled certfied piece of software. ( at least that is the requirement.)

and small chance that this is due to bad production sensors.
much higher chance this is from bad design software.


But the root cause for Lion jet was a faulty indicator that triggered MCAS, no? Where is the quality control in that? I am not downplaying the contributing factor of MCAS and all the associated shortcomings of it but let’s not forget it was not the root cause .


Nope. One of the contributing causes was that. We have no final report, nor do we have much data released. The 'MCAS is a root cause' is a media and a.net myth until the report comes out. It *might* be the root cause, but that is not proven yet and frankly, it is a good thing it has not been proven yet, because what if something else MUCH WORSE is going on and we just chalked it up to MCAS and moved on.
 
Heinkel
Posts: 346
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Please delte, double post

Fri Mar 15, 2019 6:17 pm

Please delete. Double post.
Last edited by Heinkel on Fri Mar 15, 2019 6:26 pm, edited 3 times in total.
 
Heinkel
Posts: 346
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:19 pm

ikramerica wrote:
hivue wrote:
Killing all computers operating on an airplane would have the same effect as killing all computer chips that are operating in your car while you're driving (assuming you are not driving a Stone Age car).

My car would shut off, the steering would lock, the brakes would not work (other than the parking brake) and I'd be in trouble. My wife's car, even the e-brake wouldn't work.


Nope. Every type approved car in the world will steer and brake without any computer or electricity. May be with reduced perfomance and without assistance systems but the primary functions of steering and braking have still a non-electrical backup function. So even without electricity or computers (controllers) you can always stop the car and steer it to the hard shoulder.
Last edited by Heinkel on Fri Mar 15, 2019 6:24 pm, edited 4 times in total.
 
Interested
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:20 pm

osiris30 wrote:
N14AZ wrote:
osiris30 wrote:

False assumption there; you are assuming Boeing "knew the plane wasn't safe". That is a false statement. Boeing knew there could be IMPROVEMENTS made. Just because something isn't perfect doesn't mean it is unsafe.

Wow, I really hope no one of the ET crash victim’s families will read this statement.


Why? Because it is logical. Good grief. Everyone is falling all over themselves. This thread is discussing an accident. Accidents need to be dissected in a logical manner, not an emotional one. Emotional dissections lead to biases. Biases lead to erroneous decisions and data favoring. The families of the people on BOTH ET and JT flights have my most sincere condolences, as do the families of the folks on the Atlas '67, as do the families of the folks in NZ this morning. Condolences don't do jack squat to make anything safer or better. Calling out a false assumption is not some horrible heartless act as much as people here like to think it is when they climb aboard their trusty tall steed of moral righteousness.

The statement is 100% true because: There is NOT ONE single piece of man-made equipment on the planet that is PERFECT. Every aircraft has errors, so does every car, building, bridge, toaster, fridge, stove, lightbulb, etc. It does NOT (in and of itself) make them unsafe. If you can't grasp that, perhaps this thread isn't the one for you. The poster I was replying to was conflating imperfection with unsafe. That was and still is a false assumption and I called them on it.


Boeings wording for the software upgrade they've been working on since the Lion crash is:

the upgrade is designed “to make an already safe aircraft safer”.

I'm going to suggest they've had to be very careful when choosing those words

And I'm going to suggest they are biased

And I'm going to suggest that by the standards we expect plane makers to set the actual wording should be

"To make an unsafe aircraft safer"

This plane clearly wasn't and still isn't safe to the level Boeing or any other plane maker would expect?

Do you disagree?

Boeing won't admit it. But its out of their hands now anyway.
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:22 pm

SheikhDjibouti wrote:
Neither Osiris30 nor myself were suggesting flying at (or near, or beyond) Vmo was a smart thing to do. Or "normal" procedure.
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

I still, after all this time, would like some source to confirm that.
Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

And it should be a simple matter to confirm, except here we are still dancing around.

