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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 12th Mar 2019, 00:51
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Several more airlines pull the 737 Max after the 2nd crash in Ethiopia.

Royal Air Maroc RAM, and now BA RSA franchise Comair.

whio would make he Comair decision

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Old 12th Mar 2019, 00:53
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Originally Posted by hans brinker
AFAIK there are 2 AOA-s on the 737, the MCAS uses only AOA-1
From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight....
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Old 12th Mar 2019, 00:56
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Originally Posted by hans brinker
Sorry, after 30 years it is hard not to speak in allcaps three letter words, here is the English version:
Every 737 has 2 Angle Of Attack indicators, and a warning light for a difference in value between the two. SW have paid extra to display the actual AOA value displayed on the respective pilots instruments. The left pilot seas AOA one, the right pilot sees AOA 2 values. These should be the same, and if they are not seeing the value could help in deciding who is right.
Decent write-up here. Also says American had opted for the display feature from the get go.

https://theaircurrent.com/aviation-s...737-max-fleet/
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Old 12th Mar 2019, 01:15
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I havenít flown a plane as PIC since 1994, but Iím pretty systems automation and computer savvy. Reading the above posts I get the feeling that hardly anyone understands how MCAS really works, not even its designers. It reminds me of the financial crisis a decade ago when the so-called professionals ultimately didnít understand what they created.

Pages of debate on both this and the Lion Air threads about how the thing actually behaves should be a big red flag, regardless of the actual cause of these accidents.
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Old 12th Mar 2019, 01:26
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Not airframer's

Phylosocopter, the diagram is marked with Ostrower's trademark. It's 98.9 percent clear that it is something Jon created to explain somewhat arcane and technical flight control systems to an essentially layman readership (for his publication "The Air Current"). Not carrying water for Jon here but -- Boeing has enough of headaches at the moment, without even a "rumour" that gives forum folks the "EEEKs."

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Old 12th Mar 2019, 01:27
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re post 521
11th Mar 2019, 15:33
#521 (permalink)

. . .


Ask the author where he got the data and MIS info on MCAS- re override by pilot
https://theaircurrent.com/author/jonostrower/
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Old 12th Mar 2019, 01:34
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Originally Posted by thcrozier
Pages of debate on both this and the Lion Air threads about how the thing [MCAS] actually behaves should be a big red flag, regardless of the actual cause of these accidents.
Yes. In the discussions of both crashes, it has been striking that there has been so much confusion and disagreement about the operation of MCAS, much of it on the part of transport-experienced professional aviators. And no matter how much relevant material I've read, or how often I've re-read it, some things still aren't clear. For instance, some descriptions of the "system" (software patch) suggest that it is necessary for the MAX to be in a high bank for it to be activated. That doesn't make sense and it doesn't seem to have been the case in the Lion Air or the ET crashes (if the ET incident was MCAS-related), but it pops up repeatedly in lists and graphics.

Common sense and basic principles of human engineering dictate that a system or application that creates this much uncertainty and confusion, even among experts in a discipline, is begging for redesign.



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Old 12th Mar 2019, 01:43
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Originally Posted by thcrozier
I get the feeling that hardly anyone understands how MCAS really works,
yep, I sure as hell don't and I'd love to see it explained in a way so that a dimwit like me (LSA pilot) can understand.
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Old 12th Mar 2019, 01:55
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". . . begging for redesign" [OldnGrounded]

Seems a prudent conclusion - based on present state of actual information and reasonable inferences.
But there's another design redo flopping onto agendas, isn't there? The certification process itself. Maybe the lithium-ion batteries were a vague straw in the wind, albeit not stretching out an older type design as such. Clearly the MCAS situation - even if this accident doesn't turn out to be rooted in MCAS - is a strong indicator. As others have stated here and on Lion Air 610 thread, the process being set-up and administered so that mods can be added, to a basic type that is decades old, with this result, should not be allowed to persist. I won't even try to sketch a new and improved architecture for the FARs and the industry-regulator collaboration arrangement, even if I could, but isn't this work coming into necessity?

