Boeing 737 Max Recertification Testing - Finally. [Archive]

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tdracer

27th May 2020, 21:37

Just heard this on the radio - Boeing is restarting the production of new 737 MAX aircraft in Renton.
I don't have any inside information, but I can't believe Boeing would take this step unless they had good reason to believe the MAX grounding will be lifted in the near future.

Longtimer

27th May 2020, 23:00

https://ca.finance.yahoo.com/news/boeing-resumes-737-max-production-212323178.html

b1lanc

28th May 2020, 01:23

https://ca.finance.yahoo.com/news/boeing-resumes-737-max-production-212323178.html
Err, wonder what remaining airlines want to take delivery of any new aircraft? Seems to be a plethora of available types sitting round the globe.

Matt48

28th May 2020, 07:00

esscee

28th May 2020, 07:35

Maybe they have found another big parking area?

ATC Watcher

28th May 2020, 07:45

Quite a strange announcement as it comes hours after another one announcing a 13.000 layoff in production in Seattle...and a much earlier one on delivering 777x a the priority .. But as said before maybe they know something we don't...

Anti Skid On

28th May 2020, 07:49

There'll be a load of narrow body jets that someone could buy up cheaply and set up a low cost carrier if COVID ever goes away

jimjim1

28th May 2020, 08:38

This floated past on twitter - not seen this elsewhere but have no idea if it is correct or otherwise.

"Boeing 737 Max 8 test flight of #SunExpress (https://twitter.com/hashtag/SunExpress?src=hashtag_click) TC-SOI (Boeing test reg N1779B). BFI PAE BFI as flight BOE301. Pics from 15 May 2020 at PAE. #Boeing (https://twitter.com/hashtag/Boeing?src=hashtag_click) #737Max (https://twitter.com/hashtag/737Max?src=hashtag_click) #BoeingMax (https://twitter.com/hashtag/BoeingMax?src=hashtag_click) #737Max8 (https://twitter.com/hashtag/737Max8?src=hashtag_click) #B737 (https://twitter.com/hashtag/B737?src=hashtag_click) #SunExpress (https://twitter.com/hashtag/SunExpress?src=hashtag_click) #PAE (https://twitter.com/hashtag/PAE?src=hashtag_click)"

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/800x400/1590654978_ab8e0220972467feb8bbb881e5a80325ebd00b96.jpeg

https://twitter.com/KPAE_Spotter/status/1265823857354539009

Sun Express are Turkish and operate in Turkey and to the EU.

3db

28th May 2020, 10:40

I *think* Sun Express is another trading name/subsidiary of Turkish Airlines - who have a lot of 737's.

DaveReidUK

28th May 2020, 11:21

Turbine D

28th May 2020, 14:20

From FlightGlobal:
Boeing has resumed 737 Max production, bringing the factory back on line at “low” production rates almost five months after halting Max assemblies.“The 737 programme began building airplanes at a low rate as it implements more than a dozen initiatives focused on enhancing workplace safety and product quality,” the company says on 27 May.

Boeing does not disclose an initial production rate. The company says production will resume at a “very gradual pace” and that production ramp up “will be determined by the pace of deliveries to our customers”.

Boeing said in recent weeks that it intends to produce 31 737 Max monthly in 2021. The company produces 737s in Renton, Washington.

Regulators grounded the Max in March 2019, forcing Boeing to halt deliveries. But the company kept producing roughly 42 737 Max monthly for the remainder of 2019, causing a massive backup of undelivered aircraft.

With signs suggesting no immediate end to the grounding, Boeing halted Max production in January.

Since then, Boeing mechanics and engineers “collaborated to refine and standardise work packages in each position of the factory”, Boeing says. “New kitting processes will also ensure that employees have everything they need at their fingertips to build the airplane.”

”These initiatives are the next step in creating the optimal build environment for the 737 Max,” says 737 programme vice-president and general manager Walt Odisho.

Ian W

28th May 2020, 14:31

There'll be a load of narrow body jets that someone could buy up cheaply and set up a low cost carrier if COVID ever goes away

I have just had to book a business trip domestic from Florida to Dulles. All the airlines are acting as if getting pax back on the aircraft will be difficult and have reduced their flights to the level that most of the flights are already booked out. I think that the bounce back will be a lot faster than the industry seems to be prepared for. There are several expert assessments that the SARS-CoV-2 virus may just stop. Indeed one vaccine manufacturer in UK says the race is to get a vaccine to human test stage before the cases drop too low to be useful for the test.
The population appears to have split into two groups - the type that would not get in an aircraft now and definitely not in the middle seat as the fear conditioning has been so well done; and, the type that has realized that 95% of the population appears to have innate immunity so do not expect to get sick, and want to fly and get back to working normally. The second type is already trying to fly and is actually being told no flights available!! by the airlines that seem to be convinced that the panicked first group represent 100% of the population.
The first airline to get back to normal operations - perhaps with a mix of 'hypochondriac' flights and 'normal precautions' flights without blocked seats or masks to test the reaction - will become profitable again a lot faster than people expect. The demand for new aircraft will also pick up faster than expected. Provided paranoid politicians don't get in the way, international flights will also pick up rapidly as there is 'pent up demand'. Airlines should not think that recovery will take years this time next year with COVID-19 being rare, demand could easily be back to normal.

EEngr

28th May 2020, 16:21

A news item says the Max 8 will not be flying before mid year, that's 1 month away, either Boeing know a lot or they know nothing, you would wonder how could they make sales with business how it is presently.

I had heard that they anticipated a return to service in the third quarter of this year.
https://www.aviationtoday.com/2020/04/30/boeing-737-max-certification-flight-waiting-software-validation/

The problem Boeing might be up against with both the suspension of 737 MAX production and Coronavirus shutdowns is a loss of their skilled workforce. Coming up to speed slowly will give them an opportunity to keep their best people while 'cleaning up' their production processes. Layoffs will adjust the workforce to match lower production rates (on all models). Later, as demand returns, the streamlining of shop floor processes may mean that not all who are being laid off will be called back.

Boeing has shut down a few times, but for shorter periods. Just to get paperwork straightened out and regain control of the production schedule. Their processes haven't scaled up very well under high rates in the past. It was one thing to halt 747 production when things were going full tilt. But with slow demand and the certification driven halt, what could be a better use of their time?

fizz57

28th May 2020, 16:40

I had heard that they anticipated a return to service in the third quarter of this year.

Boeing (admittedly under a different CEO) did that quite a few times last year. Share price needs propping up again? :rolleyes:

Less Hair

28th May 2020, 16:41

Suppliers need some credible perspective. And customers too.

SMT Member

28th May 2020, 16:52

I think it's fair to surmise, that Boeing has lost all creditability when it comes to projecting a return to service timeline for the Max.

Ever since the grounding they've peddled the same message every 3 months: In 3 months we'll get the approval and the grounding will be lifted. Well, it hasn't happened yet and to my knowledge neither the FAA, nor EASA or CAAC, have committed to anything or provided guidance as to when RTS may be expected. To exacerbate the situation, as long as there's Covid-19 lockdowns, closed borders and travel bans in place there's simply no way the necessary tasks can be accomplished.

His dudeness

29th May 2020, 11:11

I *think* Sun Express is another trading name/subsidiary of Turkish Airlines - who have a lot of 737's.

Its a joint venture, Turkish Airlines and Lufthansa

Slezy9

29th May 2020, 20:57

There are several expert assessments that the SARS-CoV-2 virus may just stop.

That's great news. Can you post some evidence? Perhaps peer reviewed?

3db

29th May 2020, 21:26

Thanks "His dudeness".

grizzled

29th May 2020, 21:48

A: 95% of the population appears to have innate immunity

B: this time next year with COVID-19 being rare.

Re A: And this is also great news! First: Sources please. Second: Do you understand the significance if what you say (about the 95%) is true? Hint: It's anything but good news, as relates to current numbers of folks ill in the USA and what that means in the next months and year(s).
Re B: Wanna bet? .

nonsense

30th May 2020, 02:57

... 95% of the population appears to have innate immunity so do not expect to get sick...
As evidenced by various cruise ships, meat packing plants, prisons, etc, with way more than 5% infected?

SLF3

30th May 2020, 07:09

.Scott

10th Jun 2020, 19:42

CNBC is reporting that Boeing is ready to recertify by end of June.
Boeing to Recertify (https://www.cnbc.com/2020/06/10/boeing-aims-for-737-max-recertification-flight-by-the-end-of-june.html)

tdracer

10th Jun 2020, 20:22

Free Range

10th Jun 2020, 21:28

$4.3 Trillion in Exportable US GDP

-Max Jet Certification

Boss Hawg

10th Jun 2020, 21:39

Does anyone even want or need these planes anymore? With so many planes parked, why pay for a new plane, especially one with this history? With fuel cheap, grab an NG from the desert and fly it till it's due for a D check, then get another one and do it over again.

.Scott

11th Jun 2020, 11:56

Dr Jay

11th Jun 2020, 14:01

Google Heinsberg, Gengelt, Carnival. 15% infected in the region, and I believe 40% of those who attended the carnival.

the German doctor who led the research is Hendrick Streeck. There is a very interesting interview in English with him on YouTube.

As a physician following this closely, the 95 % innate immunity figure is just not true.

The underlying interpretation problem is one that I see over and over in the modern era of social media....people take an N =1 and extrapolate to the entire population. I can give you a personal example. My 88 yo mother with severe Alzheimers lives in a nursing home. 35 of the residents tested positive for COVID. 5 did not. One could conclude from this study that 15 % have innate immunity. But that would be erroneous. There could be a myriad of other factors here.

There may be individuals with genetic immunity. Trouble is, we don't know who they are, yet.

The second bigger issue is that even when COVID19 is over via herd immunity, immunizations, preventive meds or a combination, will air travel ever be the same ? At least in the US, a plethora of businesses are locked into working from home and Zoom meetings. Face to face board meetings, business pitches etc may be much more rare.

And then there is always the next pathogen....

grizzled

11th Jun 2020, 16:18

Let me offer a rare optimistic view (and prediction)...

By late next year, the demand for air travel will be within 10% of what it was last year. But passengers will not longer tolerate the same cramped quarters that they did before COVID-19.
So revenue will be up and total number of planes and ATPs will be up even with somewhat fewer passengers and much fewer seats per plane.

