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

[MickG0105]

Originally Posted by megan

We have an experienced aviator, Byron Bailey - ex military fighter & 777 & current biz jet, who writes a regular column in our local national paper (The Australian), and had this to say,Question, is what he's saying re MCAS activation cases in the US for real?

If you've followed Captain Bailey's musings in The Australian over the years you'd know that his articles routinely feature factual errors and that he's not averse to just making stuff up to make a point.

[Bend alot]

Originally Posted by Grebe

Interesting re simulators not having capability to duplicate stabilizer aero forces as a function of speed and elevator and stabilizer position

I think they have the capability - they just did not have the correct data.

My guess is that some or all of the changes (wheel size and stab size) were not transferred to the simulator computers, a year ago I would have said unintentionally - now I have my doubts.

[JPJP]

Originally Posted by megan

We have an experienced aviator, Byron Bailey - ex military fighter & 777 & current biz jet, who writes a regular column in our local national paper (The Australian), and had this to say,Question, is what he's saying re MCAS activation cases in the US for real?

An interesting claim by Byron. It’s not backed up by any of the pilot groups that operate (operated) the MAX In the U.S. Nor the regulators, the investigators, and the unions.

Maybe he has access beyond the pilots with the jets, the Sim, and the updates. Or he’s just another out of touch Austronaut ? He does have a leather jacket. So, there’s that. Perhaps he’s been into his namesakes favorite juice ?

[JPJP]

Originally Posted by Bend alot

I think they have the capability - they just did not have the correct data.

My guess is that some or all of the changes (wheel size and stab size) were not transferred to the simulator computers, a year ago I would have said unintentionally - now I have my doubts.

‘The Sims are being updated’. The first time that was reported to operators was almost four months ago. No idea when it will be complete, or how.

It reminds me of Manual reversion in an NG Sim vs a Classic Sim. One was doable, the latter required two feet on the control column. As a positive thinker, I preferred to believe the NG Sim. As a realist, I have some doubts.

[hec7or]

As a subscriber to "Aviation Week" I cannot find any reports relating to US based MCAS activation on the Max, I believe the mentioned reports are of AoA failures on a variety of aircraft types.
These were reported by the media to highlight the vulnerability of the AoA probe to damage or failure and the likelihood of false data arriving at the ADIRU or equivalent.

[spornrad]

search for 737 trim incidents

Originally Posted by Fly Aiprt

LeadSled says he's had access to those sources. A link would be appreciated.

Peter Lemme has an article containing a long list of earlier 737 trim incidents, most on pre-MAX types. Doesn't seem to find earlier MCAS type failures.
https://www.satcom.guru/2019/05/737-...incidents.html
Conclusion
737 stabilizer trim has been very reliable. There are enough examples of runaway to assume at least one per year, with overall stab trim non-functional about one per month. There are enough examples to assume at least on jam per year.

[MickG0105]

Originally Posted by LeadSled

Folks,
I don't always agree with Byron Bailey, but in this case, I do.

Since the two crashes, the existence of previous occurrences in US have been publicly reported in Aviation Week and Space Technology magazine.

Smashing! You won't mind quoting the article title and date that previous occurrences of erroneous MCAS activations were reported in Aviation Week and Space Technology magazine then. I read that magazine routinely and have never read any such story.

Originally Posted by LeadSled

PS1: It has been some of his opinions, with which I disagree. I don't recall matters of technical fact that i regarded as incorrect, so examples please, not assertions.

From which list would you like to start? Possibly accidental, laughably stupid or deliberately malicious? One from each perhaps.

Possibly accidental. A few weeks ago Captain Bailey wrote, '... the London to Sydney non-stop record of under 20 hours is still held by a Vulcan V bomber ...' No aircraft has ever flown from London to Sydney in less than 20 hours. The 20 June 1961 non-stop flight of the Royal Air Force's No 101 Squadron Vulcan XH481 from RAF Scampton, Lincolnshire to RAAF Richmond, outside Sydney, took 20 hours and three minutes.

Laughably stupid. Writing about MH370, Captain Bailey offered the following with regards to redundancy on the B777,

'The B777 has 80 computers and, except for two engines, nearly every system on board is triplicated to ensure a practically fail safe operation, for example three radios, three radar transponders (linked to Air Traffic Control), three autopilots, three flight management computers (FMS) etc etc. ... And a failure of one will result in transfer, usually automatically, to another . This means for ATC to lose secondary radar contact with MH370 someone had to deactivate all three by manually selecting them to off.'

Three transponders, with automated fail-over no less. Spot the errors? Of course that balls up was made even more laughable as it was written under the headline, 'MH370: I have flown these jets, here’s what probably didn’t happen'

And then there's the Deliberately malicious. Out of a lengthy list of Captain Bailey just making stuff up, the following, where he deliberately concocted a nonsensical statement which he attributed to the ATSB and then set about calling the ATSB stupid for saying such a thing, well, that is probably the most memorable.

