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mm320cap
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 4:25 am

WIederling wrote:
mm320cap wrote:
The technology in the MAX is a real boon to safety. There is clearly something happening software integration wise, but the airplane has an huge amount of information to give the pilot SA.


you are talking about sugar coating.

At issue here is the basic airframe and how the designers coped with a major change in raw airframe behavior.
MCAS was not added for pilots feeling cosy and at home
it was added because the changed raw pitch up behavior is not certifiable.


They will figure this thing out and get it corrected. Just like they did with the rudder hard over in the Classic. I’ve flown the 737-200,300,500,700,800,900,900ER, and 9MAX. The new technology categorically makes the airplane safer from a pilots perspective. It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 4:51 am

VS11 wrote:
RickNRoll wrote:
VS11 wrote:

For the Lion Air crash, I don’t think the legal action is going to go far. Probably, it will end in out of court settlement. The rule of thumb is pilots follow manufacturers manuals and procedures, which is if you suspect problems with the trim, you disable it . That’s what the prior-flights pilots did. Boeing’s argument is solid in this case.

We don’t know what happened with the ET flight. It could be a different case or it could be that M.C.A.S. turned itself on during taxi or take-off roll or right after take off.
According to that article, the MCAS was not a trained trim problem, which was continuous trimming. That threw the pilots off. MCAS was not documented. MCAS was not tested properly.

Sent from my Nokia 6.1 using Tapatalk


But if two crews from the same company, presented with the same problem on the same aircraft in sequential flights had different response and outcomes then it is the crew actions at the core of it because everything else was the same. M.C.A.S. could have been perfectly designed and there could still happen an emergency involving trim. You have to apply emergency procedures even if you have perfectly designed systems.


Not really. For all we know the first crew could have been in the 1% that could deal with it at that time.

Given that both airlines have flown the predecessor of this plane without problem, and then the Max enters service and suddenly two crash for, likely, similar causes, I'm inclined to look more to the plane than the pilots...
 
weekendppl
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 4:58 am

mm320cap wrote:
But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.

And when people use the 737 Max MCAS as the example of "too complex to fly" they clearly don't understand the relative complexity of the 737 Max, with or without MCAS, compared to virtually every other large transport besides the 737NG (A32X, A330, A340, A350, A380, B748, B767, B777, B787), in production today. Perversely, if the B737 Max were a lot more complex, e.g., FBW, it probably would have had a much more elegant, and integrated, solution to the nacelle aerodynamics characteristics than MCAS.
 
flybucky
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 5:47 am

Contrary to the Ethiopian Transport Ministry spokesman's earlier statements that said U.S. teams had already validated the black box data, that has not occurred yet. However, NTSB and FAA are expected to assist in verification and validation of the data soon.

Earlier on Sunday, a spokesman for the Ethiopian Transport Ministry said the data from the black boxes was successfully recovered and teams from the United States and Ethiopia had validated it.

U.S. officials have not yet validated data from the black boxes of an Ethiopian Airlines plane that crashed killing all 157 people on board, emphasizing the investigation remains in the very early stages, two officials briefed on the matter told Reuters Sunday.

The officials said after investigators reviewing black box data return to Addis Ababa and start conducting interpretive work, the NTSB and FAA will assist in verification and validation of the data, the officials said.

https://www.reuters.com/article/us-ethi ... SKCN1QY0WD
 
ciaran
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 6:10 am

I recall reading Michael Crichtons "Airframe" novel on holiday a few years ago, I also remember sending the book airborne out the window on the conclusions in the last pages, I would think with the 737 Max 8 program there is more than enough material for a much better sequel, the CEO who cleared 30million with perks and commission, the independent regulatory body signing off on a dud, the pilots taking a battering in the press, the resultant fallout with the Airline in question sending the Boxs to a more trusted independent authority, and the plane makers investigators being escorted around the crash site with security guards in tow. I reckon it would be on the NYT best sellers list. Only it would not be a Novel!!!!
 
Pluto707
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 6:50 am

On CNN... the new software is almost there, and then ? The MAX is OK let s forget about this issue ? Anyway i'll never trust this bad design of non fitting engines corrected with a patch, and i think many persons will have this thought, sorry B....
 
lowbank
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 6:58 am

dragon6172 wrote:
Backseater wrote:
Fine. But if the condition that triggered MCAS (probably exceeding AoA threshold as a function of Mach nr) disappears due to pilot input but reappears a moment later. Does MCAS starts as if nothing happened before?

Yes.
lowbank wrote:
No what it says is if it trims 1 degree and the pilot resets it will then enact another 2.5 degrees, if reset again it will enact another 2.5 degrees. From what I read the trim can only go to 5 degrees total but MCAS will move to the total 5 degrees.

Negative. MCAS will stop inputs if the AoA is reduced below threshold.
spacecadet wrote:
That's an extremely dumb system if that's the way it works, in more ways than one. I have a hard time believing it does work that way, because a) you'd have to be an outright idiot to not see how that wouldn't have potentially catastrophic safety implications, and b) simply rechecking the data a few times a second to stop trimming where it needs to instead of the full 2.5 degrees would be a trivial addition to the programming. Essentially this would be like having an auto-pilot that's designed to just pitch up the plane 2.5 degrees every time it's engaged, regardless of the current attitude. Makes no sense.

It doesnt work that way. If it detects the aircraft has gone below whichever threshold, it will stop making inputs. It does not go the full 2.5 degrees each time. See below quote.