I wish that were the likely scenario, but it just doesn't seem plausible that a rebound would / could occur that quickly.
First, the figures around job losses mean far fewer people willl have the disposable income to fly for leisure purposes. Even many of the people that have regained or will regain their jobs have suffered BIG income losses this year. Second, substitute "businesses" for "people" and the situation re financial losses is similar. Third, the tickets for those aircraft seats will have to cost more to buy, otherwise those "fewer seats" will not generate enough revenue to make a profit.
Lastly, the only remaining way to mitigate the above is for more gov't assistance (to people, small businesses, and / or airlines). After what all levels of gov't have spent in the past 4 - 5 months on Covid related issues and support, there is simply not going to be sufficient money in the various gov't coffers for a long time.

Bend alot

11th Jun 2020, 21:31

Google Heinsberg, Gengelt, Carnival. 15% infected in the region, and I believe 40% of those who attended the carnival.

the German doctor who led the research is Hendrick Streeck. There is a very interesting interview in English with him on YouTube.
Here is another google, I shall let others do the math.

https://en.wikipedia.org/wiki/COVID-19_pandemic_on_cruise_ships

I am not sure if the FAA are intending going alone with the un-grounding the MAX, seen no comment from the other regulators that have voiced concerns.

jimjim1

11th Jun 2020, 23:19

Reg.: N7201S, B737
Type Desc.:L2J
Squawk:4722

737 Max 7 tooling round Washington State today.

Maybe they do this every day, no idea.

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/916x560/737max7_b452250f9440a662361bd822275f59289fdf6cf9.jpg

mayam13

12th Jun 2020, 04:29

That's not quite what the article says - it says complete the cert flight test by the end of June.
A good bet would be another month to six weeks after all testing is successfully completed before FAA approval is granted. So late July to mid August.
What about EASA approval to fly in EU? Well it is safer in US since the '737 max 8 simulators' -the bone of contention-are only available in US. Can Boeing supply sims to all airlines outside US continent? I doubt

Bend alot

12th Jun 2020, 04:51

rotorwills

12th Jun 2020, 08:52

Whilst I am under a nda, it doesn't cover my entire life. I have physically seen more than 1 fully installed Max Sims outside the US. I have not been to Africa or the Far East for many years. So as one can see some previous posters are not up to speed. As to why they venture outside their realm of knowledge I sometimes take my own cynical view.

On the matter of the thread and it's contents, I have no direct knowledge of when any certifications will be made. One thing I can conjecture is that the FAA alongside Boeing are under pressure from Federal authorities to get the MAX into the marketplace as quickly as possible just solely based on the USA financial positions due to the pandemic.

If I was a betting man I may take a punt that the MAX will be in operation before this year is out.

Longtimer

12th Jun 2020, 18:53

Boeing do not supply the MAX sims, two other independent companies manufacture and sell them.

Most MAX simulators including the one in Ethiopia were outside the US, but I guess they could have sold them to the US.
simulators are produced separately by CAE Inc and Textron Inc’s simulator and training division TRU
Air Canada owns 2 max simulators and has access to a 3rd.

CAE started making more simulators in Jan anticipating a need.
Canada’s CAE Inc., anticipating a surge in demand for pilot training, in November said it had begun to make 737 Max full-flight simulators without customer orders in hand, an unusual step in the build-to-order industry. The company believed more training would be needed in the wake of 737 Max crisis and wanted to be in a position to quickly supply airlines with the machines that can cost as much as $20 million apiece, CAE spokeswoman Helene Gagnon said.

GlobalNav

12th Jun 2020, 20:09

One thing I can conjecture is that the FAA alongside Boeing are under pressure from Federal authorities to get the MAX into the marketplace as quickly as possible just solely based on the USA financial positions due to the pandemic.

If I was a betting man I may take a punt that the MAX will be in operation before this year is out.

Sadly, I tend to agree with you. I wish the FAA was under more pressure to get the certification process right. There's no short path for that. I'm afraid the traveling public must rely on EASA rather than FAA leadership for aviation safety, at least for the time-being.

The economy (AKA marketplace?) is important to the lives of all of us. But, life, first of all, is important to to our lives. The rush to "get back to normal" is actually counter-productive to restoring our health and our economy.

kiwi grey

12th Jun 2020, 23:06

According to Jon Ostrower (here: Boeing's 737 Max software done, but regulators plot more changes after jet's return (https://theaircurrent.com/aviation-safety/boeings-737-max-software-done-but-regulators-plot-more-changes-after-jets-return/)) EASA want further changes, either a third AoA sensor or a "synthetic airspeed or equivalent system".
It's not clear to me from the article whether this is a pre-condition to EASA certification of the 737 MAX, or a mandatory Service Bulletin for retrofit.

Bend alot

13th Jun 2020, 00:21

The Federal Aviation Administration has formally rejected Boeing (https://www.cnbc.com/quotes/?symbol=BA)’s proposal that it not modify nor move wiring bundles in 737 Max airplanes, according to people familiar with the decision. Boeing says the bundles do not pose a potential safety threat. Nevertheless, the FAA has told the company the bundles are “not compliant.”

A spokesperson for Boeing told CNBC: “We remain in ongoing discussions with the FAA on the wire bundles. Regardless of the final determination on this matter our estimate for a mid year return to service of the MAX is unchanged.”

https://www.cnbc.com/2020/03/09/faa-tells-boeing-that-737-max-wiring-bundles-are-not-compliant.html

tdracer

13th Jun 2020, 00:45

Old news Bend alot. Boeing has conceded the point and MAX aircraft and are actively retrofitting the aircraft already built. There is a least one team of mechanics at Boeing dedicated to performing the wiring change:
On the flight line in Renton, where crews are working outdoors to rewire each already built but still grounded 737 MAX to meet Federal Aviation Administration (FAA) wiring separation requirements, an inspector described a feeling of familylike connection and protectiveness among his work crew.
They work together rewiring each MAX over two days, then another plane is rolled into their stall and they repeat. Familiar with each other’s home circumstances and their adherence to precautions, they have contact with few other employees.
https://www.seattletimes.com/business/boeing-aerospace/boeing-factory-workers-cope-with-the-coronavirus-threat-as-layoffs-loom/

Standard procedure is that type certification is highly coordinated between the FAA and EASA and final approval happens at the same time - or at worst a day or two apart. Other cert organizations (e.g. Russian, China, etc.) happen separately and can follow anywhere from days to years later.
However the 737 MAX fiasco has been anything but 'Standard', so who knows (and those who may know are not talking).

Bend alot

13th Jun 2020, 00:48

Not seen this before. EASA requirements.

Flight tests on a modified B737 max [one full week - at Boeing Flight Test Center]
 MCAS operations (nominal behavior)
 Flight without MCAS (including high speed turns and stall)
 Scenario of stabiliser runaway (uncommanded MCAS activation, manual trim wheel forces)
 Approach to stall with autopilot engaged

https://www.europarl.europa.eu/cmsdata/186500/20190903_EASA_Ky-original.pdf

megan

13th Jun 2020, 00:59

Update on Spirit's 2020 737 MAX ProductionWICHITA, Kan., June 10, 2020 /PRNewswire/ -- On June 4, 2020, Spirit AeroSystems [NYSE: SPR] received a letter from Boeing directing Spirit to pause additional work on four 737 MAX shipsets and avoid starting production on sixteen 737 MAX shipsets to be delivered in 2020, until otherwise directed by Boeing, in order to support Boeing's alignment of near-term delivery schedules to its customers' needs in light of COVID-19's impact on air travel and airline operations, and in order to mitigate the expenditure of potential unnecessary production costs.

Based on the information in the letter, subsequent correspondence from Boeing dated June 9, 2020, and Spirit's discussions with Boeing regarding 2020 737 MAX production, Spirit believes there will be a reduction to Spirit's previously disclosed 2020 737 MAX production plan of 125 shipsets. Spirit does not yet have definitive information on what the magnitude of the reduction will be but expects it will be more than 20 shipsets.

The 737 MAX grounding coupled with the COVID-19 pandemic is a challenging, dynamic and evolving situation. During this time, Spirit plans to work with Boeing to determine a definitive production plan for 2020 and manage the 737 MAX production system and supply chain.

Due to the matters described above, Spirit has elected to place certain Wichita hourly employees directly associated with production work and support functions for the 737 MAX program on a 21 calendar day unpaid temporary layoff/furlough effective Monday, June 15. In addition, Spirit will declare an immediate reduction of the hourly workforce in Tulsa and McAlester, Okla., effective Friday, June 12.
https://www.spiritaero.com/release/137073/update-on-spirits-2020-737-max-production

mayam13

13th Jun 2020, 07:44

rotorwills

13th Jun 2020, 09:15

Mayam13, is there a point you wish to make, as I don't understand the relationship to my post and your photo?

mayam13

13th Jun 2020, 11:19

Mayam13, is there a point you wish to make, as I don't understand the relationship to my post and your photo?
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/2000x1124/img_20200613_152426_133b8b6a34429d521a5027b1b07ce5cd9b15bdaf .jpg
Yes ..I have points, pardon me for not attaching my comments .
1. Both Lion Air and Ethiopian aeroplane pilots were not exposed to max simulators during their watered down 'difference' training
2. I admit one airline did acquire a simulator two months before crash.
3. The second photo I attached, gives EASA requirements, before re-certification. It asks for 70 test points in simulator.
4. The elaborate wiring re-routing suggests, the EMC-EMI checks integrity,is in question. It could be one of the delegated checks to Boeing engineers by FAA.
5. What about B 737 NG, does this aeroplane also require wiring changes?will Boeing clarify?
6. My point is that, Boeing underplayed simulator training for customer airlines .

rotorwills

13th Jun 2020, 11:56

Fine, obviously lots of comments regarding this have been made over the past year or so no need for me to add comment. I was only advising on available MAX sims outside of the USA.

Matey

13th Jun 2020, 22:15

There are 3 MAX sims in the UK at Gatwick. 2 at Boeing Flight Training and one just round the corner at L3. I have trained/checked on both Boeing sims, while the L3 sim is still, I believe, to be certified.

Turnleft080

15th Jun 2020, 06:07

https://youtu.be/mampv8DdHlU

Interesting facts here by Juan on the latest with the Max.

SLF3

15th Jun 2020, 11:58

This article seems well written and well informed. The interesting (at least to me) element is the simmering tensions between the FAA and EASA, the application of the ISSA process to the Max, and the idea that the Max may return to service and then have synthetic airpseed retrofitted later. Lots in here to disagree on!

https://theaircurrent.com/aviation-safety/boeings-737-max-software-done-but-regulators-plot-more-changes-after-jets-return/

ATC Watcher

15th Jun 2020, 20:22

Correct me if I am reading this wrongly , but I deduct the following :
FAA could alone allow the return to service by September . so for US domestic use only.
EASA will need to perform its own re-certification process to allow it in EASA land, and that will take an extra few months.
Adding Synthetic airspeed could take 2 years and adding a 3rd mechanical AoA is really not feasible , and yet one of the two is required later by EASA ?
Yes lots to disagree on !

