MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
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I'm not sure yet I find it very probable that given the way things are (or not) developing, the only great thing Max is destined for is "beyond".
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Boeing leader at Renton 737 MAX plant retires
https://www.seattletimes.com/busines...plant-retires/
https://www.seattletimes.com/busines...plant-retires/
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Somehow the Airbus 320 and following are certified and those suckers have zero feel as the plane approaches a high AoA or low AoA or any damned AoA. The sticks provide no feedback to the pilot WRT control surface deflection or aero forces, nor any trim requirement if speed is changed, nor ........ "there must be fifty ways"
So my main question is why did FAA squawk about the column force? I have not seen a technical description of a commercial airliner built after 1950 that did not have some kinda "artificial feel" add-on to the ropes, levers, pulleys and tubes. Prolly 99% of every military "light" since 1950 had zero direct mechanical feedback from the control surfaces.
So how did the latest bus get certified, but the 737 had to add the MCAS?
So my main question is why did FAA squawk about the column force? I have not seen a technical description of a commercial airliner built after 1950 that did not have some kinda "artificial feel" add-on to the ropes, levers, pulleys and tubes. Prolly 99% of every military "light" since 1950 had zero direct mechanical feedback from the control surfaces.
So how did the latest bus get certified, but the 737 had to add the MCAS?
Boeing took a different approach with 777/787, inventing C*U and providing a completely artificial feel on conventional controls, which I think allows them to meet the normal control force / stability reqs of part 25 without special conditions.
All these approaches fail in some way when stuff breaks and the a/c doesn't know (accurately) where it is in the envelope, AF477 ended up in a C* law without protection, C*U will inevitably reduce to C* if U is unknown (or deemed unreliable). There is a general principle (which turns into a requirement somewhere in the regs. I think) that any degradation of handling qualities must be inversely related to probability of occurrence and seriousness of failure consequences - that is the bit of the design and approvals process that MCAS seems to have got fatally wrong.
Here's an interesting new line.
https://www.forbes.com/sites/lorenth.../#1e2f1d3b521b
Thompson is a reliable supporter of his clients, and one may assume that he doesn't write a word without consulting with them. But what's the message here? That the FAA needs to get on with return-to-flight, and lean on the naysaying foreigners? And what "orgy of negative reporting"? I believe that even here, where journalists are seldom the flavor of the month, the work by Dominic Gates and by the WSJ team has been well regarded.
Is the message, then, that this is too important to be left to the engineering nerds?
https://www.forbes.com/sites/lorenth.../#1e2f1d3b521b
Thompson is a reliable supporter of his clients, and one may assume that he doesn't write a word without consulting with them. But what's the message here? That the FAA needs to get on with return-to-flight, and lean on the naysaying foreigners? And what "orgy of negative reporting"? I believe that even here, where journalists are seldom the flavor of the month, the work by Dominic Gates and by the WSJ team has been well regarded.
Is the message, then, that this is too important to be left to the engineering nerds?
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The main message from that article is that Boeing is too big to fail. And that Boeing failing would be a disaster for the US, so the lawmakers and the press should cut them some slack to prevent that. They also implied that Boeing doesn't "deserve" to fail, because Airbus became successful due to "illegal subsidies".
An interesting if slightly biased overview of the issues.
‘… this is too important to be left to the engineering nerds?‘ I Disagree.
The technicalities identified so far cannot be overcome by political will, financial management, etc. They are real-world aviation safety problems which relate to agreed and published standards - Federal Register, ICAO.
In addition, they have to be considered globally, not just something in the US interest, but that US interest now depends on multinational consensus.
A further difficulty is that some technical issues hinge on judgement - the human contribution in detecting and managing abnormal conditions. This is not a national judgement, but that of a range of authorities and particularly cultures - safety culture.
Whereas historically Boeing was the dominant culture in aviation, this is no longer true.
Is the article a lament, attempting to restore what once was, or the realisation that the aviation industry has changed and requires national activity to restore confidence an profitability.