"The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation."


You say negative, what I took from that article was, if the MCAS gets erroneous data it the start to trim the aircraft, if it’s got to 1 degree and pilot hits reset. If it’s still getting erroneous data it can then trim a further 2.5 degrees. If he hits reset again and MCAS is still receiving erroneous data it can continue to full extent of travel. That what I took from the article, maybe incorrectly. As you say when things are working correctly it would stop trimming the aircraft if the data is correct. But looks like in these two crashes it wasn’t correct data.
Every days a school day.
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 7:08 am

It is sadly, also now very obvious, and perfectly understandable, why Ethiopia wanted to send the recorders to anyone but the US. Their behaviour after Lionair was abysmal, and it now appears they were behaving like a school child who knows they did something wrong and desperately tries to blame someone else. Who could trust these guys anymore? Heads should roll. But corporate management are very good at looking after one another...
 
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 7:14 am

lowbank wrote:
dragon6172 wrote:
Backseater wrote:
Fine. But if the condition that triggered MCAS (probably exceeding AoA threshold as a function of Mach nr) disappears due to pilot input but reappears a moment later. Does MCAS starts as if nothing happened before?

Yes.
lowbank wrote:
No what it says is if it trims 1 degree and the pilot resets it will then enact another 2.5 degrees, if reset again it will enact another 2.5 degrees. From what I read the trim can only go to 5 degrees total but MCAS will move to the total 5 degrees.

Negative. MCAS will stop inputs if the AoA is reduced below threshold.
spacecadet wrote:
That's an extremely dumb system if that's the way it works, in more ways than one. I have a hard time believing it does work that way, because a) you'd have to be an outright idiot to not see how that wouldn't have potentially catastrophic safety implications, and b) simply rechecking the data a few times a second to stop trimming where it needs to instead of the full 2.5 degrees would be a trivial addition to the programming. Essentially this would be like having an auto-pilot that's designed to just pitch up the plane 2.5 degrees every time it's engaged, regardless of the current attitude. Makes no sense.

It doesnt work that way. If it detects the aircraft has gone below whichever threshold, it will stop making inputs. It does not go the full 2.5 degrees each time. See below quote.


"The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation."


You say negative, what I took from that article was, if the MCAS gets erroneous data it the start to trim the aircraft, if it’s got to 1 degree and pilot hits reset. If it’s still getting erroneous data it can then trim a further 2.5 degrees. If he hits reset again and MCAS is still receiving erroneous data it can continue to full extent of travel. That what I took from the article, maybe incorrectly. As you say when things are working correctly it would stop trimming the aircraft if the data is correct. But looks like in these two crashes it wasn’t correct data.


Yes, in the Lion Air crash MCAS trimmed down 10 seconds 20 times or so every 5 seconds (as the AoA reading was faulty, indicating too high AoA all the time), and each time the captain counteracted the trim. Then he passed the control to the FO, and apparently he didn't realize to counteract the trim. In the proposed fix, the MCAS would trim down only once. It is unclear if there would be some other mechanism that would "reset" the MCAS.
 
rheinwaldner
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 7:16 am

LDRA wrote:
It is really only an aircraft pitch handling quality requirement. Without MCAS, the aircraft is little bit hard to handle at high AoA, but never out of control.

In fact, "abnormal nose-up pitching" is subject to interpretation.

The information we have is:
"That limit was later increased after flight tests showed that a more powerful movement of the tail was required to avert a high-speed stall, when the plane is in danger of losing lift and spiraling down."

MCAS clearly exists to avoid loss of control. Just "remove MCAS" and do "more training" will not be sufficient to cope with the changed aerodynamics of the MAX.

Backseater wrote:
The function is reset but not the stab trim. Everytime the stab trim is increased to push the nose down, isn’t the pilot going to have to increase the AoA to achieve his intended climb rate? In which case, MCAS is likely to exceed its current threshold even earlier than before?

No,
1. because the AoA to establish a certain climb rate is always the same (as long as the speed stays constant).
2. in these crashes, the measured AoA was wrong, so while normally the reaction of the aircraft on the MCAS input causes MCAS to stop, in these cases the conditions persisted until everybody was dead.
Many things are difficult, all things are possible!
 
Pluto707
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 7:30 am

Retrofitting the 40yrs old 737 was a B-blunder, they should now burry the 737 and go on with a new one : 797 ?? I saw this text on wikipedia: The new aircraft, likely to be known as the Boeing 797, would be available in two versions: a 225-seater with 5,000 nmi (9,300 km) range ...
 
Zeppi
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 7:55 am

I've read the whole discussion since the desaster unfolded and decided not to chime in until we have some solid FDR and CVR data available, but now that things have already calmed a little and since I've had somewhat of an eye opening experience yesterday I'll do so now. Longer post coming up, apologies in advance.

mm320cap wrote:
The new technology categorically makes the airplane safer from a pilots perspective. It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.

Indeed, but IMHO exatly that is a two edged sword. It's great that modern aircraft have all sorts of electronic safeguards, assistant and deep reaching automation to help the crew reduce workload, handle difficult conditions etc. But what if (all of) those fail and fully manual hands on flying becomes the task du jour?

