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737 max returning to service ?

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737 max returning to service ?

Old 8th May 2019, 13:50
  #141 (permalink)  
 
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Originally Posted by Smythe View Post
damn, that is quite the explanation from Aboulafia..

On the other hand, this month, CEO Dennis Muilenburg asked the board “to establish a committee to review our company-wide policies and processes for the design and development of the airplanes we build,” and somehow, as Ron Epstein noted, they created a committee without a single engineer.

Lesson NOT learned...
​​​​​​Until said 'Committee' comes up with something that puts Safety and Customers joint first, AFAICS it's a 'show me the money' smoke screen
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Old 8th May 2019, 14:03
  #142 (permalink)  
 
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Originally Posted by Richard Aboulafia
​​ fixing the MAX isn’t a major technical challenge.
Of course it is is not. All that is needed is the political will to change the temporary fix into permanent.
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Old 8th May 2019, 16:20
  #143 (permalink)  
 
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Originally Posted by safetypee View Post
The other threads have been closed due to lack of information, but perhaps this is the critical point in getting the 737 Max back in service.
There still is no clarity as to what exactly contributed to the incorrect value of AoA.
I'm not sure it matters - AOA vanes fail and I haven't seen, yet, any figures to indicate Max vanes (or AOA systems inc adiru) are failing at higher rate than expected. It would be interesting to check if they are and if there is a common cause, and hopefully the investigations will, but I'm not sure it's part of any fix.

I do recall finding a document (from Boeing?) which implied that left AOA vane on Max is notably closer to the air bridge (and therefore maybe more vulnerable) - that may be enough to account for the left-side bias.

If ET AOA had also failed like Lion - to +20 degrees but tracking right side, then I'd say (not that my opinion is worth anything) a wiring investigation and fleet inspection would be warranted, but it didn't. It looks like a different failure mode and I would agree with others that the vane likely departed the aircraft in the ET case. If it was me, I might just want to look in more detail at the Sunwing Max where adiru (left, again) was replaced following AOA issues - since that plane is still in one piece.

But in the end I still come back to the first point - AOA vane failures happen (I've seen mtbfs of <100k flight hours quoted) and even if only (say) one in ten failures result in errant MCAS (probably generous) and if 99% of crews are well trained enough to cope with errant MCAS (probably very generous), the resulting crash rate is still too high. The rate at which AOA vane failure leads to uncommanded AND trim needs to be drastically reduced - fix (or remove) MCAS.
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Old 8th May 2019, 16:58
  #144 (permalink)  
 
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Originally Posted by 737 Driver View Post
Another take on Boeing's culture problem....

RichardAboulafia.com
Could pick some big holes in that (not least the "stall avoidance" description) but overall it sounds about right.

It neatly dovetails with some of Dennis Tajer's words that struck me in the 60 minutes video ( youtube.com/watch?v=QytfYyHmxtc about 16:30):
...a very strong signal to us that somewhere in there the philosophy had been tainted, poisoned...
and also the certification change covered in Seattle Times from DERs reporting to FAA to ARs reporting to Boeing management who then (after filtering - I've never known a manager who doesn't) report to FAA.

The whole system failed from regulator downwards - and yes, probably pilots/training as well as you have previously stated. Your comment on stab trim runaway not being trained as it wasn't "statistically significant" also strikes me as relevant here, not because that is a bad thing per se, but because from an engineering point of view Boeing drastically (and entirely predictably) changed the probability of stab trim runaway from NG to Max and the system (i.e. Boeing, FAA, operators etc.) did not propagate that information down to those who were basing training programs on a completely different event probability. Boeing, and indeed the industry as a whole, has a lot more work to do to fix this than just a bandaid on MCAS (or indeed a steel box round a battery - which issue shows that this is a continuing systemic problem not a one off).
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Old 8th May 2019, 17:00
  #145 (permalink)  
 
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There speaks a voice of reason. This really is Safety Management 101.
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Old 8th May 2019, 17:30
  #146 (permalink)  
 
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Originally Posted by Cows getting bigger View Post
There speaks a voice of reason. This really is Safety Management 101.
Not unlike the 737 rudder PCU problems in the 90’s, this will be a case studied in engineering schools when teaching FTA/FMEA/Functional Safety etc. One could make the argument USAir 427 and UA 585 crashed due to pilot error in response to a failure - pilots responded to uncommanded rudder deflection due to PCU jam by pulling the control column aft, increasing AoA, consequently increasing roll due to dihedral and decreasing roll authority of the ailerons to a point which recovery was impossible.

