Ethiopian Max 8 crashes, Canadians on board

[Fuzz]

^
I would assume autopilot takes care of the aircraft pitch itself, so it wouldn't need MCAS. "Manual mode" is not taking it out of autopilot in this case, it is overriding the MCAS system. They are 2 separate "auto" settings, where MCAS 's only job is to prevent runaway pitch. Autopilot is much more than that.


That's how I understand it, anyway.

[Fuzz]

It is interesting how the more you know of a subject, the more you notice how little the media gets right about it. I think the only area I really trust the media to get it right is the political wonks. But maybe that's because I don't know enough about politics to notice all the stuff they get wrong there...

[Ryan Coke]

Originally Posted by Red

And where does it say that MCAS doesnt work on auto pilot? All indications point to going to manual mode to override it so it seems logical that it only works in auto. Unless I'm missing something here.

See, that is incorrect. But lots of inaccurate reports, so I understand it.

MCAS occurs with the flaps up while in manual flight. The ‘complicated series of steps’ to disable the system is turning off 2 switches sitting side by side, which prevents the trim from operating. So if the autopilot is on, the MCAS doesn’t (or at least shouldn’t) be operative, it is already off when the MCAS is behaving incorrectly. Turning off the stab trim cutout switches will disengage the autopilot if it wasn’t already off.

And I’m not disagreeing with the decision to ground the airplane, just there is a bunch of inaccurate noise around it now. And mentioning a bunch of other minor malfunctions that have nothing to do with this issue is inaccurate.

[Ryan Coke]

Originally Posted by Fuzz

^
I would assume autopilot takes care of the aircraft pitch itself, so it wouldn't need MCAS. "Manual mode" is not taking it out of autopilot in this case, it is overriding the MCAS system. They are 2 separate "auto" settings, where MCAS 's only job is to prevent runaway pitch. Autopilot is much more than that.


That's how I understand it, anyway.

MCAS’ purpose is actually to use trim to pitch the nose down in a nose high approach to stall situation. (With autopilot off and flaps up). The problem is it trimming down due to a malfunction when it shouldn’t be. To stop it the crew needs to flip the stab trim cutout switches.

In the lion air accident it was a malfunctioning angle of attack sensor that caused the crew to be hand flying, and that erroneous sensor told the MCAS that it was approaching a stall causing it to trim down to prevent the aerodynamic stall. Which of course was incorrect.

The purpose of the system is fine, but obviously it appears that it was poorly designed.

[Red]

Originally Posted by Ryan Coke

See, that is incorrect. But lots of inaccurate reports, so I understand it.

MCAS occurs with the flaps up while in manual flight. The ‘complicated series of steps’ to disable the system is turning off 2 switches sitting side by side, which prevents the trim from operating. So if the autopilot is on, the MCAS doesn’t (or at least shouldn’t) be operative, it is already off when the MCAS is behaving incorrectly. Turning off the stab trim cutout switches will disengage the autopilot if it wasn’t already off.

And I’m not disagreeing with the decision to ground the airplane, just there is a bunch of inaccurate noise around it now. And mentioning a bunch of other minor malfunctions that have nothing to do with this issue is inaccurate.

Other issues are not inaccurate, they may be irrelevant though.

I will wait for the investigation to confirm what really happened. Pretty obvious that something is wrong if Boeing is releasing software fixes. Why else would they do that?

I thank the media for raising these issues. Based on what we know so far don't trust that plane. If we left it to Boeing to decide this would have been swept under the rug.

[Ryan Coke]

They are inaccurately being connected to the MCAS system so I agree they are irrelevant.

Boeing is making changes to the MCAS system, that’s good because it appears it was poorly designed. 2 major accidents that may be rooted in MCAS says the system needs improvement, absolutely.

And your right, media scrutiny is part of why aviation is so safe. But I hope you understand why it is frustrating when a bunch of what they report is wrong. It makes people even more confused about things.

And waiting for the actual findings from investigators is, of course, awesome.

[Stealth22]

(Warning, wall of text, but I'm catching up from the last few pages, heh)

Originally Posted by Bigtime

Yeah, like The Star this morning being all over a MAX 8 flying OGG to YYC. Except it was a 800 series NG. Loved WestJet tweeting right back at them on how factually incorrect they were.

They were probably so excited about "catching WestJet red handed" ignoring the ban, that they didn't stop to think that their info just might be incorrect.

Like Acey said, this is why you shouldn't trust sites like FlightAware to be totally correct.

Even so, there have still been 737 MAX's flying around. They're just on ferry flights with no passengers aboard, which is approved by both Transport Canada and the FAA.

-----

Originally Posted by Fuzz

It is interesting how the more you know of a subject, the more you notice how little the media gets right about it. I think the only area I really trust the media to get it right is the political wonks. But maybe that's because I don't know enough about politics to notice all the stuff they get wrong there...

That doesn't just apply to aviation either, I bet.

But the media getting things wrong when reporting on aviation disasters just spreads so much information, especially because the general public knows so little about aviation, like Ryan said.

Journalists should just stick to reporting on what they hear from official sources, and stop consulting so-called "experts" and reporting on things that they know absolutely nothing about.

