Author Topic: Another 737 down  (Read 32701 times)

Offline saggs

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Re: Another 737 down
« Reply #15 on: May 04, 2019, 05:23:53 PM »
« Last Edit: May 06, 2019, 08:57:23 AM by hitech »

Offline Vraciu

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Re: Another 737 down
« Reply #16 on: May 04, 2019, 05:26:04 PM »
Like I said, I understand the issue with the AOA/MCAS. It's an issue and Boeing and FAA are dealing with it. 

What I don't understand is why the crew could not, or did not, turn off the motor and trim manually.  A runaway, or uncommanded pitch trim input should not, in and of itself crash an aircraft. It is a simple task, a FROM MEMORY item (no checklist needed) uncommanded/runaway pitch trim = flip cutoff switches and trim the plane by hand. (then get out the checklist)

The faulty AOA reading and MCAS inputs are only one link in the accident chain, and for the life of my I can't fathom the other links.

They did, but only moved the manual trim about 20% of what was needed.   They then turned the electric trim system back on.   #LawnDart

Also, they never reduced thrust.   The aerodynamic load on the stab at 320+ KIAS was significant, complicating any effort to manually trim.   

A faulty AOA indication is easily verified as such with the use of basic airmanship. 
« Last Edit: May 04, 2019, 05:30:40 PM by Vraciu »
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Offline saggs

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Re: Another 737 down
« Reply #17 on: May 04, 2019, 05:31:52 PM »
They did, but only moved the manual trim about 20% of what was needed.   They then turned the electric trim system back on.   #LawnDart

Also, they never reduced thrust.   The aerodynamic load in the stab at 320+ was significant, complicating any effort to manually trim.

Wow!! Didn't know that.

Boggles my mind that 2 ATP rated pilots could screw up what seems so simple.

I guess it's easy for us to see without the pressure and stress they must have been under in the moment.  But still shocking to me.

Offline Vraciu

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Re: Another 737 down
« Reply #18 on: May 04, 2019, 05:44:06 PM »
Wow!! Didn't know that.

Boggles my mind that 2 ATP rated pilots could screw up what seems so simple.

I guess it's easy for us to see without the pressure and stress they must have been under in the moment.  But still shocking to me.

Technically they were Ethiopian.   I wouldn't equate their requirements for a Commercial Certificate to the US ATP.   I've seen some incompetent pilots in my career, and the US is by no means exempt, but overall I rate them (American pilots) highly.    My experience with third world pilots is the exact opposite.  It's an unfortunate mix of culture (fear of authority, graft, nepotism, etc.) and poor training.
« Last Edit: May 04, 2019, 08:35:43 PM by Vraciu »
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Offline DaveBB

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Re: Another 737 down
« Reply #19 on: May 04, 2019, 05:55:37 PM »
Funny the guy on the Lion Air jumpseat knew what to do though, isn't it?

We'll just agree to disagree.

The MCAS didn't kill them.

Pure luck and chance.  I have no dog in the fight. I can be purely objective.  In fact, I think one of my index funds is heavily invested in Boeing.
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Offline Busher

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Re: Another 737 down
« Reply #20 on: May 04, 2019, 06:21:22 PM »
Wow!! Didn't know that.

Boggles my mind that 2 ATP rated pilots could screw up what seems so simple.

I guess it's easy for us to see without the pressure and stress they must have been under in the moment.  But still shocking to me.

The sad thing is Saggs, 2 ATP qualified pilots would have found the issue to be relatively simple. Put the airplane manually into a safe attitude (with stab trim disengaged) and set a much lower thrust value (lower than the 94% N1 they kept) to establish speed in the 225 to 250 KIAS range.

These pilots by North American standards were grossly inexperienced - especially the First Officer. The pressure and stress that you mentioned was largely self imposed.
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Offline Toad

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Re: Another 737 down
« Reply #21 on: May 04, 2019, 07:56:13 PM »
Pure luck and chance.

Actually...no. Training and experience saved the first Lion Air. The next day...lack of training and experience killed them. When I say training and experience, I'm specifically talking about the Runaway Stab Trim procedure which has been essentially the same in B-707, B-727,B-737, B-747, B-757, B-767. In short, any pilot with previous Boeing experience has probably seen in the simulator many times and had it in his QRH forever.

 
Quote
I have no dog in the fight. I can be purely objective.


Feel free to be objective all you like. Nonetheless, it wasn't the MCAS that crashed those two aircraft. In both instances, it was a very basic AOA failure/problem. Any transport rated pilot should be able to recognize and overcome an AOA problem. As Vraicu and Busher pointed out upthread, all that's required to solve an erroneous AOA problem is basic airmanship and situational awareness. AOA problems are something that every ATP rated pilot should have dealt with in the sim or even in real life.

However, sometimes the crews fail. See AF 447, another AOA problem.

If you are doing 340+ knots in a reasonable climb, you aren't stalling. Fly the jet.

340kts, a 1500 fpm+ rate of climb and 94% power isn't an MCAS problem. It's a situational awareness problem.
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Offline Shuffler

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Re: Another 737 down
« Reply #22 on: May 04, 2019, 08:01:06 PM »
We already know what it is going to say. Pilot error due to not following procedure to correct MCAS system.  In all reality, the flight control software killed them.  If they knew what to do, they would have done it.  Boeing has an $800,000 software 'unlock' that would have told them if the AOA sensors were disagreeing. 
Anyhow, the flight control software killed them.

