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

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

Old 27th Jul 2019, 19:34
  #1561 (permalink)  
 
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https://www.nytimes.com/2019/07/27/b...7-max-faa.html

the rudder cable mod is news to me....

with reference to previous posts, the trim wheel rotation is completely inaudible at high airspeed such as 280kts or greater, I've tried it recently in the NG, particularly if you are wearing a noise cancelling headset which does what it's designed to do- the simulator brigade probably don't realise this as they don't need a noise attenuating headset since most simulators have a volume control so that the critical ballast can be heard pontificating.
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Old 27th Jul 2019, 20:27
  #1562 (permalink)  
 
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NTSB Recommendation within 2 months.

I have been busy lately on fulltime flying the 737-800 and a rather interesting spring and summer on the Home Front, so I have not been following this tread in detail.
The fallout of the MAX debacle is directly effecting my future so, I have great interest in what will soon happen or not happen.
The fact that NTSB soon is ready to speak on the matter is good news, as they are on the top of my list as an independent Organization and has great people with integrity working to keep an Old Skipper safe.
This I appreciate.

With regards to the schedule Boeing and FAA came out with for a return to service before XMass , I am afraid that just got pushed into late January , at best.
I sure hope I am wrong , but I seldom am in these matters. A born realist, or pessimist You may say.
Has worked for me for 31 years.

What worry me the most is the politics in this , and the fact that trust in FAA and Boeing has taken a big hit.
I hope that can be taken care of as a separate issue later and we can get on with flying this beast that I have come to love.

Greetings from Norway
( 32 Celsius , 20 in the Sea)
Cpt B
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Old 27th Jul 2019, 20:29
  #1563 (permalink)  
 
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Originally Posted by boofhead View Post
I've been criticized for blaming the pilots for the accidents because they perished and should be respected for that. I guess there is truth in that, and I don't mean to put the blame on them specifically but what about the passengers and their families? Don't they get respect too? Did they not deserve to be flown safely to their destinations? Is there not an implied contract between the passengers and the crew, and of course also between the airline company and the passengers that they will be given at least the minimum standard of professionalism to ensure that this happens? Sure Boeing has made errors but the airline that employed these pilots and did not give them the required training/checking to handle a trim runaway was the start of the problem, not the MCAS/Boeing input. A runaway trim can happen from many causes/failures and MCAS is only one. The problem presented was the trim moving without pilot command. The fix was to trim against it (which was always possible in this case) and retain control. The QRH required that the airplane be trimmed using the trim switch, then if the runaway persisted, turning off the trim switches and proceeding with manual trim. Another way to stop the runaway was to hold the manual trim wheel while turning off the trim switches. All low key stuff with no drama and for this to degenerate into a situation that caused the loss of two aircraft and 300 people is incomprehensible to me. Sure there were distractions caused by the failure of the angle of attack sensor mucking up the stall warning system, but the real problem, screaming out to the pilots, was the way the nose was going down. Simple self-preservation would force them to deal with this first. The ground was coming up fast; nobody could ignore that and there is no indication that these pilots were not aware of that or that they were not trying to stop it from happening. There is further evidence that they were successful, at first, but also evidence that they were not aware of the correct procedures to be used and evidence that they did not follow those procedures, except sporadically and piece-meal. Not professionally or correctly, as a trained flight crew would be expected to do. So what is the answer? Go down the rabbit hole of the MCAS/What did Boeing Do or Not Do, or fight for better pilot training and checking? As we lose the experience of the current airline pilots who are reaching mandatory retirement (they were trained in these procedures and have the cunning necessary to recognize a problem and have a way to handle it) and replace them with pilots who have a far more superficial training experience (CBT is the best you can get now, forget hands on) it is vital that we do more than just V1 cuts, steep turns and approach to stalls during initial and recurrent training. We must identify and train for those loss of control accidents that seem to be increasing, and I am not singling out any country/airline because failures such as this can happen to anybody. Are you ready? Would you know what to do?
I would use the return key and create multiple paragraphs.
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Old 27th Jul 2019, 21:33
  #1564 (permalink)  
 
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Originally Posted by boofhead View Post
I've been criticized for blaming the pilots …...
Sure Boeing has made errors but the airline that employed these pilots and did not give them the required training/checking to handle a trim runaway was the start of the problem, not the MCAS/Boeing input. A runaway trim can happen from many causes/failures and MCAS is only one. The problem presented was the trim moving without pilot command.
B737 require that the runaway is handled way before the trim stop is reached, or way before the maximum speed is exceeded.
My understanding of CS 25.671/25.672 is that, either:
- A trim runaway must be “extremely improbable”, this can not be claimed with the present DAL C architecture.
- Be capable of continued safe flight and landing following runaway of a flight control to an adverse position, without requiring exceptional piloting skill or strength.

