Ethiopian Airlines Crash/ B737MAX grounding

Damien360

bryangiggsy wrote: »

From Sky News

Germany's air safety authority has just said 737 MAX 8 and 9 models will be barred from their airspace until 12 June - three months

Has there ever been a determination of cause from accident authorities in 3 months ? Even a preliminary one ? It's an odd timeframe.

batman2000

Damien360 wrote: »

Has there ever been a determination of cause from accident authorities in 3 months ? Even a preliminary one ? It's an odd timeframe.

Yes, Lion Air- Crashed October 29th 2018. Prelim Report November 29th 2018

http://knkt.dephub.go.id/knkt/ntsc_aviation/baru/pre/2018/2018%20-%20035%20-%20PK-LQP%20Preliminary%20Report.pdf

Safehands

Tenger wrote: »

Those nations that issued grounding orders obviously have concerns. Those concerns will need to be addressed by Boeing.

Even when this problem is resolved are the paying public ever going to be happy flying in a Max? Over 300 people have died horribly in this model over the past 5 months. That is going to be hard to forget, no matter what assurances are given by Boeing.
The DC10 never really recovered its reputation after the bad press it received over the Paris accident. Will the Max recover? I doubt it!
It's a pity, because it's a lovely plane.

Bob24

Tenger wrote: »

Those nations that issued grounding orders obviously have concerns. Those concerns will need to be addressed by Boeing.

https://www.nytimes.com/interactive/2019/03/11/world/boeing-737-max-which-airlines.html

Updated with map of all groundings.
Only Russian, Kazakh, Canadian and US aircraft still flying. I make that 100 aircraft out of 360+.

Good link. Basically as of the latest version of the map at the beginning of the article, at this stage the plane is mostly being used within the US and a little bit between the US and a few neighboring countries - and is grounded almost everywhere else.

I don’t know if it is the US taking a calculated risk to protect a national corporate giant or other countries being overzealous because it doesn’t impact them too much (possibly a bit of both), but looking at the map it is hard not to think there is a good level of politics involved in decisions to ban or not to.

California Dreamer

Safehands wrote: »

Even when this problem is resolved are the paying public ever going to be happy flying in a Max? Over 300 people have died horribly in this model over the past 5 months. That is going to be hard to forget, no matter what assurances are given by Boeing.
The DC10 never really recovered its reputation after the bad press it received over the Paris accident. Will the Max recover? I doubt it!
It's a pity, because it's a lovely plane.

Do you really think Joe Public even knows why type of aircraft they are getting on to get to their destination? As long as it’s cheap and semi-comfortable they don’t really care.

irishgeo

Bob24 wrote: »

Tenger wrote: »

Those nations that issued grounding orders obviously have concerns. Those concerns will need to be addressed by Boeing.

https://www.nytimes.com/interactive/2019/03/11/world/boeing-737-max-which-airlines.html

Updated with map of all groundings.
Only Russian, Kazakh, Canadian and US aircraft still flying. I make that 100 aircraft out of 360+.

Good link. Basically as of the latest version of the map at the beginning of then article, at this stage the plane is mostly being used within the US and a little bit between the US and a few neighboring countries - and is grounded almost everywhere else.

I don’t know if it is the US taking a calculated risk to protect a national corporate giant or other countries being overzealous because it doesn’t impact them too much (possibly a bit of both), but looking at the map it is hard not to think there is a good level of politics involved in decisions to ban or not to.

I think the Americans aren't concerned because they have told/trained their pilots very well on how to get around the issue.

Gaoth Laidir

So is the problem erroneous AOA data during normal flight or is it that the plane was flown into a non-normal AOA? That will be interesting to see in the investigation.

From Boeing's release on March 12th:

http://avherald.com/h?article=4c534c4a&opt=0

A pitch augmentation control law (MCAS) was implemented on the 737 MAX to improve aircraft handling characteristics and decrease pitch-up tendency at elevated angles of attack. It was put through flight testing as part of the certification process prior to the airplane entering service. MCAS does not control the airplane in normal flight; it improves the behavior of the airplane in a non-normal part of the operating envelope. 

goingnowhere

That assumes you have valid AOA data...