Getting to my "eye opening experience" from yesterday mentioned above. I'm an instrument rated PPL holder, just shy of 1200H TT in 10 years. The most performant aircraft I fly are the Lancair Evo and the Citation M2, both mostly single hand. Both quite fast and nimble little beasts that will punish you if you don't stay well ahead of them at all times, yet extremely fun to fly.
Yesterday, lovely sunny sunday morning, perfect time for an Evo joyride to LOWZ. At the airfeld I meet a buddy who's captain on the B77F with over 18k hours TT, he decides to come along as his wife intended to go to a tea party he didn't fancy too much to be polite :rotfl:
We brief the weather, föhn conditions (the powerful southerly katabatic winds) across most of the northern alps, so we're prepped for a bit of a rollercoaster experience. When I'm on my own joyriding I usually handfly all the time unless I hit IMC to enjoy the scenery, yesterday we enganged the AP for having some chitchat until reaching the mountains. Well before reaching the first ridges we enounter the first mountain waves, climb to FL140 where it's still a little calmer. Reaching top of descent I disengange the AP and my buddy starts setting us up for the approach, below FL100 it starts to get interesting, we are thrown around like a leaf in the wind and I can clearly see my buddy has trouble staying in the approach pattern. Serious work with both hands and feet is required at this point. I take over at 2000AGL, on short final it's so violent that I eventually decide to go around, my buddy already looks pale white in the face. Second approach works out fine, less random crosswinds and we grease it (well not really ;) ).

Having some coffee and cake on the terrace in the sun we watch plenty of other incoming AC battle the winds, go around, try again... While chatting we are joined by a few others, talk about the weather and handflying in those conditions. The locals mind you are saying "oh it's fine today, great vis, a little choppy, no biggie" all whilst some colour is slowly returning to my buddies face. Eventually the conversation topic reaches the 737MAX and also touches AF447, we mostly agreed that airline pilots nowadays are really just sitting there pushing a few buttons and watching it go. So while they may have thousands upon thousands of hours in their logbook, a very tiny share of that is actual flying. Doesn't matter most of the time, but when the shit hits the fan, the automated systems fail or let alone they go in zombie mode like with the 737MAX, the crews seem to be totally overwhelmed by the situation. What say you?
 
mjoelnir
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 8:07 am

People seem to be rather sure that MCAS is the culprit, or pilot error regarding not switching the electrical trim system off. But as I understand it, the pilots did run into trouble right after takeoff. Trouble with handling of the frame, unreliable airspeed and so on. Directly after take off there should be still flaps engaged, so theoretically no MCAS. I believe there could be something else going wrong, or perhaps MCAS engaging when it should not.
 
WIederling
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 8:11 am

mm320cap wrote:
It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.


I think this is a terrible statement.

The crash was premeditated murder.
It was not about uncovering hidden issues.
The crashes happened because a massive issue has been covered up, carefully hidden from view.
Think about it: when embedding the cert authority does not deliver enough advantage and easement!
Murphy is an optimist
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 8:30 am

Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.
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airplaneboy
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 8:44 am

Here’s a different view of the situation, it’s worth the read.

https://www.zerohedge.com/news/2019-03- ... e-engineer
 
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Finn350
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:04 am

scbriml wrote:
Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.


They probably have communicated the new limit as part of the final certificaiton, but buried in thousands of pages of technical documentation. I don't see how they could not disclose that kind of information in technical documentation.
 
Tristarsteve
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:15 am

seat64k wrote:
remcor wrote:
Whoa, I havent heard this before, that Boeing sells the Max with an option package to have 3 AOA sensors and software to recognize disagreement. The two crash airplanes don’t have this option. Smells like mandatory retrofits may be coming

https://twitter.com/trevorsumner/status/1106934415610073091?s=21


Any way to know which airlines have this option, and which ones don't?

Easy. No Airlines have the option because it does not exist.
 
Hannah25
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:21 am

Sky news also just pinged breaking news on the ‘Clear Similarity’ story.
 
SuperGT
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:28 am

I’m absolutely astounded by this optional extra pack : extra AoA sensors! (Which would massively resolve a single point of failure).

What’s next? Better flaps optional extra to allow for landing on shorter runways? Extra wheel for landing in case some fail?

My word. Eyes opened on this thread.
 
rideforever
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:40 am

SuperGT wrote:
I’m absolutely astounded by this optional extra pack : extra AoA sensors! (Which would massively resolve a single point of failure).

Yeah, how much is the optional extras ?
Surely any software fix will include multiple AoA sensors, no-restarting on the trim down, pilot screen with AoA telemetry, sanity check with other instruments.
 
ambanmba
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:44 am

SuperGT wrote:
What’s next? Better flaps optional extra to allow for landing on shorter runways?


Yup... that's an option:

https://boeing.mediaroom.com/2006-07-31 ... age-to-GOL
https://www.flightglobal.com/news/artic ... rs-205862/

For a photo of it, refer to slide 86 here: https://www.slideshare.net/theoryce/b73 ... t-controls
Concorde 300/10/19/20/21/30/40/80 707/17/27/37/47/57/67/77/87 AT7 146 CRJ DC3/9/10 DHC8 F100 L1011 MD11/80 S340 T154M Y7C
 
wjcandee
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:51 am

Until the BEA (or NTSB) says it, I am absolutely not taking on faith the Ethiopians' assertions about this. These are the same folks who still believe their cluster with the -800 was an explosive device. Or I shouldn't say "believe" it, I should say "asset" it. They're racing to paint themselves as victims and get out in front of the story.

I think we're gonna find that this wasn't MCAS. If it was, it's a massive malfunction because with flaps out and autopilot likely engaged, MCAS should have been inhibited.

