Lion Air crash: Jakarta Boeing 737 'had prior instrument error'

[james_s]

My piloting experience is only with RC model planes so I'm not going to claim expertise on the matter, but if I were in the cockpit of an airliner and the plane trimmed itself fully nose down and started plunging to earth I can't imagine having a first reaction other than grabbing the trim wheel and cranking it back up. Clinging to it holding the trim within the authority of the elevator to keep the plane in level flight buys as much time as needed to assess the situation. I mean I realize the machine usually knows what it's doing but if the plane is in a steep dive it seems obvious something is wrong.

[KL27x]

^Agree, this sounds logical. And I hate to take over the thread with my machine gun posts. I'm hating myself.

But as far as we know, this has maybe happened on 3 occasions, and in 2 of them the plane went down. So either these 4 pilots had no common sense, or this is not as simple as it sounds.

Maybe later, we will find out this has happened a hundred times, and only 2 sets of pilots went down the wrong path. Or maybe it really was only the 3 occasions and 4 out of the first 6 pilots (7 if you include the 3rd NP on the plane that properly cut the stab trim) just happened to be out of the norm.

[djacobow]

At high angle of attack, the plane isn't flying nose first.

Right. 

I would not have put it this way, but it is essentially correct. I mean, it is always correct in the sense that when the angle of attack is not 0.0, the aircraft is not flying, relative to the wind, in the same direction it's pointing. At high AOA, this is a noticeable difference. Again, this may seem absurd to non-pilots, but this is just how planes are. The direction they are going relative to space, relative to air, and relative to which way they are pointed can all be different, and usual are.

[djacobow]

Stall characteristics of MAX is the same as NG. What's different - increased pitch up effect of the LEAP-1B engines, their placement (forward & up). Pitch-up increases AOA which may lead to stall.

But additionally, at high angle of attack, the engines themselves aerodynamically produce lift and drag. At high angle of attack, the plane isn't flying nose first. The vector of travel is at an angle to the attitude of the plane. And larger engines further forward is like an "air brake" giving the effect of the plane wanting to flip/rotate. This is very pronounced. We know this because of the degree of trim movement that MCAS needed to make.

Let's be careful to distinguish between stall characteristics, and the aerodynamics of the airplane at high AOA, but near a stall.

I don't think anyone has discussed stall characteristics of the 737 on this thread. I don't know what they are, and I suspect precious few have experienced them, mostly Boeing test pilots. The whole "system" is built around not getting there.

This whole discussion concerns avoiding getting into stall territory, and from what I've read, MCAS was designed to deal with the fact that as you get near a stall, the airplane starts to push further towards the stall on its own, and this tendency is either not present in the non-MAX versions, or it is weaker.

[djacobow]

^Agree, this sounds logical. And I hate to take over the thread with my machine gun posts. I'm hating myself.

But as far as we know, this has maybe happened on 3 occasions, and in 2 of them the plane went down. So either these 4 pilots had no common sense, or this is not as simple as it sounds.

Maybe later, we will find out this has happened a hundred times, and only 2 sets of pilots went down the wrong path. Or maybe it really was only the 3 occasions and 4 out of the first 6 pilots (7 if you include the 3rd NP on the plane that properly cut the stab trim) just happened to be out of the norm.

Something else we agree with. I think pilots should have handled this situation pretty readily, and yet they did not. That could be for any number of reasons, and we just don't know what they are yet. But I think that gets to my overarching point which is that the world seems ready to throw Boeing management in prison for pushing an unsafe airplane, and I think the reality is much more complicated. (In fact, I'm surprised at the rush to judgment regarding the very *idea* of this airplane being fundamentally flawed.) We obviously need to find out why the MCAS system "went haywire", but we *also* need to find out why pilots aren't following the emergency procedures they were supposedly trained to follow by memory.

[djacobow]

^Agree, this sounds logical. And I hate to take over the thread with my machine gun posts. I'm hating myself.