At least in this situation with the MAX, the FDR recorded the essential parameters required for investigators to perform their duties.
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Old 8th May 2019, 17:51
  #147 (permalink)  
 
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Originally Posted by infrequentflyer789 View Post
Could pick some big holes in that (not least the "stall avoidance" description) but overall it sounds about right.

It neatly dovetails with some of Dennis Tajer's words that struck me in the 60 minutes video ( youtube.com/watch?v=QytfYyHmxtc about 16:30):
...a very strong signal to us that somewhere in there the philosophy had been tainted, poisoned...
and also the certification change covered in Seattle Times from DERs reporting to FAA to ARs reporting to Boeing management who then (after filtering - I've never known a manager who doesn't) report to FAA.

The whole system failed from regulator downwards - and yes, probably pilots/training as well as you have previously stated. Your comment on stab trim runaway not being trained as it wasn't "statistically significant" also strikes me as relevant here, not because that is a bad thing per se, but because from an engineering point of view Boeing drastically (and entirely predictably) changed the probability of stab trim runaway from NG to Max and the system (i.e. Boeing, FAA, operators etc.) did not propagate that information down to those who were basing training programs on a completely different event probability. Boeing, and indeed the industry as a whole, has a lot more work to do to fix this than just a bandaid on MCAS (or indeed a steel box round a battery - which issue shows that this is a continuing systemic problem not a one off).
I agree, the interview with Dennis Tajer (APA union) was the most interesting part of that video. There are text excerpts available: https://www.9news.com.au/national/60...6-a0c47ddfe293
American Airlines veteran pilot Dennis Tajer told Hayes, “I called our safety experts and said, ‘Where is this in a book?" And they said, ‘It's not’.”

Tajer said the admission from Boeing felt like “betrayal”.

“This is an unforgiving profession that counts very heavily on the pilot's knowledge, background, and training, and there are lives depending on that.”
I can visualise a process something like this. A meeting between a manager, an engineer, and a pilot:
Manager: So if this new system fails, the pilots can handle it?
Engineer: Yes, there are procedures for that.
Manager: Pilots are trained to handle runaway trim?
Pilot: Er, yes. But it doesn't happen very often.
Manager: So, I don't see any problem...

Safety and training people: Not invited to meeting...
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Old 8th May 2019, 18:07
  #148 (permalink)  
 
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Originally Posted by GordonR_Cape View Post

Safety and training people: Not invited to meeting...
Goodness me, NO! Why would you invite anyone who might blow the whistle?
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Old 8th May 2019, 18:48
  #149 (permalink)  
 
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"We've coined a term that has become a very important focus for us: right at first flight," said Keith Leverkuhn, Vice President and General Manager for the 737 MAX program. "It means making sure that by the time we put the airplane in the air for the first time on our flight test that we know how these systems are going to act and that they are mature enough. If it weren't for certification requirements, the systems would be ready to enter our customers' fleets."
Keith Leverkuhn. Massive Fail.
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Old 8th May 2019, 22:51
  #150 (permalink)  
 
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Do not underestimate Aboulafia's words nor influence.

In regards to regulations, regulatory requirements, or certifications; those are the bare minimum to which the aircraft is unsafe to fly. Anything less, and the aircraft is unsafe.

Regulators are forbidden by law to dictate design changes to meet certification. That is called design by review and is illegal.

It is up to the manufacturer to show that the aircraft meets the MINIMUM requirements to be safe to fly.

In issuing the cert, regulators show that what the manufacturer submits, either meets or exceeds the minimum requirements, nothing more, nothing less.

Case in point: The 737 MAX REQUIRED MCAS to meet MINUMUM requirements to be safe to fly. Without MCAS the ac is NOT SAFE to fly.

