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China Ground 737MAX

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China Ground 737MAX

Old 11th Mar 2019, 10:57
  #21 (permalink)  
 
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Originally Posted by derjodel View Post
It's puzzling that EASA and FAA have not grounded it as well. And to those saying "we must first know the reason to justify grounding", I deeply disagree. E.g. the reason for Comet crashes was not understood as well (square windows and resultant forces at the edges). Should they just kept them flying and crashing saying "well it's a perfctly flying airplane, there should not be reason for them to just fall apart mid-air"?

Ground and make sure it's not mcas related first. If it's something completely unrelated, lift the ban if it seems appropriate. In the mean time, everybody is gambling with people's lives.
And running a high risk as well. Imagine, FAA doesn't ground and the next one falls out of the sky above L.A. The FAA will be sued, and rightly so!
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Old 11th Mar 2019, 11:12
  #22 (permalink)  
 
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I am surprised that other regulators havenít acted more quickly. This is supposed to be a safety first industry and the responsibity should now be on Boeing to prove their aircraft is safe. Not for the investigators to prove it isnít. On the face of intial reports, these seem eerily similar events. If this is MCAS related then;

If I understand the MCAS logic correctly, it relies on only one set of AoA instrumentation and does not fail safely? If a system critical to the continued safe operation of the aircraft does not fail safe, then IMO, it is unsafe and should not have been certified.

That is very black and white, I am not a pilot, just an interested bystander. But, people are losing their lives over what appears a poorly designed system. Blaming pilots for not following the manual is a cyncial get out of jail free card. Address the root cause which by all accounts to date is a flawed MCAS implementation. If an MCAS issue happens at altitude, it affords flight crew time to react. When altitude is limited as has been the case in Lion and Ethiopian cases, it could be that there just isnít enough time to diagnose and save the day.

Remember the US Airways into the Hudson, investigators were about to blame the flight crew for not returning to an airfield. They even had sim sessions to prove the aircraft could have made Teterboro. What those sim sessions did not account for was thinking time, the extra 30 seconds delay added befoe the sim pilots were allowed to head for Teterboro was enough to cause them to be unable to make it. Itís all well and good having a procedure to disable MCAS but MCAS would need to be identied as the issue before switching it
off. At low altitudes, how much time does that give the crew before they are doomed?

Iíve read elsewhere that SWA have installed additional AoA instrumentation on their MAXís to help pilots in a situation where MCAS decides a nose first dive is an appropriate course of action. That seems enough evidence to me to conclude that SWA see the threat worthy of at least some additional protection to help their pilots in a scenario where MCAS decides an aircraft is in danger of stalling, when infact it isnít.
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Old 11th Mar 2019, 11:17
  #23 (permalink)  
 
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I am not a pilot, just an interested bystander
says it all really. Yet you are surprised regulators, that know infinitely more on the subject matter than you, have not acted more quickly.

If you perform the memory items as prescribed by Boeing the aircraft will fly trim misbehaviour or not. They are not complicated 10 degree pitch and 80%n1, if while doing that the trim keeps getting away from you and you cannot maintain 10 degrees pitch just override the trim by the disconnecting the switches. Maybe there is a training issue. Why did 4 crews manage to fly their way out of the lion air failure yet the fifth one couldnīt. Maybe years and years of accountants telling anyone that would listen that modern aircraft will fly themselves are coming home to roost. Maybe a 200 cadet should not be doing his training with 150 pax behind them. Maybe Ethiopianīs rostering system is a fatigue inducing disaster. I wonder if China would ground the Comac c919 after two crashes with a fleet of 300 flying. I very much doubt it somehow.

Last edited by calypso; 11th Mar 2019 at 11:30.
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Old 11th Mar 2019, 11:23
  #24 (permalink)  
 
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It seems Indonesia has grounded them as well:
https://www.bloomberg.com/news/artic...thiopian-crash
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Old 11th Mar 2019, 11:27
  #25 (permalink)  
 
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Originally Posted by calypso View Post
says it all really. Yet you are surprised regulators, that know infinitely more on the subject matter than you, have not acted more quickly.
Fair point which is why I made that clear but is my general understanding of MCAS correct? If it is, are my questions not valid? Are the points I make about not fail safe and a sinlge point of failure not also valid? Are all accident investigators and regulators also pilots or do they seek advice from other professionals before making decisions? Effectively, in a similar vein to what my post above has done.
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Old 11th Mar 2019, 11:56
  #26 (permalink)  
 
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If a system critical to the continued safe operation of the aircraft does not fail safe, then IMO, it is unsafe and should not have been certified
But is not critical is it? there is certified procedure that enables the flight to continue safely if it is followed as proven by the flights previous to the crash in the lion air case. In the current accident we do not yet know what was the cause therefore blaming MCAS is jumping to conclusions.
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Old 11th Mar 2019, 12:34
  #27 (permalink)  
 
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Originally Posted by calypso View Post
But is not critical is it? there is certified procedure that enables the flight to continue safely if it is followed as proven by the flights previous to the crash in the lion air case. In the current accident we do not yet know what was the cause therefore blaming MCAS is jumping to conclusions.
If it isnít critical, why is it there in the first place? Surely a stall is a critical situation to be in therefore a system implemented as a means to prevent that should therefore be deemed critical by association?