Vraciu, don't you dare chime in.  I'm getting pretty sick of you.  Idiot.

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Offline Vraciu

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Re: Another 737 down
« Reply #23 on: May 04, 2019, 08:05:24 PM »
Pure luck and chance.  I have no dog in the fight. I can be purely objective.  In fact, I think one of my index funds is heavily invested in Boeing.

Objective?   Is that a euphemism for uninformed?
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Offline Vraciu

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Re: Another 737 down
« Reply #24 on: May 04, 2019, 08:47:24 PM »
Actually...no. Training and experience saved the first Lion Air. The next day...lack of training and experience killed them. When I say training and experience, I'm specifically talking about the Runaway Stab Trim procedure which has been essentially the same in B-707, B-727,B-737, B-747, B-757, B-767. In short, any pilot with previous Boeing experience has probably seen in the simulator many times and had it in his QRH forever.

 

Feel free to be objective all you like. Nonetheless, it wasn't the MCAS that crashed those two aircraft. In both instances, it was a very basic AOA failure/problem. Any transport rated pilot should be able to recognize and overcome an AOA problem. As Vraicu and Busher pointed out upthread, all that's required to solve an erroneous AOA problem is basic airmanship and situational awareness. AOA problems are something that every ATP rated pilot should have dealt with in the sim or even in real life.

However, sometimes the crews fail. See AF 447, another AOA problem.

If you are doing 340+ knots in a reasonable climb, you aren't stalling. Fly the jet.

340kts, a 1500 fpm+ rate of climb and 94% power isn't an MCAS problem. It's a situational awareness problem.

Heino Caesar (Lufthansa) predicted that Air Chance crash back in 1996 based purely on design philosophy.   Boy was he right. 
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Offline ACE

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Re: Another 737 down
« Reply #25 on: May 04, 2019, 09:38:19 PM »


The MCAS didn't kill them.
Don’t reckon it helped any. Guess we’ll just have to agree to disagree.
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Offline saggs

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Re: Another 737 down
« Reply #26 on: May 04, 2019, 10:34:42 PM »
Don’t reckon it helped any. Guess we’ll just have to agree to disagree.

Aviation accidents are rarely traced to a single causal factor, and most of them have some kind of contributing human factors (I can't think of any accidents off the top of my head that don't have causal human factors, be they aircrew, MX, ATC or management)

That is why in investigations they call it the accident chain, several factors linked which together lead to an accident/incident, and if any link in that chain is broken then the accident/incident is averted.

It is obvious in this case that the failure in the MCAS system was one of those links, but it is also painfully obvious that there are human factor links as well. (training, culture, philosophy, etc)

I'm not a commercial pilot, I am an A&P mechanic.  So looking at it from my perspective I can say there is never, nor never will be a perfect airplane.  Big airliners are so complex, with so many interconnected systems that something is always breaking/broken or inop. Engineers knew this and so designed aircraft with many levels of redundancy, but at some point something will fail that necessitates remedial action by the flight crew. Which is why crew training, as well as well written abnormal and emergency checklists are so important.

So, yeah.  The failures of the aircraft systems didn't help, but it also seems like it should have been a problem easily overcome by a properly trained and competent crew.

Offline saggs

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Re: Another 737 down
« Reply #27 on: May 04, 2019, 10:47:44 PM »
Heino Caesar (Lufthansa) predicted that Air Chance crash back in 1996 based purely on design philosophy.   Boy was he right.

I remember watching the NTSB animation of AF 447 which shows the throttle and stick inputs.  Watching the FOs stick inputs was infuriating, you can tell the exact moment when captain realized what was going on and tried to recover... but the FO screwed them.

I've seen a clip with Sullenberger talking about the airbus design philosophy (non linked side sticks) as a contributing factor in that too.

Offline FESS67

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Re: Another 737 down
« Reply #28 on: May 05, 2019, 02:46:57 AM »
We already know what it is going to say. Pilot error due to not following procedure to correct MCAS system.  In all reality, the flight control software killed them.  If they knew what to do, they would have done it.  Boeing has an $800,000 software 'unlock' that would have told them if the AOA sensors were disagreeing. 
Anyhow, the flight control software killed them.

Vraciu, don't you dare chime in.  I'm getting pretty sick of you.  Idiot.

Hey DaveBB.  You seem like a smart guy, let me ask you a simple question.

There is a guy, let's call him John, driving on the highway and he is using cruise control.  It is keeping him right on the limit and he does not fear the cops or speed cameras, life is sweet.  Ahead, there are some roadworks and John sees these roadworks but does not turn the cruise control off.  John crashes and dies.

Question:  Did the cruise control kill John?

Offline Toad

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Re: Another 737 down
« Reply #29 on: May 05, 2019, 06:39:40 AM »
So, yeah.  The failures of the aircraft systems didn't help, but it also seems like it should have been a problem easily overcome by a properly trained and competent crew.

This.

EXACTLY This.
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