Perhaps the actual answer doesn't suit somebody's agenda... :scratchchin:

Vmo 340 knots or 0.82 mach. They were not high enough to be near the mach limit, so 340 knots would be the limit. As for "severe"? Not sure without seeing maintenance manual required inspections. Sometimes overspeeds of up to 10 knots just need a logbook entry, higher speeds may have inspection criteria, etc.

All that being said, in the below linked incident a 737 reached 429 knots at 5600 feet in a dive (according to FDR) and there was no damage to the aircraft
https://assets.publishing.service.gov.u ... _09-10.pdf
 
Interested
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:25 pm

The exact same plane that isn't safe to fly now wasn't safe to fly in October when it first crashed. Boeing became aware it wasn't safe in November at the latest. If not before.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:25 pm

VS11 wrote:
But the root cause for Lion jet was a faulty indicator that triggered MCAS, no?


(Probably) Slightly wrong. The exchanged sensor is said to have checked out ok on the bench.

MCAS ( and other systems) was handed faulty information apparently. There is the ADIRU in between.
( I've seen synthetic data sets mentioned i.e. the ADIRU tries to supply always valid information synthesized from incoming data.)
 
Trin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:25 pm

osiris30 wrote:
The statement is 100% true because: There is NOT ONE single piece of man-made equipment on the planet that is PERFECT. Every aircraft has errors, so does every car, building, bridge, toaster, fridge, stove, lightbulb, etc. It does NOT (in and of itself) make them unsafe. If you can't grasp that, perhaps this thread isn't the one for you. The poster I was replying to was conflating imperfection with unsafe. That was and still is a false assumption and I called them on it.


Jeesh. You complain of others over-simplifying things, and then compare the issues the MAX is having to a toaster malfunctioning. Not sure what to make of that.

As much some of us want to have an emotional reaction and push agendas, at some point we really need to stop and take a breath. The fact remains that both the Lion Air and now ET incidents have showed flights with TERRIBLY erratic and dangerous modes of flight. With hundreds of souls on board. Which ultimately ended in the deaths of all. Whatever you think about the root cause, comparing what caused the deaths of all these people with a flawed bread-heater is really offputting.
Last edited by Trin on Fri Mar 15, 2019 6:28 pm, edited 1 time in total.
 
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SomebodyInTLS
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:30 pm

chicawgo wrote:
SomebodyInTLS wrote:
dragon6172 wrote:
The Lion Air crew prior to the accident flight tested this procedure and it worked as advertised.


You forgot to add "by luck"! They had no idea what was going on but happened to guess correctly that trim could be involved. THERE WAS NO PROCEDURE.


Just absolutely spreading lies. They didn't just blindly guess. They made an educated decision based on experience and the situation. The trim was running wild so they cut the auto trim switches.


No, you and dragon6172 would like me to have interpreted it as blind guess but that's not at all what I said. I wish people wouldn't be so partisan.

Unlike what dragon6172 says; there was no runaway trim, therefore the fact they followed that checklist based - indeed - on an educated decision, and the fact that that checklist HAPPENED TO SOLVE AN MCAS ISSUE is lucky... SINCE THERE WAS NO PROCEDURE TO OVERRIDE MCAS. (Nor did they even know of the existence of MCAS or what it does.)

I'm sorry if that fact offends you, but it is what it is.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:30 pm

osiris30 wrote:
At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

SheikhDjibouti wrote:
Neither Osiris30 nor myself were suggesting flying at (or near, or beyond) Vmo was a smart thing to do. Or "normal" procedure.
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

I still, after all this time, would like some source to confirm that.
Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

osiris30 wrote:
The maximum permitted speed of most models of B737 is 340 knots CAS (Calibrated Airspeed) or Mach 0.82, whichever is slower. (Ref: Detailed Technical Data ).

Edit: This flight was doing approximately: 350kias airspeed when the FR data cut out. based on 380kt ground speed, 1.12 scaling factor for air density and 10kt head wind.

