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

[etudiant]

Originally Posted by Realbabilu

What would you do as folkner when he unknowingly found that the MCAS can activated in low speed in simulator

Is not the issue that he got the FAA to allow MCAS to remain unmentioned in the pilot documentation on the basis that the system was only used to offset very extreme 'out of envelope' conditions?
Boeing did not notify the FAA subsequently that it was not only deployed all through the envelope, but also was quadrupled in terms of authority.
Folkner did say the he lied to the FAA, unknowingly. Whether he or anyone else ever corrected that is doubtful.

[BDAttitude]

Originally Posted by Zeffy

All 43 pages of the Boeing presentation MCAS Development and Certification Overview.

Thank you!
Intresting redactions.

[FullWings]

We weren't flight-critical so we could fail hard and reboot it if things got messy. I would guess B don't have that option so god only knows how they are planning to deal with disagreement between each side of the system during normal operations, dual systems can't do majority voting :-). As a result, I would expect a number of new issues to be found in the system for some time after it has come back into service.

One of the issues I would have thought is that the computing hardware stays the same but they are asking more and more of it in terms of workload. I doubt that this was allowed for in the original specification so forcing something that was primarily designed for navigation and performance to take over critical flight control function *and* monitoring seems like a bit of a step. Do the FMCs run a RTOS?

[PJ2]

Originally Posted by gums

. . . .
Basic aero still a big problem for this old pilot, so I am with folks that want to see raw MAX flight tests that have MCAS erased and look at the plots. Unless you go "full authority" FBW, the basic aero problems with the new motors and such cannot be mitigated with crude algorithms inserted in autopilot and STS functions such as we are led to see for MCAS.

, spot-on as always, gums - PJ

[OldnGrounded]

Originally Posted by kiwi grey

Anyone else think Dominic Gates ought to be in line for something like a Pulitzer Prize for this continued attention to this?

A Pulitzer. Absolutely. And, as I said some time ago, I expect he'll be on this year's short list.

[OldnGrounded]

Originally Posted by Zeffy

All 43 pages of the Boeing presentation MCAS Development and Certification Overview.

I second the thanks!

On first read-through, problematic dodging, bobbing and weaving are apparent. Seems like a lot of CYA effort that no informed reviewer taking a hard look would be likely to quietly accept.

Example from page 14 of the document:

I'm going to guess that means that countering single unintended MCAS activation by "elevator alone" applies to a single, max. 2.5 unit movement of the stabilizer, not to the combined effects of multiple (presumably pilot-interrupted) movements caused by unintended activation. Unless, of course, Boeing is confident that "elevator alone" recovery is possible after MCAS has run the stab to the stops.

Also, from page 35:


Discussed but not documented and then . . . not referenced.

There's a lot more in the document. I'm sure others will find and share.

[FrequentSLF]

Originally Posted by AviatorDave

I know. That was not my point. My point was that Boeing went the cheapest path regardless of where on this planet the most software expertise might have been located.

https://www.microsoft.com/en-in/msidc/
It is well know that most of the software today is developed in India, Microsoft is an example, see the link. I would not see as cheapest path, but probably the most efficient and fastest.
The number of software developers in India is roughly the same of the USA.
It does not seem that MCAS problems are due to the coding, but to the basic concepts.

[silverstrata]

Elevator only is required to counteract MCAS..

I noticed this comment a few times in the Seattle newspaper. But on those FDR traces of the Ethiopian accident, it clearly shows that full back elevator was being applied (at the very end), and the aircraft was not responding.

So were these assertions derived from simulators, or real-world tests? And at what speed did they do the tests? (The Ethiopian was going rather fast....)

Silver

[Takwis]

Originally Posted by OldnGrounded

I'm going to guess that means that countering single unintended MCAS activation by "elevator alone" applies to a single, max. 2.5 unit movement of the stabilizer,

As long as we are guessing, I'm going to guess that means that countering single unintended MCAS activation by "elevator alone" applies to a single .6 unit movement of the stabilizer, since 2.4 units is a hell of a lot of trim, and I wouldn't go on flying it "by using elevator alone." Even somewhat less than half a unit of mistrim, I would be trimming it out.