Another way we agree. I am not having any fun in this thread and probably need to step away from the keyboard. :-)

[BravoV]

Disturbing facts ...

Reuters : Ethiopia crash captain did not train on airline's MAX simulator: source

“Boeing did not send manuals on MCAS,”

“Actually we know more about the MCAS system from the media than from Boeing.”

“It is still very disturbing to us that Boeing did not disclose MCAS to the operators and pilots,”

[Marco]

Jumpin' Jesus on a pogo stick! They didn't have to turn off the MCAS! They had to turn off the trim system, which of course, they knew about.

The normal failure mode they seem to be trained for is a continuous run away though. The mach system they knew about could not produce such a failure mode AFAICS (though it can be dangerous in its own right on a malfunction at low altitude). Stuck switches or shorts could never produce such a failure mode ... it would be a one in a billion type failure mode without MCAS.

As I said, more a hobble away than a runaway.

[djacobow]

The normal failure mode they seem to be trained for is a continuous run away though. The mach system they knew about could not produce such a failure mode AFAICS (though it can be dangerous in its own right on a malfunction at low altitude). Stuck switches or shorts could never produce such a failure mode ... it would be a one in a billion type failure mode without MCAS.

You're right. The word "continuous" in the instructions is not exactly consistent with this scenario, and I guess that could have kept pilots from following it. However, though this problem was intermittent, when the trim motor ran, it ran for a rather long time - 10 seconds, and I believe 2.5 degrees of stab movement per go; as I understand it, that's an awful for a 737.

[floobydust]

The AOA DISAGREE dash LED is optional, Boeing just announced it's making it mandatory. Airbus includes it for free.
I wonder how much it cost, this aviation-spec LED, some wire and a connector. It must be $10,000's of dollars on a $120M aircraft.

Missing a lousy LED on the instrument panel is beyond pathetic  caught up in politics and marketing.
I have to agree:
"Boeing's 'Optional' Safety Equipment on the 737 Max is a Monument to Corporate Greed"

[iMo]

https://www.ft.com/content/d726faea-4b36-11e9-bbc9-6917dce3dc62

Boeing will install an extra safety alarm in the cockpits of all its 737 Max aircraft after intense criticism in the wake of two fatal crashes.

The US aerospace group has decided to include a warning light in new 737 Max planes and to retrofit all existing ones, according to a person familiar with the situation.

The alarm will tell pilots if two “angle of attack” sensors — which indicate the angle of a plane’s nose — disagree, a sign that one is not working.

[ogden]

I mean, it is always correct in the sense that when the angle of attack is not 0.0, the aircraft is not flying, relative to the wind, in the same direction it's pointing.

Right. Boeing does good job explaining AOA:



http://www.boeing.com/commercial/aeromagazine/aero_12/attack_story.html

[julianhigginson]

This new 737 model  was built as and designated as a 737 in order to save certification time and training costs for airlines that were the customers of the planes.

At the end of the day, the 737 MAX should NOT have been a 737. The basic 737 airframe is not compatible with the engine size they needed to put on the plane. and when they did it anyway the airframe became unstable, in that approaching a stall the plane becomes more likely to go into a stall. this is nothing like the behaviour of any 737 in the nearly 50 years 737s have been in the sky.

And now it appears that the massive control system hack put in place to try and neutralise the massive mechanical problem caused by using engines that were too large ended up being "downplayed" so that the 737 certification could stand. "downplayed" to the point that it doesn't even tell you when it's operating! (and massive incompetence in the actual execution of the control system - the active control system only even looks at one vane to make decisions that can kill everyone on board if the vane is faulty!)

Yes in a perfect world a non-panicked pilot is sometimes able to work out what is wrong with a crashing 737 max, because we know  a few did... It seems they are especially able to work it out if they have had training on how this new 737 isn't like every other 737 they ever flew... but in 2 cases now, the pilots didn't... so.... it's kind of obvious that whatever was done was nowhere near enough. Just by the results we have seen in the world.

