BBC: 737 Max - Still Not Fixed
 

Any comments on the BBC article today quoting ex-Boeing Ed Pierson's recent report about other problems at Renton having played a direct role in the crashes? His Report is the title of this post.

Ah got it,
The BBC item is Boeing 737 Max cleared to fly again 'too early' https://www.bbc.co.uk/news/business-55751150
Which contains a link to Ed Pierson testifying before the U.S. Congress https://edpierson.com/
Which contains a link to 737 MAX - STILL NOT FIXED (pdf)https://img1.wsimg.com/blobby/go/ec1...=1611532831723

It will be interesting (to this SLF/attorney, at least) to see whether the lawsuit against the FAA in Washington, D.C. federal district court, which seeks disclosure by FAA of substantially all the documents FAA has received from Boeing regarding the return to service of the 737 MAX aircraft, will try to add this recent report to its arguments. The lawsuit is filed under the FOIA, Freedom of Information Act.

It was filed by an affiliate of the Flyers' Rights advocacy group (Flyers Rights Education Fund, Inc). a little more than a year ago. Capt. Sullenberger is the most prominent of the group of expert consultants the advocacy group assembled. Both sides in the case have filed motions for summary rulings by the court and it appears the briefing on these motions was completed a few days before Christmas. (The judge's staff surely had a magnificent holiday break, neck-deep in legal papers.)

Pierson's report certainly appears to support the basic argument in the lawsuit, namely that the FAA decision process about the return to service cannot be evaluated properly unless and until substantially all the documents received from Boeing are disclosed to a suitably qualified public interest advocacy group (the Flyers Rights expert consultants).

Whyever should some self-appointed, self-publicist group, of what appear to be lawyers looking for an ambulance to chase, have any overriding position in this process ?

"Public interest advocacy group". Hah !

I'm just trying to be objective, in describing the group that way. But some facts might be interesting. The law firm involved is far from ambulance-chasing rungs - it is very politically connected up in Washington but that's a different point, isn't it? Also, the people assembled by the group, you can check out their credentials, they appear pretty highly qualified, maybe very highly qualified. Sullenberger certainly is.

And the lawyer who heads up the group sits on one of the FAA's main advisory committees. Other than these facts, I have no basis to say the group is on a stunt or not - though FAA in how it has conducted the litigation has taken it quite seriously.

Wow, the "Still not fixed" pdf is quite something. Very cogently argued and chilling.

The paper appears to revolve around AoA sensor reliability.

It doesn't seem to acknowledge anyhere that, while the sensor failure rate will never be zero, the redesigned MCAS is intended to mitigate the effect of AoA discrepany.

In my reading of it, it seems as much to revolve around installation/construction issues (especially electrical systems) as it does around AoA sensor reliability - I am interested to know how abnormal is the incident rate (4%) that he refers to on pages 11/12 for new (or even not new) aircraft:

"Some aviation professionals might argue [...] This track record is unprecedented in modern day aircraft."

There are some distinct questions/problems that are legitimate but thrown into a blender.
- Manufacturing problem with the Lion Air original AOA-Sensor and no known to the public measures derived from it.
- Unknown root cause of Ethopian AOA sensor failure (who tried to attribute it so a bird strike? I honestly can't remember.)
- Obvious E/E deficiencies on both new aircraft that could not be diagnosed and sorted out by local maintenance.
- The usual business of manufacturing problems, not only the MAX suffers from.

Maybe the more appropriate headline with regard to those problems would be Boeing - Still not fixed.

No, I don't think the MAX is fixed, but that is due to yet another balcony, another warning, another algorithm and tons of MEL items, Check list entries added to 60ies ramshackle base structure.

My reading of page 8 of the pdf is that the aoa sensor can fail at any time due to a magnet wire in it is placed between 2 different components that with variances in temperature expand and contract at different rates so cause fatigue in the wire until it eventually breaks. Except that when the heating for the sensor is on and it heats up to above 60 degrees the wire itself expands enough to make it connect again.
One would assume that this could happen to all aoa sensors produced before this was found in June 2019, and for a time after that until the production method was altered, if it was. There is something to be said for 3 aoa sensors from 3 different manufacturers on each plane.