[Grebe]

Originally Posted by OldnGrounded

A Pulitzer. Absolutely. And, as I said some time ago, I expect he'll be on this year's short list.

For those who really think Dominic should get a pulitzer- suggest you take the time to look up the ' requirements' and then make the effort to contact the Committee. even if he does not get the award, your support may well make him eligible for some other related awards.

While its not like voting for the dancing with the stars or popular vote- written support with some detail can make a difference.

[OldnGrounded]

Originally Posted by Takwis

As long as we are guessing, I'm going to guess that means that countering single unintended MCAS activation by "elevator alone" applies to a single .6 unit movement of the stabilizer, since 2.4 units is a hell of a lot of trim, and I wouldn't go on flying it "by using elevator alone."

OK, but note the "Upon each design iteration of MCAS . . ." statement.

[BDAttitude]

Originally Posted by FrequentSLF

https://www.microsoft.com/en-in/msidc/
It is well know that most of the software today is developed in India, Microsoft is an example, see the link. I would not see as cheapest path, but probably the most efficient and fastest.
The number of software developers in India is roughly the same of the USA.
It does not seem that MCAS problems are due to the coding, but to the basic concepts.

"We are not developing in low cost countries, we are using best cost locations". Been there, done that, don't sort their mess out anymore.

Originally Posted by OldnGrounded

Also, from page 35:
Discussed but not documented and then . . . not referenced.

There's a lot more in the document. I'm sure others will find and share.

Lecture from first day in any business or bureaucracy career:
If it's not in the meeting minutes it's not agreed, if it's not in a mail, it did't happen.

What do they suppose to gain with that whining. Seems pretty desperate.
​

[Takwis]

OldnGrounded OK, but note the "Upon each design iteration of MCAS . . ." statement.

I guess the "stab trim was available..." statement means, in typical Boeing speak, that they DID use the trim, after "using elevator alone."

[OldnGrounded]

Originally Posted by Takwis

[QUOTE OldnGrounded] OK, but note the "Upon each design iteration of MCAS . . ." statement.

I guess the "stab trim was available..." statement means, in typical Boeing speak, that they DID use the trim, after "using elevator alone."

Yeah, they are not exactly covering themselves with glory -- or inspiring confidence in their honest and transparency -- are they?

[DieselOx]

This is the only mention of flight testing of loss of MCAS I've ever seen confirmed here or elsewhere.

Somewhere else in all the pages posted, I got the impression that because MCAS only fires up outside the normal flight envelope, it gets a lower criticality rating, so did not require flight testing, or even sim testing of certain failure modes.

And so if it only fires up outside the normal envelope, why test the loss of it only in the normal envelope?

And what about when failures push you past the normal envelope, and into or beyond the operational envelope?
And all the redactions really are curious, 2 of 4 failure scenarios in particular. What else is hiding in plain sight?

[Drc40]

I can understand redactions of names but the other redactions are clearly CYA in full view. I seriously doubt some top secret Boeing tech was being redacted considering the placement on those docs. The malfeasance continues.

[Peter H]

Originally Posted by DieselOx

And so if it [MCAS] only fires up outside the normal envelope, why test the loss of it only in the normal envelope?

I read that as reporting that the MAX's "suboptimal" aerodynamics (which MCAS is designed to tame) only has a "minor"
safety impact within the normal envelope. (Pedantically - for at least one point on the edge of that envelope.) Maybe
somebody doubted the aerodynamics sufficiently to require a test.

I'm only SLF, but "No Safety Effect" would have sounded nicer.

[gums]

Salute!

Good points Diesel

The problem was not failure of MCAS to activate, but activation when not required for the control force requirement. To be honest, 99% of the pilots would not notice MCAS if they were pulling too hard or if it did not kick in.

Gums sends...

[WillowRun 6-3]

Boeing Seeking FAA Delivery Approval - But Approval of Training Would Lag Behind

WSJ:

https://www.wsj.com/articles/boeing-...=hp_lista_pos2

[Australopithecus]

Originally Posted by WillowRun 6-3

WSJ:

https://www.wsj.com/articles/boeing-...=hp_lista_pos2

Not paying Murdoch a cent to look past the paywall