To me the B737 seem to have a certification gab..
There is a factor 10000 between “extremely improbable” (DAL A), and what DAL C can deliver.
This means that pilots must be able to recover 10000 times, before one failure, in order to be as good as a DAL A flight control system capable of preventing runaway.
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Old 27th Jul 2019, 21:55
  #1565 (permalink)  
 
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The days of physical strength being a requirement to fly an airliner should be well behind us by now. The B707 demanded a fair degree of exertion from the PF, particularly in the case of engine failure or loss of rudder boost and the check rides looked for this. If you couldn’t supply the required force to make the aircraft perform as required then you didn’t get it on your licence.

If the B737 trim wheel requires strength in excess of what could reasonably be expected from anyone who holds a class 1 medical then the licence holder must demonstrate that they have the capability to turn the wheel as needed if they want the rating. Alternatively a powered system with the required degree of reliability and redundancy could be fitted and the manual back up done away with.

The trim wheel on the A320 is only used to input the take off setting and wouldn’t be touched again unless the FBW system degraded into mechanical back up mode. This is a last resort and only meant to give some degree of control whilst a flight computer can be reset. Even this requires hydraulic power to work so strength isn’t needed.
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Old 27th Jul 2019, 22:01
  #1566 (permalink)  
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The new NY Times article paints a pretty damning picture of the FAA's relationship with Boeing, in general, and a particularly disturbing one with regard to the MAX and MCAS.

Engineers at the agency were demoralized, the two agency employees said. One engineer submitted an anonymous complaint [about the risk of an uncontained engine failure to the rudder cables] to an internal F.A.A. safety board, which was reviewed by The Times.

"During meetings regarding this issue the cost to Boeing to upgrade the design was discussed,” the engineer wrote. “The comment was made that there may be better places for Boeing to spend their safety dollars.”An F.A.A. panel investigated the complaint. It found managers siding with Boeing had created “an environment of mistrust that hampers the ability of the agency to work effectively,” the panel said in a 2017 report, which was reviewed by The Times. The panel cautioned against allowing Boeing to handle this kind of approval, saying “the company has a vested interest in minimizing costs and schedule impact.”

By then, the panel’s findings were moot. Managers at the agency had already given Boeing [rather than the FAA] the right to approve the cables, and they were installed on the Max.
And much more.
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Old 27th Jul 2019, 22:12
  #1567 (permalink)  
 
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The Times article is damning. Reading between the lines, the FAA has no idea how many MCAS-class problems made it through certification. Meanwhile, the rudder cable issue, and many like it, got rammed through, against what little independent oversight the FAA had left.

​​​​​​As a non-US xAA, what would you want before recertifying?
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Old 27th Jul 2019, 22:43
  #1568 (permalink)  
 
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Apologies if this has already been posted under a different URL.
https://www.moonofalabama.org/2019/0...g-737-ngs.html
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Old 27th Jul 2019, 22:56
  #1569 (permalink)  
 
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Originally Posted by Rozy1 View Post
I would use the return key and create multiple paragraphs.
You are mistaken. Paragraphs are for demarking different ideas / messages. When the only message is "the pilots screwed up, Boeing are not to blame", why waste whitespace when you can just leave it as one ugly unreadable monotonous chunk?
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Old 28th Jul 2019, 01:38
  #1570 (permalink)  
 
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The rudder cable issue is for me the truly scary indication of how deep the rot at Boeing and FAA oversight has become. I could almost see how the MCAS slipped through the cracks because the conditions where it would activate are very unlikely to ever occur out on the line so the fail modes never got properly investigated and thus the consequences were not appreciated.

The rudder cable issue is totally different. The rudder cables are in the direct path of major rotating parts of the engine. If the engine grenades and engine bits cut the rudder cables the airplane will almost certainly be lost . This doesn't require an aeronautical engineering degree to understand. The fail mode is totally obvious.