So all the armchair pilots sitting here saying "but they should have adjusted the trim back" - yeah I'm sure you're a cool and in control genius, and you would have magically worked out what exactly was going on with the whole visual field full of dials and controls while the plane was randomly just pulling your control column away from you and falling out of the sky while you tried to fly it, and saved the day. But so far two flight crews managed to not save the day and hundreds of people are dead. So it seems that unfortunately real commercial pilots aren't as good as you...

This is 100% the result of a corporation using weakened regulatory systems to cut costs at the expense of human lives.

[tooki]

The AOA DISAGREE dash LED is optional, Boeing just announced it's making it mandatory. Airbus includes it for free.
I wonder how much it cost, this aviation-spec LED, some wire and a connector. It must be $10,000's of dollars on a $120M aircraft.

Missing a lousy LED on the instrument panel is beyond pathetic  caught up in politics and marketing.
I have to agree:
"Boeing's 'Optional' Safety Equipment on the 737 Max is a Monument to Corporate Greed"

LED?? No. It’s an on-screen indicator on one of the color LCDs, according to a video I saw.

[james_s]

So all the armchair pilots sitting here saying "but they should have adjusted the trim back" - yeah I'm sure you're a cool and in control genius, and you would have magically worked out what exactly was going on with the whole visual field full of dials and controls while the plane was randomly just pulling your control column away from you and falling out of the sky while you tried to fly it, and saved the day. But so far two flight crews managed to not save the day and hundreds of people are dead. So it seems that unfortunately real commercial pilots aren't as good as you...

This is 100% the result of a corporation using weakened regulatory systems to cut costs at the expense of human lives.

But that isn't what it was doing. It didn't "pull the control column" anywhere, it spun the trim wheels fully nose down, an action that is impossible to not notice happening or recognize. When you say "visual field full of dials and controls" it makes it sound like an aircraft instrument panel is a sea of random controls that the crew has no idea what they do, while in reality any competent pilot knows precisely what all of them do and where they all are from memory. A pilot needs to be able to deal with situations like this, whether due to a design fault with the aircraft, a mechanical failure or some external factor. The fact that these crews apparently didn't do that suggests a degree of incompetence. I'm not going to judge them entirely until we have all the details but to assert that this is "100%" anything at this point is quite frankly bullshit, we don't know what happened with certainty yet, but assuming things played out the way early evidence suggests, then the crew gets at least a portion of the blame here. I will remind you that there are at least a couple actual certified pilots in this thread, not just a bunch of armchair goobers who haven't got a clue.

There have been a LOT more incidents throughout aviation history where flight crews not only failed to save the day, but actively caused the accident through their own error or neglect. The fact that two may have failed to deal with the same situation here does not necessarily absolve them from blame.

[Dundarave]

Is it just me, or does anyone else think that there's something immoral about Boeing designating functionality that is for the sole purpose of increased flight safety (such as the "disagree light") as "optional" and charging extra for it?  And thus allowing corporate airline customers to opt-out of paying for it to be implemented in their aircraft?  Comfort and operational economy options, sure.  But items that can only be classified as "safety-related" and designed to notify when the rest of the aircraft isn't performing up to its paid-for specifications at the potential expense of all the lives aboard?  Apparently, Boeing has a corporate policy which holds that not all passengers deserve equal levels of flight safety.

On each flight, there are, like, 200-odd passengers who assume when they buy their ticket that the aircraft they are flying in is as safe as the aircraft industry can reasonably make it.   Airlines who fly equipment that is not "as safe as the industry can reasonably make it" due to missing safety options that could have been purchased, but were not, should be forced to make that information public.  Letting consumers vote with their feet about what airlines they want to fly based on who's "cheaped out" on their safety is likely the only way to put a stop to what I consider outrageous, money-chiseling, negligent behaviour.