Brilliant!
And thank you. :bigthumbsup:

350kias in perfect conditions is probably ok. It would warrant a ground-check afterwards, much as a heavy landing requires.

But 350kias whilst riding a rollercoaster may have twisted or warped some surfaces.

I'll leave it to others to take it from here.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:34 pm

SheikhDjibouti wrote:
osiris30 wrote:
At 380kts at 8600' alt, the aircraft was definitely in a 'severe overspeed' condition. That is a speed that can incur structural failure unless managed very well.

SheikhDjibouti wrote:
Neither Osiris30 nor myself were suggesting flying at (or near, or beyond) Vmo was a smart thing to do. Or "normal" procedure.
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

I still, after all this time, would like some source to confirm that.
Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

osiris30 wrote:
The maximum permitted speed of most models of B737 is 340 knots CAS (Calibrated Airspeed) or Mach 0.82, whichever is slower. (Ref: Detailed Technical Data ).

Edit: This flight was doing approximately: 350kias airspeed when the FR data cut out. based on 380kt ground speed, 1.12 scaling factor for air density and 10kt head wind.

Brilliant!
And thank you. :bigthumbsup:

350kias in perfect conditions is probably ok. It would warrant a ground-check afterwards, much as a heavy landing requires.

But 350kias whilst riding a rollercoaster may have twisted or warped some surfaces.

I'll leave it to others to take it from here.


Bear in mind also that 340kts is the clean speed for that aircraft. The number is lower with flaps etc. Also, bear in mind based on what we have seen reported (without supporting data) the AC continued to accelerate to an unknown speed. When you factor in potential sudden control inputs it IS possible the frame was overstressed at points. Overspeed at that altitude is a bad thing due to density. Plus my 350 figure assumes constant and not gusting winds which could easily push momentary AS to 360kts based on the data we DO have available to us mortals.

Also, you are welcome. Cheers.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:35 pm

dragon6172 wrote:
SheikhDjibouti wrote:
ET302 found themselves at high speed (381 kts has been quoted), but was it "severe overspeed"?
Osiris30 says it is (severe overspeed)

Did the pilots of ET302 damage the plane simply by flying too fast, too low.
It is not an unreasonable question.

Vmo 340 knots or 0.82 mach. They were not high enough to be near the mach limit, so 340 knots would be the limit. As for "severe"? Not sure without seeing maintenance manual required inspections. Sometimes overspeeds of up to 10 knots just need a logbook entry, higher speeds may have inspection criteria, etc.

All that being said, in the below linked incident a 737 reached 429 knots at 5600 feet in a dive (according to FDR) and there was no damage to the aircraft
https://assets.publishing.service.gov.u ... _09-10.pdf

And my thanks go to you too, sir. :bigthumbsup:
 
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:35 pm

VS11 wrote:
WIederling wrote:
VS11 wrote:
MCAS may have its issues and like all software it is work in progress



Outch, Outch, Outch.
This is not "beta test by user" stuff from Microsoft.
This is a qualitycontrolled certfied piece of software. ( at least that is the requirement.)

and small chance that this is due to bad production sensors.
much higher chance this is from bad design software.


But the root cause for Lion jet was a faulty indicator that triggered MCAS, no? Where is the quality control in that? I am not downplaying the contributing factor of MCAS and all the associated shortcomings of it but let’s not forget it was not the root cause .


Based on the current information, the defective AoA vane is definitely a contributing factor. Pilots failing to follow the runaway trim non-normal checklist might be a a contributing factor (if investigators conclude conditions for the Runaway trim NNC existed). It looks like the root cause for the accident might be considered to be the MCAS design itself.
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:36 pm

SomebodyInTLS wrote:

Unlike what dragon6172 says; there was no runaway trim, therefore the fact they followed that checklist based - indeed - on an educated decision is lucky... SINCE THERE WAS NO PROCEDURE TO OVERRIDE MCAS. (Nor did they even know of the existence of MCAS or what it does.)