Iím not jumping to conclusions. If you read my post it is very clear in stating that Ďifí MCAS is the issue. Itís remains to be determined if that is the case but so far, these seem very similar incidents. My follow up questions were related to the McAS system
and whether those questions were relevant to a potential fleet grounding.

Iíve now seen your edit of the original post. If other crews have flown out of this, it doesnít really help. Can you implement that memory item you mention on climb out from ADD where high terrain is a consideration? Or, is that just going to fly you into another world of pain?

My point is simple and it is not based on this Ethiopian crash. MCAS is a botched implementation of a system which has a single point of failure. That the crew can switch it of is irrelevant. It is there for a reason and just switching it off removes a protection that one can only assume was required to ensure the aircraft was certifiable. Otherwise why would Boeing spend the $$$ís developing it?

Eg. Lets say my car had a flaw where it decided I was driving over a centre line into oncoming traffic therefore it was designed to steer me away from a Ďhazardí. The car gets it wrong and it steers me into a ditch. I donít just sit around and wait for it to happen again and override it. I bring it
back to the manufacturer and tell them to fix the dangerous behavior of the system. In the meantime they can provide me with a safe alternative. Why is it any different here? Boeing have in effect admitted previously, by their emergency directives, that MCAS is flawed. A ífixí has yet to be released by all accounts.

EDIT: FDRís have now been recovered. It shouldnít take long now to have some initial hypothesis around the potential cause.
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Old 11th Mar 2019, 12:34
  #28 (permalink)  
 
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Is it really the case that the A of A information fed to the stall protection system, which can cause full nose down stab trim, which cannot be overcome by elevator input, has only ONE source of data?

Many years ago, in the RAF, the Canberra had a number of tpi runaways, with fat al results, caused by malfunction if the single trim switch. This was cured by adding another switch in series, problem solved. Similarly we had an issue with stab trim runaways in the Valiant, and were trained to deal with the known problem, which could be overcome by elevator input.

But if Boeing are not giving crews the very last detail of the flight control system, they need to seriously review that decision.

With 20 years as a Boeing captain (73, 75 and 76) I have always held, and hold, Boeings in the highest regard, BUT, not giving pilots the full story about the most inportant system on the airplane seems a very strange decision indeed.
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Old 11th Mar 2019, 12:57
  #29 (permalink)  
 
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Originally Posted by RetiredBA/BY View Post
Is it really the case that the A of A information fed to the stall protection system, which can cause full nose down stab trim, which cannot be overcome by elevator input, has only ONE source of data?

Many years ago, in the RAF, the Canberra had a number of tpi runaways, with fat al results, caused by malfunction if the single trim switch. This was cured by adding another switch in series, problem solved. Similarly we had an issue with stab trim runaways in the Valiant, and were trained to deal with the known problem, which could be overcome by elevator input.

But if Boeing are not giving crews the very last detail of the flight control system, they need to seriously review that decision.

With 20 years as a Boeing captain (73, 75 and 76) I have always held, and hold, Boeings in the highest regard, BUT, not giving pilots the full story about the most inportant system on the airplane seems a very strange decision indeed.
https://theaircurrent.com/aviation-s...em-mcas-jt610/ seems to sum
up much of what I have read.

In essence each side of the aircraft operates independently from the other. The AoA is not cross checked with the other side. So, eg. if the Captain is flying and their AoA fails, MCAS can command nose down without cross checking with the other functioning AoA sensor. One broken AoA can lead to an incorrect action and intervention by MCAS. Thatís how I read it at the time
of JT610. Unfortunately I canít find the exact article right now.
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Old 11th Mar 2019, 13:24
  #30 (permalink)  
 
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Originally Posted by EGAC is Better View Post
Remember the US Airways into the Hudson, investigators were about to blame the flight crew for not returning to an airfield. They even had sim sessions to prove the aircraft could have made Teterboro..
That was a film... itís about as real as most Hollywood films where the USA captures the enigma machine, sinks the Bismarck or blows up the sodding guns of Navarone.
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Old 11th Mar 2019, 13:42
  #31 (permalink)  
 
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Originally Posted by calypso View Post
says it all really. Yet you are surprised regulators, that know infinitely more on the subject matter than you, have not acted more quickly.
After 340 lifes lost, they should act on the shadow of doubt!