[Brumby]

At the end of the day, the 737 MAX should NOT have been a 737.

Firstly, that statement suggests to me you do not understand the type rating system at all.  I'm not a pilot, but I have been following some of the ecology...

There are many variants of the 737 and just because a pilot has been "type rated" for one model does not mean they can hop into the cockpit of any 737.  Where the changes are significant enough - and these do exist in the 737 line - pilots must go through the full "type rating" process, which impacts both pilots and airlines.  However, there are several models where the differences are minor and a pilot rated for a previous model may only need to undergo "difference training" to be qualified to fly the new version.  This is easy to achieve and represents minimal impact to an airline and their pilots.  This is the reason why any aircraft will not have too many things change, to make sure the differences are small enough so that "difference training" is all that is needed.

There's nothing wrong with the MAX-8 being presented as a 737.  What may be the case (which could be part of the fall-out of these incidents) is that it should have been classed as a new type.  In that case, pilots will need to do type rating - and that is going to impact everyone.

[floobydust]

LED?? No. It’s an on-screen indicator on one of the color LCDs, according to a video I saw.

I thought it is located on the center forward panel?  Air Canada and WestJet had already ordered the aircraft with the indicator light but I don't have pics.

Why would Boeing charge $ for some text annunciator on an LCD?  Putting the word AOA DISAGREE on an LCD. They charge money for that!?! 
Southwest Airlines is adding an AoA "indicator" (gauge) on the primary flight display. I'm not sure that is useful- what happens when there is a sensor disagreement, to not create confusion.

[julianhigginson]

There have been a LOT more incidents throughout aviation history where flight crews not only failed to save the day, but actively caused the accident through their own error or neglect. The fact that two may have failed to deal with the same situation here does not necessarily absolve them from blame.

what happened is we have had two crashes one after the other with new planes of the exact same model, killing hundreds of people.... Even if those two crews weren't the best pilots in the world, I expect that they had managed to not kill everyone while flying plenty of other 737s before. Both crews came unstuck on this new model.

I think it's safe to say that the the differences of this particular plane from any previous ones, and the way those differences were handled, was a massive error of judgement that has cost hundreds of lives.

And when i say "error of judgement" I mean "conspiracy of criminal negligence that should see the people involved in the highest levels of managing the project imprisoned for the rest of their lives, and Boeing out of business if it can't afford to do either a full recall of their not-fit-for-purpose planes. Or at very least, complete some kind of retrospective "new plane" process on this model for all the planes of this type currently out there."

There's a particular concern with the allegation that their software bodge was baked into the system and hidden in a way that it was not obvious it even existed, letalone obvious it was operating.... And the allegation that it only used the mechanical vane sensor on one side of the plane to make string of repeated decisions that ended up killing everyone on board, and didn't even have the ability to cross check the plane's dual sensors for sensor faults.

[julianhigginson]

There's nothing wrong with the MAX-8 being presented as a 737.  What may be the case (which could be part of the fall-out of these incidents) is that it should have been classed as a new type.  In that case, pilots will need to do type rating - and that is going to impact everyone.

Thanks for the terminology tip.

But it's more than just pilots doing the training to be allowed to fly it.
They should have to prove the that this new type (of which over a hundred planes just like the 2 crashed ones are out there in the world by now) is even fundamentally ok to have pilots trained to operate it.

[BravoV]

All the dirt that had swiped underneath the carpet, are starting to pop out one by one.


CNN : Pilots transitioned to 737 Max 8 with self-administered online course

Quotes :

Pilots of Southwest Airlines and American Airlines took courses -- lasting between 56 minutes and three hours -- that highlighted differences between the Max 8 and older 737s, but did not explain the new maneuvering characteristics augmentation system, know as MCAS, the spokesmen said.