Ryan's quote below says it the best - there aren't many people who think grounding the plane is the wrong decision. But putting a microscope to every single 737 malfunction ever reported, and equating it to MCAS (not anyone in this thread, just referring to the inaccurate noise out there in general) and calling the plane a death trap before all the facts are known (from the official investigation) is just totally irresponsible.

Originally Posted by Ryan Coke

I’m not disagreeing with the decision to ground the airplane, just there is a bunch of inaccurate noise around it now. And mentioning a bunch of other minor malfunctions that have nothing to do with this issue is inaccurate.

Originally Posted by Ryan Coke

And your right, media scrutiny is part of why aviation is so safe. But I hope you understand why it is frustrating when a bunch of what they report is wrong. It makes people even more confused about things.

Thanks for all your insight on this, Ryan. While I'm somewhat knowledgeable on the subject, having someone around who actually flies these things is awesome!

-----

Originally Posted by Red

And where does it say that MCAS doesnt work on auto pilot? All indications point to going to manual mode to override it so it seems logical that it only works in auto. Unless I'm missing something here.

Originally Posted by Fuzz

I would assume autopilot takes care of the aircraft pitch itself, so it wouldn't need MCAS. "Manual mode" is not taking it out of autopilot in this case, it is overriding the MCAS system. They are 2 separate "auto" settings, where MCAS 's only job is to prevent runaway pitch. Autopilot is much more than that.

That's how I understand it, anyway.

Like Ryan said, MCAS is not engaged when the autopilot is on, or when the flaps are deployed.

The sole purpose of MCAS is to "trim" (i.e. tilt) the horizontal stabilizer slightly nose down to circumvent the possibility of the nose being pushed upwards too much.

https://theaircurrent.com/aviation-s...em-mcas-jt610/

Like Ryan explained, the working unconfirmed theory is that Lion Air was caused by a faulty AOA sensor that caused MCAS to continuously trim the nose down when it wasn't supposed to, because it thought the nose was too high when it wasn't.

The glitch essentially causes "runaway trim" (Ryan, feel free to correct me if I'm wrong on any of this!), and if the pilots don't know what's going on, then they don't know that all they need to do is flick the stabilizer trim cutoff switches.

That said, if MCAS was causing runaway trim, the trim wheel makes a lot of noise, and in my opinion any seasoned 737 pilot should recognize the symptoms right away. The report doesn't say if the pilots followed the checklist to override the system, though. (EDIT: I'm told that it would also be easy to not recognize the trim wheel running, because you hear that sound quite a bit during normal flight, so there is that)

"[...] Data from the flight data recorder summarized in the report also makes clear that, as on the previous flight, the airplane experienced automatic nose down trim. [...] Unlike as is stated with respect to the prior flight, the report does not state whether the pilots performed the runaway stabilizer procedure or cut out the stabilizer trim switches."

https://boeing.mediaroom.com/news-re...ts?item=130336

http://knkt.dephub.go.id/knkt/ntsc_a...y%20Report.pdf

The whole point behind the emergency airworthiness directive by the FAA after the Lion Air crash was to update all the training documents to include information about MCAS, which Boeing previously did not disclose.

We don't know if the same thing (faulty AOA sensor -> runaway trim by MCAS -> pilots didn't know the fix) is what caused the crash of ET302. But the fact that the radar data shows similarities between the two flights is what warrants the MAX to be grounded.

Originally Posted by Red

I will wait for the investigation to confirm what really happened. Pretty obvious that something is wrong if Boeing is releasing software fixes. Why else would they do that?

I thank the media for raising these issues. Based on what we know so far don't trust that plane. If we left it to Boeing to decide this would have been swept under the rug.

As Ryan mentioned, the purpose and intent behind MCAS is useful, but it appears that it's acting when it isn't supposed to, hence the software update. While a pilot can easily disable the system, the fact that Boeing did not include details on MCAS in it's training documents is the issue, which is why the pilots of the Lion Air flight (allegedly) did not know what course of action to take.

The problem I have with the media is that they are erroneously equating other minor issues (which all aircraft have from time to time) as being related to the MCAS issues, when they are not.

Given all that I know and have read about this whole thing, personally, if the 737 MAX was still flying now, I don't think I'd have an issue with getting on board. I trust the track record of the 737, and overall, I believe that the aircraft is safe.

But I don't disagree with grounding it until all of the facts come out for sure. I am personally going to reserve judgement regarding the cause of the crashes until the official investigations are completed. Until that happens, anything that anyone says is pure speculation.

[sureLoss]

FAA is going to take some flack for delegating the safety analysis of some of the MAX's systems including the MCAS to Boeing itself.

https://www.seattletimes.com/busines...ion-air-crash/

The FAA, citing lack of funding and resources, has over the years delegated increasing authority to Boeing to take on more of the work of certifying the safety of its own airplanes.

Early on in certification of the 737 MAX, the FAA safety engineering team divided up the technical assessments that would be delegated to Boeing versus those they considered more critical and would be retained within the FAA.