In one of his articles titled MH370: report’s ‘stupid’ flaws hinder search, referring to the ATSB report "MH370 - Definition of Underwater Search Areas" dated 3 December 2015, Captain Bailey wrote,

'First, the ATSB [Australian Transport Safety Bureau ] states “the right engine flamed out and in each test case the aircraft then turned left and remained in a banked turn”.
That’s strange because, as any experienced multi-engine pilot knows, if the right engine stops, the aircraft will want to turn right because of simple moment of forces. Strange also because when I flamed out an engine in the FFS, the thrust asymmetry compensation via the autopilot kept the aircraft flying straight."

The ATSB did not say "the right engine flamed out and in each test case the aircraft then turned left and remained in a banked turn." That quotation cannot be found in any ATSB report or update.

When queried as to the source of that quote, Captain Bailey replied as follows :

"God this is boring
page 11 00:05:00 Right engine flamed out - page 13 aircraft behaviour after engine flameout...each test case left turn. Learn to put 2 and 2 together. ...". (I've left out the accompanying petty ad hominem invective.)

The pages Captain Bailey referred to are from the report. On page 11, in a section of the report entitled "End-of-flight", there is a colour-coded timeline diagram headed "Figure 6: End of flight sequence." The first point in the timeline is named "Right engine flamed-out". On page 13 is the next section of the report, "Search area width". A quarter of the way down page 13, the second sub-section is entitled "Simulator data"; the second sentence of that section reads "In each test case, the aircraft began turning to the left and remained in a banked turn." The diagram heading and the sentence are separated by over 550 words.

Captain Bailey's idea of 'putting two and two together' was to take a heading from a diagram on one page, then flipping over a couple of pages (and 550-odd words) to a completely different section and grabbing a sentence half way into a paragraph and then splicing them together. For fear of stating the blindingly obvious, Captain Bailey made that sentence up and passed it off as a statement from the ATSB. The Australian had to subsequently issue a correction and remove that section of the article.

I've got stacks more of his factual errors if you'd care for them.

[Fly Aiprt]

So for the moment, those Bailey articles may be safely disregarded.

[LandIT]

Originally Posted by MickG0105

Captain Bailey's idea of 'putting two and two together' was to take a heading from a diagram on one page, then flipping over a couple of pages (and 550-odd words) to a completely different section and grabbing a sentence half way into a paragraph and then splicing them together. For fear of stating the blindingly obvious, Captain Bailey made that sentence up and passed it off as a statement from the ATSB. The Australian had to subsequently issue a correction and remove that section of the article.

I've got stacks more of his factual errors if you'd care for them.

Thanks for trying to set this record straight MickG the grain of salt tastes good.

[Lookleft]

So for the moment, those Bailey articles may be safely disregarded.

And any other posts that support him.

[LowObservable]

If the Langewiesche story was a plant, it just backfired. As in, megaton-range.

My Letter to the Editor of New York Times Magazine ? Sully Sullenberger

[Fly Aiprt]

Originally Posted by LowObservable

If the Langewiesche story was a plant, it just backfired. As in, megaton-range.

My Letter to the Editor of New York Times Magazine ? Sully Sullenberger

Thanks for that, LowObservable.
So much for the armchair or sim 'experts' who still believe 'they just had to...'.

[inducedrag]

A new B797 should be replaced instead of Ma

[OldnGrounded]

Originally Posted by Fly Aiprt

Thanks for that, LowObservable.
So much for the armchair or sim 'experts' who still believe 'they just had to...'.

"I know firsthand the challenges the pilots on the doomed accident flights faced, and how wrong it is to blame them for not being able to compensate for such a pernicious and deadly design."

~Sully

Oof. Just in case anyone thought Sully hadn't previously made his views perfectly clear.

[Notanatp]

Originally Posted by Fly Aiprt

Thanks for that, LowObservable.
So much for the armchair or sim 'experts' who still believe 'they just had to...'.

I'm going to get slammed by the ATP's for this, but what the heck.

Sullenberger's letter, like his congressional testimony, reads like an audition for a job as an expert witness in the many lawsuits against Boeing (assuming he hasn't already been hired). And to steal a phrase from his letter, "I know a thing or two" about expert witnesses.

Nobody in their right mind would argue that MCAS wasn't defective or that it didn't place the pilots in a challenging situation.

But Sullenberger is clearly advocating, not analyzing, when he effectively takes the position that recovery was not "possible." He says "The National Transportation Safety Board has found that Boeing made faulty assumptions both about the capability of the aircraft design to withstand damage or failure, and the level of human performance possible once the failures began to cascade." I'm not aware that the NTSB has made any such findings. The JATR has questioned assumptions about crews consistently recognizing and responding within 4 seconds, but that's a far cry from saying the NTSB has made a general finding that Boeing made faulty assumptions about what was "possible."