BDAttitude

15th Jun 2020, 20:46

It's either synthetic airspeed or harware third vane,
Synthetic airspeed incorporates a modelled third vane so to speak.

I am reading some speculation about a possible "deal" between the lines to add the synthetic airspeed some time down the road. How feasible that is from a regulatory point of view ... I find it doubtful.

Less Hair

15th Jun 2020, 20:54

Wouldn't that require another major software change later on to integrate the "third" vane into the systems and protections?

tdracer

15th Jun 2020, 21:11

Assuming the synthetic airspeed is only a software update, that can be done on the aircraft quickly and easily - a few hours, including any functional checks/validation. Such software changes are fairly routinely done on an overnight.
Flight critical software updates are not real common, but are not exactly rare either - once every year or two being fairly typical. The main reason they are not more common is that the validation and certification of flight critical (i.e. DAL A) software is very time consuming and expensive. What tends to happen is less important changes/updates go on a sort of wish list. Then, when something important comes down (or sometimes if the wish list gets long enough) that justifies a change, they decide which of the wish list items should also be included.

turbidus

15th Jun 2020, 21:55

A few hours?!?!?! This requires the programming of cascading sets of Kalman filters...the first set of calculations has to normalize the pitot/static differences due to the local flow effects of the respective locations. Since the MAX pitot are fixed, and AoA are free to rotate, the effects must be compensate for in the sideslip flow. (MAX does not have sideslip indicators.)
Since the MAX only has 2 ADIRU's, the computing power is already used up.
The second set of Kalman filters will balance the differences, and the third set of filter will provide the synthetic resultant.

Who expects this many levels of filter to provide an accurate resultant, especially given the software issue that BA currently has???

They should have simply added another AOA sensor to the tail, and either hard wired it in...What about replacing the 2 pitots with the combi pitot AoA??? now instead of 2 AoA, they would have 4, and how difficult would that wiring have been???

Slsman100

15th Jun 2020, 23:31

In regards to Ian W’s post: Can you link to the expert assessments that this virus “will just stop”? I’ve never heard any such thing. And what’s with the term “hypochondriac' flights” after an accounting of hundreds of thousands of deaths worldwide between January and June just this year? We all hope for the best but this post is by Ian W doesn’t contain any factual or attributable information. The issue of restarting Max 8 production likely has rationale that Boeing, as a business, is justifying. Not the non-fact that Covid-19 will just stop.

krismiler

16th Jun 2020, 00:28

FlightlessParrot

16th Jun 2020, 00:30

A few hours?!?!?! This requires the programming of cascading sets of Kalman filters...
I'm pretty certain tdracer was referring to the time involved in installing an update, not the time required to do the software writing.

tdracer

16th Jun 2020, 01:22

Surely a synthetic airspeed system would be more than a simple software upgrade ? The sources used to calculate it would need to be tied in to some form of computer with the ability to reject an erroneous input, calculate a value and then display it. This is more likely to require a major upgrade of the system, possibly a hardware change as well.
My educated guess is that they are going to use the flight control computers - which already receive data from several other systems (ADIRU, GPS, etc.) - to calculate a synthetic airspeed when the normal ones either disagree or are judged to be unreliable. So it would be a basic s/w update to the flight control computers.
If they can't do it all in s/w and need some sort of hardware update, all bets are off. But updating the flight control computer s/w is a long established process once the new software is certified.

BDAttitude

16th Jun 2020, 08:03

It's fair to say, I think, that implementing synthetic airspeed is a far greater effort - development resource wise as well as computational resource wise - then validating two AOA readings against each other.
Given the time it took them (or better takes them, 'cause their are still not done) and the problems they encountered when implementing the later gives a pretty clear idea of a lower limit time and trouble wise synthetic airspeed is going to take. Do not forget that the synthetic airspeed information has yet to be included in other systems, their diagnostic routines, mode switching, warnings, etc.
Personally I would expect either upgraded hardware or maybe even another box (e.g. 3rd air data unit), which might be a more effective solution, becoming neccessary. Kalman filters are efficient but have tight real time requirements. From what we have learnt about that FCU ... difficult.

DaveReidUK

16th Jun 2020, 08:48

It's fair to say, I think, that implementing synthetic airspeed is a far greater effort - development resource wise as well as computational resource wise - than validating two AOA readings against each other.

Was the latter ever a realistic option ?

safetypee

16th Jun 2020, 08:49

With caveat that we do not have full details of the MCAS modification, it is difficult to connect what has been been disclosed with the reported certification differences - #48.

Cross monitoring two vanes shuts down MCAS, preventing a hazardous condition. This should enable the aircraft to be flown safely to complete the flight - with care. Three vanes would be better and could enable a higher level of safety.

AoA error post mod, apparently, also shuts down both ADCs and FGCs (?) (pressure error correction - UAS, no airspeed, and other system effects), this also degrades or removes stall warning (continuous stick shake); again three vanes would help.

MCAS mods could be acceptable in isolation, but the consequences of loss of AoA on a safe recovery might not (stby airspeed / alt, manual trim, no stall warning, autoslat, feel), i.e. technical mods meet CS 25, but the operational consequences would not meet CS 25.1301/1309; thus focus on JOEB, ISSA.
There could be technical agreement enabling return to service, operational modification could be deferred (exposure time / magnitude risk), but proposed action would have to be agreed before return to service.

A further puzzle is reference to Synthetic Airspeed. It could be a valuable aid with loss of ADC function, alleviating consequential concerns, but current SA designs appear to rely on AoA, the loss of which caused the loss of ADC in the first place !!!
Can inertial data alone replace AoA aspects used in SA (787), would it be sufficiently accurate for continued flight, approach, and landing, or to restore lost functions.

Airbus views the temporary use of BUSS for the management and recovery of ADC malfunction (AirbusWIN, flt ops support); what is the Boeing view re 787 - procedure detail?

golfyankeesierra

16th Jun 2020, 08:55

Ironic that while the aviation community is threatened in its existence, the Corona pandemic will turn out to be the saviour of Boeing.
(If) they are going to get away with a software uodate😡 Nobody cares at the moment..

BDAttitude

16th Jun 2020, 09:11

I was actually wondering if the situation wasn't a good opportuinity to can the entire project. It would be much cheaper now.

calypso

16th Jun 2020, 10:23

BDAttitude

16th Jun 2020, 15:27

Many of the customers having a perspective of survival in the current situation might be happy to defer their orders for a 737 replacement or happily accept cancelation without penalty.
I guess I am not a follower of the "V-shaped" recovery theory.

krismiler

17th Jun 2020, 05:39

With the current situation in the South China Sea, the Chinese government are unlikely to approve any solution Boeing come up with, particularly as the aircraft already in China aren't needed anyway due to the reduction in air traffic.

A downturn of 1 - 2 years would suit COMAC very well as it gives them time to catch up with the C919 program and be ready once airlines start buying again, possibly grabbing a few orders which would have gone to Boeing because their aircraft wasn't ready earlier.

Duck Pilot

17th Jun 2020, 07:11

Bit of the topic, did Boeing ever develop any combi or freighter variants of the Max?

Skyjob

17th Jun 2020, 07:50

Nope........

DaveReidUK

17th Jun 2020, 08:10

I don't think Boeing has built a narrow-body freighter or combi since the mid 1980s ...

Less Hair

17th Jun 2020, 08:21

There are military versions of the 737NG with a big cargo door used in combi coniguration. USN is one operator.

DaveReidUK

17th Jun 2020, 10:47

Ah yes, I'd forgotten about the C-40A (based on the -700C). Seventeen built for the USN, plus five more -700Cs in total with Aramco, TAAG Angola and Air Algerie.

Duck Pilot

17th Jun 2020, 10:54

Thanks for answering my question, case closed.

Dave Therhino

17th Jun 2020, 15:35

There are military versions of the 737NG with a big cargo door used in combi coniguration. USN is one operator.

FYI, yes the 737-700C has a big cargo door, but the "C" in 737-700C stands for "convertible," not "combi." I believe the FAA approval allows the airplane to be operated in either all passenger or all cargo configurations. I don't believe it is FAA approved for "combi," or partial passenger and partial cargo on the main deck, operation. See the FAA TCDS for TC A16WE on page 47, available on rgl.faa.gov.

The military utilization is not necessarily limited by the FAA approval, though, so it's possible a military service somewhere has a combi configuration. However, in general these days the US military is having the FAA approve all basic configurations of airplanes that are also civil products, so I doubt the US military is using a combi configuration.

DaveReidUK

17th Jun 2020, 16:02

The military utilization is not necessarily limited by the FAA approval, though, so it's possible a military service somewhere has a combi configuration. However, in general these days the US military is having the FAA approve all basic configurations of airplanes that are also civil products, so I doubt the US military is using a combi configuration.

The Navy (which operates 17 out of the 22 -700Cs built) seems to think they can be configured as combis:

The C-40A is certified to operate in three configurations: an all-passenger configuration that can carry 121 passengers, an all-cargo configuration of eight cargo pallets, or a combination of three cargo pallets and 70 passengers.

https://www.navy.mil/navydata/fact_display.asp?cid=1100&tid=600&ct=1

tdracer

17th Jun 2020, 16:19

grizzled

17th Jun 2020, 17:32

With a backlog of over 4000 orders how can it possibly be cheaper to can it? there are tens of airliners that have gone from design to production and sold much less than a tenth of that. 4000 orders is in the region of 200billion, how is that ever going to get canned? even if they had to do a clean sheet design that sort of cash will still make it way more than viable.

AND yes for the last couple of months we do have a pandemic going on but these are projects with a horizon of decades. Several Booms and Busts are unavoidable and expected.

The notion that all, or most, or even 20% of those orders will remain on the books is, in my view, optimistic. Most of the companies that have placed orders are no longer forecasting the same future and / or planning the same expansion, or even fleet replacement, as they were pre-Covid. And many are simply no longer in a financial position to pursue the orders.

