MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
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On page 38 there was discussion about AP disengagement when trying to trim manually and the question what has priority given the AP would not disconnect due to FCC problems.
Wooof, wooof.
Wooof, wooof.
The intent of my original query was to point out that three of the five pilots who actually operated the flight controls during this malfunction broke the code on Step 1. MCAS was misbehaving, and they kept the blue side up. However, the next two didn’t. Personally, I think it is worth asking why that was the case? What was the difference in the training, experience, and environment that allowed the first three pilots to succeed where the others did not? I don’t really think it was just a matter of luck.
Like all of us, my ego makes me want to sit here and think to myself and promise you that *I* surely would have done a better job in that situation. But I cannot guarantee that. Perhaps I would have done the same thing, basically sitting frozen on the controls for those eight brief seconds. I like to believe I'm Chuck Yeager/Aaron/Norris all rolled into one awesome human bean. Most of the time though I'm just Chuckles the Clown. I cut that Dave guy a lot of slack
Yoko1, I am not a pilot. But if I understand correctly the 737 has a hull loss rate of roughly 1 per 5 million take offs and landings, and the Max 1 per 90,000.
The pilot community is the same, and the standards of training are the same. Doesn’t that suggest the problem is the plane?
The pilot community is the same, and the standards of training are the same. Doesn’t that suggest the problem is the plane?
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Statistical fallacy
Yoko1, I am not a pilot. But if I understand correctly the 737 has a hull loss rate of roughly 1 per 5 million take offs and landings, and the Max 1 per 90,000.
The pilot community is the same, and the standards of training are the same. Doesn’t that suggest the problem is the plane?
The pilot community is the same, and the standards of training are the same. Doesn’t that suggest the problem is the plane?
..
One thing I do know is that groundschool and associated technical training has been repeatedly cut over the last forty years as airlines, in particular, seek to reduce costs.
System information has been reduced to “this black box does this” in the pilots manuals, with more detailed information only available in the engineers books.
The days of a ground school having engineers using actual aircraft parts and demonstration boards to explain aircraft systems are nearly over.
Originally Posted by yoko1
No lawyer, for the defense or the plaintiff, is going to be lifting their arguments or facts from PPRuNe - sorry to burst your bubble if anyone was thinking otherwise.
However wrong journalists sometimes get things, the influence of the press on government should never be underestimated, and while its work should have no bearing on legal outcomes it can certainly influence the process.
Last edited by Easy Street; 6th Jul 2019 at 10:02.
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Specifically, what "trim wheel problem" are you talking about? The reported problem was with disconnecting the autopilot in certain situations. Obviously, if correct, this issue ought to be fixed.
If you think this is related to the accident scenarios, I should remind you that MCAS is not active when the autopilot is engaged.
However, did you notice that in the discussion of other things that needed to be resolved there was no mention of anything having to do with the Main Electric Trim system (switches, relays, motors, etc)? Conspicuously absent, and another one of those non-barking dogs.
If you think this is related to the accident scenarios, I should remind you that MCAS is not active when the autopilot is engaged.
However, did you notice that in the discussion of other things that needed to be resolved there was no mention of anything having to do with the Main Electric Trim system (switches, relays, motors, etc)? Conspicuously absent, and another one of those non-barking dogs.
I'm afraid you missed the point.
Maybe reading again the sentence in bold ?
Unless just one is left and checked for integrity with the problem Max - MCAS included I imagine that all NG and Max sims will have trim wheel forces closely examined and updated if required in any case. We are already so much into costs and losses that this item seems worth it.
Why? Because redesigning the ship may well cure the aircraft behaviour but will not provide lessons in airmanship from these crashes, which might need to be known.
Specifically, what "trim wheel problem" are you talking about? The reported problem was with disconnecting the autopilot in certain situations. Obviously, if correct, this issue ought to be fixed.
If you think this is related to the accident scenarios, I should remind you that MCAS is not active when the autopilot is engaged.
However, did you notice that in the discussion of other things that needed to be resolved there was no mention of anything having to do with the Main Electric Trim system (switches, relays, motors, etc)? Conspicuously absent, and another one of those non-barking dogs.
If you think this is related to the accident scenarios, I should remind you that MCAS is not active when the autopilot is engaged.
However, did you notice that in the discussion of other things that needed to be resolved there was no mention of anything having to do with the Main Electric Trim system (switches, relays, motors, etc)? Conspicuously absent, and another one of those non-barking dogs.
The referenced Bloomberg article specifically stated
"...EASA’s checklist included a number of issues that have been disclosed; the potential difficulty pilots have in turning the jet’s manual trim wheel."
and the subject has been covered in various aviation articles which you must have read including https://www.satcom.guru/2019/04/stab...and-range.html
relevant quote..
"...One possible explanation is that the loads on the jackscrew due to the severe stabilizer nose down out-of-trim situation were too great for the pilot to overcome using the trim wheel with folding handle. The pilots restored electric trim as a means to trim.
Boeing published a technique in the past that discussed this issue and the need to release the column briefly in a series of "roller coaster" or "yo yo" maneuvers, by cranking in stabilizer trim alternatively with large column commands...."
So I repeat, why ask a question when you already know the answer?
Alchad
2 events, one every 90,000 flights, versus millions of flights and 1 every 5,000,000. You are correct, regression to the mean cannot be ignored. But superficially it's pretty damning.
Both the EASA and the FAA don't seem to think it is a coincidence, and we can hope at least one of those bodies is independent and competent. They grounded the plane, not the pilots.
Otherwise, all Boeing need as a cheap, quick fix for the Max is a label on the yoke: 'Not to be flown by third world pilots.' Cheaper than a passport scanner in every cockpit. Should be an easy sell to the regulator, at least in some jurisdictions. Or just self certify it.