"MCAS was installed in the aircraft and Boeing didn't disclose that to the pilots," said Trevino, while adding that Southwest pilots are experienced with 737s.

"This is ridiculous," said Captain Dennis Tajer, a representative of the Allied Pilots Association, which represents 15,000 American Airlines pilots. "If you're going to have equipment on the airplane that we didn't know about, and we're going to be responsible for battling it if it fails, then we need to have hands-on experience."

[mtdoc]

The basic 737 airframe is not compatible with the engine size they needed to put on the plane. and when they did it anyway the airframe became unstable, in that approaching a stall the plane becomes more likely to go into a stall. this is nothing like the behaviour of any 737 in the nearly 50 years 737s have been in the sky.

Yes, and if true, this is why the 737 Max will not (or should not) fly again.  All the focus in this thread on armchair piloting and engineering bodges seem to be ignoring this fundamental and overwhelming design flaw. A different or better bodge wil not fix the underlying problem which if the plane is continued to be allowed to fly will eventually result in more deaths. 

But I do not want to underestimate the corporate power, greed and regulatory capture at work here so maybe they will be stupid enough to allow it to fly again after the new bodges are in place....

[james_s]

There have been a LOT more incidents throughout aviation history where flight crews not only failed to save the day, but actively caused the accident through their own error or neglect. The fact that two may have failed to deal with the same situation here does not necessarily absolve them from blame.

The blame here has already been established: 737M8 and M9 are grounded worldwide. Simple as that.

No it has not been established, and it's not as simple as that. The planes have been grounded until the investigation determines what happened and what if any corrective actions must be taken. There may well be a problem with the aircraft but grounding them by no means establishes blame.

[james_s]

Yes, and if true, this is why the 737 Max will not (or should not) fly again.  All the focus in this thread on armchair piloting and engineering bodges seem to be ignoring this fundamental and overwhelming design flaw. A different or better bodge wil not fix the underlying problem which if the plane is continued to be allowed to fly will eventually result in more deaths. 

But I do not want to underestimate the corporate power, greed and regulatory capture at work here so maybe they will be stupid enough to allow it to fly again after the new bodges are in place....

It will absolutely fly again, I would wager a substantial amount of money on that fact. It will probably go on to have a good safety record, just as many other planes have in the past. There have been numerous cases of design flaws on new aircraft causing deadly crashes, aircraft type groundings and investigation, and in not one single one of these cases did the type not fly again. Won't happen here either, it's silly to even suggest it as a possibility. These incidents will certainly cost Boeing sales but the problem will be solved and the planes will be back in the air.

Absolute most drastic case, MCAS will be removed and pilots will require re-training to deal with the different handling characteristics of the max. Some people here seem to fail to comprehend this, it is not unstable or badly mannered, it simply handles differently than the 737 classic and thus requires the MCAS in order for it to be flown by pilots certified on the 737 classic. The upward pitch when thrust is increased is a characteristic of ALL airliners with engines slung under the wings. The difference here being the max exhibits this to a greater degree.

[james_s]

Oh yeah, de facto it has been established, on official paper it just takes more time. Otherwise find me other pilot error produced accident in which a global fleet was grounded. Or a pilot induced accident in which the justice department did subpoena Boeing and the FAA, or ....

Unless you know something that the rest of us don't, you don't know whether it was pilot induced, or caused by a flaw in the aircraft, or caused by a combination of these, or something else entirely. It's sensible to ground the aircraft because there is reasonable suspicion of a problem with the design but that is not the same as establishing blame. The investigation is underway, it will be months before blame is established, and it will probably turn out to be a cascade of events that all worked together to cause the accidents.


When a person is suspected of a crime they are arrested and charged, if it is a serious crime they will be detained, but that does not establish blame. They are innocent until proven guilty in a court of law, in other words the court establishes blame, and only after the crime is investigated and the evidence examined. Sadly many people do not understand this and jump the gun trying to be an armchair judge and jury all rolled into one.