Why Boeing 737 Max production has stopped, and its more than MCAS

[davidpt40]

You are wrong about almost everything you said. You seem to have read a few things you don't understand.

The sensor that failed is in all commercial aircraft.  Everything else, except the pilots, worked properly.

The pilots that crashed were certified by basically the same people that said it wasn't their fault.

Neither of the accidents were caused by the upgraded engines and the change in the thrust line that the MCAS was added for.

Boeing makes money by building good products. The assumption that profit over-rides safety is an unwarranted slander.

If you want to be clever about motivation think about how Airbus can benefit by pushing stories that Boeing is greedy, because profits are evil, and they don't care about safety.

There are probably still people who think a Toyota could accelerate by pressing the brake pedal.

Why does the 737 Max need an MCAS at all? Because Boeing put much larger engines on the aicraft which could not be simply placed under the wing like the current engines.  They have to be placed far forward of the wing, and as such, throttle increases now result in the aircraft pitching up.  Pitching up enough to potentially stall the aircraft, and needing a complicated software system with sensors that have turned into this giagantic mess.

Do you think that is a pretty good aerodynamic design?

[Vraciu]

Why does the 737 Max need an MCAS at all? Because Boeing put much larger engines on the aicraft which could not be simply placed under the wing like the current engines.  They have to be placed far forward of the wing, and as such, throttle increases now result in the aircraft pitching up.  Pitching up enough to potentially stall the aircraft, and needing a complicated software system with sensors that have turned into this giagantic mess.

Do you think that is a pretty good aerodynamic design?

Oh, boy...      

Listen carefully: This exact same type of system in the NG is called the STS.   STS = MCAS

STS and MCAS are intended for use at the extreme edge of the flight envelope, a regime almost never encountered.   It’s a certification requirement, not a day-to-day feature that’s regularly needed or used.

You really have no idea what you are talking about.   It’s beginning to sound like trolling at this point. 

The airplane has always pitched up with power increases.   It’s a byproduct of underslung engines.   The -200 didn’t do it as much as the -300 etc. but it’s a common trait.   That’s why many designs still use aft-mounted engines (which have their own set of characteristics).

Heck, the Cessna 152 pitches up with power increases, and it is one of the best trainers ever built.   

Good grief.   I’m seriously done with this. 

https://m.youtube.com/watch?v=UPw-3e_pzqU

[FLS]

Why does the 737 Max need an MCAS at all? Because Boeing put much larger engines on the aicraft which could not be simply placed under the wing like the current engines.  They have to be placed far forward of the wing, and as such, throttle increases now result in the aircraft pitching up.  Pitching up enough to potentially stall the aircraft, and needing a complicated software system with sensors that have turned into this giagantic mess.

Do you think that is a pretty good aerodynamic design?

I don't think it's an accurate description of the upgraded engines.

The MCAS system is designed to pitch down in the unlikely event that the 737MAX approaches the critical angle of attack with high power. That's to avoid a stall where the nose falls off to one side. That's the time you're likely to notice the higher thrust line difference. For your normal flying it's not a problem, it's not even noticeable. It wasn't a factor in the accidents.

The accidents occurred in VFR conditions that you can fly without instruments.

A faulty sensor wasn't fixed and the pilots weren't ready to go.

[Vraciu]

I don't think it's an accurate description of the upgraded engines.

The MCAS system is designed to pitch down in the unlikely event that the 737MAX approaches the critical angle of attack with high power. That's to avoid a stall where the nose falls off to one side.   That's the time you're likely to notice the higher thrust line difference. For your normal flying it's not a problem, it's not even noticeable. It wasn't a factor in the accidents.

The accidents occurred in VFR conditions that you can fly without instruments.

A faulty sensor wasn't fixed and the pilots weren't ready to go.

It’s for extreme aft CG controllability at low speeds.   It is in effect a pitch augmentation system to get the nose down with the airplane loaded to the rear.    This is almost never seen.   In fact, in normal ops the opposite is usually the case. 

