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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures Mk II

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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures Mk II

Old 25th Dec 2019, 02:24
  #241 (permalink)  
 
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Originally Posted by Icarus2001 View Post
I am pretty sure both pilots will have TWO hands so my calculator says ONE pilot can wind the trim wheel.
The TWO trim wheels have ONE handle, each, big enough for ONE hand.
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Old 25th Dec 2019, 03:18
  #242 (permalink)  
 
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Originally Posted by Takwis View Post
One small snag. The handles on the trim wheels are not long enough to accommodate two hands. Only one hand will fit. The two wheels are on opposite sides of the throttle quadrant. A pilot reaching over or around the throttle quadrant will get no leverage on the handle, especially as the the handle moves through 6 o'clock. It would be a very awkward and ineffective exercise.
Two hands one pilot.
Two hands two pilots (19:10m)
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Old 25th Dec 2019, 04:27
  #243 (permalink)  
 
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The pilots may in a developed case have their hands full with pulling on both control columns.

Even with MCAS itself solved, with the existing mechanical trim hardware (also for the NG), a cabin crew member might apparently need to be trained to come to the rescue and kneel over the center stand (pedestal) to help cranking the mechanical trim wheels.

Logically, another assistant will already be required to be in the vacant pilot’s seat during any absence of one pilot from the cockpit to assist with pulling on the control column just in case a serious trim problem suddenly occurs.

How much chance for the adoption and how much time for the certified training of all this?

Last edited by Plumb Bob; 25th Dec 2019 at 04:39. Reason: Layout; NG applicability added.
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Old 25th Dec 2019, 07:55
  #244 (permalink)  
 
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I flew thev737 long enough to remember when it used to fall from the sky due to the rudder problem. I believe two major crashes and a few more averted by skilled pilots. It was a similar design flaw but at time there was no social media. I would say Boeing has made a terrible mistake not starting on a clean sheet with a new narrowbody aircraft instead to keep alive something designed 60 years ago. I predicted this the day I read the first time of this project
The plane remains old, challenging to fly especially in the light of degrading piloting skills resulting from absurd rules in certain
​​​regulatory environment ( EASA) allowing pilot with as low as 200 hours type rate ( and often in pay to fly environment with poor training) de facto making of it a single pilot aircraft. I remain convinced that should the crew on both cases have been more experienced and skilled in manual flying nothing would have happened. As a passenger I would be concerned about that more than MCAS.
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Old 25th Dec 2019, 10:47
  #245 (permalink)  
 
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”I remain convinced that should the crew on both cases have been more experienced and skilled in manual flying nothing would have happened. As a passenger I would be concerned about that more than MCAS.”

Agree porkflyer.

Still cant quite understand why there hasn’t been more discussion about the attempted use of the autopilot and mishandling of the autothrottle. I think it is now time to concede that expecting a crew with the experience levels of both accident crews to simultaneously complete both the Airspeed Unreliable and Runaway Stabilizer Non Normal Checklists was a bridge too far.
Hate to say it , but Airbus is right.
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Old 25th Dec 2019, 11:24
  #246 (permalink)  
 
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Originally Posted by Icarus2001 View Post
I am pretty sure both pilots will have TWO hands so my calculator says ONE pilot can wind the trim wheel.
In a sim, not that long ago, in a trim runway scenario who went quit far, because it was really difficult for me to turn the wheel with one hand as Pilot monitoring, I told the PF (Who was pulling the yoke, plane was trimed nose down), that we should both have one hand on the yoke to pull and the other empty to trim, the 2 handle are always quit in "opposite" location on the 2 wheel, so I always understood it was designed like this, in some case to be used by the 2 pilots ... And guess what ! All worked really well and we were able to have the trim back in easy movable position ...
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Old 25th Dec 2019, 11:36
  #247 (permalink)  
 
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Obviously

Originally Posted by GlobalNav View Post
What will they do for the "anxious pilot?"
hand him or her the exact same card😁
A very merry Christmas to all on PPRuNe
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Old 25th Dec 2019, 14:14
  #248 (permalink)  
 
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Discussion of control forces makes me think about the second level of MCAS, where the authority was increased. Theory follows:

The stabilizer can overpower the elevators, as we know. It can also move into a position where the pilots physically cannot pull hard enough to get the required elevator deflection, or wind back the nose-down trim.

So while MCAS was originally designed to smooth out a bump or dip in the stick-force-to-alpha gradient, it evolved into a system that can block the controls and prevent the aircraft from entering a certain corner of the envelope. In short, a full-authority envelope-protection system.

And that's why a single-channel system was a disaster, and why a dual or pseudo-triplex system can't be certificated.
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Old 25th Dec 2019, 20:15
  #249 (permalink)  
 
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Originally Posted by LowObservable View Post
Discussion of control forces makes me think about the second level of MCAS, where the authority was increased. Theory follows:

The stabilizer can overpower the elevators, as we know. It can also move into a position where the pilots physically cannot pull hard enough to get the required elevator deflection, or wind back the nose-down trim.