Ed Pierson's own website (the paper's author) says this
Also, Wakner - when you quote Ed Pierson as saying, I think your connection of those two sentences is misleading. What that paragraph says in full isSo Ed P is actually stating his own view that the track record is unprecedented.

vikingivesterled

The part is carry over from NG. So the general construction would have been sound. I understood the situation you describe was a manufacturing error.

vikingivesterled

Resolvers have been used in aircraft systems for MANY years, and they are used specifically because they are VERY reliable. If two resolvers are used, then the failure of one can be worked around. They are capable of handling large temperature variations. There are likely hundreds of resolvers in a 737, in the engine controls, flight controls and other places. But, yes, of course, any device can fail at any time. Vane-type AOA sensors are really difficult, as they are prone tio damage in ground handling or bird strikes, water ingress and freezing and similar issues.

There's a super-detailed "brief" (hesitate to say so as a lawyer as it's 126 pages long) called MAX-Ungrounding-Notice-of-Appeal-12.3.2020.pdf on the Flyer's Rights dot org site if anyone's interested in reading it. This must have a docket number by now. Unless they're actually appealing the previous adjudication, which is likely what's going on. I don't see that the case called
Flyers Rights Education Fund, INC., D/B/A FLYERSRIGHTS.ORG, and Paul Hudson, Petitioners, v. Federal Aviation Administration, Et Al has much to do with the 737 MAX.
mo

Sully did an amazing ditching on the Hudson. An extraordinary feat of aeronautical decision making with an incredible all surviving outcome. However the net result of that is the deification of Sully and the notion that every word he utters is somehow sacrosanct. The Hudson has given him a platform which no aviator could expect unless they inhaled a pair of Canadian geese with similar results. His views are relevant but probably not significantly more important than many other experienced aviators particularly the Boeing variety. The Max debacle was a stain on Boeing’s reputation which as the true horrible story emerges is going to take quite some overcoming. The loss of the 2 Max’s was utterly tragic. However, I have to believe that the now finished product will be as safe as it is possible to be. Boeing can not afford another disaster. Finally, anything the BBC produces these days will be distorted to fit an agenda coupled with technical inaccuracies. Just my view.

Olster, you believe thatand thatBut the BBC was quoting from a well-argued paper from an insider who was ideally placed to observe Boeing manufacturing during the appropriate periods. And that paper suggests that there is much more that should be examined before anyone can conclude that the 737 Max is “as safe as it is possible to be”.

Yes air sound I do believe that the Max will be safe. I don’t think Boeing could countenance another accident. I believe that Boeing engineers have produced solutions coupled with operational guidance which should of course have been in place at the start. Please believe that I am no defender of Boeing; the original service introduction was an absolute disgrace. You can look at the aftermath in two ways. A realisation that there is a moral responsibility to put it right. Plus an economical agenda. I believe that one has to have confidence in the aircraft now as further disasters are untenable.

In the early weeks and months after the grounding, we saw boeing doing all it could to rush the Max back into service. Are we all convinced?

For my part, I'll wait a few years before getting on one. YES it is a numbers game every time you board a car or aircraft. But there are several carriers and aircraft on my personal no fly list.

Moral responsibility? They blamed those poor pilots and they would still be blaming them if they could.

Please read my post. I am not a defender of Boeing at all. I have personal experience of Boeing personnel attempting to blame the pilots. You can be assured those were robustly rebutted. The pilots were hapless scapegoats at the end of a very large slice of Swiss cheese. I also believe that the Max was a stretch too far for the 737 series. I have flown many variants from the -200 up to the -800 plus instructed / examined on most. If Boeing had asked me prior to developing the Max (a highly unlikely scenario) I would have said stop it here at the NG. I think that Boeing had lost its moral compass and they have a responsibility to show humility and contrition for the subsequent disasters.

airsound10976027]Ed Pierson's own website (the paper's author) says this

Sorry - was not my intention to connect the two sentences, rather highlight this whole paragraph for reading.