It is also directly covered by certification criteria, yet Boeing didn't want to deal with it because it would cost money to fix and the FAA management over ruled their own expert staff and gave Boeing a pass. I feel confident that pre merger Boeing ( ie up to the late 1990's) would never have balked at fixing the issue and the FAA in any case would have insisted on a fix.

The part I can't understand is if after the return to service a Max engine grenades, pieces cut the rudder cables and the airplane crashes, the resulting shyte storm will make the MCAS issue look trivial. So I can only conclude that Boeing management are willing to bet the company on a totally preventable accident sequence not happening, rather then spend what is the grand scheme of things is a trivial amount of money to make the scenario impossible to occur.

What springs to mind is the old adage about managers knowing the price of everything and value of nothing......
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Old 28th Jul 2019, 01:52
  #1571 (permalink)  
 
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Pilotmike: Have you got anything that refutes what I said? Any factual errors in my piece? You disagree that we need to do more with pilot training and with airline company emphasis on training and checking? With the need to include aspects of loss of control in the training? Otherwise your comment is obviously ad hominem.
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Old 28th Jul 2019, 02:35
  #1572 (permalink)  
 
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Originally Posted by Bend alot View Post
This suggests something was wrong 3 or 10 seconds prior to the start of MCAS first activation.
Perhaps this was a symptom of being overweight? Not only did the captain ask to continue runway heading and say flight control problems, but the DFDR data looks a little odd (at least to me). There's a pretty steep pitch up initially (yanking it off at the end of the runway?), a shallow climb profile, and then a bit of sink when flaps retract.

The Preliminary Report says they were a around 1,130 pounds under Regulated Takeoff Weight, but they seem to have assumed around 167 lbs./pax (incl. carry on bags). If you use a more standard 190 lbs., I think you come in a couple of thousand lbs. over RTOW. And who knows how they calculated RTOW. The temp was rising so if they used an old METAR to make the calculation, they would have underestimated density alt. And I'm not sure the pax count includes crew: were they included in the Operating Empty Weight?

FWIW, does it look to anyone else like they were ferrying fuel? 10,700 kg = 23,540 lbs. I've read t/o fuel is around 1,500 lbs. and cruise is around 4,500 lbs. Nairobi was less than an hour away. I believe it was VMC. No idea what the airline's reserve policy is, but if they carried enough for the return to Addis Ababa plus 45 min., they'd need a total of around 14,000 lbs., not 23,540.

Am I all wet here? Did I do the math wrong? If not, is a couple of thousand lbs. over RTOW not a concern?

If they were heavy, and the plane wasn't climbing as expected, would that provide a reasonable explanation for why the crew never reduced power?
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Old 28th Jul 2019, 04:30
  #1573 (permalink)  
 
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Originally Posted by boofhead View Post
Pilotmike: Have you got anything that refutes what I said? Any factual errors in my piece? You disagree that we need to do more with pilot training and with airline company emphasis on training and checking? With the need to include aspects of loss of control in the training? Otherwise your comment is obviously ad hominem.
No boofhead, you've got it completely backwards. I'm going to go out on a limb here and speak for PilotMike and others: Our issue is that you are taking substantially incomplete information and coming to a definitive conclusion about a complex series of events that resulted in the deaths of many people. Not only are you coming to a conclusion prematurely you are placing the blame/responsibility squarely on those who are not here to defend themselves, which is precisely why waiting until the facts have been released to make such judgments is not only critical, it is the only decent thing to do. Finally, you are making these declarative judgments about actual now-deceased individuals and their performance not in a thread about pilot performance, training or whatever you want, but in a thread about the eventual (??) return of the 737 MAX and the impact of the FAA's review of their own certification process that led to the disaster in the first place.

Posting an off-topic post (or a dozen) is just rude. Flaying the dead before the facts have been fully revealed is pure cruelty.

My .02 as always, and thankfully I'm headed to a far away place where it is entirely possible I will be deprived of having to respond to posts like these. Lucky me!!

Cheers all-
dce
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Old 28th Jul 2019, 05:55
  #1574 (permalink)  
 
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Originally Posted by Big Pistons Forever View Post
The rudder cable issue is for me the truly scary indication of how deep the rot at Boeing and FAA oversight has become. I could almost see how the MCAS slipped through the cracks because the conditions where it would activate are very unlikely to ever occur out on the line so the fail modes never got properly investigated and thus the consequences were not appreciated.