But several FAA technical experts said in interviews that as certification proceeded, managers prodded them to speed the process. Development of the MAX was lagging nine months behind the rival Airbus A320neo. Time was of the essence for Boeing.

A former FAA safety engineer who was directly involved in certifying the MAX said that halfway through the certification process, “we were asked by management to re-evaluate what would be delegated. Management thought we had retained too much at the FAA.”

“There was constant pressure to re-evaluate our initial decisions,” the former engineer said. “And even after we had reassessed it … there was continued discussion by management about delegating even more items down to the Boeing Company.”

Even the work that was retained, such as reviewing technical documents provided by Boeing, was sometimes curtailed.

“There wasn’t a complete and proper review of the documents,” the former engineer added. “Review was rushed to reach certain certification dates.”

When time was too short for FAA technical staff to complete a review, sometimes managers either signed off on the documents themselves or delegated their review back to Boeing.

“The FAA managers, not the agency technical experts, have final authority on delegation,” the engineer said.

Current and former engineers directly involved with the evaluations or familiar with the document shared details of Boeing’s “System Safety Analysis” of MCAS, which The Seattle Times confirmed.

The safety analysis:

• Understated the power of the new flight control system, which was designed to swivel the horizontal tail to push the nose of the plane down to avert a stall. When the planes later entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document.
• Failed to account for how the system could reset itself each time a pilot responded, thereby missing the potential impact of the system repeatedly pushing the airplane’s nose downward.
• Assessed a failure of the system as one level below “catastrophic.” But even that “hazardous” danger level should have precluded activation of the system based on input from a single sensor — and yet that’s how it was designed.

The people who spoke to The Seattle Times and shared details of the safety analysis all spoke on condition of anonymity to protect their jobs at the FAA and other aviation organizations.

[Snuffleupagus]

Not confirmed thru US officials but the Ethiopian transport ministry has confirmed data from the black boxes showed "clear similarities" with the Lion Air crash.

Ethiopian-airlines-737-max-8-similarities-to-lion-air-crash/10910460

[snootchiebootchies]

https://twitter.com/user/status/1106669957952106496

[Northendzone]

i'd imagine this may have already been mentioned, but to me it is really shocking how many Canadians were on this flight - 18/157 - a little over 11%. Seems very surprising for a flight on eithiopian air - but what do i know.

[Bigtime]

Commentary and a video on the 737's trim system by a WestJet Captain:


https://www.facebook.com/duaneb737/p...57292361340625

[Resolute 14]

Originally Posted by Northendzone

i'd imagine this may have already been mentioned, but to me it is really shocking how many Canadians were on this flight - 18/157 - a little over 11%. Seems very surprising for a flight on eithiopian air - but what do i know.

Most passengers were heading to a UN Environmental conference. Since our government loves sending large entourages to such events, it's my guess that's why.

[Firebot]

Originally Posted by Northendzone

i'd imagine this may have already been mentioned, but to me it is really shocking how many Canadians were on this flight - 18/157 - a little over 11%. Seems very surprising for a flight on eithiopian air - but what do i know.

My uncle was in Ethiopia and was part of a different group going to Rwanda at the same time as the crash. Let's just say that the news hit close to home at the time it happened, but he gave our family news very quickly to assure he was safe. He likely knew a person or two from the crashed plane.

And at the same time, 6 out of 18 all belonged to one family

https://www.cbc.ca/news/world/vaidya...sure-1.5060441

[Acey]

To play devil's advocate in response to the Facebook video, one might fairly ask why you have to flip up a hood and hit a covered switch to stop your airplane from killing you. Runaway trim isn't a new thing. MCAS is a new scapegoat.

[GGG]

Originally Posted by Bigtime

Commentary and a video on the 737's trim system by a WestJet Captain:

https://www.facebook.com/duaneb737/p...57292361340625

The question to ask then is what is the rate of human failure to execute a task while monitoring a large number of pieces of information? The answer is a non-zero number.

So does the rate of instrument failure x rate of operator failure = an acceptable level of risk?

I don’t believe the Pilot making the commentary identifies himself as a potential source of failure.

[Acey]

How is the question anything other than "why is the trim system trying to crash the airplane?"

[Ryan Coke]

While the correct response to a malfunctioning MCAS system is relatively straight forward, the reality of 2 hull losses in a short period of time can’t be dismissed. Chalking it up to ‘the pilots could’ve/should’ve done better’ isn’t enough.

No matter how high the average skill level of airline pilots is, there will always be some number below that average. And air travel hasn’t gotten as safe as it has by relying on pilots to ‘just be better’.

It appears that the potential consequences of this system malfunctioning were severely underestimated. Thankfully the fix appears very doable and shouldn’t take long.

[Manhattanboy]

How does Boeing’s CEO survive this? The lawsuits will be in the billions depending on how long the jets are grounded. This may go beyond gross negligence.

[temple5]

Really good and informative video, best I have seen thus far. I dont want to blame pilots for this but this video shows 2 relatively simple buttons that would disable MCAS completely. I really hope these arent cases of malfunctioning pitot tubes that we have seen from other crashes before.

The facebook post above seems to describe basically what this video shows.