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Originally Posted by exwannabe
(Post 30906488)
The worst was the decision to downplay the existence of the system. Had pilots been trained to recognize the failure they would not have spent precious minutes making useless trim adjustments that the MCAS would revers shortly afterwards. Cuting the electiic trim control completley and mechanically wheeling it in would presumably have worked in both cases.
So Boeing made a human decision to conceal that the MAX was more difficult to handle, and that decision cost lives. We don't know what cost lives yet, since the accident reports aren't out yet. |
Originally Posted by exwannabe
(Post 30906488)
Disagree with you here. The engineering mistakes and decisions will look bad, but are not the worst.
The worst was the decision to downplay the existence of the system. Had pilots been trained to recognize the failure they would not have spent precious minutes making useless trim adjustments that the MCAS would revers shortly afterwards. Cuting the electiic trim control completley and mechanically wheeling it in would presumably have worked in both cases. In other words, I'm arguing that the failure should have been recognized, both by the Lion Air (like the crew that brought the ill-fated jet into CGK the night before) or Ethiopian crew (which received training on the post-Lion Air MCAS faults). Human factors and altitude-critical phase of flight likely precluded the timely recognition of the issue and application of corrective measures in both instances. What should not be happening is one single failure very rapidly setting in motion a chain of events leading to the necessity of a 'do-or-die' intervention by the crew. Simply put, that introduces far too many variables (pilot workload, experience, quality of training, CRM, mental recall, fatigue etc.) to ensure a reasonably acceptable expectation of success when/if said failure happens. If that's ultimately what brought down the ET302 flight, then I think Boeing's biggest problem is right there. The alleged "concealment" is a bit of sensationalism, IMO. |
Originally Posted by mduell
(Post 30906538)
Which the runaway pitch trim procedure addresses, MCAS or not. As the actual pilots upthread said, they're more informed about MCAS now, but it's irrelevant to their reaction, they're still going to do the runway pitch trim procedure.
We don't know what cost lives yet, since the accident reports aren't out yet. I am not a pilot, so read through several hundred posts by such on another thread. Looked to me like the majority had a valid point that the initial MCAS trim actions would not have looked abnormal. Only a modest adjustment by the system. Not like a runaway stab trim where it just goes straight to the limit. Some said it should be obvious because the trim moved for 10 seconds vs a few seconds, but really? Are the pilots supposed to know to note that (especially the Lion Air pilots who did not even know the concept existed). We will see how it plays out, agreed. |
Originally Posted by exwannabe
(Post 30906738)
The recovery is the same, but recognizing the issue is not.
I am not a pilot, so read through several hundred posts by such on another thread. Looked to me like the majority had a valid point that the initial MCAS trim actions would not have looked abnormal. Only a modest adjustment by the system. Not like a runaway stab trim where it just goes straight to the limit. Some said it should be obvious because the trim moved for 10 seconds vs a few seconds, but really? Are the pilots supposed to know to note that (especially the Lion Air pilots who did not even know the concept existed). Objectively, it's hard to argue with the logic that continuing to fight with the airplane through 25+ cycles of uncommanded nose down trim inputs (with the trim wheel spinning as trim is automatically added) was an inappropriate course of action, under the circumstances. Unfortunately, what appears to have happened is the JT crew fought with the airplane, instead of executing a procedure to correct a potential, and arguably obvious, cause of the improper input. There were likely a number of cues to suggest it was a stab trim issue. The Lion Air pilots knew the concept existed - they were trained on it - and the crew that brought the accident airplane in the night before responded to the malfunction correctly. Runaway stabilizer doesn't have to look or feel like AS261. |
Originally Posted by amtrakusa
(Post 30905026)
i wonder if there are similar systems in the new versions of A320? folks, there are bunch of things people don't know about. don't think Boeing is unique in any of these.
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A thread was just started this morning on the Air Canada forum about AC cancelling all MAX flights through at least July 1.
Is AC being too conservative? Or is Boeing releasing bad news to the airlines (including UA) behind the scenes that warranted this move by AC, and UA will shortly be doing announcing similar? In any case, it is not surprising to me that this will take at *least* several months to resolve. |
Saw a link to this elsewhere online today. Click to view it in full resolution. 6 of UA's MAX planes just hanging out grounded at Hobby Airport in Houston. I like how you can see the Southwest liveries in the background, and that gigantic plume of smoke is a raging industrial fire. Oh Houston...
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Originally Posted by EWR764
(Post 30906260)
The rule is controversial, but as a general matter it is premised on the theory that more hours = more experience = better/safer pilot. Importantly, it's not to say that 1500 hours = safe pilot, or 1500 hours = well-trained pilot, but there is no doubt that an ATP must demonstrate a higher degree of proficiency to earn the ticket.
There is a whole list of different kinds of flights and experience as well as an additional knowledge test and required instruction. You can't spend 1,500 hours flying around your local airport then suddenly qualify for an ATP. If anyone wants to read the requirements, they are in 14 CFR 61 Subpart G. |
To me, as bad as it is, design flaws and programming/manufacturing defects happen. The worst parts are definitely the decisions to conceal the system and not immediately coming clean on the issue right after the 1st and even 2nd crash. That is unethical, immoral and criminal!