Last edited by Smythe; 9th May 2019 at 00:16.
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Old 9th May 2019, 03:38
  #151 (permalink)  
 
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Who is investigating the Boeing 737 MAX?

things are heating up...

https://www.seattletimes.com/busines...boeing-737-max

• The Department of Justice’s Fraud Section has opened a criminal investigation into the development and certification of the Boeing 737 MAX by the Federal Aviation Administration and Boeing. The Department of Transportation’s Inspector General and the FBI are participating in the investigation. Federal attorneys are gathering evidence through a federal grand jury seated in Washington, D.C. Grand jury proceedings are conducted in secret and the Justice Department has declined to comment on the investigation. The FAA and Boeing have also declined to comment.

• The Transportation Department’s Inspector General is conducting a separate administrative audit into the certification of the MAX. At a Senate subcommittee hearing in March, Inspector General Calvin L. Scovel III said such audits generally take about seven months, but could take longer given the complexity of the issue.
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Old 9th May 2019, 06:56
  #152 (permalink)  
 
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That one will hurt!

Anyone at the FAA going to sign off on the MCAS "fix" by Boeing with all this heat around?

Unless a escape goat is nominated, any person putting their name to paper with all these open investigations is taking a career deciding decision on the outcome of some very serious investigations.

If it fell on my desk for "approval" I would need an urgent vacation or sick leave or some sort of very long leave, until a few investigations had passed judgement.

I wounder when or if Boeing will put forward the "fix" to the FAA. If they do it now and FAA do not play ball and refuse it - that is very bad for Boeing. But if these investigations take a while and are not favourable, it is still bad for Boeing.

How much storage area at Renton?
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Old 9th May 2019, 08:11
  #153 (permalink)  
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The Transportation Department’s Inspector General is conducting a separate administrative audit into the certification of the MAX. At a Senate subcommittee hearing in March, Inspector General Calvin L. Scovel III said such audits generally take about seven months, but could take longer given the complexity of the issue.
7 months ? we are then in 2020.
any person putting their name to paper with all these open investigations is taking a career deciding decision
Agree. Do not know in the FAA but knowing a bit how EASA works I can see nobody signing certification papers on the Max until all the currents reports from the various groups looking at it have published their conclusions. That probably includes this one.
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Old 9th May 2019, 08:21
  #154 (permalink)  
 
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Meanwhile -

Meanwhile back at the Boeing factory, does production of the MAX in current config continue and at what production rate?
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Old 9th May 2019, 08:51
  #155 (permalink)  
 
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Originally Posted by sixchannel View Post
Meanwhile back at the Boeing factory, does production of the MAX in current config continue and at what production rate?
I have not heard of any other production rate cuts since the one a few weeks ago.

Again the double edge sword, cut production more or altogether or do a mechanical modification to the airframe?

With so little of the 5,000 orders delivered, this is a very hard decision to make.

Personally I do not think a software patch can cover the requirements, based on information given to-date (much of that reluctantly).
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Old 9th May 2019, 09:25
  #156 (permalink)  
 
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If the MAX is permanently grounded Boeing could revert back to producing the B737-800 series and selling them at a deep discount, possibly just over the cost of production, while they work flat out on a new narrowbody replacement to compete with Airbus. This would keep the factory going, the employees paid and the customers reasonably happy. Any airline agreeing to take a 800 instead of a previously ordered MAX could receive guarantees regarding price and delivery date when the replacement becomes available.

Taking a less efficient aircraft at a very low price and operating it for a few years, then replacing it with a brand new design which would likely offer a slight improvement over the A320 NEO could work out for some airlines.
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Old 9th May 2019, 09:39
  #157 (permalink)  
 
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It would take years to change back the Renton pipeline from MAX to NG. Boeing cannot afford to wait that long. So that sounds very unlikely to happen.
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Old 9th May 2019, 11:37
  #158 (permalink)  
 
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Originally Posted by Less Hair View Post
It would take years to change back the Renton pipeline from MAX to NG. Boeing cannot afford to wait that long. So that sounds very unlikely to happen.
Yes, interestingly, analysts have been loathe to point out the different tooling necessary and the lag it generates.
Presently, the forecasts 'assume' production will simply ramp back up the instant after the aircraft is given its wings again by the FAA.

Lots of building short side risk for Boeing.
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