It's not to say that there wasn't some other massive malfunction with the aircraft -- there well could have been. But the idea that this was MCAS in "normal" erroneous operation (i.e. runaway stab trim) still seems very remote to me.
 
Aviation737
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 9:56 am

scbriml wrote:
Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.

But isn't it still their duty? I mean yes you can blame the FAA all you want, but it is EASA's responsibility to ensure that the 737 MAX is safe to fly over European airspace, not the FAA. To me the EASA has as much blame as the FAA if the MCAS is indeed the cause of the crash. I mean isn't it obvious that something will go wrong if the MCAS only receives one input from the AOA sensor? You don't need real planes to figure that out.
 
flybucky
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:12 am

mjoelnir wrote:
People seem to be rather sure that MCAS is the culprit, or pilot error regarding not switching the electrical trim system off. But as I understand it, the pilots did run into trouble right after takeoff. Trouble with handling of the frame, unreliable airspeed and so on. Directly after take off there should be still flaps engaged, so theoretically no MCAS. I believe there could be something else going wrong, or perhaps MCAS engaging when it should not.

Until we get FDR data, it's all speculation. But in JT610, the pilots retracted the flaps about 70 seconds after airborne, and then MCAS kicked in and they immediately started losing altitude. They may have retracted the flaps due to confusion over the constant stick shaker since airborne.

For ET320, they first started losing altitude about 70 seconds after when I believe they became airborne (at the first spike of vertical speed, 50s after takeoff roll). It is possible that they got stick shaker from the beginning, and retracted the flaps early, which allowed MCAS to activate. This will be clear after we see FDR data.
 
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AirlineCritic
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:22 am

There's a lot of discussion of the evidence of what actually happened, and the need to figure out in detail what happened, as we really don't have more than a tiny fraction of the data yet.

All of that is obviously necessary. However, I want to point out that:

1/ grounding can happen when there's a suspicion even before lack of proof; abundance of caution

2/ an investigation will follow, and they will carefully go through the *entire* situation and associated systems, training, maintenance and other aspects

3/ that investigation will reveal the causes of the accident, which in most modern times have been compound issues, e.g., equipment and pilots or maintenance

4/ but that investigation will also reveal issues that when looking carefully at something, we realise something is not right or can be improved

5/ the positive outcome of an investigation is that it will not merely point out the specific cause (e.g., pilots or equipment) but also identify what actions can help prevent both the specific cause and the other identified issues from causing accidents in the future

In other words, even if the accident would be caused by system S1 and pilots P, it is likely that the industry will need to to improve systems S1, S2, S3, .... in addition to pilot training and maintenance procedures.

And that's a good thing.

(But should perhaps reduce the need in this thread to select a single root cause or guilty party. Even if there's some blame to be shared. )
 
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:24 am

Aviation737 wrote:
scbriml wrote:
Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.

But isn't it still their duty? I mean yes you can blame the FAA all you want, but it is EASA's responsibility to ensure that the 737 MAX is safe to fly over European airspace, not the FAA. To me the EASA has as much blame as the FAA if the MCAS is indeed the cause of the crash. I mean isn't it obvious that something will go wrong if the MCAS only receives one input from the AOA sensor? You don't need real planes to figure that out.


I didn't blame or absolve anyone of responsibility. Blame shouldn't be the aim of the exercise here (but may happen much later in court).

Allowing the 'logic' of MCAS to be certified in its current state is a collective failure of the certifying authorities, of which the FAA was the lead. Boeing's documentation not accurately reflecting the current state of play with respect to MCAS trim limits is beyond poor.

This should be a major wake-up call for the global aviation certification authorities. The days of simply rubber-stamping each other's certifications may have just ended.
Time flies like an arrow. Fruit flies like a banana!
There are 10 types of people in the World - those that understand binary and those that don't.
 
XRAYretired
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:32 am

Aviation737 wrote:
scbriml wrote:
Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.

But isn't it still their duty? I mean yes you can blame the FAA all you want, but it is EASA's responsibility to ensure that the 737 MAX is safe to fly over European airspace, not the FAA. To me the EASA has as much blame as the FAA if the MCAS is indeed the cause of the crash. I mean isn't it obvious that something will go wrong if the MCAS only receives one input from the AOA sensor? You don't need real planes to figure that out.



Abysmal and sad.

EASA are to blame for not catching Boeing and FAA in a lie? Lets see who is defending against liability and potentially criminal negligence in court. It wont be EASA.

350 real people have died in terrible circumstances, thousands more will be struggling with the horror of their loss. Those responsible must be held to account.
 
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teme82
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:33 am

scbriml wrote:
I didn't blame or absolve anyone of responsibility. Blame shouldn't be the aim of the exercise here (but may happen much later in court).

Allowing the 'logic' of MCAS to be certified in its current state is a collective failure of the certifying authorities, of which the FAA was the lead. Boeing's documentation not accurately reflecting the current state of play with respect to MCAS trim limits is beyond poor.

This should be a major wake-up call for the global aviation certification authorities. The days of simply rubber-stamping each other's certifications may have just ended.


Yeah and I think the DOT needs to take a really good and deep look of the relations of the FAA and Boeing. Specially if this article has any truth in it. Link : https://www.bloomberg.com/news/articles ... ium-europe
Flying high and low
 
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flyingturtle
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:35 am

weekendppl wrote:
flyingturtle wrote:
Nuke Boeing from orbit. It's the only way to be safe.

