Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Max Q wrote:Who is this guy in the video and how is he credible?
Zeke2517 wrote:Usually when I hear that the “fix is in” it means something else...
stratclub wrote:Zeke2517 wrote:Usually when I hear that the “fix is in” it means something else...
No, it means that the fix has been defined by engineering and is ready to be proven as airworthy which in this case would be very straight forward.
tealnz wrote:Then there's the minor matter of the stabiliser trim wheels. Evidence they are unusable in a range of situations without some aerobatics to unload the stabiliser/jack screw. Instructions for the yo-yo manoeuvre long since removed from the 737 manual. Haven't seen any solid info on Boeing's response. A non-minor issue for the FAA and other regulators.
tealnz wrote:Then there's the minor matter of the stabiliser trim wheels. Evidence they are unusable in a range of situations without some aerobatics to unload the stabiliser/jack screw. Instructions for the yo-yo manoeuvre long since removed from the 737 manual. Haven't seen any solid info on Boeing's response. A non-minor issue for the FAA and other regulators.
Wacker1000 wrote:I can't wait to hear how software changes physics.....
strfyr51 wrote:I applaud that they Have a fix. Though? I think they were a bit Lazy in putting in the system in the first place by NOT putting in a comparator system to check whether the AOA vane wasn't actually damaged and let it's input be locked out from taking control of the airplane. This is why you HIRE Engineers!! That there was no, or little oversight? Unacceptable!! Boeing is Better than this!!
WPvsMW wrote:"Stall and recover" in a fully loaded DC-8 would require about 5,000 ft of altitude with CFM56-2s? Even more with JTD3s?
SheikhDjibouti wrote:The engine type itself would more likely come into play if the engines had been idled on the approach to stall, and needed time to spool up again.
In the case of reverse thrust, maybe less of an issue.
(there is even an article here on a.net somewhere regarding engaging reverse thrust in-flight as a standard procedure for rapid descents)
longhauler wrote:The fix is in, and Transport Canada has started to outline requirements for return to service.
One of the requirements, is that the MAX pilots have to review new procedures in the simulator. Fair ball, but ...
Air Canada has the only MAX simulators in North America, and ... they can not replicate the MCAS event. The NG simulators used by other North American airlines also (for obvious reasons) can not replicate an MCAS event. So why bother dragging everyone into the simulators?
frmrCapCadet wrote:Is there anything between an iPad lesson and a $zillion simulator?
kalvado wrote:And what would you suggest? Regulators feel that certain things must be experienced and practiced. It may be excessive, but hard to blame them after 2 crashes. Reading 1 page of AD didn't quite work.
kalvado wrote:So how would you proceed? Waive "must be experienced and practiced" requirement and wake up at night to check if there was another crash?
I suspect that MCAS should be just a software update for existing MAX sim, and possibly even for NG sim, at least to some extent.
longhauler wrote:You suspect incorrectly. CAE (among others) have said that while the MCAS fix can be programmed into the simulator, the chain of events that caused the two crashes can not. This should make sense, as the majority of the fix involves adding the second AOA source to the MCAS, then disabling the MCAS if the two sources do not agree.
I understand your "experienced and practised" thoughts, but to me, it is like a cause that has been corrected. For example, after McDD changed the bulk cargo door locking system, then enlarged the vents of the aft cabin floor, the achilles heel of the DC-10 was corrected. Dragging three guys into the similator to watch it "not happen" doesn't make a lot of sense.
longhauler wrote:kalvado wrote:And what would you suggest? Regulators feel that certain things must be experienced and practiced. It may be excessive, but hard to blame them after 2 crashes. Reading 1 page of AD didn't quite work.
Maybe if the Ethiopian crew had followed the AD, it might have worked. But in reading the latest report, there is now thought that it was not even distributed among their crews!kalvado wrote:So how would you proceed? Waive "must be experienced and practiced" requirement and wake up at night to check if there was another crash?
I suspect that MCAS should be just a software update for existing MAX sim, and possibly even for NG sim, at least to some extent.
You suspect incorrectly. CAE (among others) have said that while the MCAS fix can be programmed into the simulator, the chain of events that caused the two crashes can not. This should make sense, as the majority of the fix involves adding the second AOA source to the MCAS, then disabling the MCAS if the two sources do not agree.
