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-   -   BBC: 737 Max - Still Not Fixed (https://www.pprune.org/rumours-news/638259-bbc-737-max-still-not-fixed.html)

SRMman 25th Jan 2021 08:47

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.

Peter H 25th Jan 2021 09:35

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

WillowRun 6-3 25th Jan 2021 13:18

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).

WHBM 25th Jan 2021 13:26

Originally Posted by WillowRun 6-3 (Post 10975883)
... 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 !

WillowRun 6-3 25th Jan 2021 13:36

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.

BRE 25th Jan 2021 14:23

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

DaveReidUK 25th Jan 2021 14:38

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.

Wakner 25th Jan 2021 15:01

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."

BDAttitude 25th Jan 2021 15:58

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.

vikingivesterled 25th Jan 2021 16:12

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.

airsound 25th Jan 2021 16:49

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

Captain Sullenberger has read this paper and said that “it raises many important questions that must be answered.” Dr. Daniel Ossmann, a recognized expert in aerospace fault detection, has also reviewed the paper and “concluded that it illustrates an excellent compact summary of the events and raises concerns that should be thoughtfully addressed.”
Also, Wakner - when you quote Ed Pierson as saying

Some aviation professionals might argue [...] This track record is unprecedented in modern day aircraft
, I think your connection of those two sentences is misleading. What that paragraph says in full is

Some aviation professionals might argue these safety incidents are not statistically relevant and they are just “teething” problems from a new model airplane. They might say these incidents represent a tiny fraction of the thousands of Boeing planes that safely fly millions of miles around the world each day. Although impressive, these big numbers are misleading. It is true that before the pandemic, there were more than 10,000 Boeing airplanes in service around the world flying millions of miles each day. But when the 737 MAX was grounded in March 2019, there were only 371 MAX airplanes in service around the world. 15 safety incidents represent 4% of the entire MAX fleet (15/371=4%). Thus, 1 in 25 MAX airplanes had already experienced a safety incident within the first year of being in service, two of which happened to be fatal crashes. This track record is unprecedented in modern day aircraft.
So Ed P is actually stating his own view that the track record is unprecedented.

BDAttitude 25th Jan 2021 16:57


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.

jmelson 25th Jan 2021 17:25


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.

chriscrepon88 25th Jan 2021 17:39

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.

olster 25th Jan 2021 18:55

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.

airsound 25th Jan 2021 19:18

Olster, you believe that

the now finished product will be as safe as it is possible to be.
and that

anything the BBC produces these days will be distorted to fit an agenda coupled with technical inaccuracies.
But 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”.

olster 25th Jan 2021 19:28

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.

PAXboy 25th Jan 2021 19:30

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.

Banana Joe 25th Jan 2021 19:38

Originally Posted by olster (Post 10976121)
. A realisation that there is a moral responsibility to put it right.

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

olster 25th Jan 2021 19:52

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.

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