PilotLZ

17th Jun 2020, 22:56

If successfully certified, the MAX will be around for anywhere between 20 and 30 years, I think. For that long a period, we'll likely witness at least two or three complete boom-and-bust cycles, with all their associated effects. The fact that many airlines won't take their deliveries in the next 2 years doesn't mean that they won't in the subsequent 20 years either. The existing aircraft will not last forever, the pressure to lower costs will not go anywhere and aviation will not remain forever in a state of global crisis.

Either way, any deliveries for now are a far cry away. FAA certification this fall might easily mean that EASA certification will not happen before 2021. And who knows what life will look like by then.

tdracer

17th Jun 2020, 23:40

The notion that all, or most, or even 20% of those orders will remain on the books is, in my view, optimistic. Most of the companies that have placed orders are no longer forecasting the same future and / or planning the same expansion, or even fleet replacement, as they were pre-Covid. And many are simply no longer in a financial position to pursue the orders.
The situation post 9/11 was not much different - aircraft were being parked by the hundreds (if not thousands), airlines were in no position to take delivery of new aircraft and had no money to pay for them. Yet nearly every order that Boeing and Airbus had on the books on the first of September, 2001 was eventually delivered. Most months to years later than the original schedule, but aside from a few operators that went bankrupt and disappeared, the aircraft on the books were delivered.

Dave Therhino

18th Jun 2020, 03:42

Duck
After the Helderberg disaster, the regulations governing "Combi" aircraft were significantly changed. While out of my area of expertise, those who are in the know have told me it would be close to impossible to certify a new Combi style aircraft to the updated regulations.
All the Combi's currently in operation where certified prior to the regulations being updated in response to the Helderberg.
As DR notes, military operations do not need to comply with commercial certification restrictions.

I recognize I'm continuing a major thread drift, but this information may be of interest to some:

TD - It wouldn't be impossible - just more costly. The main deck cargo compartments on the various combi jet transports produced in past decades were Class B compartments as defined in 14 CFR 25.857 at the time. Class B compartments are required to have fire /smoke detection, but are not required to have built in fire extinguishing/suppression. The change in the definition of a Class B cargo compartments in the rule effective in 2016 went from one where the crew had to have adequate access to enter the compartment and fight a fire to now requiring the crew to be able to effectively fight any fire in the compartment with a handheld fire extinguisher from one access location without entering the compartment. This has the effect of severely limiting the size of compartments that can meet the Class B definition relative to the old definition. "Combi" large main deck cargo compartments on passenger airplanes as previously designed typically were much too large to meet that new requirement, forcing any such compartment on a new airplane to be classified as a Class C cargo compartment like the lower deck compartments, which requires an extinguishing (suppression) system.

So it's not impossible to obtain a type certificate for a combi today, but it's apparently not cost effective to design, certificate, build, and operate a combi compared to running cargo separately on all-cargo airplanes that have less costly fire safety requirements, as evidenced by combis not being proposed in recent years.

Changes were required by AD after the 1987 South African Airways 747-200 Combi accident prior to this rule change, but this 2016 change was one of the eventual part 25 changes that resulted from that accident. The FAA lessons learned library has an extensive section on this accident and the various actions that resulted. Here's a link to it:

https://lessonslearned.faa.gov/ll_main.cfm?TabID=1&LLID=33

beachbumflyer

18th Jun 2020, 17:47

tdracer

18th Jun 2020, 18:01

Using what funding, exactly?
Boeing is borrowing money in the tens of $billions just to stay in business, while Airbus is apparently going to be getting billions in bailout funding from the EU.
It'll be a tad difficult to come up with another ten or twenty billion dollars to launch a new clean sheet design when they're struggling to remain solvent...

golfyankeesierra

18th Jun 2020, 20:05

Sorry, Tdracer, I think you’re a bit biased. I have some alternative facts here (from politico.com):
The federal government had designated $17 billion for the American aircraft builder in its $2 trillion CARES Act, The Wall Street Journal reported. (https://www.wsj.com/articles/boeing-taps-investment-banks-as-it-weighs-government-aid-11586537738) The company proposed further federal funding to save it from one of the worst crises in the history of commercial aviation.
But Boeing doesn’t want it, they prefer to raise it elsewhere.

And BTW, am not so familiar with funding of Airbus but you probably think us socialists here in Europe are giving away free money but most loans are repayable loans with high interest. Where governments are involved that usually relates to guarantees.

What governments do pay for is employee retention programs. That is indeed “free” money but is, I guess, a luxury of paying taxes;)

tdracer

18th Jun 2020, 20:26

Seriously, you want to go there?
Boeing is avoiding the US government bailout money because the strings that were attached were untenable - for starters the massive employment cutbacks that Boeing has committed to in order to survive would not be allowed. So far, Boeing thinks they are better off without the bailout money (although many of their suppliers are taking it).
Define the "high interest rates" that Airbus is paying. What are the interest rates on the billions in 'launch aid' that Airbus receives (hint, they are below market - sometimes by a lot). Oh, and how much of those billions in A380 launch will Airbus ever repay? And the news reports from your side of the pond say that Airbus is receiving bailout funds (although the exact numbers are pretty vague):
https://www.dailypost.co.uk/news/north-wales-news/airbus-secures-bailout-cash-return-18386776
Oh, and you still haven't addressed my point - where Boeing is supposed to obtain the tens of billions necessary to launch a new aircraft program. The money that they are currently getting is just to keep the company solvent.
Yes, I'm biased. That's why I normally avoid making posts of this nature. Maybe you might want to recognize you're own bias before calling someone out.

Zeffy

19th Jun 2020, 03:40

https://www.seattletimes.com/business/boeing-aerospace/boeing-whistleblower-alleges-systemic-problems-with-737-max/

Boeing whistleblower alleges systemic problems with 737 MAX
June 18, 2020 at 4:40 pm Updated June 18, 2020 at 6:23 pm

By Dominic Gates
Seattle Times aerospace reporter

A Boeing engineer who last year lodged an internal ethics complaint alleging serious shortcomings in development of the 737 MAX has written to a U.S. Senate committee asserting that systemic problems with the jet’s design “must be fixed before the 737 MAX is allowed to return to service.”

The letter to the Senate, a copy of which was obtained by The Seattle Times, was written by engineer Curtis Ewbank, a 34-year-old specialist in flight deck systems whose job when the MAX was in early stages of development involved studying past crashes and using that information to make new planes safer.

His letter, sent earlier this month, argues that it’s not enough for Boeing to fix the flawed Maneuvering Characteristics Augmentation System (MCAS) that’s known to have brought down the aircraft in two crashes in Indonesia and Ethiopia.

“I have no doubt the FAA and lawmakers are under considerable pressure to allow the 737 MAX to return to service as quickly as possible and as soon as the public MCAS flaw is fixed,” Ewbank told the Senate. “However, given the numerous other known flaws in the airframe, it will be just a matter of time before another flight crew is overwhelmed by a design flaw known to Boeing and further lives are senselessly lost.”

He goes on to suggest that similar shortcomings in the flight-control systems may affect the safety of Boeing’s forthcoming 777X widebody jet.

Ewbank’s letter also reveals that he has been interviewed about his concerns by the FBI, which suggests his allegations have at least been considered as part of the Justice Department’s probe into what went wrong on the 737 MAX and whether the actions of anyone at Boeing were criminal.

He mentions that he has also delivered details of his allegations to the lead investigator on the U.S. House Committee on Transportation, chaired by Rep. Peter DeFazio, D-Ore.

In 2014, during early work on the MAX’s development, Ewbank worked unsuccessfully to have Boeing upgrade the MAX’s flight-control systems by adding a new data measurement system called Synthetic Airspeed that would have served as a check on multiple sensors. If it had been implemented, he believes it might have prevented the fatal crashes.

Ewbank’s original internal ethics complaint, first reported last October by The Seattle Times, alleged that Boeing rejected his safety upgrades because of management’s focus on schedule and cost considerations and the insistence that anything that might require more pilot training would not be considered.

He also alleged that Boeing pushed regulators at the Federal Aviation Administration (FAA) to relax certification requirements for the airplane, particularly in regard to the cockpit systems for alerting pilots that something is wrong inflight.

Those systems on the MAX have been under scrutiny because during the two fatal MAX crashes that killed 346 people, pilots struggled to understand the cascade of warnings in their cockpits.

‘Hand-waving and deception’
Ewbank’s letter to the Senate Committee on Commerce, Science, and Transportation was sent June 5, ahead of a public hearing Wednesday that featured scathing criticism of FAA Administrator Stephen Dickson for his agency’s lack of progress in addressing the lapses of oversight in certifying the MAX.

Ewbank criticizes not only Boeing for its design of the MAX but also the FAA for approving the design without proper oversight.

“The 737 MAX’s original certification was accomplished with hand-waving and deception to hide the numerous ways the 1960s-era design of the 737 does not meet current regulatory standards,” he wrote.

And he hit out at a recent Department of Transportation (DOT) advisory panel report on the MAX crashes that recommended only minor changes to the way airplanes are certified, preserving Boeing’s central role in that process. Ewbank called the report “a serious threat to aviation safety and the flying public.”

“If the FAA was truly regulating in the public interest, it would take action against Boeing for its continued deception and gross errors in the design and production of the 737 MAX by withdrawing Boeing’s production certificate,” he concluded.

Ansley Lacitis, deputy chief of staff for Democratic Sen. Maria Cantwell of Washington, said her office “was made aware of the letter right before the hearing” on Wednesday.

“The first step of a whistleblower investigation is to make contact with the whistleblower and we have done that,” Lacitis said. “We take these and other allegations seriously and continue to investigate them.”

In a statement, Boeing said company officials have not seen the letter.

“Boeing offers its employees a number of channels for raising concerns and complaints and has rigorous processes in place that ensure complaints receive thorough consideration and protect employee confidentiality,” the statement said. “Boeing does not comment on the substance or existence of such internal complaints.”

Boeing’s statement adds that “when the MAX returns to service, it will be one of the most thoroughly scrutinized aircraft in history, and we have full confidence in its safety.”

Ewbank could not be reached for comment.

After the Seattle Times made public his internal ethics complaint, Boeing placed Ewbank on leave. “We can confirm that Mr. Ewbank remains an employee in good standing,” company spokesman Bernard Choi said this week.

Flawed flight deck systems
One conclusion of the DOT report on the MAX crashes was that if the 737 MAX had been certified as an all-new jet instead of as a derivative of the earlier model, it “would not have produced more rigorous scrutiny … and would not have produced a safer airplane.”

Ewbank calls this “utterly incorrect.”