Not enough? Maybe (as a priced option) a label on the trim wheel: 'To be used by (real) men only.' Of course, you would have to make sure you did actually stick on the label. (And, if the videos are to be believed, this would rule out Viking pilots, so could be a problem for Norwegian.)
Then watch the passengers flock back.
Of course, if it didn't then regress to the mean Boeing would not be in a very good place.
Both the EASA and the FAA don't seem to think it is a coincidence, and we can hope at least one of those bodies is independent and competent. They grounded the plane, not the pilots.
Otherwise, all Boeing need as a cheap, quick fix for the Max is a label on the yoke: 'Not to be flown by third world pilots.' Cheaper than a passport scanner in every cockpit. Should be an easy sell to the regulator, at least in some jurisdictions. Or just self certify it.
Not enough? Maybe (as a priced option) a label on the trim wheel: 'To be used by (real) men only.' Of course, you would have to make sure you did actually stick on the label. (And, if the videos are to be believed, this would rule out Viking pilots, so could be a problem for Norwegian.)
Then watch the passengers flock back.
Of course, if it didn't then regress to the mean Boeing would not be in a very good place.
Last edited by SLF3; 6th Jul 2019 at 09:54. Reason: Style.
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Of course he knows ;-)
Trying to raise controversy on a forum, derailing conversations while accusing others of doing so, doesn't that ring a bell ?
Actually all trim wheel issues should be on the table.
The one post on a tread many moons ago - from what seemed a seasoned 737 pilot starting from the 100 with reference from it's design parents (aircraft).
Elevator trim has always been a Gotcha thing and never let it get away from you (my wording) then every adjustment since has made the trim and all controls - more an issue not less.
So 50 years making elevator trim less effective on every model, when verson1 was very bad.
Not a good move.
The one post on a tread many moons ago - from what seemed a seasoned 737 pilot starting from the 100 with reference from it's design parents (aircraft).
Elevator trim has always been a Gotcha thing and never let it get away from you (my wording) then every adjustment since has made the trim and all controls - more an issue not less.
So 50 years making elevator trim less effective on every model, when verson1 was very bad.
Not a good move.
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The third person in the scenario really is key, that is why real captains (
) never touch the wheel or throttles of the ship that they command. Although a well trained person does a lot of their job unconsciously, that unconscious effort of keeping the wings level, fighting the stick shaker, scanning the gauges, etc. takes a lot of processing power that would otherwise be devoted to reasoning. You have much more ability to control things if you stand back and let others do the grunt work, which is also why admirals aren't up on the bridge directing the captain how to maneuver his ship to conform to the general battle plan.
) never touch the wheel or throttles of the ship that they command. Although a well trained person does a lot of their job unconsciously, that unconscious effort of keeping the wings level, fighting the stick shaker, scanning the gauges, etc. takes a lot of processing power that would otherwise be devoted to reasoning. You have much more ability to control things if you stand back and let others do the grunt work, which is also why admirals aren't up on the bridge directing the captain how to maneuver his ship to conform to the general battle plan.- When do warning hooters, shakers and such cease to be an aid and become part of the problem?
- Should the pilot be allowed to cancel/semi-mute them (indicating recognition of the warning and reducing the distraction).
- Should the software try another approach to attract the pilots attention as this one isn't working, or just shut up and try not to make things worse?
Designing useful HCI (human computer interfaces) is difficult.
On the other hand, doing something sort-of puts the manufacturer (A or B) in a good light at any future investigation:
India First week of monsoon
Used MAX Autobrake reguarly into VABB on the 777 during Monsoon Season, why?..It looks better on the accident report (crew used all available means of retardation)..!!
Peter
In this case the pilots seem to have been in an intentionally distracting environment.
- When do warning hooters, shakers and such cease to be an aid and become part of the problem?
- Should the pilot be allowed to cancel/semi-mute them (indicating recognition of the warning and reducing the distraction).
- Should the software try another approach to attract the pilots attention as this one isn't working, or just shut up and try not to make things worse?
Designing useful HCI (human computer interfaces) is difficult.
On the other hand, doing something sort-of puts the manufacturer (A or B) in a good light at any future investigation:
India First week of monsoon
Used MAX Autobrake reguarly into VABB on the 777 during Monsoon Season, why?..It looks better on the accident report (crew used all available means of retardation)..!!
Peter
- When do warning hooters, shakers and such cease to be an aid and become part of the problem?
- Should the pilot be allowed to cancel/semi-mute them (indicating recognition of the warning and reducing the distraction).
- Should the software try another approach to attract the pilots attention as this one isn't working, or just shut up and try not to make things worse?
Designing useful HCI (human computer interfaces) is difficult.
On the other hand, doing something sort-of puts the manufacturer (A or B) in a good light at any future investigation:
India First week of monsoon
Used MAX Autobrake reguarly into VABB on the 777 during Monsoon Season, why?..It looks better on the accident report (crew used all available means of retardation)..!!
Peter
First things first - rescue ass and everyone else’s and argue about it later...
They used to call it airmanship.
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Sorry, you're correct. I read your post too quickly (plus being late and tired) and was looking at the article headline and not the sentence you put in bold. Apologies. And yes, something should be done to address the issue with manual trim.
Last edited by yoko1; 6th Jul 2019 at 12:42.
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Except that in a number of cases (at least on the 737) there is no way to silence the alarm. High speed clacker is probably the most annoying one in this category.
In case of Eng fire warning it is routine on many AC to silence the alarm. In other cases not. However if the alarm is distracting and false it’s the old man’s call.