Why did 4 crews manage to fly their way out of the lion air failure yet the fifth one couldnīt.
Are you serious? 1 out of 5 is a disastrous quota...
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Old 11th Mar 2019, 13:47
  #32 (permalink)  
 
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Originally Posted by Daysleeper View Post


That was a film... itís about as real as most Hollywood films where the USA captures the enigma machine, sinks the Bismarck or blows up the sodding guns of Navarone.
No. I think youíll find it portrayed, maybe with a bit
of
artistic licence, the fact there was a belief in the investigation team that the aircraft could have returned to LGA or made TEB, rather than ditch in the Hudson. If my memory serves, the pilots union representing the crew raised the issue with regard to thinking time required to make a decision. After that, low and behold the sims are re-run and they vindicated (in the circumstances) the crews decisions that the only safe place to go was the Hudson.

Anyway, thatís off topic. I only used it as example to demostrate the humans need thinking time. Time that in some scenarioís will make a critical situation a fatal one.
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Old 11th Mar 2019, 14:16
  #33 (permalink)  
 
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TUI about to stop 737max operation...

TUI
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Old 11th Mar 2019, 14:20
  #34 (permalink)  
 
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Interesting, while the regulators are sleeping, the market is moving. My bet is there are cancellations going on behind the scenes. Perhaps even pilots refusing to fly? Also the companies who decided to stop Max operations are creating pressure to the ones who have not. I predict that even if the regulators don't ground it, the dominos will continue rolling and we'll se more and more suspensions until almost all operators suspend flights, at least until the fdr/cvr are read.
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Old 11th Mar 2019, 15:19
  #35 (permalink)  
 
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Memory items are put in place when there is a requirement to perform a procedure in a prompt manner to return the aircraft to a safe state without sufficient time to refer to a paper procedure. Modern airliners have on average 8 or 9 such procedures which include such things as emergency descents, unreliable airspeed, engine failures, etc. The failure of a crew to perform such a procedure when required unsurprisingly might have fatal consequences but does not render that aircraft type un-airworthy. Unreliable airspeed in particular requires the sort of hand to eye coordination and instrument scan that seldom gets practiced by some pilots and that is actively discouraged by some airlines.

While I am not saying that is the cause for this accident unreliable airspeed is not the sort of failure one would like if inexperienced or rusty on your hand flying. Of course if the failure did not happen in the first place there would be no accident but we, as pilots, should be able to survive an unreliable airspeed incident even if coupled with an undesirable runaway stabiliser. Grounding the fleet does not address the core issue which goes beyond one aircraft type or one manufacturer.
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Old 11th Mar 2019, 16:03
  #36 (permalink)  
 
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Originally Posted by EGAC is Better View Post


No. I think youíll find it portrayed, maybe with a bit
of
artistic licence, the fact there was a belief in the investigation team that the aircraft could have returned to LGA or made TEB, rather than ditch in the Hudson. If my memory serves, the pilots union representing the crew raised the issue with regard to thinking time required to make a decision. After that, low and behold the sims are re-run and they vindicated (in the circumstances) the crews decisions that the only safe place to go was the Hudson.

Anyway, thatís off topic. I only used it as example to demostrate the humans need thinking time. Time that in some scenarioís will make a critical situation a fatal one.
actually it's critical to aviation safety to recognise the flaws in that film's portrayal of the NTSB and the investigative process. The NTSB were well aware of startle effect, it was planned into the sim profile by the NTSB with zero input from other parties. Nobody tried to stitch up Sully or anyone else for that matter. The movie makers had to fill out a 6 minute event and decided to create a "baddy" so they could meet the Hollywood fantasy of good v evil. It's untrue and needs to be recognised as such.
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Old 11th Mar 2019, 16:18
  #37 (permalink)  
 
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Originally Posted by EGAC is Better View Post
the fact there was a belief in the investigation team that the aircraft could have returned to LGA or made TEB, rather than ditch in the Hudson. If my memory serves, the pilots union representing the crew raised the issue with regard to thinking time required to make a decision. After that, low and behold the sims are re-run and they vindicated (in the circumstances) the crews decisions that the only safe place to go was the Hudson.
The fact is, that the NTSB must investigate ALL aspects of an incident, not just that what the public believes it should be. Until it was attempted in a simulator, the answer could very well have been that there was a viable option to return and if there were, then it would have been something to use for future training. It's not always about assigning blame. In this case it was clear that returning was not an option and that air crew's experience paid off.

Even if it would have been an option, it would have carried a lot of risk. Remember that there are people on the ground as well; failing to make the runway would also have caused harm below. That by itself should be sufficient reason to not have decided to go back, and ditch instead. I'm sure the NTSB would have evaluated the risks in the same manner and not have blamed the crew. The real NTSB that is, not the Hollywood version.
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Old 11th Mar 2019, 16:39
  #38 (permalink)  
 
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Royal Air Maroc just stop it too...
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Old 11th Mar 2019, 21:53
  #40 (permalink)  
 
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I would fly as a passenger on a B737 Max only if it was operated by an airline in which I had confidence in the operational and maintenance standards. British Airway, Qantas, Air New Zealand etc would be okay. Any third world operator, forget it.
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