He cites specific regulations for which Boeing, because the MAX was considered a derivative model, didn’t have to meet the latest safety standards. And he points to how these shortcomings could have affected the pilots in the two crashes.

He wrote that because Boeing, for certification purposes, had to evaluate only flight-deck systems that had changed from the 737 NG model, Boeing missed the opportunity to evaluate pilot reaction times.

Boeing has admitted that it made incorrect assumptions about those reaction times in designing the new system — the MCAS — that brought down both MAX planes that crashed.

Although MCAS was new, its operation depended on other unchanged systems and its interactions with those systems were not analyzed, Ewbank wrote.

By choosing to certify the jet as an amended version of the earlier model, Boeing “severely limited the range of human factors evaluation of 737 MAX systems,” he said.

And in a comment on Boeing’s forthcoming large widebody jet, Ewbank added: “The changed/unchanged system line on the 777X is even more convoluted and involves more complicated systems than the 737 MAX.”

Ewbank reiterates his internal critique of the crew-alerting systems on the MAX, saying that they failed to meet the current standards for such alerts, which are supposed to be “designed with the latest understanding of human factors to present information to flight crews and prompt appropriate reaction in critical scenarios.”

“These flaws were known to Boeing as it worked with the FAA to certify the 737 MAX, and awareness of this was creatively hidden or outright withheld from regulators,” he wrote.

Ewbank also revisits his unsuccessful push to have Synthetic Airspeed added to make the MAX safer, which would have made more reliable the various air-data measures used by the flight-control computer, including the angle of attack, the angle between the jet’s wing and the oncoming air stream.

It was a faulty angle of attack reading on each of the crash flights that initiated the operation of MCAS.

“The known unreliability of air data, due to the potential for erroneous data caused by external factors, makes the initial design of MCAS simply unacceptable” Ewbank wrote. Yet, he says, “upper management shut down the (Synthetic Airspeed) project over cost and training concerns.”

According to a person familiar with the discussions, the FAA and Boeing, along with the European air safety regulator EASA, are discussing various system “enhancements” that Boeing could add to the MAX after it returns to service, with no firm decisions yet made.

Last week, on the specialist aviation website The Air Current, Jon Ostrower reported that Synthetic Airspeed or an equivalent system is one of the enhancements under consideration. Boeing would not confirm that.

Michael Stumo, whose daughter Samya died in last year’s MAX crash in Ethiopia, on Thursday also received a copy of Ewbank’s letter.

“This is the most comprehensive engineering analysis I’ve seen yet,” Stumo said. “It calls into question whether the MAX should ever fly again.”

“People have to die”
Ewbank notes that he left Boeing in 2015 “in protest of management actions to rationalize the poor design of the 737 MAX. I did not think I could do my duty as an engineer to protect the safety of the public in the environment created by management at Boeing.”

He asserts that, “Prior to my departure in 2015, my manager argued against the design changes I wanted to make by stating, ‘People have to die before Boeing will change things.'”

Ewbank returned to Boeing in 2018 to work on the 777X.

“I returned to the company and quickly witnessed the nightmare of the very accidents I had tried to prevent happen in real life,” he writes.

After the second MAX crash in Ethiopia, he filed his internal ethics complaint.

Ewbank concludes his letter to the Senate by calling for a series of actions to improve the rigor of the airplane certification process, particularly in his area of expertise: flight deck systems.

He asks that FAA regulations be thoroughly revamped “to ensure they reflect a modern understanding of computer technology and human-machine interfaces.”

He calls for a shift in the way certification work on new airplanes is delegated by the FAA to Boeing itself and how the flow of information between the two is restricted.

“The decision to sign off on any particular design at Boeing has been culturally expropriated from the engineers to management,” he wrote.

In this critique, he mirrors criticism by the Senate committee itself, which this week proposed legislation to tighten controls on the FAA’s delegation of work and ensure direct communication between FAA and Boeing technical experts on certification details.

Dominic Gates: 206-464-2963 or [email protected]; on Twitter: @dominicgates.

Ddraig Goch

19th Jun 2020, 05:06

Congratulations to Curtis Ewbank, who has In one letter, summed up all that is wrong in this sad tale of corporate greed.

Bidule

19th Jun 2020, 05:20

Using what funding, exactly?
while Airbus is apparently going to be getting billions in bailout funding from the EU.

Any evidence of that? With facts, no political speeches.

tdracer

20th Jun 2020, 06:17

krismiler

21st Jun 2020, 11:14

https://youtu.be/gvDf0WHyWMs

calypso

21st Jun 2020, 11:59

"what do you think?" he says at the end --- I think this is low-end clickbait

WillowRun 6-3

21st Jun 2020, 13:26

Ewbank's letter as reported above by the eminently reliable Dominic Gates in the Times of Seattle was sent coincident with Senate Commerce Committee hearings held on the 17th (Wednesday). Both parties' senior-most Committee members - Wicker (Miss.) and Cantwell (Wash.) - excoriated FAA for stonewalling on document disclosure to their Committee, in terms more scathing than previously. (If this was noted above in the thread, how I missed it, I couldn't say.)
Also of note are reports that the Senate legislation in the works would curtail the extent to which a manufacturer can do the regulator's certification work "for" the regulator as opposed to doing such work in a strict delegation sense (my own characterization of the differences in approach).
Common sense as well as an assessment of all the litigation and investigations encasing the status of the 737 MAX lead this observer to think production at this point is mostly an expression of some corporate financial accounting imperative. The once-proud airframer up in Seattle isn't fooling anybody.....this time.

Bidule

21st Jun 2020, 15:32

Did you bother to check the link in my post?
This one?
https://www.dailypost.co.uk/news/nor...eturn-18386776 (https://www.dailypost.co.uk/news/north-wales-news/airbus-secures-bailout-cash-return-18386776)
The one that has this headline?

I had checked your link and it was the resaon why I asked for facts and no political speeches, newspapers mainly being the copy of the political speeches. I very rarely trust the headlines of the newspapers (!).

In fact, when you look at the details of the so-called "bailout plan" (https://fly-news.es/covid19/la-ayuda-la-industria-aeronautica-francesa-incluye-sustiuir-al-a320/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+fly-news%2FaSno+%28Fly+News%29, sorry it is in Spanish but Google translation is your friend): the 15 billions include:
- 7 billions for Air France (those had been announced three weeks earlier);
- the anticipated order (meaning that such orders are in the pluriannual plan for the next years and they will be done earlier) of some aircraft for the French Air Force (3 x A330MRTTs, one King Air - this one is to support the US industry ;) -, drones - likely non European -) and eight helicopters for the French Gendarmerie (Military Police); this is about 600 millions.

In fact, the R&D support is only 1.5 billion - likely not for Airbus alone - and Airbus will have to contribute for 116 millions to support the smaller companies in France.

So, at the end, it is very far from what you imagine and hardly 10% of what Boeing rejected in the USA .

MechEngr

21st Jun 2020, 21:14

What, precisely, does Mr. Ewbanks propose as the significant difference? What are the design flaws?

I have no doubt the he believes what he says, but engineering often produces a plateau of similar ideas where any particular one might be better in some exact situation and is terrible in most others. So there is ample room for claims to be made that their particular idea is the one to solve all problems, but they actually don't solve all problems. It doesn't matter to them; they will argue to the death that their idea is best.

So, what is the problem Ewbanks is talking about and what is his solution? Would it have avoided the Pakistani crash by better alerting the crew to their problem or is this a Boeing-only human factors solution?

Vendee

22nd Jun 2020, 07:51

What, precisely, does Mr. Ewbanks propose as the significant difference? What are the design flaws?

Would it have avoided the Pakistani crash by better alerting the crew to their problem or is this a Boeing-only human factors solution?

Not sure the PIA 8303 crash had anything to do with a design flaw. From the information currently available, that crew would have crashed whatever aircraft type they were flying.

WillowRun 6-3

22nd Jun 2020, 09:41

Re: Mech Engr...
As noted the letter pertains in no way to the problems created by the pilots operating PIA 8303 into Karachi. I suppose we could spend many posts parsing the U.S. working papers presented at the ICAO 40th Triennial Assembly last fall in the aftermath of two 737 MAX crashes, insofar as part - part - of the fundamental errors Boeing committed tie together with the larger more general problems involving over-reliance on cockpit automation or lack of proper training (and related requirements) to assure airmanship stays required and relevant even amidst wide-spread automation - or both over-reliance and insufficient training.
But Ewbanks isn't directing the attention of members of the international aviation safety community (or read it as, infrastructure or ecosystem if you prefer) to that larger context. Yet I think he is pointing back at the fundamental error of taking the old venerable 737 airframe and goosing it up into something it was not really suited to be. A tough feat to pull off, even for Boeing in its prime. But the deception, the overt gaming of the system of certification proofs which may very well lead to civil and even criminal liabilities, is not hard to discern as the letter-writer's most basic concern.
Maybe I should have stuck with my aspiration in kidhood of studying aeronautical engineering and then handing down, to a younger generation, slide rules as tokens of the art as well as science involved, as they were handed down to me as a child. But I picked up the drag chain of the law instead, so you'll have to ask Ewbanks directly what his answer to your question should be. (Howard Cosell, a non-practicing lawyer besides sports broadcaster, used the phrase, 'drag chain of the law'.)

ElectroVlasic

22nd Jun 2020, 18:17

https://youtu.be/mampv8DdHlU

Interesting facts here by Juan on the latest with the Max.
This article seems well written and well informed. The interesting (at least to me) element is the simmering tensions between the FAA and EASA, the application of the ISSA process to the Max, and the idea that the Max may return to service and then have synthetic airpseed retrofitted later. Lots in here to disagree on!

https://theaircurrent.com/aviation-safety/boeings-737-max-software-done-but-regulators-plot-more-changes-after-jets-return/
Juan is more or less reading the article from "The Air Current" to the camera without crediting its source, something the publisher of "The Air Current" complained about, IMO with good cause.
But the deception, the overt gaming of the system of certification proofs which may very well lead to civil and even criminal liabilities, is not hard to discern as the letter-writer's most basic concern.

As a lawyer you'll know to be successful at civil and especially criminal law suites hard evidence will need to be produced. So far Boeing has contained the situation by laying the core blame at over reliance on the "industry standard" notion that the pilot would be able to figure out what they were experiencing was a runaway stabilizer trim and apply correction within four seconds, and the attempts at deception were limited to one or two bad actors in the training department. Oh, yes, and they have even had the temerety to suggest that they are immune from prosecution because FAA certified the design! But so far, suitable evidence to undermine these arguments doesn't seem to have been produced. The whistleblower complaints don't seem to hit at the core issue of how MCAS's safety evaluation was botched.