Thank you for clarification, olster and Wakner

olster

Sully's CV is a bit more extensive than the Hudson in a BUS, and post that he was given the opportunity to fly the fatal MAX flights in the sim.

We can only assume he was given the same computer based differences training to supplement his original 737 type rating.

Wakner

Allegedly, those issues with some electrical connectors/connections were found during flight line tests after the MAX left the factory, which I assume were found by internal QA.

So, reading that PDF, the MCAS anti stall system was actually doing what it was designed to do? You cant expect a computer program to work as designed with faulty inputs.
The faulty AoA sensors are the real culprits here?
(among other Boeing and Lion Air systemic failures as contributing factors)

chriscrepon88
The case filed in the U.S. Court of Appeals for the District of Columbia Circuit by the Flyers Rights group is docketed as 20-1486. It is an administrative law appeal of FAA's actions, specifically (1) the ungrounding order (I'm omitting the technical name for this order), and (2) the final AD. The underlying administrative rulings are filed, as published in the Federal Register in November. There are a number of procedural briefs and motions already in the appellate court (though without reading these, no further comment here).

The other current action by the Flyers Rights group, continuing in the federal District Court in D.C., is most definitely about the 737 MAX. It is a Freedom of Information Act lawsuit seeking disclosure by FAA of all documents relating to the ungrounding decision which, at the time the case was filed, was far from imminent. (There are cross-motions for summary judgment pending, last time I checked it out on Pacer.)

(And as SLF/attorney, I'm obliged to say, the foregoing attorney-talk is only for the purpose of clarification. Please return to the regularly conducted aviation subject matter thread.)

With all that said, I just returned a Max to service after 11 months in storage.
The aircraft performed well on the test flight returning without a write up.
Up until this stage I not encountered any abnormal electrical or avionics defects after the wiring mods.

Bend alot

If Sully was given the same aoa/sirspeed unreliable faults at take off why was he not able to control the aircraft applying memory items for the condition, aircraft still with flaps in take off configuration?

I am well aware that Sully is a highly experienced aviator and I completely endorse his incredible handling of the Hudson ditching. A great story mainly because everyone walked away. I am not one of them but certainly colleagues of my vintage can be a bit ahem, sniffy about the never ending Sully worship. Professional jealousy? Perhaps. However, Sully’s background while not particularly or radically different has given him a platform whereby the rest of aviation hangs on every word. He may or may not always be right. Personally I am glad I never had the misfortune to encounter corpulent Canadian geese @ 250 knots. So, to clear up any misunderstanding I have great admiration for the man but he shouldn’t be seen as the oracle without challenge either.

olster

What agenda?
What technical innacuracies...?
Very quick to slag off the messenger with no evidence at all...

The BBC article is purely factual, reporting the stated concerns of Piersen, Sullenberger and others.

It even takes care to ensure that the judgement of the above re the lifting of the grounding, is described as "too early" (their quotes, not mine) to make it clear that the BBC itself has no view either way.

Couldn't agree more with Nige321 and DaveReid, Olster's views about the BBC are just plain wrong.

Unregistered

One could argue that relying on a single sensor was the original sin. At the time, it was rationalized by the fact the system was slow and not very powerful, so any competent pilot would be able to reconize it and do the runaway trim routine. However, later on, it became much more powerful, which is when they really should have turned to at least two sensors.

A man with one watch knows the time. A man with two is never sure.

In such a safety critical system, if you are using multiple sensors, you need an odd number so you can implement a voting system (and hope that there are no common-mode failures that afflict a majority of sensors, or at least engineer away the frequently occurring ones).

And, to be clear, MCAS, even when acting on incorrect information from the AoA sensors, never 'ran away' - it applied a one-shot adjustment which could easily be confused with normal running of STS. Unfortunately, adjusting trim with the pickle switches reset the MCAS trigger, allowing it to add another 'one-shot' adjustment, which if not fully recovered by the trim adjustment switches, added up with previous adjustments until the out-of-trim aerodynamic forces could not be overcome by use of the yoke. As history shows, this behaviour managed to fool several certified competent pilots who had not been fully informed of MCAS behaviour.