If they can essentially add a software layer for the MAX to emulate the NG and call it NG for training and certification purposes, what's next? Imagine if you were the engineers in these design meetings....there is got to be some other reasons for them to design it like this (increased correction and the number of times), right? Then only using 1 AOA sensor input....why? |
737 FREAK
Originally Posted by username
(Post 30907762)
To me, as bad as it is, design flaws and programming/manufacturing defects happen. The worst parts are definitely the decisions to conceal the system and not immediately coming clean on the issue right after the 1st and even 2nd crash. That is unethical, immoral and criminal!
If they can essentially add a software layer for the MAX to emulate the NG and call it NG for training and certification purposes, what's next? Imagine if you were the engineers in these design meetings....there is got to be some other reasons for them to design it like this (increased correction and the number of times), right? Then only using 1 AOA sensor input....why? Maybe instead of it being called the 737 MAX, it should be called 737 FREAK. |
Originally Posted by EWR764
(Post 30906835)
I have to respectfully disagree with you here. The initial trim actions may not have looked abnormal, but after a few cycles, with nose down trim rolling in despite repeated trim inputs to nose up, it most certainly would not have appeared normal. This realization should have been well before the point at which full back pressure on the yoke still resulted in a nose-down pitch attitude.
Objectively, it's hard to argue with the logic that continuing to fight with the airplane through 25+ cycles of uncommanded nose down trim inputs (with the trim wheel spinning as trim is automatically added) was an inappropriate course of action, under the circumstances. Unfortunately, what appears to have happened is the JT crew fought with the airplane, instead of executing a procedure to correct a potential, and arguably obvious, cause of the improper input. There were likely a number of cues to suggest it was a stab trim issue. The Lion Air pilots knew the concept existed - they were trained on it - and the crew that brought the accident airplane in the night before responded to the malfunction correctly. Runaway stabilizer doesn't have to look or feel like AS261. |
Originally Posted by JimInOhio
(Post 30909201)
Those are all good points. What would have been "new" to the Lion Air crew was the reason for the repeated aircraft overrides. When you don't know a system exists, you really don't know to even look for the correct reason the aircraft is behaving wrongly. Without that knowledge, how do you know what to do to really fly the plane safely from that point? The UA pilot I know quite well told me they were not trained on how to deactivate the MAX MCAS in this situation until after the Lion Air crash (and wouldn't be a problem for them now). Who knows why the ET crew didn't apparently know what to do as well.
There was a notable revelation yesterday that the Lion Air crew which flew the airplane to CGK the night before (and experienced the same unwanted MCAS activation) had to be reminded of the stab trim cutout by a jumpseating pilot. Once automatic trim was shut off, controlled flight was reestablished. I'm not going to repeat my thesis as to the system design, we know that's a major problem for Boeing. But I maintain that every type-rated 737 pilot even before JT610 was trained in a procedure which corrects auto stabilizer trim problems, which would include unwanted MCAS inputs. There are problems with execution, too. |
Originally Posted by EWR764
(Post 30909283)
The point is, there was no "MCAS deactivation procedure" and there still isn't. If an unscheduled stabilizer trim input is experienced, pilots are taught, as a memory item, to cut off electric stab trim. An improper MCAS activation would present to the pilot in this manner (as uncommanded nose down trim), and the pilot would be expected to respond appropriately. This was the case before and after Lion Air. It's way too early to comment on Ethiopian causes, but it must be understood that the ET302 crew received the post-Lion Air MCAS "training", which was mostly a reminder about electric trim cut out procedures and background information on the purpose and function of MCAS.
There was a notable revelation yesterday that the Lion Air crew which flew the airplane to CGK the night before (and experienced the same unwanted MCAS activation) had to be reminded of the stab trim cutout by a jumpseating pilot. Once automatic trim was shut off, controlled flight was reestablished. I'm not going to repeat my thesis as to the system design, we know that's a major problem for Boeing. But I maintain that every type-rated 737 pilot even before JT610 was trained in a procedure which corrects auto stabilizer trim problems, which would include unwanted MCAS inputs. There are problems with execution, too. |
What has be the fall-out of those 14 planes for UAs schedule?
Which routes are seeing cut-backs? |
What was the preponderance of runaway trim on the ng without mcas vs the max? I just want to know if mcas is causing more runaway trim scenarios than what is statistically expected. If so this is a problem about CRM especially at critical phases of flight such as low altitude scenarios.
Would the crew even suspect runaway trim before other issues based on failure rates?...could that be a cause for slow or non responsive actions by the crew? Does runaway trim need to move up further up the most likely failure list? MTBF should decrease with legacy systems.. if this has caused more runaway trim scenarios then boeing will have to show the fix puts this failure back in line with the ng rates. on another note how is the 73X affected by mcas? Could the 10 be delayed even if then 8 and 9 are fixed. The flight profile of the 10 is even more dependent on a system like mcas due to aircraft length to "feel" like the ng. Then add in the failure rates of telescoping gear. Lastly the announcement by AC and UA a few days ago about summer impacts is just bad timing...no need to even mention revenue projections with a prolonged grounding...do people even think how that may be viewed less than week since the grounding... furthers the perception of $ over safety Been enjoying the candid discussion |
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