Another 737 down

[Puma44]

Following normal runaway trim procedure would still have saved both aircraft. 

So very true, and simple. 

[davidpt40]

Why wasn't the MCAS system designed to use two pitot tubes simultaneously, and if they didn't match, MCAS would simply shut off?  Instead it simply crashes the aircraft. 

[FLS]

The MCAS was designed for a particular unlikely scenario, which so far I've haven't heard has ever happened, and the possibility of runaway trim from a bad sensor is managed by the normal runaway trim procedure.

If the MCAS was actually needed and it shut off because of a faulty sensor you might get a stall spin which could be disastrous. If it's not needed and it turns on because of a faulty sensor it's an easy fix if the pilots follow procedure.

The MCAS can be redesigned to slow the pitch change which might help when it's not needed but won't help when it is.

The primary cause of aircraft accidents is pilot error.  There is still no reason to think the 737 crashes were exceptions.

The faulty AOA sensor and MCAS response were just links in a chain the pilots are trained to break.

[mikeWe9a]

Why wasn't the MCAS system designed to use two pitot tubes simultaneously, and if they didn't match, MCAS would simply shut off?  Instead it simply crashes the aircraft.

MCAS didn't crash those aircraft.  Poor piloting crashed both aircraft, because the pilots failed to maintain basic aircraft control or to perform the standard emergency procedures which would have allowed them to safely operate the aircraft after the system failure.

Mike

[Puma44]

MCAS didn't crash those aircraft.  Poor piloting crashed both aircraft, because the pilots failed to maintain basic aircraft control or to perform the standard emergency procedures which would have allowed them to safely operate the aircraft after the system failure.

Mike

What he ^ said, exactly.

[Busher]

https://www.bbc.com/news/business-50177788

I found this but I have yet to un-earth the 353 page Indonesian report. I hope its published in English. It remains to be seen if it compares to the detailed nature of an NTSB report.
It seems to place the cause of the accident on a combination of events:
1: The airplane was dispatched and was not airworthy
2: The failure of the airline to assure a safety culture where all snags should be clearly documented.
3: An aircrew that lacked in both experience and training to deal with the problems presented to them.
4: The MCAS failure triggered by the snags that existed when the aircraft took off.

The worldwide pilot shortage assures that the average pilot experience level in cockpits around the world will be declining.
Aircraft manufacturers despite their best efforts, will never make an airplane that is immune to snags or pilot errors.

It remains that Boeing was guilty by accusation rather than investigation.

[guncrasher]

redundant systems not available.


semp

[SysError]

https://www.c-span.org/video/?465775-1/boeing-ceo-dennis-muilenburg-testifies-737-max-safety


IMO aircrew experience probably the least relevant factor.

[Mister Fork]

https://www.c-span.org/video/?465775-1/boeing-ceo-dennis-muilenburg-testifies-737-max-safety
IMO aircrew experience probably the least relevant factor.

Would it be safe to say that most of us here think the pilot's poor training is about half the issue?

Indonesia and Ethiopia and their respective airlines want you to think that it's 100% the plane. The fact that the four pilots didn't know the 'runaway elevator trim' procedure is very troubling. A lack of pilot training, poor maintenance (no surprise there), and poorly documented procedures for the MCAS from Boeing doomed those flights.  And I'll give some credit to the Indonesian report for highlighting that the aircraft wasn't serviceable and shouldn't have been flying as a major cause.

We all acknowledge, Boeing has plenty of ownership on this issue, but to 99.9% blame the aircraft and .1% on the pilot, it's not reasonable. 

[FLS]

Runaway trim is not specific to MCAS or to Boeing. It's taught to every pilot. If the trim is doing something you don't want it to, you turn it off.

The Ethiopia crash was doomed by the throttles left at takeoff thrust. No reason to blame the pilots for the throttle setting? The Boeing CEO would be crucified if he correctly blamed the pilots for the crash. We just can't talk about that here. The pilots failed to break the chain of mistakes, including their own poor choices.

[SysError]

Would it be safe to say that most of us here think the pilot's poor training is about half the issue?

Indonesia and Ethiopia and their respective airlines want you to think that it's 100% the plane. The fact that the four pilots didn't know the 'runaway elevator trim' procedure is very troubling. A lack of pilot training, poor maintenance (no surprise there), and poorly documented procedures for the MCAS from Boeing doomed those flights.  And I'll give some credit to the Indonesian report for highlighting that the aircraft wasn't serviceable and shouldn't have been flying as a major cause.

We all acknowledge, Boeing has plenty of ownership on this issue, but to 99.9% blame the aircraft and .1% on the pilot, it's not reasonable.

Runaway trim is not specific to MCAS or to Boeing. It's taught to every pilot. If the trim is doing something you don't want it to, you turn it off.

The Ethiopia crash was doomed by the throttles left at takeoff thrust. No reason to blame the pilots for the throttle setting? The Boeing CEO would be crucified if he correctly blamed the pilots for the crash. We just can't talk about that here. The pilots failed to break the chain of mistakes, including their own poor choices.

I do not know how to break this into % here. 

I think that might be fair to say that "The pilots failed to break the chain of mistakes", but it didn't start with them.

I am not sure why Boeing didn't take action after the initial reports and after the first crash.  (I may have missed something in these posts and in the press).

As often is often said here, we should all wait for the final FAA report.

[Shuffler]

Why wasn't the MCAS system designed to use two pitot tubes simultaneously, and if they didn't match, MCAS would simply shut off?  Instead it simply crashes the aircraft.

Why not have any devices so we can see just how bad the pilots are without excuses?

[Oldman731]

I think that might be fair to say that "The pilots failed to break the chain of mistakes", but it didn't start with them.

That's a very good way of putting it.

- oldman

[Puma44]

https://www.c-span.org/video/?465775-1/boeing-ceo-dennis-muilenburg-testifies-737-max-safety


IMO aircrew experience probably the least relevant factor.

Completely disagree.  These pilots had a malfunction that was completely controllable had they used basic airmanship and maintained aircraft control.

I think that might be fair to say that "The pilots failed to break the chain of mistakes", but it didn't start with them.

A lot of the time it doesn’t.  Typically a sequence of events adds up and it’s up to the pilots to cut the chain.

[FLS]

...
I think that might be fair to say that "The pilots failed to break the chain of mistakes", but it didn't start with them.
...

Did you ever avoid a traffic accident? Did it really matter how it started? Nobody is being mean to the pilots. They reportedly met the local standards. Perhaps the mechanics did too.

The pilot's job, and there are two of them to help with this, is to break the chain of mistakes because nobody else is there to do it.