Gaoth Laidir

goingnowhere wrote: »

That assumes you have valid AOA data...

Which is what my question was.

kippy

In the Lion Air crash, was the root cause a faulty "sensor" or how the plan handled a perfectly normal part of flight or how the pilots dealt with the plane dealing with a perfectly normal part of flight?

I am just wondering if a faulty sensor is the root cause of both as opposed to anything else, but the faulty sensor has exposed issues with the automation systems on the plane.
If the root issue is a faulty sensor surely the fact that possibly two out of 350 have had this issue is grounds to ground ALL aircraft of this type.

murphaph

Safehands wrote: »

Even when this problem is resolved are the paying public ever going to be happy flying in a Max? Over 300 people have died horribly in this model over the past 5 months. That is going to be hard to forget, no matter what assurances are given by Boeing.
The DC10 never really recovered its reputation after the bad press it received over the Paris accident. Will the Max recover? I doubt it!
It's a pity, because it's a lovely plane.

If they can satisfactorily explain the crashes and demonstrate a working fix I'd fly on them. legacy 737s and A320s have had other flaws that unfortunately were only discovered through fatal accidents yet we all see those planes as safe. The MAX will be no different I suspect.

Bob24

kippy wrote: »

In the Lion Air crash, was the root cause a faulty "sensor" or how the plan handled a perfectly normal part of flight or how the pilots dealt with the plane dealing with a perfectly normal part of flight?

I am not sure how official all that is and take my understanding with a pinch of salt, but what I gather form the article I read is that a wrong sensor reading would have caused the plane to trigger an automated control system which caused the crash while the pilot was trying to fight it (I also read the pilot could technically have disabled the system when it started to malfunction but either didn’t know how to go it or didn’t have time to do it).

Budawanny

Bob24 wrote: »

I am not sure how official all that is and take my understanding with a pinch of salt, but what I gather form the article I read is that a wrong sensor reading would have caused the plane to trigger an automated control system which caused the crash while the pilot was trying to fight it (I also read the pilot could technically have disabled the system when it started to malfunction but either didn’t know how to go it or didn’t have time to do it).

Faulty AOA readings caused the MCAS system to repeatedly send nose down commands to the stabilisation fin at the back assuming that the AOA was approaching stall. The pilots repeatedly fought against this. until there final effort was not enough to affect the MCAS inputs.

At least one salient point from this is that I believe the MCAs system was taking input from only one AOA sensor. Logically I would expect dual input and if they disagree, disable the system, or preferentially , three inputs so you can identify which one is right or wrong.

It is possible to disable the system, by flipping a couple of switches, but you have to know what the problem is first , considering this was a new unannounced system, its perhaps understandable they didnt. The plane was at low altitude with a risk of terrain impact so they had a lot going on in the cabin also.

mickdw

But would they have done something as stupid as building such a safety critical system around a single sensor?
What happened to 2 or 3 levels of redundancy in aircraft systems?

Budawanny

mickdw wrote: »

But would they have done something as stupid as building such a safety critical system around a single sensor?
What happened to 2 or 3 levels of redundancy in aircraft systems?

they have multiple AOA sensors, but apparently this system gets triggered by one.

"This AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer"

more details here fwiw,
http://www.b737.org.uk/mcas.htm

Bob24

Budawanny wrote: »

Faulty AOA readings caused the MCAS system to repeatedly send nose down commands to the stabilisation fin at the back assuming that the AOA was approaching stall. The pilots repeatedly fought against this. until there final effort was not enough to affect the MCAS inputs.

At least one salient point from this is that I believe the MCAs system was taking input from only one AOA sensor. Logically I would expect dual input and if they disagree, disable the system, or preferentially , three inputs so you can identify which one is right or wrong.

It is possible to disable the system, by flipping a couple of switches, but you have to know what the problem is first , considering this was a new unannounced system, its perhaps understandable they didnt. The plane was at low altitude with a risk of terrain impact so they had a lot going on in the cabin also.

Thanks, although I had the gist of it, that’s a better way to explain it than I did :-)

Am I right that these nose down commands are an additional safety measure (when working as intended) which doesn’t exist on all airplanes, and that if working as intended they would only be required in rare scenarios whereby a pilot would be expected to know there is a problem and to be able to address it?