So while MCAS was originally designed to smooth out a bump or dip in the stick-force-to-alpha gradient, it evolved into a system that can block the controls and prevent the aircraft from entering a certain corner of the envelope. In short, a full-authority envelope-protection system.
Excellent deduction.
Originally Posted by LowObservable View Post
And that's why a single-channel system was a disaster, and why a dual or pseudo-triplex system can't be certificated.
Can't it? Even not with enough lipstick and citing "alternate means of compliance" ?
I'm still guessing it all has been agreed on and they are just fighting about documention, training and other "formalities" . Everyone needs that plane back in the air - even the Chinese.
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Old 25th Dec 2019, 22:08
  #250 (permalink)  
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Originally Posted by LowObservable View Post
Discussion of control forces makes me think about the second level of MCAS, where the authority was increased. Theory follows:

The stabilizer can overpower the elevators, as we know. It can also move into a position where the pilots physically cannot pull hard enough to get the required elevator deflection, or wind back the nose-down trim.

So while MCAS was originally designed to smooth out a bump or dip in the stick-force-to-alpha gradient, it evolved into a system that can block the controls and prevent the aircraft from entering a certain corner of the envelope. In short, a full-authority envelope-protection system.

And that's why a single-channel system was a disaster, and why a dual or pseudo-triplex system can't be certificated.
Excellent narrative."In short, a full-authority envelope-protection system".Which could also be meant to mean "anti-stall system", which is why Boeing went out of their way to dispense with the anti-stall verbiage.

Last edited by 568; 25th Dec 2019 at 22:08. Reason: text
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Old 25th Dec 2019, 22:18
  #251 (permalink)  
 
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Originally Posted by 568 View Post
Excellent narrative."In short, a full-authority envelope-protection system".Which could also be meant to mean "anti-stall system", which is why Boeing went out of their way to dispense with the anti-stall verbiage.
Yes, an excellent description. And, while there are still some who insist that MCAS is only about stick force gradient, it appears that they are now outnumbered, among those who have been paying close attention, by observers who are, at least, fairly skeptical.

Will the relevant bare-airframe test results be released, or will Boeing be able to convince the world and the courts that they are properly proprietary?
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Old 25th Dec 2019, 22:30
  #252 (permalink)  
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Originally Posted by OldnGrounded View Post
Yes, an excellent description. And, while there are still some who insist that MCAS is only about stick force gradient, it appears that they are now outnumbered, among those who have been paying close attention, by observers who are, at least, fairly skeptical.

Will the relevant bare-airframe test results be released, or will Boeing be able to convince the world and the courts that they are properly proprietary?
Equally excellent narrative!MCAS really shared 2 common themes, IMHO;1) Stick force gradient at the lower end of the speed envelope.2) Monitoring AoA to ensure that excessive pitch wouldn't end up as a stall.Somewhere along the design phase and flight test, I believe that there must have been numerous discussions on "how best to implement MCAS" and satisfy part 25 requirements, without raising further objections, concerns and engineering issues.
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Old 25th Dec 2019, 22:48
  #253 (permalink)  
 
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It will be back in the air. Hopefully based on good engineering and testing to ensure Boeing can regain the significant lack of trust it has at present.
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Old 25th Dec 2019, 23:34
  #254 (permalink)  
 
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Originally Posted by maxter View Post
It will be back in the air. Hopefully based on good engineering and testing to ensure Boeing can regain the significant lack of trust it has at present.
There are several regulators and groups that are looking and want to look very deeply at the raw airframe data of the MAX.

This is partly because of Boeing's flexibility with the truth, it's incorrect risk classifications and failure to disclose information during original certification.

As the days and weeks flow on is seems very possible that Boeing did some Jedi Mind Tricking of it's own to obtain Grandfather rights.

If that turns out to be true, the MAX will not fly again, as it will need a new type certificate. If a new type certificate is required a new aircraft is required, as the MAX would not meet the current requirements.

The re-certification is no longer certain - The FAA must meet the standards for the other regulators expectations of them, no more buddy deals between Boeing and the FAA as the FAA have indicated.

Last edited by Bend alot; 26th Dec 2019 at 01:36. Reason: needed "new" in new aircraft is required.
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Old 25th Dec 2019, 23:41
  #255 (permalink)  
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Originally Posted by Bend alot View Post
There are several regulators and groups that are looking and want to look very deeply at the raw airframe data of the MAX.

This is partly because of Boeing's flexibility with the truth, it's incorrect risk classifications and failure to disclose information during original certification.

As the days and weeks flow on is seems very possible that Boeing did some Jedi Mind Tricking of it's own to obtain Grandfather rights.

If that turns out to be true, the MAX will not fly again, as it will need a new type certificate. If a new type certificate is required a aircraft is required, as the MAX would not meet the current requirements.

