China Ground 737MAX
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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.
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.
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I am surprised that other regulators haven’t 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 isn’t. 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 isn’t 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. It’s 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?
I’ve read elsewhere that SWA have installed additional AoA instrumentation on their MAX’s 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 isn’t.
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 isn’t 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. It’s 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?
I’ve read elsewhere that SWA have installed additional AoA instrumentation on their MAX’s 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 isn’t.
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I am not a pilot, just an interested bystander
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 couldn´t. 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 Ethiopian´s 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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It seems Indonesia has grounded them as well:
https://www.bloomberg.com/news/artic...thiopian-crash
https://www.bloomberg.com/news/artic...thiopian-crash
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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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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
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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.
I’m not jumping to conclusions. If you read my post it is very clear in stating that ‘if’ MCAS is the issue. It’s 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.
I’ve now seen your edit of the original post. If other crews have flown out of this, it doesn’t 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 $$$’s 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 ‘hazard’. The car gets it wrong and it steers me into a ditch. I don’t 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 ’fix’ has yet to be released by all accounts.
EDIT: FDR’s have now been recovered. It shouldn’t take long now to have some initial hypothesis around the potential cause.
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.
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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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.
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.
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. That’s how I read it at the time
of JT610. Unfortunately I can’t find the exact article right now.
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That was a film... it’s 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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Why did 4 crews manage to fly their way out of the lion air failure yet the fifth one couldn´t.
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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, that’s off topic. I only used it as example to demostrate the humans need thinking time. Time that in some scenario’s will make a critical situation a fatal one.
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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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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.
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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No. I think you’ll 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, that’s off topic. I only used it as example to demostrate the humans need thinking time. Time that in some scenario’s will make a critical situation a fatal one.
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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.
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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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.