Where I am getting at is: if these are only used in rare cases and that a pilot would be able to handle that scenario without the automated commands, would it not make sense to disable this feature until everything is clarified knowing that it has currently probably taken more lives than it might have saved?

Nijmegen

Bob24 wrote: »

Thanks, although I had the gist of it, that’s a better way to explain it than I did :-)

Am I right that these nose down commands are an additional safety measure (when working as intended) which doesn’t exist on all airplanes, and that if working as intended they would only be required in rare scenarios whereby a pilot would be expected to know there is a problem and to be able to address it?

Where I am getting at is: if these are only used in rare cases and that a pilot would be able to handle that scenario without the automated commands, would it not make sense to disable this feature until everything is clarified knowing that it has currently probably taken more lives than it might have saved?

But the feature was a requirement for them to get common type rating with the previous 737. So if they disable it, you now have an aircraft that flies significantly different without the software making it feel like a NG and nobody is actually certified to fly it. Goes back to the nub of the entire issue really.

billie1b

Bob24 wrote: »

Thanks, although I had the gist of it, that’s a better way to explain it than I did :-)

Am I right that these nose down commands are an additional safety measure (when working as intended) which doesn’t exist on all airplanes, and that if working as intended they would only be required in rare scenarios whereby a pilot would be expected to know there is a problem and to be able to address it?

Where I am getting at is: if these are only used in rare cases and that a pilot would be able to handle that scenario without the automated commands, would it not make sense to disable this feature until everything is clarified knowing that it has currently probably taken more lives than it might have saved?

The Lion Air crash involved the MCAS system, the Ethiopian one nobody knows yet. In the case of the Lion Air Pre-Lim report, not confirmed, but before the crash there was an abnormal reading of a 20 degree difference in the AOA sensors before take-off, there is an optional package that airlines can purchase to inform the flight crew of the readings, a light in the flight deck that illuminates to say there is an abnormality with the sensors and allow the crew to run checks on the problem, Lion Air didn’t pay for the optional package and thus their crew of 610 took off without knowing there was a problem before they even got in the air.
In my opinion, these packages should come as standard and not be an optional extra when they are attached/part of such a critical component of the aircraft.

Nijmegen

In a very odd turn of events, it seems the US is throwing its weight around lobbying the Ethiopians to have the FDRs sent to the NTSB for inspection rather than, as planned by the Ethiopians, to the UK. From the article:

U.S. officials wanted to have the recorders sent to the National Transportation Safety Board on grounds that American government experts would provide the most reliable and accurate data downloads, according to the report. The U.S. hadn’t received a final decision as of late Tuesday, according to the Journal.

I would really question the notion that US government experts would be any more reliable at downloading the data than British ones. Doesn't smell right.

Budawanny

Bob24 wrote: »

Thanks, although I had the gist of it, that’s a better way to explain it than I did :-)

Am I right that these nose down commands are an additional safety measure (when working as intended) which doesn’t exist on all airplanes, and that if working as intended they would only be required in rare scenarios whereby a pilot would be expected to know there is a problem and to be able to address it?

Where I am getting at is: if these are only used in rare cases and that a pilot would be able to handle that scenario without the automated commands, would it not make sense to disable this feature until everything is clarified knowing that it has currently probably taken more lives than it might have saved?

Yeah you had it right, was more meant as an expansion rather than a correction.
The design of this plane has the engines moved forward which I believe causes an instability in that the plane pitches up in some circumstances.

the MCAS was brought in to alleviate this and effectively make its flight characteristics closer to that of the previous generation. I think it effectively has to have this system to be certified though, I might be wrong.

Budawanny

billie1b wrote: »

The Lion Air crash involved the MCAS system, the Ethiopian one nobody knows yet. In the case of the Lion Air Pre-Lim report, not confirmed, but before the crash there was an abnormal reading of a 20 degree difference in the AOA sensors before take-off, there is an optional package that airlines can purchase to inform the flight crew of the readings, a light in the flight deck that illuminates to say there is an abnormality with the sensors and allow the crew to run checks on the problem, Lion Air didn’t pay for the optional package and thus their crew of 610 took off without knowing there was a problem before they even got in the air.
In my opinion, these packages should come as standard and not be an optional extra when they are attached/part of such a critical component of the aircraft.

wow I hadn't heard that one before. effectively safety features as an add on package sounds bloody ludicrous!

cnocbui

Nijmegen wrote: »

In a very odd turn of events, it seems the US is throwing its weight around lobbying the Ethiopians to have the FDRs sent to the NTSB for inspection rather than, as planned by the Ethiopians, to the UK. From the article:



I would really question the notion that US government experts would be any more reliable at downloading the data than British ones. Doesn't smell right.