The re-certification is no longer certain - The FAA must meet the standards for the other regulators expectations of them, no more buddy deals between Boeing and the FAA as the FAA have indicated.
Exactly on point. Boeing and the FAA are probably at this cross roads (behind closed doors and email).
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Old 26th Dec 2019, 01:28
  #256 (permalink)  
 
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Originally Posted by maxter View Post
It will be back in the air. Hopefully based on good engineering and testing to ensure Boeing can regain the significant lack of trust it has at present.
It has been grounded for almost 10 months. If software were the only problem, it would have been weeks, not months. Something more than just software, I am assuming
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Old 26th Dec 2019, 02:00
  #257 (permalink)  
 
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Originally Posted by Flocks View Post
In a sim, not that long ago, in a trim runway scenario who went quit far, because it was really difficult for me to turn the wheel with one hand as Pilot monitoring, I told the PF (Who was pulling the yoke, plane was trimed nose down), that we should both have one hand on the yoke to pull and the other empty to trim, the 2 handle are always quit in "opposite" location on the 2 wheel, so I always understood it was designed like this, in some case to be used by the 2 pilots ... And guess what ! All worked really well and we were able to have the trim back in easy movable position ...
Flocks,

One of the discoveries when a magnifying glass was passed over the trim runaway training in light of some real-world incidents with the MAX is that it appears that BA "forgot" to implement correct force feedback on the trim wheels in the sims, including the NG. Due to the shrunk trim wheels implemented in the NG, the real forces required may be above what can be expected of some crews.

Another discovery is that BA has become bad at passing essential information to the pilot community.

Edmund
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Old 26th Dec 2019, 09:22
  #258 (permalink)  
 
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I thought the whole MAX saga was already a PR disaster of the highest order, but apparently there's always someone that can do worse. To think that some people actually held a meeting and decided that a 3-by-5-inch card would get the message across to the anxious traveller that the MAX is now really, really safe...

- "So what kind of jedi mind-trick would make the public trust our aircraft again?"
- "Well, you know, we could hand over a safety leaflet or something..."
- "No, a leaflet won't grasp enough attention. We need something more substantial, say... a card!"
- "Brilliant idea! Let's hand over safety cards!"
- "So what size should we use? I was thinking something portable, like 3 x 4 inch?"
- "Meh, a bit small, ain't it? What about 4 x 4?"
- "No, too square. You know what - we'll settle for 3 x 5 inch"
- "Great, consider it done! One more problem solved then."


Un!be!lie!va!ble!
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Old 26th Dec 2019, 12:00
  #259 (permalink)  
 
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Originally Posted by xetroV View Post
I thought the whole MAX saga was already a PR disaster of the highest order, but apparently there's always someone that can do worse. To think that some people actually held a meeting and decided that a 3-by-5-inch card would get the message across to the anxious traveller that the MAX is now really, really safe...

- "So what kind of jedi mind-trick would make the public trust our aircraft again?"
- "Well, you know, we could hand over a safety leaflet or something..."
- "No, a leaflet won't grasp enough attention. We need something more substantial, say... a card!"
- "Brilliant idea! Let's hand over safety cards!"
- "So what size should we use? I was thinking something portable, like 3 x 4 inch?"
- "Meh, a bit small, ain't it? What about 4 x 4?"
- "No, too square. You know what - we'll settle for 3 x 5 inch"
- "Great, consider it done! One more problem solved then."


Un!be!lie!va!ble!
Impressive work by the PR department over the holidays!

Seems like they came up with a "Method to Continuously Aggravate the Situation", or MCAS:
Shoot yourself in the foot, repeat as necessary with 5 second intervals.

Not sure how it will help get the planes back in the sky, but at least it could trigger some golden parachutes.
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Old 26th Dec 2019, 13:14
  #260 (permalink)  
 
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The FAA must meet the standards for the other regulators expectations of them
This is a very important theme. The world's other regulators work for their citizens. The citizens, both as passengers, and as taxpayers, employ the regulators to be the knowledgeable and objective intermediaries to assure the safety of the flying public. The regulators develop and then apply internationally accepted design and manufacturing standards. And, commonly, they accept each other's work via bilateral certification agreements. Not so much this time. The FAA has broken faith with the other regulators, and they are questioning the completeness of the FAA's certification process. The bilateral agreements allow any authority to independently "familiarize" themselves with the certification of another authority - for the re introduction of the MAX, they're doing it!

The citizens have every right to assert their demand for design compliant planes for their safe travel. They can do this by asking what type they're being booked on, and by demanding the independent evaluation of their national authority. Some national authorities, including the FAA, employ a system of delegation of certification activities to specified persons in the manufacturer's company. If the system works properly, the public's interests are well represented. If the manufacturer has too much influence over their delegated staff, there could be a problem. In the case of the MAX, there was a problem. The FAA would rather not admit it, but the other authorities see what's going on, and are going to check for themselves.

The FAA's and Boeing's desire for a schedule for this will be missed. Worse, would be the FAA tries to recertify the MAX before the other authorities do, that would look bad! And, worse when they realize that though that might enable the MAX to fly US domestic, it would not be accepted internationally, That would be embarrassing!

The FAA's miss on past certification activities on the MAX have been exposed to the world, and they have no choice but to be thorough and transparent in the recertification effort, and they and Boeing take their lumps in the process.
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