Nose falloff in a stall is normal for many airplanes, even something like a 777.  It’s not a big deal.

[FLS]

If you take off in AH3 and select auto-speed you may find yourself diving down with runaway trim. Some people crash, some turn it off.   

[Busher]

I politely asked davidpt40 to provide me with his background in aviation and thus far we have nothing. But he does play Aces High - if that makes a pilot.

How did we come to the point where everyone's opinion is formed in comfort, rather than living in the discomfort of learning (my apologies to JFK for paraphrasing his great words)?

Maybe its time to stop using the word "fault" when discussing these and any other accidents. No pilot goes to work planning to die and contrary to some beliefs, no airplane manufacturer cuts corners with the idea what it won't like kill too many. Lets leave that to the car makers - Examples available on request.

There are many contributing factors to every accident. The MCAS was a contributor but it was only one.

To my fellow airmen, you command my greatest respect. Don't allow the trolls to frustrate you as much as they do me.

[Vraciu]

To my fellow airmen, you command my greatest respect. Don't allow the trolls to frustrate you as much as they do me.

Right back at you, good sir.   

[Toad]

I want to hear from you guys say, well yeah, the sensor thingy should be redundant just in case. 
semp

Is that what the mainstream media told you was necessary? Because they don't understand modern aviation either.

The aircraft I teach has TWO REDUNDANT AOA SENSOR "THINGIES".  Guess what? If EITHER sensor malfunctioned that malfunctioning sensor ALONE, ALL BY ITSELF, will trigger the "stick pusher", which will repeatedly push the nose down as long as the malfunctioning sensor is not promptly disabled (by a competent, trained pilot I might add.)

So there you are. REDUNDANT sensors pushing the nose down! Does this confuse you?

It shouldn't. Because when the aircraft has redundant sensors, when one goes bad the aircraft designers make the system do the safest thing. Without the pilot determining which sensor is correct, the default is to use the sensor that senses the stall.

Which answers this accurately put question the FLS asked you:

Two sensors disagree. Now what?

What should be fixed is letting unqualified pilots fly poorly maintained aircraft.

In short, if Boeing had the MCAS using BOTH AVAILABLE SENSORS ON THE AIRCRAFT (there are two) the MCAS would STILL have activated when only ONE sensor malfunctioned. Because that is the safest thing to do until A COMPETENT, TRAINED PILOT analyses the situation and disables the malfunctioning sensor.

I bet you are still confused.

[Toad]

These emergencies did not present as a classic runaway stabilizer problem, but initially as ambiguous unreliable airspeed and altitude situations, masking MCAS.

- oldman

Indeed, an AOA malfunction, which was the initial problem in both the Lion Air and Ethiopian crashes, does NOT present as a classic runaway problem.

No, it presented as a classic AOA malfunction. That is, the pilot gets a stick shaker when the plane is nowhere near stall speed. Now if the pilot reacts to the classic AOA malfunction with the classic Pitch + Power = Performance response, the MCAS will never activate.

Further if the classic pilot moves the flaps up and the nose immediately pitches down, the classic pilot will immediately return the flaps to their previous position. Again, the MCAS cannot activate.

And you don't need to know a damn thing about MCAS to survive a classic AOA malfunction with those two classic pilot responses.

[DmonSlyr]

This thread is golden. However, this Davidpt guy is clearly trolling you all with propaganda and isn't rationalizing anything you guys say. He's pushing an agenda.

He obviously believes that Boeing is "muh evil greedy corporate business" that don't care about nothing but "evil profits that only go right in the owners pocket". Do you really believe a company would risk billions in lawsuits, contracts, and integrity to do something stupid and put millions at risk?

Literally 2 planes in sweet Africa go down and we have a world wide crisis that is crippling a major aeronautical business worldwide. Think about that.

The real question is, why the attack on Boeing? CEO just resigned today. What's the real reason the media is so outraged? Why do they really hate Boeing now?

[Oldman731]

Indeed, an AOA malfunction, which was the initial problem in both the Lion Air and Ethiopian crashes, does NOT present as a classic runaway problem.

