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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 12th Mar 2019, 08:51
  #621 (permalink)  
 
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Originally Posted by silverstrata View Post

I have been wondering about Rostov. Is it possible that the Fly Dubai was fitted with a Max speed-trim computer? I bet they are compatible, because that is cheaper, and Boeing does everything on the cheap. So did an engineer not have the right spare unit, so fitted one from a Max instead? - Not realising that there was a fundamental software difference between the two units?

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?

Silver
Given that accident was in Dec 2016 to an aircraft built in 2010 and the Max didn't enter service until Aug 2017 I think that's a pretty fanciful hypothesis.
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Old 12th Mar 2019, 08:51
  #622 (permalink)  
 
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Originally Posted by silverstrata View Post




Rostov.

I have been wondering about Rostov. Is it possible that the Fly Dubai was fitted with a Max speed-trim computer? I bet they are compatible, because that is cheaper, and Boeing does everything on the cheap. So did an engineer not have the right spare unit, so fitted one from a Max instead? - Not realising that there was a fundamental software difference between the two units?

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?

Silver
The issue with your theory is that the Rostov accident happened only two months after the Max first flew and at least a year before FZ took delivery of their first MAX, so it is pretty unlikely that a flydubai engineer happened to find a spare MAX component kicking around in a parts bin and then randomly fit it into an 800.
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Old 12th Mar 2019, 08:52
  #623 (permalink)  
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Something else to ponder is that the 737 is controllable with the trim at either the forward or rear extreme. However, it's a two hands on the column job.
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Old 12th Mar 2019, 08:57
  #624 (permalink)  
 
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Australia joins the list:

https://www.bbc.com/news/world-asia-47536502
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Old 12th Mar 2019, 08:57
  #625 (permalink)  
 
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Originally Posted by silverstrata View Post


I don’t agree at all.

If the f/o was flying, he only had 200 hours. After flaps up, the stick shaker goes off, which is mighty disconcerning, and MCAS bungs in a load of trim. The captain cannot see why the trim is trimming, and the low-hours f/o has no clue (seen that many times). The captian thinks he has an airspeed problem and is stalling, and tells the f/o to lower the nose - which the f/o does rather easily, because he is holding a load of back pressure. MCAS then bungs in another load of trim, and the f/o is now really struggling with the controls - never having felt an aircraft behave like this (at this stage, you need about 30 kg of force to hold the aircraft level).

The captain is still convinced the airspeed is wrong and they may be stalling (stick shaker still going), and shouts “I have control”, but does not realise so much pitch force is necessary, so the aircraft instantly pitches forward into a steep dive. Captain is mighty startled by this - is this pitch down the result of a stall? He has forgotten all about the previous trim episodes, and just hauls back on the stick. But MCAS now gives another load of forward trim, which makes the aircraft completely unflyable (60 kg of force necessary on the stick). And here comes terra firma....

Silver
Woah!! They should hire you for the inevitable National Geographic over-dramatization.
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Old 12th Mar 2019, 09:02
  #626 (permalink)  
 
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Originally Posted by Jeps View Post
I don’t drive the MAX but I think I understand what MCAS does and doesn’t do (maybe). Is it possible that two things could be true and that whilst Boeing have stuffed up on a few different levels as I see it could it also be the case that if training were appropriate neither of these incidents would’ve been fatal?
It is also possible this flight discovered a new failure mode for the software logic.
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Old 12th Mar 2019, 09:09
  #627 (permalink)  
 
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Originally Posted by juice View Post
Australia has suspended operations of all Boeing 737 Max aircraft

https://www.rte.ie/news/world/2019/0...irlines-crash/
Well that’s easy. Considering there are none operating in Australia.

Cheaply bought spine CASA!
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Old 12th Mar 2019, 09:10
  #628 (permalink)  
 
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Originally Posted by Chesty Morgan View Post
Something else to ponder is that the 737 is controllable with the trim at either the forward or rear extreme. However, it's a two hands on the column job.
and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?
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Old 12th Mar 2019, 09:14
  #629 (permalink)  
 
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Originally Posted by KRUSTY 34 View Post


Well that’s easy. Considering there are none operating in Australia.

Cheaply bought spine CASA!

The Australian suspension affects Singapore's SilkAir (which has already grounded its fleet) as well as Fiji Airways that will have to substitute their two 737 Maxs on routes to Australia for other aircraft. So they have bought a spine within some, albeit limited impact.