I'm sorry if that fact offends you, but it is what it is.

I never said there was runaway trim. I said there was uncommanded electrical trim. And the pilot was smart enough to realize that uncommanded electrical trim could be dealt with in the same manner as runaway trim. I don't consider that luck.
 
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flyingturtle
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:37 pm

osiris30 wrote:
If MCAS just shouted 'I AM DOING STUFF' all this would be squarely pilot error.


When MCAS is active, then the crew must trust it's doing the right thing.

Given two deadly crashes, an announcement like "I AM DOING STUFF" will just make the pilots do the Runaway Trim Procedure.


David
 
JoeCanuck
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:39 pm

SomebodyInTLS wrote:
chicawgo wrote:
SomebodyInTLS wrote:

You forgot to add "by luck"! They had no idea what was going on but happened to guess correctly that trim could be involved. THERE WAS NO PROCEDURE.


Just absolutely spreading lies. They didn't just blindly guess. They made an educated decision based on experience and the situation. The trim was running wild so they cut the auto trim switches.


No, you and dragon6172 would like me to have interpreted it as blind guess but that's not at all what I said. I wish people wouldn't be so partisan.

Unlike what dragon6172 says; there was no runaway trim, therefore the fact they followed that checklist based - indeed - on an educated decision is lucky... SINCE THERE WAS NO PROCEDURE TO OVERRIDE MCAS. (Nor did they even know of the existence of MCAS or what it does.)

I'm sorry if that fact offends you, but it is what it is.


That's not true. They knew they had a TRIM problem and hit the switches to shut down the electric trim system. That was not an educated guess, but a logical assumption based on good troubleshooting. An MCAS problem, IS a trim problem, and all electric based trim problems go away using the same technique.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:40 pm

flyingturtle wrote:
osiris30 wrote:
If MCAS just shouted 'I AM DOING STUFF' all this would be squarely pilot error.


When MCAS is active, then the crew must trust it's doing the right thing.

Given two deadly crashes, an announcement like "I AM DOING STUFF" will just make the pilots do the Runaway Trim Procedure.


David


MCAS should never be active frankly. It is only designed to be a corner case 'you are about to stall the plane idiot' type of system. If MCAS goes active during normal parts of flight they probably SHOULD be running that procedure.
 
Trin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:48 pm

osiris30 wrote:
flyingturtle wrote:
osiris30 wrote:
If MCAS just shouted 'I AM DOING STUFF' all this would be squarely pilot error.


When MCAS is active, then the crew must trust it's doing the right thing.

Given two deadly crashes, an announcement like "I AM DOING STUFF" will just make the pilots do the Runaway Trim Procedure.

David


MCAS should never be active frankly. It is only designed to be a corner case 'you are about to stall the plane idiot' type of system. If MCAS goes active during normal parts of flight they probably SHOULD be running that procedure.


If MCAS "should never be active frankly", why did Boeing bake it in to the MAX in such a way that it:

1. Can be activated at any altitude;
2. Relies only on one point of data that has no redundancy;
3. Can overrride pilot input repeatedly to the point of increasing control surface forces to the point of making the plane difficult to control;
4. Is required in order to get certification for the new type to operate legally.

I realize at this point I am poking someone who is already triggered into yet another response.....but somewhere deep down I really do want to know your opinions to those points.
 
smartplane
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:51 pm

estorilm wrote:
For 50 years, normal stall recovery procedures were perfectly adequate on prior aircraft, even when it came time to certify the NG. For some reason, that's not the case with the MAX. It's not really a "feature" Boeing added as an upgrade with the new plane or something - it's a requirement for certification.

It's a feature Boeing added to perpetuate grandfathering. It is a requirement for certification, in order to mimic, within approved tolerances, the flight behaviour of the NG.

The MAX, within approved tolerances mimics the NG. The NG, within tolerances mimics the Classic. The Classic, within approved tolerances, mimics the 100/200. But the ultimate parent is the 100/200, which after applying multiple layers of tolerances, bears little or no resemblance to the flight behaviour of the MAX, even with electronic cloaking to make it seem so.
 