I understand your "experienced and practised" thoughts, but to me, it is like a cause that has been corrected. For example, after McDD changed the bulk cargo door locking system, then enlarged the vents of the aft cabin floor, the achilles heel of the DC-10 was corrected. Dragging three guys into the similator to watch it "not happen" doesn't make a lot of sense.
planecane wrote:I'd be curious to know what, exactly, they will practice in the simulator? Return to the airport or divert when one stuck shaker goes off and there is an AoA disagree warning?
The whole point of the fix is that MCAS won't activate except when is is supposed to so what situation are they training for?
longhauler wrote:It was shown how subtle the MCAS is, how to recognize it and what to do. Even though with the fix, that is unlikely to happen again. What else would one expect to be done?
kalvado wrote:Probably trim runaway - including severe trim runaway, blowback, and recovery from that. Maybe landing in severe mistrim (although bench press may be a better option than the sim for this one).
If nothing else, it should contribute to so-called "airmanship", whatever that means.
longhauler wrote:kalvado wrote:Probably trim runaway - including severe trim runaway, blowback, and recovery from that. Maybe landing in severe mistrim (although bench press may be a better option than the sim for this one).
If nothing else, it should contribute to so-called "airmanship", whatever that means.
All of that is already covered during initial and recurrent training, which is one of the reasons a lot of the airline world were scratching their heads on the initial reports of both accidents.
"Severe mistrim" is a Jammed Stabiliser. Instead of muscle exercise, normally the aircraft is landed as close as possible to its actual trimmed speed .. leading to high landing speeds in unusual flap configurations. But, as I say, it is practised a lot.
kalvado wrote:As far as I understand, MCAS trimmed way beyond speed trim range, so there was no such option.
Or consider this a demonstrated soft spot in training which needs to be covered.
kalvado wrote:But I am playing devil's advocate, my feeling is that strong sim requirement without further details is a punitive one. I understand the mentality behind such decision, though.
kalvado wrote:I am not sure what they mean by "chain of event cannot be programmed". If a new set of control logic is loaded into a sim, same problem should not be possible any more; that is the nature of a fix. Getting two sets of logic to reproduce previous problem is meaningless, as pilots would have to practice on a system which is already obsolete. Since instruments are a bit different, maybe familiarization is a good idea, but that can be "supervised flying"....
I would rather see a better engineering review of overall control system, software, trim operation. Am I asking for too much?
longhauler wrote:kalvado wrote:As far as I understand, MCAS trimmed way beyond speed trim range, so there was no such option.
Or consider this a demonstrated soft spot in training which needs to be covered.
Left unchecked, MCAS will trim itself to a very high speed range, but that is because the (incorrect) information it is receiving, is that the aircraft AOA is very high. It is not like the A320 (for example) where speed protections exist.
"Left unchecked". That is the elephant in the room. Understand though, one of the accident investigation directions being followed, is not that a mistake was made ... but why? Why were the actions of the MCAS left unchecked?
Another part of the "fix" goes further than what we have discussed, but also a warning to the pilots when the MCAS is activated.kalvado wrote:But I am playing devil's advocate, my feeling is that strong sim requirement without further details is a punitive one. I understand the mentality behind such decision, though.
To me it looks like a lot of governmental bodies being caught with their pants down and pretending to now (years too late) being very thorough. It's like the DC-10 example I used before. When the DC-10 finally was grounded in 1979, it was following the AA crash in ORD. A crash caused by improper maintenance practices, not a flaw in the aircraft. (I am simplifying things here).
The DC-10 should have been grounded five years earlier, as there actually were flaws in the aircraft and the Turkish DC-10 crash at ORY was a direct result of that failure to ground the aircraft. I think the FAA, being embarassed about this chain of events, decided to overkill five years later.
I see the same mentality today.
Please ... play Devil's Advocate. Sometimes the other side of the story leads to very interesting discussions!
stratclub wrote:Zeke2517 wrote:Usually when I hear that the “fix is in” it means something else...
No, it means that the fix has been defined by engineering and is ready to be proven as airworthy which in this case would be very straight forward.
longhauler wrote:Please ... play Devil's Advocate. Sometimes the other side of the story leads to very interesting discussions!
justloveplanes wrote:Is there any data on how many times in normal operations MCAS has deployed? How often does this high AoA happen?
AshisMaity wrote:justloveplanes wrote:Is there any data on how many times in normal operations MCAS has deployed? How often does this high AoA happen?
Very important question. Any experts throwing light on this?
Depending on the weather condition and incorrect engine speed, it has the tendency to get a incorrect pitch. That's why MCAS was put to correct it periodically so that the pilot does not have to do that task. But the correction should be have been when there is correction need for very low value like a half a degree or so.
stratclub wrote:Wacker1000 wrote:I can't wait to hear how software changes physics.....