Last edited by Drjojo; 12th Mar 2019 at 09:27.
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Old 12th Mar 2019, 09:18
  #630 (permalink)  
 
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Is this a good summary of what the crew may have experienced:

normal rotation to takeoff attitude and within a few seconds;

GEAR RETRACTION
IAS DISAGREE WARNING
ALT DISAGREE WARNING
STICK SHAKER ACTIVATION
STAB OUT OF TRIM WARNING (?)
MASTER CAUTION FLIGHT CONTROLS
TROUBLESHOOTING AND MEMORY ITEMS
DISCONNECT AUTOTHRUST
TURN OFF BOTH FLIGHT DIRECTORS
SET 10 DEGREES PITCH UP
SET 80%N1
CHECK PROBE HEAT ON
SPEED TRIM SYSTEM ACTIVATION (in background) - PUSHING THE NOSE DOWN
FLAP RETRACTION AT 1000ft OR AS SPEED INCREASES, OR OVERSPEED OF FLAPS
MCAS ROLLING IN NOSE DOWN STAB TRIM INCREMENTLY (NOT A RUNAWAY)
PM GETS OUT THE QRH TO READ CHECKLIST
PF IS ON THE RADIO AND STARTING TO FIGHT AGAINST THE NOSE DOWN BIAS
VARIOUS ALERTS SOUNDING:
”TOO LOW GEAR”
”CAUTION TERRAIN”
”TERRAIN TERRAIN”
“DONT SINK”
”PULL UP”

At this stage either the PF remembers the Bulletin and goes for the MCAS cutout switches - AKA STAB TRIM CUTOUT SWITCHES or he doesn’t.

The difference between an excellent pilot and an average pilot at this point is minuscule due to information overload and serious anxiety - a bad result is highly possible.

PLEASE sit in a quiet space, close your eyes and imagine its you sitting in that flightdeck. Just like the Air France and Perpignan accidents the AoA played a part - so its not just a Boeing problem.

Last edited by SMYDSTS; 12th Mar 2019 at 14:01. Reason: More distraction
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Old 12th Mar 2019, 09:24
  #631 (permalink)  
 
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There is a Fiji MAX inbound to Sydney right now a few hundred miles to go but no obvious diversion point at this late stage.

I wonder if they will let it leave?
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Old 12th Mar 2019, 09:30
  #632 (permalink)  
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Originally Posted by oldoberon View Post
Several more airlines pull the 737 Max after the 2nd crash in Ethiopia.

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

Who would make that Comair decision?

Oldoberon
That is a very good point old chap - I wonder if BA Waterside called JNB?

Meanwhile over on TUI's Facebook and Twitter pages they are Inundated with their 1000's of their customers who are really not happy to be going on their holidays on a TUI or a Norwegian MAX right now...
(Even Enter Air who flies for some UK Greek tour operators is getting flack for not grounding their Max for now)

The bog standard tweeted reply continually coming from TUI has a slight smack of arrogance about it which, if that has come from the TUI PR department is rather disconcerting.
Although I doubt some little social media customer agent would be allowed to pass off a message like that...

However,
I would like to think that (as has been mentioned here in other posts) that all well respected TUI or DI MAX pilots would have burnt the midnight oil late into the night reading up on the MACS systems and how to deal with that - plus any spurious data that may occur. (and how to switch it all off)
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Old 12th Mar 2019, 09:38
  #633 (permalink)  
 
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Originally Posted by silverstrata View Post
Rostov.

I wonder because the report said that the Fly Dubai pilots trimmed forward for 10 seconds. And everyone was aghast by that news, because no pilot would ever trim forward for 10 seconds. We were thinking in terms of a health issue, with someone freezing on the controlls. But as it happens, this is exactly what MCAS does - it trims forward for 10 seconds. So was the Fly Dubai fitted with a Max speed-trim computer?
Avherald explicitly says "lasted for 12 seconds"
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Old 12th Mar 2019, 09:38
  #634 (permalink)  
 
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Capt was flying. Or should be. As he had only a few months on the MAX, and - Addis is a 'Capt only" airport. At least in Ethiopian it is
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Old 12th Mar 2019, 09:40
  #635 (permalink)  
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Originally Posted by quentinc View Post
and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?
If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you, then distribute work load accordingly. It'll take something like 30 odd turns to get it back to somewhere more manageable.