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litz
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:53 pm

Jetty wrote:
Chemist wrote:
If they had problems almost immediately after takeoff, then would MCAS be the issue? MCAS doesn't go into effect until flaps are retracted.

It shouldn’t go into effect until flaps are retracted. That doesn’t mean it doesn’t go into effect until flaps are retracted. From the Lion Air crash we know it has gone into effect when it shouldn’t before and there’s no way of knowing if this is isolated to one specific set of circumstances or an wider issue.


The comments I've heard about MCAS tend to describe it as "when the aircraft is in steep turns or in low-speed, flaps-retracted flight" ... just like you noted.

This was evidently NOT a low speed flight in its latter stages, and certainly at takeoff, not a flaps-retracted flight in its early stages.

That FDR readout is pretty critical to clarify some of these questions.
 
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litz
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 6:55 pm

cat3appr50 wrote:
In response to post #2340
Regarding the Lion Air JT610 accident flight, at 23:22:05 UTC, the DFDR recorded the aircraft altitude was approximately 2,150 feet and the flaps were retracted. After the flaps reached 0, the DFDR recorded automatic aircraft nose down (AND) trim active for 10 seconds followed by flight crew commanded aircraft nose up (ANU) trim. MCAS was not activated on this flight until the flaps were up.


That's the thing that makes me wonder in the JT610 crash .... you retract the flaps, airplane does something crazy ... so you put them back out ... and retract them again, and it again does something crazy. That's two strikes. What on earth kind of mental processes led to them retracting the flaps, again, over and over, when the airplane went and did something crazy and unexpected each and every time?

At some point, you just don't DO it any more, and go find some terra firma to land on and let the mechanics figure out the ghost in the machine.
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:00 pm

Trin wrote:

If MCAS "should never be active frankly", why did Boeing bake it in to the MAX in such a way that it:

1. Can be activated at any altitude;
2. Relies only on one point of data that has no redundancy;
3. Can overrride pilot input repeatedly to the point of increasing control surface forces to the point of making the plane difficult to control;
4. Is required in order to get certification for the new type to operate legally.

I realize at this point I am poking someone who is already triggered into yet another response.....but somewhere deep down I really do want to know your opinions to those points.

Correction on #3.... MCAS does not over ride pilot input. Pilot input over rides MCAS.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:00 pm

Finn350 wrote:
Based on the current information, the defective AoA vane is definitely a contributing factor.


don't make things simpler than they are.

What we know is that one downstream AoA value was wrong ( #1 showing offset vs .#2)
AoA sensors, other sensors -> ADIRU -> downstream sinks ( for air data sets ).
The initially replaced "defective" AoA is said to have been ok in a bench test aftewards !?
Last edited by WIederling on Fri Mar 15, 2019 7:01 pm, edited 1 time in total.
 
osiris30
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:01 pm

Trin wrote:
osiris30 wrote:
flyingturtle wrote:

When MCAS is active, then the crew must trust it's doing the right thing.

Given two deadly crashes, an announcement like "I AM DOING STUFF" will just make the pilots do the Runaway Trim Procedure.

David


MCAS should never be active frankly. It is only designed to be a corner case 'you are about to stall the plane idiot' type of system. If MCAS goes active during normal parts of flight they probably SHOULD be running that procedure.


If MCAS "should never be active frankly", why did Boeing bake it in to the MAX in such a way that it:

1. Can be activated at any altitude;
2. Relies only on one point of data that has no redundancy;
3. Can overrride pilot input repeatedly to the point of increasing control surface forces to the point of making the plane difficult to control;
4. Is required in order to get certification for the new type to operate legally.

I realize at this point I am poking someone who is already triggered into yet another response.....but somewhere deep down I really do want to know your opinions to those points.


1) Because you can stall an aircraft at any altitude.