Maybe, but you cannot buy safety (or even tweet it), it’s an activity, that which is done; for that you require domain expertise, but if this is overlooked then … …
https://www.dropbox.com/s/7425e8yykg...20%2B.pdf?dl=0
Dominant Culture 2003
‘… this is too important to be left to the engineering nerds?‘ I Disagree.
The technicalities identified so far cannot be overcome by political will, financial management, etc. They are real-world aviation safety problems which relate to agreed and published standards - Federal Register, ICAO.
In addition, they have to be considered globally, not just something in the US interest, but that US interest now depends on multinational consensus.
A further difficulty is that some technical issues hinge on judgement - the human contribution in detecting and managing abnormal conditions. This is not a national judgement, but that of a range of authorities and particularly cultures - safety culture.
Whereas historically Boeing was the dominant culture in aviation, this is no longer true.
Is the article a lament, attempting to restore what once was, or the realisation that the aviation industry has changed and requires national activity to restore confidence an profitability.
Maybe, but you cannot buy safety (or even tweet it), it’s an activity, that which is done; for that you require domain expertise, but if this is overlooked then … …
https://www.dropbox.com/s/7425e8yykg...20%2B.pdf?dl=0
Dominant Culture 2003
Plastic PPRuNer
'...........the penultimate flight crew did not log use of stab trim cutouts or the continuous stick shaker........."
Now THAT is something that I find completely incomprehensible.
"Hi darling. Careful with the car when you next go shopping. It pulls really hard to the left when you brake. Almost hit a semi on the highway. What's for supper?"
Mac
Now THAT is something that I find completely incomprehensible.
"Hi darling. Careful with the car when you next go shopping. It pulls really hard to the left when you brake. Almost hit a semi on the highway. What's for supper?"
Mac
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'...........the penultimate flight crew did not log use of stab trim cutouts or the continuous stick shaker........."
Now THAT is something that I find completely incomprehensible.
"Hi darling. Careful with the car when you next go shopping. It pulls really hard to the left when you brake. Almost hit a semi on the highway. What's for supper?"
Mac
Now THAT is something that I find completely incomprehensible.
"Hi darling. Careful with the car when you next go shopping. It pulls really hard to the left when you brake. Almost hit a semi on the highway. What's for supper?"
Mac
Do we have a trace or could the CB have been pulled (3 Pilots - big book etc)?
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Accident report says stick shaker was on for remainder of flight after trim was cutout. There is not actual procedure to pull the CB plus general policy not to pull CB unless part of a procedure, so unless pilot wanted to freelance he may have been more comfortable leaving it be than explaining to his superiors why he violated company policy.
Accident report says stick shaker was on for remainder of flight after trim was cutout. There is not actual procedure to pull the CB plus general policy not to pull CB unless part of a procedure, so unless pilot wanted to freelance he may have been more comfortable leaving it be than explaining to his superiors why he violated company policy.
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Good point. Hindsight is 20/20. Since this is the crew that lived to tell about it I suspect they've had there chance to explain there thinking so perhaps we will get to read about in the final report.
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G
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Multiple reports from reliable major international news outlets have reported that concerns about the effort required to trim using the manual wheels are on the EASA list.
Have you seen this video from Mentour Pilot?
https://www.youtube.com/watch?v=aoNOVlxJmow
Have you seen this video from Mentour Pilot?
https://www.youtube.com/watch?v=aoNOVlxJmow
And this jpeg
should help
note that on the video showing jack screw in motion- the difference in speed as it reaches full nosedown position ( top of jackscrew )
Last edited by walkon19; 12th Jul 2019 at 20:53. Reason: fatfinger
Dave, I didn’t say the CB was pulled. I said that he may as well have pulled it as not to report continuous shaker.
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Bill, not try to fence here. The preliminary has a figure showind FDR tracks for this flight and you can see where left stick shaker was on until landing. I'd post the page but havent figured out how to do that yet. Maybe someone else could.
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From discussion on older threads I don't believe we know for sure if the FDR trace reflects the stick tracer request/condition -or- the motor actually running, in other words not 100% clear what FDR would show if CB pulled.