Apparently the US tried to persuade the Indonesians to hand over the Lion Air recorders to them also but they declined and downloaded the data in-house at their National Transportation Safety Committee (KNKT).

The US are collectively so far up themselves it beggars belief.

plodder

cnocbui wrote: »

Apparently the US tried to persuade the Indonesians to hand over the Lion Air recorders to them also but they declined and downloaded the data in-house at their National Transportation Safety Committee (KNKT).

The US are collectively so far up themselves it beggars belief.

It's hardly that surprising they would want to see the data first. Maybe they can claim better expertise in dealing with damaged recorders, but I would agree with sending them to an agency like the AAIB first in any case.

Roger_007

Boeing risks suffering irreparable reputational damage if it appears to gloss over something that it got wrong. The reason why aviation has become so safe is because, over the years, manufacturers have usually cooperated fully in the investigation of accidents and incidents and took responsibility for deficiencies.
Aviation safety is not an area where you can play politics and it seems that politics may be at play in decisions being made in the grounding or otherwise of the 737 MAXs.
I hope I'm wrong.

murphaph

Roger_007 wrote: »

Boeing risks suffering irreparable reputational damage if it appears to gloss over something that it got wrong. The reason why aviation has become so safe is because, over the years, manufacturers have usually cooperated fully in the investigation of accidents and incidents and took responsibility for deficiencies.
Aviation safety is not an area where you can play politics and it seems that politics may be at play in decisions being made in the grounding or otherwise of the 737 MAXs.
I hope I'm wrong.

Yeah it's concerning not just that Boeing may not be as forthcoming as one might hope but also that the FAA is still not really a neutral safety agency. It has this commercial role to promote aviation that must clash sometimes with their role as regulator.

I am much more comfortable with the recorders going to the AAIB.

plodder

murphaph wrote: »

Yeah it's concerning not just that Boeing may not be as forthcoming as one might hope but also that the FAA is still not really a neutral safety agency. It has this commercial role to promote aviation that must clash sometimes with their role as regulator.

I am much more comfortable with the recorders going to the AAIB.

I guess it would be the NTSB rather than the FAA investigating though.

murphaph

plodder wrote: »

I guess it would be the NTSB rather than the FAA investigating though.

Yeah but I'm not sure how deep Trump's rot has set in there either. It's just better if the AAIB downloads the data first. They can always ask for NTSB or Honeywell (or whoever makes them) help but can ensure the data is reliable.

Irish Steve

Sky news are now saying that a spokesman for Ethiopian has gone on record stating that the black boxes are being shipped to Europe for analysis.

Happy to see that, hopefully there will be some clarity soon, for the sake of all concerned.

Mebuntu

Budawanny wrote: »

It is possible to disable the system, by flipping a couple of switches, but you have to know what the problem is first , considering this was a new unannounced system, its perhaps understandable they didnt.

Yes, but I'd have thought that MAX pilots would have had a unique interest in the earlier high-profile Lion Air crash (and that aircraft's previous flight incident) and how it came about and would be on high alert after takeoff even without any input from Boeing. I find it difficult to believe that when it happened to them they were "wondering what might be wrong here ".

Reati

Mebuntu wrote: »

Yes, but I'd have thought that MAX pilots would have had a unique interest in the earlier high-profile Lion Air crash (and that aircraft's previous flight incident) and how it came about and would be on high alert after takeoff even without any input from Boeing. I find it difficult to believe that when it happened to them they were "wondering what might be wrong here ".

You can't understand what a persons thought train will be. It's easy from the comfort of a chair with hindsight to say "surely they know what was happening" but no one can know that. If they knew what it was and how to overcome it, they wouldn't have crashed.

cnocbui

jasper100 wrote: »

That's an extremely serious allegation right there, with nothing at all to support it.