The hyperbole about this is getting a little much.

...

But to think that somehow the world would be better off to give Boeing the death penalty over it, or abandon wholesale the present system for regulation and compliance certification over it, is just silly.


Of course Ripley's line from "Aliens" is over the top, but well: Giving companies leeway to oversee their own safety critical products is just bonkers. Your company does it, then the company doesn't deserve to exist. A young lawyer, freshly graduated from a community college, could have saved more than 300 lives by simply asking: "Should we give the FAA the actual specs of that MCAS thing? And is it redundant enough, given its classification?"

Part of a professional attitude it recognizing the conflicts of interest, and always be sure of what your goal is. A safe plane? Or trying to beat the 320 NEO?


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

Mon Mar 18, 2019 10:40 am

WIederling wrote:
mm320cap wrote:
It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.


I think this is a terrible statement.

The crash was premeditated murder.
It was not about uncovering hidden issues.
The crashes happened because a massive issue has been covered up, carefully hidden from view.
Think about it: when embedding the cert authority does not deliver enough advantage and easement!


well
i would not see that pushed to far

but it seems that BA and the FAA have been knowing the problem since the publishing of the lion air FDR data
that have been months of time

the AD after the lion air crash was simply a try of safeguarding the regulator
nice try btw ...

and it was surrounded by statements of a lot of US crews and US officials stating that this is NOT a serious thing
the main problem has been told should be the third world crew and third world mantainance (..." this will not happen to a US crew ...")

so a lot of fake news to let the affected think this whole case is insignificant
if u ask me i think its pure coincidence that the second disaster happend in africa and not in europe or the US


some would think BA learned their lesson now
but it seems like they try to get away with a software fix

thats unbelievable from my point of view
the problem is that the 737 with the big engines is instable in flight
its completely insignificant that this is certificable - if you measure it with the margines of 1960 ..

this is a 2017 aircraft design and its really beyond my understanding how the other regulator worldwide accept(ed) this bird in their airspace
 
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BoeingVista
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 10:47 am

scbriml wrote:
Aviation737 wrote:
What I don't get is why didn't the other countries aviation authorities spot the problem also? Since it is their duty to certify whether the 737 MAX is safe to fly over their airspace. Did all of the aviation authorities miss out the MCAS issue?


Probably not helped by understanding that MCAS would only trim down 0.6deg per Boeing paperwork while Boeing had changed that to 2.5deg during flight testing but hadn't updated documentation?

It's not like EASA or others are given real planes to test.


Doesn't this change also point to Boeing uncovering an unexpected and unpleasant flight characteristic during fight testing? i.e major unexpected nose up moment and inability to control it as predicted.
BV
 
XRAYretired
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 11:27 am

airplaneboy wrote:
Here’s a different view of the situation, it’s worth the read.

https://www.zerohedge.com/news/2019-03- ... e-engineer


This is how most SW engineers see the world and is very often true. I would be surprised if the SW implementation did not fully comply with the requirements it was set. Its the system design/concept that would appear to be a pig in a poke.

Ray
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 11:45 am

lowbank wrote:
You say negative, what I took from that article was, if the MCAS gets erroneous data it the start to trim the aircraft, if it’s got to 1 degree and pilot hits reset. If it’s still getting erroneous data it can then trim a further 2.5 degrees. If he hits reset again and MCAS is still receiving erroneous data it can continue to full extent of travel. That what I took from the article, maybe incorrectly. As you say when things are working correctly it would stop trimming the aircraft if the data is correct. But looks like in these two crashes it wasn’t correct data.


You're right about how it acts with erroneous data. But that isn't what I was talking about. This whole back and forth started with me saying:

dragon6172 wrote:
My guess is that in an actual near stall event it wouldn't move the stab the full 2.5 degrees. It's only going to trim down enough to reduce the AoA below whatever threshold and then it stops.


Maybe I should have been more clear that I was talking about all systems operating normally.

hivue wrote:
Hypothetical example: MCAS gets activated by a faulty AoA sensor. It trims down the max 2.5 deg. The pilot backs that out 2 degrees. Now 0.5 deg nose down trim. MCAS kicks in again with another 2.5. Now 3.0 deg nose down trim. The pilot backs out 1.5 deg. Now 2 deg nose down trim. You probably can see where this is leading.


Absolutely I can see where it is heading. The pilot is not properly trimming the aircraft in response to the uncommanded trim inputs by MCAS, resulting in a crash. If a pilot trims the aircraft as needed then the aircraft could really fly along forever. Both sides of this scenario are seen in the Lion Air crash. The PIC flys along for 6-7 minutes, properly trimming the aircraft to counter the erroneous MCAS inputs 20+ times (MCAS trims ~2.5 down, pilot trims ~2.5 up). Then when the controls are transferred to SIC, there is little to no trimming of the aircraft from the cockpit, and the aircraft nose dives into the ocean. This is absolutely one of the holes in the swiss cheese model, and shouldn't be ignored.

Finn350 wrote:
Yes, in the Lion Air crash MCAS trimmed down 10 seconds 20 times or so every 5 seconds (as the AoA reading was faulty, indicating too high AoA all the time), and each time the captain counteracted the trim. Then he passed the control to the FO, and apparently he didn't realize to counteract the trim. In the proposed fix, the MCAS would trim down only once. It is unclear if there would be some other mechanism that would "reset" the MCAS.