Physics wasn't really the problem. MCAS engineering was rushed and it ended up being implemented without adequate training or operational and failure analysis. Pure and simple, Boeing screwed the pooch and got bit extremely hard on MCAS.
kalvado wrote:What would YOU do in such a situation? Probably doing as much as you can so they will say "he signed off MAX, but it crashed despite he did his best..." is a good option. Or do you see any other way out?
I do have my list of what I would do; but anyone is welcome to give their list as well.
kalvado wrote:Imagine you're a Superior Supervisor for Flight Safety at Transport Canada - or whatever that position is called; and it is totally your responsibility to sign MAX Return to Service order.
If you sign it and there is another accident, your colleagues will be pointing fingers at you - it was Longhauler who signed off MAX before it crashed for the third time! Your boss - who is either an elected official or appointed by such, has no problem trashing you. (and thinking about your counterpart in CAAC: he may also face firing - not by HR office, but by a firing squad). You're not finding any good job - you're THAT guy for life. Not to talk about how you feel about the situation.
longhauler wrote:kalvado wrote:Imagine you're a Superior Supervisor for Flight Safety at Transport Canada - or whatever that position is called; and it is totally your responsibility to sign MAX Return to Service order.
If you sign it and there is another accident, your colleagues will be pointing fingers at you - it was Longhauler who signed off MAX before it crashed for the third time! Your boss - who is either an elected official or appointed by such, has no problem trashing you. (and thinking about your counterpart in CAAC: he may also face firing - not by HR office, but by a firing squad). You're not finding any good job - you're THAT guy for life. Not to talk about how you feel about the situation.
I understand what you are saying, but in reality, it goes back to the old adage ... you can not eliminate risk, you can only manage it. The Official at Transport Canada ultimately responsible for the safety of the Max, is actually the Minister of Transport himself. It was his decision to ground the aircraft in Canada and it will be his decision to allow the aircraft to fly in Canada again.
If another Max crashes, then he has to answer for it. But ... not that a mistake was made, (as clearly if another crashes, a mistake was made), but did he make a mistake that was lax, lazy or negligent, or more likely ... a mistake was made that under the same circumstances, anyone else would have made. This tenet is actually one of the main thoughts of today's Safety Management Systems.
So in allowing the aircraft to fly again, do you mandate training to solve an engineering issue? Namely, was the cause of these crashes an engineering mistake, or a training mistake? While it appears the Ethiopian First Officer was aware of the AD and effected one of the memory items, the Captain appeared not to be aware.
Presently, one would have to have their head up their ass not to know how and why the MCAS works. In my opinion that dead horse is beaten and that training mistake is solved. So ... solve the engineering mistake of why it happened and both sides of the issue are solved.
But back the Minister of Transport. Up until recently, Transport Canada "trusted" the FAA and certified new aircraft types on their blessing. Not so any more. FAA, "trusted" Boeing and gave them more freedom than will likely occur in the future.
In my opinion, M. Garneau, will look at both sides of the issue. Look at training that Air Canada has done, (and I assume Westjet and Sunwing) and be satisfied. Then, listen to Boeing (not the FAA) and see what has been done to make sure it doesn't happen again. When satisfied, he will allow the aircraft to fly in Canada again.
Also understand though, as the Max was equipped at Air Canada and Westjet, (I don't know about Sunwing), these two accidents were a lot less likely to occur.
longhauler wrote:Presently, one would have to have their head up their ass not to know how and why the MCAS works. In my opinion that dead horse is beaten and that training mistake is solved. So ... solve the engineering mistake of why it happened and both sides of the issue are solved.
IADFCO wrote:Qualitatively, yes. Enough to discuss it intelligently in front of a beer or a cup of coffee or on A.net.
stratclub wrote:https://www.youtube.com/watch?v=zGM0V7zEKEQ
I'm posting a credible source that describes the 737 MAX MCAS fix. After validation testing is complete, the fix appears to be a software bump that should only take a few hours per aircraft to load the software and perform what ever functional tests are required. There could be some hardware changes, IDK. The video didn't seem to indicate anything more than possibly some AOA sensor hardware revisions.
This really is great news for everyone involved.............
longhauler wrote:Also understand though, as the Max was equipped at Air Canada and Westjet, (I don't know about Sunwing), these two accidents were a lot less likely to occur.