Are you kidding? Boeing have been strenuously pushing the blame on Lion Air and the pilots since that accident happened.

However, Boeing pushed back, stating that standard operating procedures would have address the MCAS failure. Also, a Lion Air ground crew may have inadvertently tampered with the MCAS sensor on the doomed flight.

with Boeing hinting it thinks poor maintenance practices may be to blame for the crash and Lion Air pointing the finger at "design changes" and "anti-stall" features built into the plane's Maneuvering Characteristics Augmentation System (MCAS).

Rusdi Kirana, the co-founder of the Lion Air Group, is “furious” over Boeing’s attempts to deflect attention from the recent design changes and blame the airline for the crash.

Such blame has been put over the poor maintenance records from the carrier, suggesting that its aircraft are not very well looked after.
...
Boeing has said all information necessary to fly the 737 safely is available to pilots and that its workhorse model is safe.

Nijmegen

I guess it could be pretty simple arrogance (send it to us, because we trust ourselves most) but it does breed conspiracy theory. When China grounded the a/c it was "trade war", but by the time Australia, Europe, and many other countries had got round to it but it's still flying in North America; combined with Boeing's PR strategy post Lion; combined with the backgrounds of political appointees running many other agencies in the current US government; it just doesn't pass the smell test when it appears they're demanding to get first sniff at downloading the data. Nobody in their right mind can question the professionalism or competency of the UK AAIB.

The truth will out, no amount of aggressive PR will fix a fundamental flaw if one exists; and if it doesn't, then that will out too.

Quin_Dub

Trump speaks to Boeing CEO following tweets on airline technology

The officials did not share details of their conversation, but both confirmed the call to CNN. Later, a Boeing spokesman said Muilenburg "reiterated to the President our position that the MAX aircraft is safe."

Muahahaha

cnocbui wrote: »

I have stalled an aircraft many times - saying they fall out of the sky is melodramatic hyperbole. In a stall, the wings lose lift and so long as the plane isn't in a turn, the plane noses over sharply and enters a dive, which causes the airspeed to increase very rapidly - re-establishing lift over the wings and returning full control to the pilot allowing them to pull the nose up and to continue flying.

Thats very interesting. Can I ask when you say that in a dive the airspeed increases very rapidly how rapidly are we talking? Like if a plane was at 30,000ft how much atlitude would you expect to lose in the nose dive before it corrects itself? And in a stall/nose dive situation what would happen passengers without seatbelts, how do they experience it?

bryangiggsy

Norwegian to operate Dreamliner from Dublin following suspension of Boeing 737 MAX

cnocbui

Muahahaha wrote: »

Thats very interesting. Can I ask when you say that in a dive the airspeed increases very rapidly how rapidly are we talking? Like if a plane was at 30,000ft how much atlitude would you expect to lose in the nose dive before it corrects itself? And in a stall/nose dive situation what would happen passengers without seatbelts, how do they experience it?

I was flying gliders. After a stall, you would have enough airspeed to sustain level flight in as little as 4 seconds. Obviously a commercial passenger plane could be expected to take a bit longer to reestablish lift in the thin air at 9,500m, but this plumetting into the ground stuff is ridiculous.

Time to take a 737 up in X-Plane and suck it and see.

Hotblack Desiato

murphaph wrote: »

It has this commercial role to promote aviation that must clash sometimes with their role as regulator.

Quite. Many's the time the NTSB made safety recommendations which would have prevented future accidents, but the FAA didn't implement the recommendations.

plodder

Irish Steve wrote: »

Sky news are now saying that a spokesman for Ethiopian has gone on record stating that the black boxes are being shipped to Europe for analysis.

Happy to see that, hopefully there will be some clarity soon, for the sake of all concerned.

Does that mean I wonder that no data had been extracted by yesterday afternoon? There was speculation here that maybe some back channel was used to provide some information to other safety authorities already. If that's not the case, then I wonder what basis they had to ground the aircraft. There seems to be very little official data to actually go on at this point.