My guess is that the software fix that will limit MCAS trim down inputs to "once" will only be in effect if there is NO pilot input to counter the trim. In other words... the software fix wont allow MCAS to trim down its full amount (2.5 degrees now), pause, and then begin further trim down inputs.

However, I would think that if there is pilot trim input after the MCAS input, there will be further MCAS inputs. This makes sense, because in a scenario with all systems operating as normal you do not want the pilots to trim the aircraft back to the threshold that caused the MCAS inputs to begin with. In other words, you do not want to offer the stall protection on only the first time the high AoA is reached. So in this scenario MCAS detects high AoA and trims down, pilot responds with trim up, MCAS responds with trim down after a delay, just like now.
Phrogs Phorever
 
RickNRoll
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 12:00 pm

The whole point of it is to manage a near stall condition by altering the control feel for the pilot. If it stopped as soon as he reacted then it wouldn't be able to do that. It will always do the 2.5 or 0.6 degrees no matter what.
 
planecane
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 12:30 pm

mjoelnir wrote:
People seem to be rather sure that MCAS is the culprit, or pilot error regarding not switching the electrical trim system off. But as I understand it, the pilots did run into trouble right after takeoff. Trouble with handling of the frame, unreliable airspeed and so on. Directly after take off there should be still flaps engaged, so theoretically no MCAS. I believe there could be something else going wrong, or perhaps MCAS engaging when it should not.

This is the key that I want to know more about. If the ET crash was MCAS related as is being strongly insinuated, why was it active so early?

Unless the reports of when they started having trouble were erroneous, MCAS shouldn't have been activated due to flaps extended.

Last week, I flew a 737-800 on Southwest from BWI to FLL on a cool evening with only 85 people on board. I timed from wheels up to full flap retraction and it was 54 seconds. I would assume with the heavier load and hotter temps and higher elevation, the ET flight would have had flaps extended at least that long.

If they were having trouble controlling the aircraft from takeoff, there was either another issue as well or MCAS activated in a configuration that it wasn't supposed to. If that's the case, there is a bigger problem than just relying on a single sensor for a system that can trim full nose down.
 
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SheikhDjibouti
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 12:51 pm

Zeppi wrote:
Yesterday, lovely sunny sunday morning, perfect time for an Evo joyride to LOWZ. At the airfeld I meet a buddy who's captain on the B77F with over 18k hours TT, he decides to come along as his wife intended to go to a tea party he didn't fancy too much to be polite :rotfl:

..

Eventually the conversation topic reaches the 737MAX and also touches AF447, we mostly agreed that airline pilots nowadays are really just sitting there pushing a few buttons and watching it go. So while they may have thousands upon thousands of hours in their logbook, a very tiny share of that is actual flying. Doesn't matter most of the time, but when the shit hits the fan, the automated systems fail or let alone they go in zombie mode like with the 737MAX, the crews seem to be totally overwhelmed by the situation. What say you?

That was a lovely story, which I much enjoyed.
However, at the end of the day it was just one 77F pilot, and as much as anything maybe he hasn't messed around in small stuff too much in recent years.

Your question is valid, and there are plenty of high hours pilots on these forums who would chide you for even suggesting such a thing.
Don't hold your breath too long waiting for an unbiased answer.

Once again, thanks for the entertaining story. :bigthumbsup:

November X-ray Alpha? ;)
Nothing to see here; move along please.
 
kalvado
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 12:58 pm

mm320cap wrote:
WIederling wrote:
mm320cap wrote:
The technology in the MAX is a real boon to safety. There is clearly something happening software integration wise, but the airplane has an huge amount of information to give the pilot SA.


you are talking about sugar coating.

At issue here is the basic airframe and how the designers coped with a major change in raw airframe behavior.
MCAS was not added for pilots feeling cosy and at home
it was added because the changed raw pitch up behavior is not certifiable.


They will figure this thing out and get it corrected. Just like they did with the rudder hard over in the Classic. I’ve flown the 737-200,300,500,700,800,900,900ER, and 9MAX. The new technology categorically makes the airplane safer from a pilots perspective. It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.


Question is how deep are the problems, is it an isolated issue or a tip of an iceberg. The way it starts to sound, things may be much worse than just single omission with pre-stall handling.
Challenger space shuttle investigation is a great example of such systemic issues, where one guy basically plowed through all the shit and forced NASA to do things right. Unfortunately, the final result was not cost effective...
 
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InsideMan
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 1:10 pm

Pluto707 wrote:
On CNN... the new software is almost there, and then ? The MAX is OK let s forget about this issue ? Anyway i'll never trust this bad design of non fitting engines corrected with a patch, and i think many persons will have this thought, sorry B....


Exactly. The 737MAX is a flawed design. Boeing's laziness for a clean sheet to counter the A320 neo resulted in a bad situation regarding the COG. You can perfect MCAS and when and how it works, the problem remains in the design. I'll avoid the 737MAX wherever I can.
 
XRAYretired
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 1:21 pm

planecane wrote:
mjoelnir wrote:
People seem to be rather sure that MCAS is the culprit, or pilot error regarding not switching the electrical trim system off. But as I understand it, the pilots did run into trouble right after takeoff. Trouble with handling of the frame, unreliable airspeed and so on. Directly after take off there should be still flaps engaged, so theoretically no MCAS. I believe there could be something else going wrong, or perhaps MCAS engaging when it should not.