The rudder cable issue is totally different. The rudder cables are in the direct path of major rotating parts of the engine. If the engine grenades and engine bits cut the rudder cables the airplane will almost certainly be lost . This doesn't require an aeronautical engineering degree to understand. The fail mode is totally obvious.

It is also directly covered by certification criteria, yet Boeing didn't want to deal with it because it would cost money to fix and the FAA management over ruled their own expert staff and gave Boeing a pass. I feel confident that pre merger Boeing ( ie up to the late 1990's) would never have balked at fixing the issue and the FAA in any case would have insisted on a fix.

The part I can't understand is if after the return to service a Max engine grenades, pieces cut the rudder cables and the airplane crashes, the resulting shyte storm will make the MCAS issue look trivial. So I can only conclude that Boeing management are willing to bet the company on a totally preventable accident sequence not happening, rather then spend what is the grand scheme of things is a trivial amount of money to make the scenario impossible to occur.

What springs to mind is the old adage about managers knowing the price of everything and value of nothing......
What would the insurance implications be on a severed rudder cable by a LEAPing blade?

Now it is on the open record and airlines and crew are aware - will any pilot/union speak up or any airline or any foreign regulator?

This can not be addressed with training, but now is a time affected party's could have it addressed.
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Old 28th Jul 2019, 07:46
  #1575 (permalink)  
 
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What amazes me is that Boeing seemed to be under the illusion that none of this would be made public
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Old 28th Jul 2019, 09:33
  #1576 (permalink)  
 
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A question from an unlearned professional,

How well is the code in the MCAS understood by non-software engineering guru's outside of Boeing?.

Is it still the case in software design engineering that the "Bit Bucket" exists to catch those hard errors for which monitoring and recovery code has not yet been written. Also, does the "Bit Bucket" remain in the code even after delivery of the software and the product?

Does the code in the MCAS have a "Bit Bucket"?

Thanks,

IG
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Old 28th Jul 2019, 10:19
  #1577 (permalink)  
 
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Originally Posted by Imagegear View Post
A question from an unlearned professional,

How well is the code in the MCAS understood by non-software engineering guru's outside of Boeing?.

Is it still the case in software design engineering that the "Bit Bucket" exists to catch those hard errors for which monitoring and recovery code has not yet been written. Also, does the "Bit Bucket" remain in the code even after delivery of the software and the product?

Does the code in the MCAS have a "Bit Bucket"?

Thanks,

IG
I would guess that MCAS is written in ADA. Probably no "bit bucket" as ADA is designed to :...

Ada improves code safety and maintainability by using the compiler to find errors in favor of runtime errors.
FN
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Old 28th Jul 2019, 10:55
  #1578 (permalink)  
 
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I can't help but wonder that as there are a lot more issues coming to light than straight grandfathering, how many of them are shared on other models....
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Old 28th Jul 2019, 11:10
  #1579 (permalink)  
 
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Oh boy ...

... if only someone had warned them stockpiling an airliner with a history of rushed and deficient design being subejected to immense scruntity by regulators and the public might not be such a great idea.
At least no engineers, subcontractors, suppliers and subordinates to blame for this decision. They will have to take the consequences though. No golden parachute for them .
Originally Posted by Imagegear View Post
A question from an unlearned professional,

How well is the code in the MCAS understood by non-software engineering guru's outside of Boeing?.

Is it still the case in software design engineering that the "Bit Bucket" exists to catch those hard errors for which monitoring and recovery code has not yet been written. Also, does the "Bit Bucket" remain in the code even after delivery of the software and the product?

Does the code in the MCAS have a "Bit Bucket"?

Thanks,

IG
As embedded software engineer I can assure you, that there will be no genie in the bottle trying to fix unspecified exetions somehow. Deterministic behaviour is king. This ain't no crappy web app aiming to present a seamles UI even if the code under the hood faults every now and then.
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Old 28th Jul 2019, 11:24
  #1580 (permalink)  
 
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To be fair to Boeing: There is no point in now suddenly requiring the grandfathered MAX to be built like a new airplane in every detail. Sort the sensors, MCAS, the trim, the processor, the training and/or pod aerodynamics and that's it. Opening a can of worms will lead to nothing. If future grandfathering should be abandoned by the authorities let manufactures know about well in advance for the next types and programs.
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