Muahahaha

cnocbui wrote: »

I was flying gliders. After a stall, you would have enough airspeed to sustain level flight in as little as 4 seconds. Obviously a commercial passenger plane could be expected to take a bit longer to reestablish lift in the thin air at 9,500m, but this plumetting into the ground stuff is ridiculous.

Time to take a 737 up in X-Plane and suck it and see.

So if a passenger jet stalled and goes into a nose dive for are you looking at bodies going flying through the cabin?

cnocbui

plodder wrote: »

Does that mean I wonder that no data had been extracted by yesterday afternoon? There was speculation here that maybe some back channel was used to provide some information to other safety authorities already. If that's not the case, then I wonder what basis they had to ground the aircraft. There seems to be very little official data to actually go on at this point.

When the media reported the Germanwings Flight 9525 black boxes had been found and recovered, the black boxes had actually been found many hours previously and had been taken to somewhere in France and the data had already been recovered at the time the media were reporting the recorders had just been found.

I speculated that the Ethiopian Air black boxes had already had their data downloaded and been made known as it would explain the actions of multiple countries taking such prompt action, due to the known lag between the media being told things and them actually happening.

cnocbui

Muahahaha wrote: »

So if a passenger jet stalled and goes into a nose dive for are you looking at bodies going flying through the cabin?

Very probably, if they weren't in their seats and belted in, but that shouldn't be an issue for a plane still climbing to cruising altitude with the seatbelt light still on. In order to get a plane to stall, dramatically from level flight, you would first have to pitch the nose up quite significantly, and for a while, in order to get it to bleed off airspeed enough to initiate a stall and passengers might find themselves shifting in the cabin due to that, before the nose down bit.

Mebuntu

Reati wrote: »

You can't understand what a persons thought train will be. It's easy from the comfort of a chair with hindsight to say "surely they know what was happening" but no one can know that. If they knew what it was and how to overcome it, they wouldn't have crashed.

I'd agree with you under normal circumstances but if the exact same thing is happening on your MAX as that which you know happened to Lion Air fairly recently and brought it down would you not recognise it as such. Of course, maybe they didn't know about Lion Air or MCAS or maybe the exact same thing didn't happen. We shall see.

plodder

Grounded by Canada now.

Limpy

Nikki Haley is on the boeing board. No doubt she has huge influence in the government and is a senator.

I'm sure they will be funding her future presidential campaign too.

There is some much overlap between state departments and private companies. Politics are always at play.

murphaph

plodder wrote: »

Grounded by Canada now.

Apparently they got "some new information this morning" which influenced their decision.

The FAA position looks very odd now. I suspect Canadian firms are big suppliers to Boeing given the geographic proximity.

Tenger

I would agree. Canada and Russia were the only 2 non-US countries not issuing a grounding as of late last night.
So the FAA are the sole holdout with approx 58 jets active between 2 US airlines.


Interesting article on how we ended up in this position:
https://theaircurrent.com/aviation-safety/the-world-pulls-the-andon-cord-on-the-737-max/

The B737MAX is a 50+ year old design, a marvelous design but one that’s been upgraded and enlarged well beyond its first form. Meanwhile the A320 is only at its mature stage (1st flight 1987)
I feel the A320neo is almost akin to the B737NG in terms of development cycle.

murphaph

You'd need your head examined to board one of these remaining flying Max's. If there is a flaw that brought two of them down within months then you have a pretty good chance of it happening to you.

Hard to believe the unions at the remaining airlines aren't pushing for voluntary grounding though. Any word on that?

Tenger

Posted earlier in the thread that American Airlines flight crew were raising objections.

murphaph

Spiegel Online reports that the FDRs will be sent to Germany. Strange that there is so much confusion about this.

circular flexing

murphaph wrote: »

You'd need your head examined to board one of these remaining flying Max's. If there is a flaw that brought two of them down within months then you have a pretty good chance of it happening to you.

Hard to believe the unions at the remaining airlines aren't pushing for voluntary grounding though. Any word on that?

Don't forget the Concorde flew with a known serious design flaw for years and this flaw eventually led to a serious crash. At the end of the day airlines and manufacturers are bean counters who do put a value on a human life and make decisions based on that.

I was due to fly 737 MAX 8 later on today from Canada, plane has since been swapped for a 777.