Jonnyknoxville

22nd Jun 2020, 18:18

"management’s focus on schedule and cost considerations and the insistence that anything that might require more pilot training would not be considered."

This is what happens when you allow Southwest and Ryanair to dictate how you should run your business .

Boeing was being run indirectly by Low cost airline executives who dictated their every move .

GlobalNav

22nd Jun 2020, 18:42

Boeing listened to whom they wanted to listen to. SWA and Ryan were not asking for unsafe or poorly designed aircraft. They were merely stating economic conditions for selecting a “new” aircraft. The promise of financial gain is an immoral defense for bad design decisions.

WillowRun 6-3

22nd Jun 2020, 19:07

As to Southwest, there is a very hotly contested lawsuit by the SW Airlines Pilots Assn which alleges (and quite strongly it appears) that Boeing grossly and willfully circumvented their CBA and otherwise acted wrongfully. I would not concur that SW was driving that process. (Not commenting on Ryan, not familiar enough, yet.)

As to evidence, the discrete items of even some significance, plus the more serious items, plus the complete eventual sets of evidence items taken as a whole, are a lot, lot stronger than suggested above. But that said, I'm referring here just to assessing the various civil lawsuits (cases).

MechEngr

23rd Jun 2020, 02:23

Not sure the PIA 8303 crash had anything to do with a design flaw. From the information currently available, that crew would have crashed whatever aircraft type they were flying.
He plainly states that some unidentified human factors design flaw was the problem with the 737 MAX and the 777x and that it has to do with not giving pilots critical information; this is very much at the heart of the PIA 8303 crash.

Ewbank reiterates his internal critique of the crew-alerting systems on the MAX, saying that they failed to meet the current standards for such alerts, which are supposed to be “designed with the latest understanding of human factors to present information to flight crews and prompt appropriate reaction in critical scenarios.”

I'd say lining up on a runway far too high and far too fast is a critical scenario.

Bend alot

23rd Jun 2020, 05:15

I would say two MAX aircraft were un-serviceable (had issues that needed accurate warnings - it was NOT a runaway trim!), PIA 8303 was fully serviceable.

As stated before the PIA would have crashed given pretty much any type they were flying, comparing it to the MAX crashes is a long bow.

How is the certification flight going this month?

Vendee

23rd Jun 2020, 08:36

Pray tell me what critical information the PIA 8303 crew were missing? The "how to land an aircraft safely" information? Its like me driving into a brick wall at 70mph and complaining that my car didn't tell me it was a bad thing to do. Obviously subject to confirmation by the investigation but it really looks like the crew would have crashed an Airbus, Boeing or anything else they were flying.

FlyingStone

23rd Jun 2020, 08:53

I would say two MAX aircraft were un-serviceable (had issues that needed accurate warnings - it was NOT a runaway trim!)

QRH for B737 aircraft has long stated under the Runaway Stabilizer NNC as below:
Condition: Uncommanded stabilizer trim movement occurs continuously.

Pilot DAR

23rd Jun 2020, 12:50

So, what is the problem Ewbanks is talking about and what is his solution? Would it have avoided the Pakistani crash by better alerting the crew to their problem or is this a Boeing-only human factors solution?

The relevant design requirement applicable to the 737 says in part:

Sec. 25.1309 [Equipment, systems, and installations.]
.......
(c) Warning information must be provided to alert the crew to unsafe system operating conditions, and to enable them to take appropriate corrective action. Systems, controls, and associated monitoring and warning means must be designed to minimize crew errors which could create additional hazards.

'Sounds to me that the MCAS system malfunctioning as it did on the two crash airplanes constituted an unsafe system operating condition. The MCAS failing to operate as intended might be an unknown to the pilots? (I don't know, I'm not 737 rated). If the MCAS was malfunctioning, and the pilots did not know it did, or did not know what the correct action would be, would that design requirement have been met?

The 737MAX's delivered to American Airlines were equipped with an optional MCAS failure warning system? (which sounds like it would meet the design requirement). Other airlines received 737MAX's which were not equipped with this optional warning system? Would those airplanes meet the design requirement?

hec7or

23rd Jun 2020, 12:52

QRH for B737 aircraft has long stated under the Runaway Stabilizer NNC as below:

But in an MCAS nose down trim situation it doesn't. It can be stopped by main trim and then runs again when main trim is not active. So the condition statement is not completely correct and may explain why the crew who switched the trim system off in the first LionAir incident wrote it up as "speed trim working in reverse"

WillowRun 6-3

23rd Jun 2020, 13:36

But Pilot DAR, even if American's aircraft had the "MCAS warning system", was it not the case that the MCAS system overall and its functioning were covered only very briefly if at all in training, and likewise in the FCOM? Additionally, the intent of the regulation you have quoted - and it clearly is part of the context for the certification failures by both Boeing as well as FAA - is not to have the manufacturer skate, or to just get by, on a system with such significant effect on basic aeronautical stability.
Second, this set of warnings and systems was presented to airlines and the FAA within a template that very deliberately and very overtly said (in effect) "you know that 737NG version of the good ol' 737?...wellsir, there's hardly a dime's worth of difference between this brand-spankin' new MAX, and what you already know about all the wonderful safe operation maneuvering and handling characteristics of the airplanes you already have! So sign right here on the dotted line. . . ." It's one thing to make erroneous judgments - in this specific context about warning, relating to crew alerting and response times - to enable certification where it probably would not have been obtainable without those erroneous judgments. Isn't it a greater dereliction of responsibility to intensify the relevance of those erroneous judgments while telling airline customers, pilots and the FAA (and foreign regulators) alike that there are hardly any differences worth noting in the new variant?
(As SLF I am not emphasizing what I think could be another point: in an earlier thread there was a lot of discussion about whether the purpose of MCAS actually was largely or mostly to affect stick force gradients and also questions about basic aeronautical longitudinal stability and whether the airframe should have been tested, relative to that issue of stability, without MCAS. If that description of those other comments is accurate enough, then the warnings issue under the reg you cited, while relevant, I think is a secondary level point. The FARs do not contemplate an unsafe airframe which, with compliant warning systems, can be operated safely by fast-reacting pilots - until it is exposed as . . .. well, you know the rest.)

MechEngr

23rd Jun 2020, 19:45

'Sounds to me that the MCAS system malfunctioning as it did on the two crash airplanes constituted an unsafe system operating condition. The MCAS failing to operate as intended might be an unknown to the pilots? (I don't know, I'm not 737 rated). If the MCAS was malfunctioning, and the pilots did not know it did, or did not know what the correct action would be, would that design requirement have been met?

The 737MAX's delivered to American Airlines were equipped with an optional MCAS failure warning system? (which sounds like it would meet the design requirement). Other airlines received 737MAX's which were not equipped with this optional warning system? Would those airplanes meet the design requirement?

He claims the same flaw is also in the 777x. If it is specific why would he omit the exact solution he had identified that is in accordance with the latest human factors practice?

DaveReidUK

23rd Jun 2020, 19:59

The 737MAX's delivered to American Airlines were equipped with an optional MCAS failure warning system?

Is that not simply a reference to the previously-discussed (at length) "AOA DISAGREE" indication ?

If so, then hardly an "MCAS failure warning".

ElectroVlasic

23rd Jun 2020, 20:09

The root cause is not human factors, unless you consider Boeing engineering screw ups to be human factors.

The root cause is Boeing Engineering gave MCAS lots of control authority and unlimited applications of this authority, and tied its activation to a electro-mechanical sensor with some pretty obvious and well known failure modes, yet never did any range checking in software to detect any of these well known failure modes, and never did any end to end testing to show these failure modes had benign outcomes because they do not. The fix was the one Boeing was close to releasing last April when the 2nd crash happened: fix all these glaring issues in MCAS. Let it have its one push to smooth the corner in the flight envelope, pass the certification test, move on.

The pilot community seems to be happy to fixate on "if I only had information X I would have sorted it out". Sure, but the better idea is to do as much as possible to make sure you don't need to rely on the pilot sorting it out. Fix the damn code so the plane won't keep pointing its nose at the ground repeatedly the minute the flaps go up. Sure, also, tell the pilots about the "feature" and how to deal with it, but start by not producing such a dangerous product.

I think Boeing is happy to keep the discussion focused on human factors because as the name says they are human factors and are thus subjective rather than objective. It's a lot better outcome from a liability point of view than focusing on how Boeing Engineering produced such a deeply flawed product.

Bend alot

23rd Jun 2020, 20:41

QRH for B737 aircraft has long stated under the Runaway Stabilizer NNC as below:
But it got changed after the first crash, as it was incorrect to cover for a MCAS malfunction.

BDAttitude

24th Jun 2020, 06:02

ElectroVlasic

:ok:
as to ...

I still think Mr. Forkner involuntarily did exactly that and was very loquatious about it. Curious on how that plays out in the legal aftermath.

WillowRun 6-3

24th Jun 2020, 11:01

The general rule is that (using terminology from U.S. civil litigation rules) when a "transaction or occurence" is something which becomes the subject of multiple civil lawsuits and those court actions are filed by various categories of parties (groups, individuals, companies) who claim they were harmed, then where there are potential criminal charges to be brought by prosecutors, the larger the number of civil lawsuits, the higher probability the charges will be evaluated as proper and will be initiated. Especially when the prosecutors are federal government authorities rather than at the state level. (I'm omitting any factor of election-year and/or Congressional or legislative political factors, beyond this parenthetical.)
But the sad and tragic saga of Boeing's excursion off of sound engineering and corporate accountability standards is so unprecedented, that any forecast is really just a seat-of-the-pants piece of guesswork.
The roster of lawsuits in Chicago continues to grow.....flight attendants also have filed claims in federal district court against the once-proud airframer.

safetypee

25th Jun 2020, 13:29

Seattle Times reports (24 June) that Boeing may be restarting test flying as early as next Monday. Then providing the modified MCAS is accepted, the aircraft could return to service in Sept.

The initial inter-authority agreement would relate to MCAS, although Canada could include pulling SS cbs.

Full agreement on other system changes, consequences of AoA failure, is being debated, but likely to be a requirement for MAX -10, and retrofit to all variants by -10 certification date.