2) The redundancy in the designed system (and that was approved by the FAA and EASA) was redundancy 2 is PF and 3 is NFP.

3) It doesn't override pilot input. If they trim the system it cuts out and waits before re-engaging. I *do* agree it should have control limits, but it doesn't directly undo something the pilot has done immediately. It *can* overpower the yoke input via trim, but that's a bit different (and frankly not new, the auto-trim could do the same on the 737NG)

4) Incorrect. It was required to get certification under an existing type certificate. If it was certified as an all-new type, MCAS would NOT be needed and there would be a training requirement about the handling characteristics of the aircraft.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:01 pm

flyingturtle wrote:
osiris30 wrote:
If MCAS just shouted 'I AM DOING STUFF' all this would be squarely pilot error.


When MCAS is active, then the crew must trust it's doing the right thing.

Given two deadly crashes, an announcement like "I AM DOING STUFF" will just make the pilots do the Runaway Trim Procedure.
David

You may have a point.

However, I liken it to ABS on a car.
It is hugely beneficial to the pilot (er, driver) to know that the ABS is saving their bacon for some reason.
It might be that they were unaware of black ice on the road.
Or that one of their tires was punctured. Or covered in oil.

Knowledge is everything.

(There will always be some drivers for whom the tell-tale action of ABS is beyond their comprehension. Mostly, Darwin's theorem will ensure their removal from the general population...)
 
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:04 pm

WIederling wrote:
Finn350 wrote:
Based on the current information, the defective AoA vane is definitely a contributing factor.


don't make things simpler than they are.

What we know is that one downstream AoA value was wrong ( #1 showing offset vs .#2)
AoA sensors, other sensors -> ADIRU -> downstream sinks ( for air data sets ).
The initially replaced "defective" AoA is said to have been ok in a bench test aftewards !?


Yes, it should have been "defective AoA value", whatever the source for that.
 
GalaxyFlyer
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:15 pm

hivue wrote:
trnswrld wrote:
danj555 wrote:
Couldn't the pilots in any case of malfunction just turn off all electronic bs? Like you're a pilot. You know how to fly a plane. You have flown thousands of take-offs. You know the right speed, right angle, right altitude. You know how to do it without electronic interference if need be.

So why not hit the kill switch if the computer is having a fit?


I asked this exact question many pages ago. It got pretty much no response. Big problems in IMC is one thing, but to not be able to fly an airplane in clear blue VMC daylight conditions just baffles me....computer issues or not. How does this happen? Look out the window.....fly the airplane FIRST, then figure what the heck is going on. I know easier said than done.


Killing all computers operating on an airplane would have the same effect as killing all computer chips that are operating in your car while you're driving (assuming you are not driving a Stone Age car).


In a 737, no that would not be the effect. The visual view remains, the pilots connection to the flight controls is unimpeded, the trim is manual and operative. You can turn off the stab trim, the stall warning, fly the airplane without even hydraulics.

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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Fri Mar 15, 2019 7:28 pm

ikramerica wrote:
hivue wrote:
trnswrld wrote:

I asked this exact question many pages ago. It got pretty much no response. Big problems in IMC is one thing, but to not be able to fly an airplane in clear blue VMC daylight conditions just baffles me....computer issues or not. How does this happen? Look out the window.....fly the airplane FIRST, then figure what the heck is going on. I know easier said than done.


Killing all computers operating on an airplane would have the same effect as killing all computer chips that are operating in your car while you're driving (assuming you are not driving a Stone Age car).

My car would shut off, the steering would lock, the brakes would not work (other than the parking brake) and I'd be in trouble. My wife's car, even the e-brake wouldn't work.

An awful lot of vehicles these days have electric power steering and electric vacuum pumps, so the engine doesn't need to be running to have the power assist. The battery does need to be in good shape, though.

If your car has the engine stop/start feature to save fuel, then it automatically has electric assist for the steering and the brakes, and a second battery to keep them powered while the engine is not running.

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