And Sullenberger rehashes the argument about MCAS not presenting as classic runaway trim; however, the facts are that both crews recognized that they had a malfunctioning stabilizer trim system and both crews countered with MET. Sullenberger has never explained why the JT610 crew didn't turn off electric trim. In effect, he is arguing that the crew knew they had a malfunctioning stab trim system but shouldn't be expected to have known to turn it off. Nor does he explain why the ET302 crew (fully briefed on the previous accident and familiar with the Emergency AD) turned stab trim with the airplane out of trim, then turned it back on without using MET to relieve control column forces.

Neither Indonesia nor Ethiopia have released CVR transcripts. Until they do, nobody will know what was going through the crews' minds and why they did what they did. But even without that data, Sullenberger is prepared to say the crews did nothing wrong, and couldn't have done better. That smells like fear that any focus on the pilots' performance will let Boeing off the hook.

[OldnGrounded]

Originally Posted by Notanatp

But Sullenberger is clearly advocating, not analyzing, when he effectively takes the position that recovery was not "possible." He says "The National Transportation Safety Board has found that Boeing made faulty assumptions both about the capability of the aircraft design to withstand damage or failure, and the level of human performance possible once the failures began to cascade."

If you're going to parse Sully's statements you should try to do a better job of it. To say that the NTSB pointed out faulty assumptions about possible levels of human performance is not to say that the NTSB found any particular level of performance "not possible." Really. The English simply doesn't mean what you appear to want it to mean.

Here's the relevant NTSB document:

Assumptions Used in the Safety Assessment Process and the Effects of Multiple Alerts and Indications on Pilot Performance

Edit: It is certainly possible that Sullenberger will end up as an expert witness in litigation related to the MAX crashes. But it would be very surprising if he needed to "audition" for the role. The chances that he hasn't been heavily recruited by plaintiffs' counsel are almost certainly slim and none.

[CurtainTwitcher]

Every single one of your posts involves the MAX accidents. Reading back through you posts lead me to conclude that you don't have too much of a clue about operating an aircraft or the engineering decisions & why Boeing designed the MCAS AoA inputs the way they did. Who are you to criticise someone with the knowledge and experience of Sullenberger?

In short, I wouldn't regard you as a credible witness.

[Fly Aiprt]

Originally Posted by Notanatp

But Sullenberger is clearly advocating, not analyzing, when he effectively takes the position that recovery was not "possible." He says "The National Transportation Safety Board has found that Boeing made faulty assumptions both about the capability of the aircraft design to withstand damage or failure, and the level of human performance possible once the failures began to cascade." I'm not aware that the NTSB has made any such findings. The JATR has questioned assumptions about crews consistently recognizing and responding within 4 seconds, but that's a far cry from saying the NTSB has made a general finding that Boeing made faulty assumptions about what was "possible."

It is possible sir, that we are not reading the same versions of the JATR and NTSB reports, or that you have a better knowledge than Capt Sullenberger of the matter in discussion.

But, what exactly is your point ?

I propose we thoroughly re-read the JATR document, especially the O2-8 and F2-8 observations and findings and the analysis of the NTSB while you'll reformulate your conjecture.

[gums]

Salute!
The Joint report and Grebe's suggestion for a "fix" and Sully's assertion concerning crew recovery with a rogue MCAS brings me back to some of my original thots.
- if a sim can duplicate the change in pitch control force versus AoA, how come the real plane "feel" system can't? And my copy of the FCOM shows some sort of pitch feel doofer and I m not ure exactly how that thingie works. So a high tine 737 driver should comment here, huh?
- could a 737 driver comment on the control force as the plane approaches the shaker criteria/ Does the sucker tell you that you are puilling hard and if you pull harder you will crash and burn?
- My opinion is that the rope, cable, pushrod and pulley mentality of the jet;s legacy required it to pass the same requirements as my old Champ or Luscombe. Ditto for the T-37 most USAF pilots flew from early 60's, and the T-33 as well. Meanwhile the Airbus 320 and heirs paid no attention to control force versus AoA or airspeed ( "q') or mach. They were certified and have flown since early 90's.

I would love to see the data for the plane as the pilots increased AoA at 20K and 2K. How much actual aero force feedback is transmitted back thru all the mechanical gear to the controls? Better, I would pay a zillion to try it myself.

Gotta go back to my cave now, but will stay tuned.

Gums sends...

[Loose rivets]

#3055

Note the cheap way of indexing the sensor to the vane - a loose screw can result in odd readings very subtly

In my belt and suspenders world as a SLF-engine-ear - I would think a d shaped shaft or a spline and d ring assembly ( spline for location of sensor- snap or dring to keep on spline ) or similar would have long ago been used- mandated.

While I agree that looks a cheap way of indexing, I assume it's like it is so that it can be calibrated. Just looking at that grub screw makes me shudder. LockTight? I'm at a loss.