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Old 12th Mar 2019, 09:40
  #636 (permalink)  
 
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Originally Posted by silverstrata View Post


I don’t agree at all.

If the f/o was flying, he only had 200 hours. After flaps up, the stick shaker goes off, which is mighty disconcerning, and MCAS bungs in a load of trim. The captain cannot see why the trim is trimming, and the low-hours f/o has no clue (seen that many times). The captian thinks he has an airspeed problem and is stalling, and tells the f/o to lower the nose - which the f/o does rather easily, because he is holding a load of back pressure. MCAS then bungs in another load of trim, and the f/o is now really struggling with the controls - never having felt an aircraft behave like this (at this stage, you need about 30 kg of force to hold the aircraft level).

The captain is still convinced the airspeed is wrong and they may be stalling (stick shaker still going), and shouts “I have control”, but does not realise so much pitch force is necessary, so the aircraft instantly pitches forward into a steep dive. Captain is mighty startled by this - is this pitch down the result of a stall? He has forgotten all about the previous trim episodes, and just hauls back on the stick. But MCAS now gives another load of forward trim, which makes the aircraft completely unflyable (60 kg of force necessary on the stick). And here comes terra firma....

Silver
Capt was flying. Or at least he should be. He was a few months into his 737 carreer. And Addis is a "Capt Only" airport
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Old 12th Mar 2019, 09:43
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The Fiji MAX will be grounded in Sydney. Thankfully they didn’t send the other to Melbourne otherwise they would be screwed. The Brisbane flight just got out in time.
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Old 12th Mar 2019, 09:54
  #638 (permalink)  
 
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Originally Posted by quentinc View Post
and whilst you have two hands on the yoke, the FAA directive to follow the trim runaway memory checklist, requires you to operate the guarded stabilizer trim cut out switches. Maybe the FO can do this. Once done, you still have the aircraft out of trim but now your trim switches on the yoke wont work. You need to shout at the copilot, to operate the trim wheels manually. If way out of trim, he's got plenty of spinning to do. Too much speed? Will reducing thrust result in more pitch down or give more time for the copilot to save the aircraft?
Yes and the poor souls at Lion Air were likely focused on another memory item checklist, ultimately one that didn't rectify the issue.
The FAA Boeing Bulletin might seem simple in hindsight, but with a cacophony of noise and spurious alerts and call outs, it is not too hard to imagine a sense of overwhelm.

Have Boeing unknowingly introduced a single point of failure into the aircraft?

That the SWA 737MAX fleet was 'fitted' with a Boeing factory option displaying AOA on both PFD, not just the Captain's HUD is suggestive that at least some airlines consider that indications need cross checking.
The sense one gets is that the pilots with the AOA displayed can cross-check and likely the display would assist a rapid diagnosis of the issue.

Indeed the early QF orders of the 738, were destined for another customer and had the option already 'fitted' , all additional aircraft have the same indication.
Perhaps it is time Boeing 'fitted' it to all 737 MAX? Or are their lawyers suggesting to do so implies a problem?

https://theaircurrent.com/aviation-s...737-max-fleet/

The FAA look the odd one out as increasingly a risk aversion mindset takes hold.
Regulatory capture it may well be, but other aircraft have been grounded for a lot less, all in the name of safety.
How much short open interest in BA (NYSE) ? How much of an eye has the regulator on the economics?

That this event occurred in the same phase of flight is the concern. Until they categorically rule out that the MCAS system was at play here, the aircraft ought be sitting idle on the ground.

Last edited by Rated De; 12th Mar 2019 at 10:06.
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Old 12th Mar 2019, 09:54
  #639 (permalink)  
 
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Just been on Twitter, as said above TUI pax are in revolt over whether or not they should be flying the MAX. If my kids were having to jump on one tomorrow I think I’d have to pull the pin on that decision, regardless of whether or not the crews had been up all night getting au fait with the latest bulletins.
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Old 12th Mar 2019, 09:57
  #640 (permalink)  
 
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Originally Posted by Chesty Morgan View Post
If it gets to the forward stop there's no rush to get to the stab trim cut outs cos it ain't going any further. Fly it away from the ground, might take both of you, then distribute work load accordingly. It'll take something like 30 odd turns to get it back to somewhere more manageable.
Didn’t work with Lion Chesty. Perhaps it is easier said than done?
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