This is the key that I want to know more about. If the ET crash was MCAS related as is being strongly insinuated, why was it active so early?

Unless the reports of when they started having trouble were erroneous, MCAS shouldn't have been activated due to flaps extended.

Last week, I flew a 737-800 on Southwest from BWI to FLL on a cool evening with only 85 people on board. I timed from wheels up to full flap retraction and it was 54 seconds. I would assume with the heavier load and hotter temps and higher elevation, the ET flight would have had flaps extended at least that long.

If they were having trouble controlling the aircraft from takeoff, there was either another issue as well or MCAS activated in a configuration that it wasn't supposed to. If that's the case, there is a bigger problem than just relying on a single sensor for a system that can trim full nose down.


Don't forget unreliable airspeed would appear to be a common factor at least in the early phases. If config were flaps down so MCAS OFF at the point ET flight had the first nose down, I suspect if the autopilot was initiated and read unreliable airspeed LOW, even with AOA reading correctly, suspect AP would command nose down.

So, we end up with both A/C in fast level flight probably with stick shaker pilots tidy up with flaps up AP OFF (and manually trimming certainly in the case of LionAir). Both A/C initiate fast turn to return to runway at relatively low altitude, suspect MCAS kicks nose down with insufficient recovery time.

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

Mon Mar 18, 2019 1:39 pm

What if the root cause is something in a manufacturing defect? A wire loom damaged in installation, for example, chaffing occurs and multiple effects.

GF
 
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caoimhin
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 1:40 pm

WIederling wrote:
mm320cap wrote:
It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.


I think this is a terrible statement.

The crash was premeditated murder.
It was not about uncovering hidden issues.
The crashes happened because a massive issue has been covered up, carefully hidden from view.
Think about it: when embedding the cert authority does not deliver enough advantage and easement!


You can’t help yourself, can you?

I just want to clarify my understanding of your position. It’s your belief that Boeing have acted with a “premeditated” intent to kill? You seriously believe this? You’re nothing if not consistent in your pure hatred for that corporation.

Boeing may have been negligent, or even reckless, given an cynical read of the scant facts we actually have. If you know some more information that the rest of us don’t that elevates their conduct to “premeditated murder” please provide it for the benefit of the world.
 
dragon6172
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:05 pm

RickNRoll wrote:
The whole point of it is to manage a near stall condition by altering the control feel for the pilot. If it stopped as soon as he reacted then it wouldn't be able to do that. It will always do the 2.5 or 0.6 degrees no matter what.

No... it stops trimming if the pilot trims the opposite direction OR if the AoA is reduced below the threshold. It does not go the full 2.5 degrees every time. If the system descriptions which say this aren't believable enough then you can look at the FDR traces that have been released for the Lion Air accident and see that the ONLY time it went the full 2.5 degrees was the first event. Every MCAS event after that is less than 2.5 degrees, typically around 1.5 to 2.0 degrees depending on how quickly the pilot makes a trim up input.
Phrogs Phorever
 
kalvado
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:17 pm

GalaxyFlyer wrote:
What if the root cause is something in a manufacturing defect? A wire loom damaged in installation, for example, chaffing occurs and multiple effects.

GF

If it is a one-off defect in both crashes, Boeing's ISO 9001 is at stake. If it is a systematic manufacturing defect, grounding is a prudent thing to do - and pushing for return to flight with software patch is negligence; I would leave it to court to add "criminal" part.
 
frmrCapCadet
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:27 pm

Zeppi wrote:
I've read the whole discussion since the desaster unfolded and decided not to chime in until we have some solid FDR and CVR data available, but now that things have already calmed a little and since I've had somewhat of an eye opening experience yesterday I'll do so now. Longer post coming up, apologies in advance.

mm320cap wrote:
The new technology categorically makes the airplane safer from a pilots perspective. It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.

Indeed, but IMHO exatly that is a two edged sword. It's great that modern aircraft have all sorts of electronic safeguards, assistant and deep reaching automation to help the crew reduce workload, handle difficult conditions etc. But what if (all of) those fail and fully manual hands on flying becomes the task du jour?

Getting to my "eye opening experience" from yesterday mentioned above. I'm an instrument rated PPL holder, just shy of 1200H TT in 10 years. The most performant aircraft I fly are the Lancair Evo and the Citation M2, both mostly single hand. Both quite fast and nimble little beasts that will punish you if you don't stay well ahead of them at all times, yet extremely fun to fly.
Yesterday, lovely sunny sunday morning, perfect time for an Evo joyride to LOWZ. At the airfeld I meet a buddy who's captain on the B77F with over 18k hours TT, he decides to come along as his wife intended to go to a tea party he didn't fancy too much to be polite :rotfl:
We brief the weather, föhn conditions (the powerful southerly katabatic winds) across most of the northern alps, so we're prepped for a bit of a rollercoaster experience. When I'm on my own joyriding I usually handfly all the time unless I hit IMC to enjoy the scenery, yesterday we enganged the AP for having some chitchat until reaching the mountains. Well before reaching the first ridges we enounter the first mountain waves, climb to FL140 where it's still a little calmer. Reaching top of descent I disengange the AP and my buddy starts setting us up for the approach, below FL100 it starts to get interesting, we are thrown around like a leaf in the wind and I can clearly see my buddy has trouble staying in the approach pattern. Serious work with both hands and feet is required at this point. I take over at 2000AGL, on short final it's so violent that I eventually decide to go around, my buddy already looks pale white in the face. Second approach works out fine, less random crosswinds and we grease it (well not really ;) ).