Possible areas being considered discussed here :- https://www.pprune.org/10812141-post60.html

https://www-seattletimes-com.cdn.ampproject.org/c/s/www.seattletimes.com/business/boeing-aerospace/foreign-regulators-demand-substantial-new-changes-to-boeing-737-max-flight-controls/?amp=1

WillowRun 6-3

25th Jun 2020, 14:14

Flight Global report with regard to wiring inspections:
https://www.flightglobal.com/airframers/faa-requires-inspections-of-737-max-wire-shields-to-address-electrical-risks/138982.article

Bend alot

28th Jun 2020, 08:38

Any news on the certification flight/s rumoured for this month?

Less Hair

28th Jun 2020, 08:47

Rumored to start tomorrow.
https://www.bloomberg.com/news/articles/2020-06-26/key-faa-test-flight-of-boeing-s-737-max-jet-expected-next-week?sref=ez43dC45

WillowRun 6-3

28th Jun 2020, 09:26

Reported also by Wall Street Journal (on website early June 28 with very reputable by-line):
https://www.wsj.com/articles/faa-to-start-boeing-737-max-test-flights-11593324222?mod=hp_lead_pos5

inOban

28th Jun 2020, 16:13

On the BBC as well.

WillowRun 6-3

28th Jun 2020, 23:15

Reuters reporter, David Shepardson, posted on Twitter text from FAA email to Congress about next steps to return to service, including JOEB, FSB, TAB, CANIC....(Joint Operations Evaluation Bd., Flight Standardization Bd., ....)

davidshepardson (@davidshepardson) Tweeted: After @boeing 737 MAX certification flights here are remaining steps per @faa email to Congress today (Reuters reported no ungrounding expected before September) https://t.co/b7S9BF7y2O https://twitter.com/davidshepardson/status/1277316409459200000?s=20

Lake1952

29th Jun 2020, 15:41

Boeing has already flown the aircraft on multiple test flights for hundreds of hours. It would be interesting to hear a retrospective on those flights, many of which were deliberately wild rides. What issues, if any, were uncovered? Was there indeed s pitch up tendency that required something as ham handed as MCAS ?

Also, aside from Lion Air times two and the ET flight, have any verified reports of MCAS actively being engaged surfaced?

DaveReidUK

29th Jun 2020, 17:19

As at the grounding, there had been no recorded incidents of MCAS engagement in the NASA ASRS database.

GlobalNav

29th Jun 2020, 17:30

Except for forensic data analysis, how could anyone report MCAS activation? There are no indications in the flight deck (pre-modification), no alerts of AoA disagree, etc.

Airbubba

29th Jun 2020, 17:34

Any news on the certification flight/s rumoured for this month?

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/999x963/fr24_2_0e93c36e407b61d714db48dc18554177fd701add.jpg

https://flightradar24.com/BOE701/24cfc773

.Scott

29th Jun 2020, 19:53

Moved to: https://www.pprune.org/rumours-news/632804-boeing-restart-737-max-production-7.html#post10824722

.Scott

29th Jun 2020, 19:54

https://www.cnbc.com/2020/06/29/faa-boeing-737-max-test-flights-a-milestone-in-recertification-after-crashes.html

The Federal Aviation Administration began recertification flights of the Boeing 737 Max on Monday, a key step toward permitting the planes to return to service after two fatal crashes more than a year ago.

The 737 Max, Boeing’s bestseller, has been grounded worldwide since March 2019 after the crashes — one in Indonesia and another in Ethiopia — within five months of one another. All 346 people on the flights were killed in the crashes. Boeing has since changed a flight-control system that was implicated in both crashes and has made other tweaks. Additional scrutiny of the aircraft contributed to repeated delays in the recertification process.

Boeing shares added to earlier gains after the first Max certification flight took off and were up more than 12% in afternoon trading Monday, leading the Dow Jones Industrial Average higher.

“The FAA is following a deliberate process and will take the time it needs to thoroughly review Boeing’s work,′ the FAA said in a statement. “We will lift the grounding order only after we are satisfied that the aircraft meets certification standards.”

The first flight departed 10 a.m. Pacific time from Seattle with other flights scheduled over about three days. “The tests are being conducted by test pilots and engineers from the FAA and Boeing,” the FAA said.

Regulators’ evaluation of the planes will continue for several more weeks and Boeing expects they will be back in commercial service by late fall. Other steps include an international evaluation of minimum pilot training requirements, the FAA said over the weekend.

“It is important to note, getting to this step does not mean the FAA has completed its compliance evaluation or other work associated with return to service,” the FAA said in a note to members of Congress on Sunday. “The FAA has not made a decision on return to service. We have a number of steps remaining after the conclusion of the certification flights.”

Boeing late last month resumed production of the planes after a pause earlier this year.

While it still has a robust backlog, Boeing has logged dozens of cancellations from customers. The Covid-19 pandemic is also expected to mean lower-than-usual travel demand for years, Boeing and airline executives have said, which could further hurt demand for new planes.

towerview

1st Jul 2020, 09:23

Assuming all the recertification goes smoothly, what will happen?

For the 400 or so aircraft at Boeing, are these on mostly 'take or pay' contracts, or can the airlines cancel or delay with little penalty, at least in some cases if so how many? I expect this has been covered earlier, but I wondered what the latest estimates are.

rotorwills

1st Jul 2020, 12:25

MOL has openly stated that he can't wait to sit down with Boeing to discuss the take up of his planes on order as well as discuss future scheduled additions. His fleet is around 400 and he is expecting to increase that to somewhere in the 600 number in the future. Very ambitious, but when you look at their growth it's not in the realm of being unlikely.

I figure he reckons he can annihilate what in his mind is his competition.

You have to admire his business acumen, not but it does come at a price for all of us in the aviation world.

Pilot DAR

1st Jul 2020, 12:38

Let's stay on topic on this thread - the testing, recertification, and return of C of A's by the international authorities, of the 737MAX. Discussions of commercial, operational and fleet aspects will be appropriate after the recertification effort has resulted in international acceptance for return to service. It will be more than just the FAA who will test fly and evaluate the improved airplane.

The AvgasDinosaur

1st Jul 2020, 15:00

The 52-page report by the U.S. Department of Transportation’s Office of Inspector General (IG), dated June 29 and set to be made public Wednesday, laid bare mistakes made by both the planemaker and FAA in the development and certification of Boeing’s top-selling aircraft.
Has this been published yet ?
David

Less Hair

1st Jul 2020, 15:27

This one?
https://www.oig.dot.gov/library-item/37940

WillowRun 6-3

1st Jul 2020, 16:28

For anyone wishing to read a good news report on the DOT IG document, from D. Gates reporting for the Seattle Times:
https://www.seattletimes.com/business/boeing-aerospace/inspector-general-report-details-how-boeing-played-down-mcas-in-original-737-max-certification-and-faa-missed-it/

gums

1st Jul 2020, 17:45

Thank you, Pilot

Maybe you could start a thread over where it belongs in order to get some of the politics outta the way, huh? We have too many real pilots here that can discuss the changes and the results of them and ......

No doubt many management and even engineering decisions resulted in th Max debacle, but I feel that should be left here and have the aero and system design stuff over on tech log, huh?

Spooky 2

2nd Jul 2020, 15:35

FAA Statement

The FAA and Boeing today completed the certification flight tests on the Boeing 737 MAX. During three days of testing this week, FAA pilots and engineers evaluated Boeing’s proposed changes in connection with the automated flight control system on the aircraft. While completion of the flights is an important milestone, a number of key tasks remain, including evaluating the data gathered during these flights. The agency is following a deliberate process and will take the time it needs to thoroughly review Boeing’s work. We will lift the grounding order only after FAA safety experts are satisfied that the aircraft meets certification standards.

The remaining tasks include:

· JOEB Validation & FSB Review – The FAA’s Flight Standardization Board (FSB) and the Joint Operations Evaluation Board (JOEB) which includes international partners from Canada, Europe, and Brazil will evaluate minimum pilot training requirements. The FSB will issue a draft report for public comment addressing the findings of the FSB and JOEB.

· Final FSB Report – The FAA will publish a final FSB report after reviewing and addressing public comments.

· Final Design Documentation and TAB Report – The FAA will review Boeing’s final design documentation in order to evaluate compliance with all FAA regulations. The multi-agency Technical Advisory Board (TAB) will also review the final Boeing submission and issue a final report prior to a final determination of compliance by the FAA.

· CANIC & AD – The FAA will issue a Continued Airworthiness Notification to the International Community (CANIC) providing notice of pending significant safety actions and will publish an Airworthiness Directive (AD) that addresses the known issues for grounding. The AD will advise operators of required corrective actions before aircraft may re-enter commercial service.

· FAA Rescinds Grounding Order – This marks the official ungrounding of the aircraft, pending completion by operators of the work specified in the AD, along with any required training.

· Certificates of Airworthiness – The FAA will retain its authority to issue airworthiness certificates and export certificates for all new 737 MAX airplanes manufactured since the grounding. The FAA will perform in-person, individual reviews of these aircraft.

· Operator Training Programs – The FAA will review and approve training programs for all part 121 operators.

Here is a link to B-roll video from the flight tests:

https://youtu.be/MDgWYO3B5LY

https://mail.google.com/mail/u/0?ui=2&ik=450755f5d7&attid=0.1&permmsgid=msg-f:1671055900943915125&th=1730c87cff951875&view=fimg&sz=s0-l75-ft&attbid=ANGjdJ9ja7grq8UR1gTfQqcjdwYm0uMQ3kBK1whwEdzU6nyFcKaaM asZd0vfZNn_7m40byGyXgEIeBw_EBkdoZVdE0EYWTBQc7yGcnz04047yQBr1 DndMFtd9WrrWvU&disp=emb

Photo caption: Flight test crew from the Federal Aviation Administration and Boeing Co. during certification flights of Boeing 737 MAX.

Attachments area
Preview YouTube video Video from 737 MAX Certification Flights on 6/29/2020 – 7/1/2020
https://i.ytimg.com/vi/MDgWYO3B5LY/hqdefault.jpg
https://ssl.gstatic.com/docs/doclist/images/mediatype/icon_2_youtube_x16.png
Video from 737 MAX Certification Flights on 6/29/2020 – 7/1/2020

Spooky 2

2nd Jul 2020, 16:16

rotorwills

2nd Jul 2020, 20:17

Exactly that's a big step, we need to wait and see some detail. Looking forward to that information being released. Must say I was rather surprised.

gums

2nd Jul 2020, 20:45

Maybe I read the initial para wrong, Rotor, but thot FAA said:

We will lift the grounding order only after FAA safety experts are satisfied that the aircraft meets certification standards.