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Old 12th Mar 2019, 01:56
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Boeing to upgrade software in 737 MAX 8 fleet in 'weeks'
https://www.reuters.com/article/ethi...-idUSL1N20Z01K

Just wow... Begs the question, how long have they known about the issues???
Was the aircraft pushed out too early to "meet schedule" and increase profit?
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Old 12th Mar 2019, 02:03
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How?


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Old 12th Mar 2019, 02:04
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The FAA Has No Current Plans to Ground Boeing’s 737 MAX After Deadly Crash

Agency to mandate software fix by end of April


from WSJ behind paywall
By
Robert Wall,Andrew Tangel andAndy Pasztor
Updated March 11, 2019 8:35 p.m. ET

The Federal Aviation Administration said Monday it doesn’t plan to ground Boeing Co.’s BA -5.33% 737 MAX planes, despite concerns by other countries, passengers and airline employees after the model’s second crash in less than five months.
But yet they grounded 787 worldwide for two battery fires with no deatchs or injuries ..

Now that A covers are in place - we ill follow SOP and carefully avoid pointing fingers at ???


Last edited by CONSO; 12th Mar 2019 at 02:28.
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Old 12th Mar 2019, 02:18
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lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

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Old 12th Mar 2019, 02:21
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Switch direction.

I recently transitioned to an Airbus from an old British machine. It wasn’t until some months into flying the bus that I realised the switch directions were opposite to what I was supposedly used to. You see, what I’d been doing is this, if I knew something was off and I wanted to turn it on, I would locate the appropriate switch and move it to its other position. I would then check that what was once off was now on and I would carry on. I do something similar with light switches in a room, if the lights are off, I locate a light switch and move it to its opposite position, I then check that the lights have come on. If they haven’t, I look for another light switch and repeat the procedure .

I find it very hard to believe that someone could be confused by switch direction. If the trims need to be cutout, you lift the guard and move the switch. Right? You don’t lift the guard, observe the switch in a particular position, mistake that position for OFF, and then assume that somehow the switch was already off! Talk about overthinking.
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Old 12th Mar 2019, 02:23
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Fiji Airways have not grounded their two - I am about to board one
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Old 12th Mar 2019, 02:25
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AerolŪneas Argentinas has suspended their MAX operations, currently 5 in the fleet.
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Old 12th Mar 2019, 02:32
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Originally Posted by oldoberon
lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem

Oldoberon
There is no information in the current B738M AOM that tells crews that the "MCAS cycles between the left AoA and the right AoA sensor". What is the source for the above statement?
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Old 12th Mar 2019, 02:37
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In Boeing's Nov 6 2018 (FAA as of that date unapproved) bulletin, p. 25, Skyjob's post#496, no mention is made anywhere by Boeing of MCAS.

In Post #511, the clear graphic from Air Current states that MCAS activates when 'steeply turning'.
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Old 12th Mar 2019, 02:42
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Originally Posted by oldoberon
lancs said " From the Lion Air thread, I believe MCAS cycles between the 2 AOAs between each flight..""..

If the system uses 1 &2 on alternate flights both are wired in, I would think it is relatively simple to put a 1-2 switch in the cockpit but it is only active when the red light / HUD shows there is a difference, that could possibly immediately allow crew to rectify problem
Boeing's software update for the 737 MAX should address the AOA-1 vs -2 inconsistency (assuming that is its scope), obviating the need for physical switches. That also seems a good stage to include reasonability checks on AOA data before triggering MCAS.
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Old 12th Mar 2019, 02:46
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Originally Posted by jolihokistix
In Boeing's Nov 6 2018 (FAA as of that date unapproved) bulletin, p. 25, Skyjob's post#496, no mention is made anywhere by Boeing of MCAS.

In Post #511, the clear graphic from Air Current states that MCAS activates when 'steeply turning'.
But there is more for example post 427 also applies and AirCurrent does a lot of interpretation



MCAS activates automatically when all of the following conditions are met:
High angle of attack ( could be high bank angle for example )
Autopilot disengaged
Flaps are up
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