A continuous runaway is easy to recognise. An intermittent, slow piling up of small increments of unhelpful trim turns out not to have been obvious, especially in a busy work environment with falsely triggered alarms.

I almost started this thread after reading the BBC 'paper' on my FireFox tab. I didn't because it was filled with a LOT of technical misinformation. In particular, they'd gone to the trouble of nose angle drawings but as was so often the case, got muddled with simple pitch and AoA measurements.

Many of the statements were entirely familiar to me. This is happening at a time when Boeing know they can't have another MCAS induced incident, and now they have an entirely new incident to start a lot of heads nodding. There are some striking similarities, but hopefully not a single causal factor that is the same.

We all know pretty much what happened. What we seem to let slip into dark corners of our memories is that the two vanes failed in disparate ways. To me, this spells a very high bad luck factor in the equation. The second crash might well have been avoided had there been time, or the inclination, to practice such an occurrence after the first crash. However, it's been mooted that the psychology at that moment was probably worsened - now having the awareness of some mystery system causing problems but nowhere near enough thought and training on how to handle it. i.e., the limited knowledge causing a greater feeling of disbelief and resultant stress.

There are many factors that take some of the share of blame, though such arguments become almost philosophic.

IIRC, The first vane had been sourced from FLA from a company that sells and or refurbishes parts. If this is true, a virtually new late-model Boeing had a critical part that was not only not new, but had been serviced (then) by an unknown. Service might mean nothing more than bench testing.

Loose rivets

"I almost started this thread after reading the BBC 'paper' on my FireFox tab. I didn't because it was filled with a LOT of technical misinformation. In particular, they'd gone to the trouble of nose angle drawings but as was so often the case, got muddled with simple pitch and AoA measurements."

That's grossly unfair to the BBC.

Firstly, the article simply reports on the judgment of some individuals whose views are widely accepted as relevant. I'd be interested to know which parts qualify as "technical misinformation".

Secondly, the infographic you object to has been kicking around for a couple of years. While it's an oversimplification in that it uses the term "angle" without explaining whether it's AoA or pitch attitude, that's perfectly reasonable given (a) the target audience and (b) the fact that the distinction is arguably irrelevant in the context of the MCAS failures.

Hot 'n' High

On the contrary, my apologies. You are correct. The original incarnation of MCAS did trim again after 5 seconds if the triggering conditions continued to apply. Thank youfor the correction.

Details of MCAS here: 737 MAX - MCAS

Interesting to note FAA AD 2020-24-02 issued 2020-11-18 changed the Runaway Stabilizer wording (page 105) to "If uncommanded stabilizer movement occurs continuously or in a manner not appropriate for flight conditions:" (My italics). The document's discussion of MCAS is worth reading.

My pleasure Semreh! IIR, it took a while to figure out how it really worked right when all this started so I was more worried that I had lost the plot .... again! Thankfully, in this case, I remembered correctly it seems. And the rest of your Post #34 was spot on!

Semreh

AFAIK MCAS would apply up to 5ish degrees of AND trim if it sensed too high AOA. If the out of trim conditions were still there it would not apply trim again until one of several system reset triggers happened. One of those was the pilots using the trim thumb switches. If the pilots hadn’t used the trim after the first MCAS trim application MCAS would not have reactivated. Obviously, that doesn’t make MCAS okay, as we are all trained to fly with the aircraft in trim.

Ah, cheers hans. My memory playing tricks here it seems. I just checked and found this - https://www.faa.gov/foia/electronic_...TS_Summary.pdf. Safety Item #2, page 7. Semreh, my apologies to you - it was my poor memory after all!

As an aside, I don't recall seeing the FAA doc at the link so may be of interest to others - unless it was only me who missed that too!! It seems quite comprehensive (at first glance) covering both tech and administrative issues (such as FAA oversight). Anyway, back under my stone before I confuse people even more.