No, it presented as a classic AOA malfunction. That is, the pilot gets a stick shaker when the plane is nowhere near stall speed. Now if the pilot reacts to the classic AOA malfunction with the classic Pitch + Power = Performance response, the MCAS will never activate.

I bolded the quote because so many people have said that the malfunction instantly should have been recognized as runaway trim.

I have to tell you that this makes me happy I do not have to fly (or, viewed correctly, I am not permitted to fly) a plane with all these automated features.  I am very content that a 3-axis autopilot is all I've got.

- oldman

[Vraciu]

I bolded the quote because so many people have said that the malfunction instantly should have been recognized as runaway trim.

I have to tell you that this makes me happy I do not have to fly (or, viewed correctly, I am not permitted to fly) a plane with all these automated features.  I am very content that a 3-axis autopilot is all I've got.

- oldman

It doesn’t HAVE to be instantly recognized.    But it doesn’t take very long to realize the jet is trimming opposite of what you want.    We are talking a couple of seconds.   

[Toad]

I bolded the quote because so many people have said that the malfunction instantly should have been recognized as runaway trim.

- oldman

In the case of an actual runaway trim situation, runaway trim is very easily and quickly recognized as Vraciu pointed out. Particularly in the Boeings where the big dinner plate sized black trim wheel is whirling away right next to your knee.

After the first links in the accident chains were incorrectly recognized and incorrectly dealt with then, yes, Lion Air and Ethiopian would likely look like runaway trim. Had THAT link in the accident chain been recognized and dealt with per the QRH...once again....no accident.

The point being that there were several opportunities for the pilots to break either one of these accident chains. They failed to do so.

But...yeah...blame Boeing. (Not that Boeing is blameless either. The root cause, however, isn't the aircraft. As some here will apparently never "get".)

[davidpt40]

In the case of an actual runaway trim situation, runaway trim is very easily and quickly recognized as Vraciu pointed out. Particularly in the Boeings where the big dinner plate sized black trim wheel is whirling away right next to your knee.

After the first links in the accident chains were incorrectly recognized and incorrectly dealt with then, yes, Lion Air and Ethiopian would likely look like runaway trim. Had THAT link in the accident chain been recognized and dealt with per the QRH...once again....no accident.

The point being that there were several opportunities for the pilots to break either one of these accident chains. They failed to do so.

But...yeah...blame Boeing. (Not that Boeing is blameless either. The root cause, however, isn't the aircraft. As some here will apparently never "get".)

Not to be too pedantic on Christmas Eve, but have you ever been part of a Root Cause Investigation?  If there is no complicated equipment malfunction, there is no crash.  That is the root cause.  If these guys had been flying a DC-9 instead of a 737 Max, the folks would still be alive.  The "root cause" is the complicated aircraft malfunction.

[Vraciu]

Not to be too pedantic on Christmas Eve, but have you ever been part of a Root Cause Investigation? If there is no complicated equipment malfunction, there is no crash.  That is the root cause.  If these guys had been flying a DC-9 instead of a 737 Max, the folks would still be alive.  The "root cause" is the complicated aircraft malfunction.

You're kidding, right?

And let's not pretend a DC-9 has never had a trim runaway.

A trim runaway is a trim runaway is a trim runaway.  It doesn't matter what the cause is.  The response is the same. 

You feel it in the yoke.  You hear it with the aural trim movement indicator:

 - In the Falcon it is a machine gun clacker, "Dit-dit-dit-dit-dit-dit-dit-dit."
 - In the 145/Legacy it is Ms. Embraer saying, "*DING* Trim."
 - In the Boeing it is a giant wheel right next to your leg going, "KA-CHUNK!  KA-CHUNK!  KA-CHUNK!"


When that occurs you turn it off.    Fly the airplane.  Sort the problem.   You do *NOT* continue at takeoff thrust up to 350+ KIAS and then turn the thing back on.

The crew blew it in part because the guy in the right seat couldn't fly to literally save his life.

There is no sugar coating it.