Having some coffee and cake on the terrace in the sun we watch plenty of other incoming AC battle the winds, go around, try again... While chatting we are joined by a few others, talk about the weather and handflying in those conditions. The locals mind you are saying "oh it's fine today, great vis, a little choppy, no biggie" all whilst some colour is slowly returning to my buddies face. Eventually the conversation topic reaches the 737MAX and also touches AF447, we mostly agreed that airline pilots nowadays are really just sitting there pushing a few buttons and watching it go. So while they may have thousands upon thousands of hours in their logbook, a very tiny share of that is actual flying. Doesn't matter most of the time, but when the shit hits the fan, the automated systems fail or let alone they go in zombie mode like with the 737MAX, the crews seem to be totally overwhelmed by the situation. What say you?


Every few years I suggest that pilots should be doing some edgy flying in a small plane for 2-4 hours a year. I am told that current training and simulators are enough, and that such flying would be too expensive. It is truer now than 5 years ago that pilots are mostly doing systems management ( in a highly skilled and difficult job - much of the real work is before the engines even start). Ideally that small plane would be two engines, and software enabled to duplicate some of the characteristics of a large airliner. The more edgy flying would be done with an appropriate flight instructor. It would supplement training and simulators. And likely be fun for most pilots. I would prefer that pilots on flights I take would look at it that way.
Last edited by frmrCapCadet on Mon Mar 18, 2019 2:29 pm, edited 1 time in total.
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scbriml
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:28 pm

planecane wrote:
This is the key that I want to know more about. If the ET crash was MCAS related as is being strongly insinuated, why was it active so early?

Unless the reports of when they started having trouble were erroneous, MCAS shouldn't have been activated due to flaps extended.


Two things, (happy to be corrected on either if I'm mistaken):

1 - ET302 apparently reported suffering from unreliable IAS very soon after take-off, which I understand would disable the auto-pilot (even if it had ever been engaged).

2 - They were reported as flying at "high speed". If they were over 250kts (which seems likely), flaps would have been retracted.

From everything I've read in these threads, both those conditions would mean that MCAS could activate.
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Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:47 pm

Interesting article linked in the grounding thread again from the Seattle times during rhe hardover catashtrophes

http://old.seattletimes.com/news/local/737/part05/

A leopard doesn't change its spots. Its alarmingly clear Boeing, qute possibly with the support of the FAA, would obfuscate and prevent necessary changes to its plane, even as people continued to die. Their strategy after the LionAir crash becomes ever clearer, and its despicable.

Im also alarmed at thenumber of American pilots quoted as saying everything is OK and arrogantly assuming this couldnt possibly happen to them, even without knowing exactly what those pilots faced. That arrogance does not belong in a cockpit, and it shows a disturbing lack of curiousity about what happened and how to avoid it.
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:51 pm

caoimhin wrote:
WIederling wrote:
mm320cap wrote:
It’s horribly sad that it took a massive loss of life to uncover the issue (or issues). But when people say that modern airplanes have become too complex to fly, they should probably ask the people that do the flying.


I think this is a terrible statement.

The crash was premeditated murder.
It was not about uncovering hidden issues.
The crashes happened because a massive issue has been covered up, carefully hidden from view.
Think about it: when embedding the cert authority does not deliver enough advantage and easement!


You can’t help yourself, can you?

I just want to clarify my understanding of your position. It’s your belief that Boeing have acted with a “premeditated” intent to kill? You seriously believe this? You’re nothing if not consistent in your pure hatred for that corporation.

Boeing may have been negligent, or even reckless, given an cynical read of the scant facts we actually have. If you know some more information that the rest of us don’t that elevates their conduct to “premeditated murder” please provide it for the benefit of the world.


Considering their deliberate attempts to shift the focus of the LionAir investigation and deny the plane had a problem, while they unquestionably knew whaf had gone on in its design and certification, I think the poster may have a point. Read the article I linked about their behaviour during the hardover crashes. Not sure why anyone would defend this company, they certainly dont care about you.
 
Planetalk
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 2:56 pm

wjcandee wrote:
Until the BEA (or NTSB) says it, I am absolutely not taking on faith the Ethiopians' assertions about this. These are the same folks who still believe their cluster with the -800 was an explosive device. Or I shouldn't say "believe" it, I should say "asset" it. They're racing to paint themselves as victims and get out in front of the story.

I think we're gonna find that this wasn't MCAS. If it was, it's a massive malfunction because with flaps out and autopilot likely engaged, MCAS should have been inhibited.

It's not to say that there wasn't some other massive malfunction with the aircraft -- there well could have been. But the idea that this was MCAS in "normal" erroneous operation (i.e. runaway stab trim) still seems very remote to me.


Where do you get you information flaps were out and autopilot likely engaged?

We know they reached 3000' above airport altitude. They probably had unreliable airspeed and werw way above flap retraction speed. Seems impossible flaps weren't retracted, and I doubt through all that the autopilot stayed in.
 
Backseater
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Re: Ethiopian Airlines 737MAX crashes enroute to Nairobi

Mon Mar 18, 2019 3:32 pm

The problem is not just to protect against “AoA fault”.
It is to protect against “AoA > threshold” fault!
And “threshold” is a dynamic value that is probably most related to Mach number.
So, who computes it? And how?
And in the case of unreliable airspeed, what value is used, if any?

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