Where's our Boeing or FAA "mole" now? Heh heh. And what exactly have they done, as it soumds like a lot more than a sfwe tweak?

172driver

2nd Jul 2020, 21:20

Out of interest: are these certification flights crewed by Boeing company or FAA pilots?

tdracer

2nd Jul 2020, 21:52

Short answer is 'both'.
SOP for certification flight testing is that the FAA pilot is in the Left seat and and a Boeing Flight Test Pilot is in the Right seat. There will generally be at least one other FAA observer on board - typically in the left side observer seat (the right observer seat is normally occupied by the Boeing Flight Test Director). Other observers (both Boeing and FAA) will be in the back monitoring whatever instrumentation that have installed - or crammed into the back of the flight deck during specific test conditions (obviously everyone needs to be seated and strapped in for takeoff and landing or any test conditions which could result in excessive aircraft upset.
There are some pretty major insurance and liability implications if there isn't a company pilot in one of the pilot seats - I've never heard of an instance that FAA pilots were in both seats. It's similar when Boeing does remote flight tests using an operators aircraft - there is always one of the operators pilots in one of the front seats.

dingy737

3rd Jul 2020, 02:33

This is an opportunity for the travelling public to send a strong message that only they have the final say on if they will travel on the MAX and not the FAA, EASA, or Boeing.

BDAttitude

3rd Jul 2020, 06:43

The apparel is giving it away who's who on that plane.
Love how the Boing guy in the back is flicking bored through his paperwork :}

42...

3rd Jul 2020, 13:38

This is an opportunity for the travelling public to send a strong message that only they have the final say on if they will travel on the MAX and not the FAA, EASA, or Boeing.
They are lining up to fly for $49 a ticket, they don't care about the MAX as long as masks are needed, that will protect them.

Dave Therhino

3rd Jul 2020, 17:47

The apparel is giving it away who's who on that plane.
Love how the Boing guy in the back is flicking bored through his paperwork :}

The guy sitting in the door is the Boeing test director, and the TD is in general one of the busiest people on the airplane both before and during a test flight.

Longtimer

4th Jul 2020, 01:48

The best part.
· FAA Rescinds Grounding Order – This marks the official ungrounding of the aircraft, pending completion by operators of the work specified in the AD, along with any required training.
I think you missed the maybe...
he FAA and Boeing today completed the certification flight tests on the Boeing 737 MAX. During three days of testing this week, FAA pilots and engineers evaluated Boeing’s proposed changes in connection with the automated flight control system on the aircraft. While completion of the flights is an important milestone, a number of key tasks remain, including evaluating the data gathered during these flights. The agency is following a deliberate process and will take the time it needs to thoroughly review Boeing’s work. We will lift the grounding order only after FAA safety experts are satisfied that the aircraft meets certification standards.

The remaining tasks include:

· JOEB Validation & FSB Review – The FAA’s Flight Standardization Board (FSB) and the Joint Operations Evaluation Board (JOEB) which includes international partners from Canada, Europe, and Brazil will evaluate minimum pilot training requirements. The FSB will issue a draft report for public comment addressing the findings of the FSB and JOEB.

· Final FSB Report – The FAA will publish a final FSB report after reviewing and addressing public comments.

· Final Design Documentation and TAB Report – The FAA will review Boeing’s final design documentation in order to evaluate compliance with all FAA regulations. The multi-agency Technical Advisory Board (TAB) will also review the final Boeing submission and issue a final report prior to a final determination of compliance by the FAA.

· CANIC & AD – The FAA will issue a Continued Airworthiness Notification to the International Community (CANIC) providing notice of pending significant safety actions and will publish an Airworthiness Directive (AD) that addresses the known issues for grounding. The AD will advise operators of required corrective actions before aircraft may re-enter commercial service.

· FAA Rescinds Grounding Order – This marks the official ungrounding of the aircraft, pending completion by operators of the work specified in the AD, along with any required training.[/QUOTE]
[QUOTE]

atakacs

4th Jul 2020, 06:44

Any idea what was concretely changed? Is it software only?

In any case I guess the "no specific training" design goal is out of the window?

WillowRun 6-3

6th Jul 2020, 11:55

WSJ today reporting, under headline "Next Boeing 737 MAX Government Test Flight Scheduled for Coming Days", that next flight or flights will include what the news item refers to as "federal pilots along with airline crews from around the world" - which would indicate the JOEB, Joint Operations Evaluation Board, I think. (Article on WSJ website includes a bit more content than the version in the print edition.)
https://www.wsj.com/articles/next-boeing-737-max-government-test-flight-scheduled-for-coming-days-11593983305?mod=hp_lead_pos4

Not explained by the article is the source of reported friction between Transport Canada and FAA. Also of note is the content on the website edition regarding FAA dispensing with - the word used in the Journal is "jettisoned" - the average pilot response time assumption which is one of the root sources of the debacle and tragedies. One must wonder, what has replaced it, though? An old Ann Arbor wisdom holds that one must add before one may drop - and while that relates to course registration changes (back in the days of paper forms, press hard you are making seven copies and so on), it works a lot more broadly.

So then, what is the assumption now about response or reaction times?; does it account for differing training backgrounds and particularly with respect to expected completion of hand-flying and/or airmanship experience quanta; does it account for cultural-based cockpit gradients? What exactly does it account for, in other words, what went into the definition of the "new" assumption - if there is one - in the first place? One could reasonably say the former "average" assumption was based on some long-since discarded Right Stuff movie conception, watered down to some baseline destined to be overtaken and swamped by technology advances so badly that the word "average" did not even apply any longer.

FAA's July 1, 2020 update announcement states that the FSB will issue a draft report on "minimum pilot training requirements" based on its findings and those of the JOEB - the draft will be open for public comments when it is completed.

WillowRun 6-3

11th Jul 2020, 14:29

Aviation Week's Sean Broderick reporting on Twitter (( article is behind paywall, though ))

"First look at draft of new 737 MAX training, incl. changes to 7 checklists. Two reflect new MCAS; other design changes; other 5 re-worked based on human factors. 190 pg of new/updated material incl. new bulletins, checklists. Pilots, airlines reviewing.
https://aviationweek.com/air-transport/safety-ops-regulation/revamped-max-training-prioritizes-getting-pilots-information… (https://t.co/bK3fAJ5nW8?amp=1)One notable from the piece: the FAA's 737 MAX return-to-service directive may go through a formal public notice-and-comment period before it's final. Not always done, but typical for non-emergency directives. If it happens, add 15-30 days to projected ungrounding timelines."

Added: Flight Global article re: American Airlines' pilots union review, apparently more accessible w/o paywall:
https://www.flightglobal.com/airframers/american-pilots-review-boeings-latest-max-training-draft/139253.article

WillowRun 6-3

20th Jul 2020, 11:46

AD issued by FAA relating to biocide in fuel tanks and applicable to 737 MAX.
It appears that the AD prohibits operating 737 MAX aircraft involved in current flight testing programs until compliance with the AD has been attained. Pertains to CFM LEAP 1-B powerplants specifically.

http://services.casa.gov.au/airworth/airwd/ADfiles/OVER/B737/2020-14-09.pdf

(Further discussion, see Tech Log)

WillowRun 6-3

22nd Jul 2020, 12:32

FAA July 21 Update on 737 MAX Recertification:

https://www.faa.gov/news/updates/?newsId=93206

"In the near future, the FAA plans to issue a Notice of Proposed Rulemaking (NPRM) for an Airworthiness Directive (AD) affecting the Boeing 737 MAX. In keeping with our commitment to remain transparent, the NPRM will provide 45 days for the public to comment on proposed design changes and crew procedures to mitigate the safety issues identified during the investigations that followed the Lion Air and Ethiopian Airlines accidents.

"The agency continues to follow a robust certification process. In addition to the standard FAA certification team, the 737 MAX Technical Advisory Board (TAB) continues to provide valuable review and consultation.

"While the posting of the NPRM is an important milestone, a number of key steps remain. The remaining tasks include:

JOEB Validation & FSB Review – Final planning is underway for the FAA’s Flight Standardization Board (FSB) and the Joint Operations Evaluation Board (JOEB) review of proposed training for flight crews, based on the design change and crew procedures. The results of this evaluation will be included in the updated Flight Standardization Board report, which will also be posted for public comment.
The JOEB will include regulators from Canada, Europe, and Brazil and will evaluate minimum pilot training requirements. The FSB will issue a draft report for public comment addressing the findings of the JOEB.
Final FSB Report – The FAA will publish a final FSB report after reviewing and addressing public comments.
Final Design Documentation and TAB Report – The FAA will review Boeing’s final design documentation to evaluate compliance with all FAA regulations. The multi-agency Technical Advisory Board will also review the final Boeing submission and issue a final report prior to a final determination of compliance by the FAA.
CANIC & AD – The FAA will issue a Continued Airworthiness Notification to the International Community (CANIC) providing notice of pending significant safety actions and will publish a final Airworthiness Directive (AD) that addresses the known issues for grounding. The AD will advise operators of required corrective actions before aircraft may re-enter commercial service.
FAA Rescinds Grounding Order – This marks the official ungrounding of the aircraft, pending completion by operators of the work specified in the AD, along with any required training.
Certificates of Airworthiness – The FAA will retain its authority to issue airworthiness certificates and export certificates for all new 737 MAX airplanes manufactured since the grounding. The FAA will perform in-person, individual reviews of these aircraft.
Operator Training Programs – The FAA will review and approve training programs for all Part 121 operators.

"The FAA will not speculate when the work will be completed. The agency continues to follow a deliberate process and will take the time it needs to thoroughly review Boeing’s work. We will lift the grounding order only after FAA safety experts are satisfied that the aircraft meets certification standards."

Also today's Wall Street Journal (by-line, Andy Pasztor and Andrew Tangel) reports that the NPRM and public comment phase are seen as likely to push return to passenger service into 2021 (along with other factors especially the global pandemic and cratering of air travel demand).

The sorry and tragic saga continues on.

safetypee

22nd Jul 2020, 16:23

The FAA is to use the NPRM process leading to the final rule.

How common is it for a FSB Review to be put to NPRM, or published in draft before public comment ?
Similarly for the JOEB Validation; unusual ?

These processes provide opportunity for world-wide public review of the proposals and expose any conflicting views between FAA and world authorities (previous leaks), all within a US certification process. Choosing to exclude world opinion could inflame the differences, particularly as the accidents were 'non-US'.

This suggests that descending opinion (public opinion *) on operations and training could influence the final FAA rule. If so, interesting times; possible that US operators would have to train to world standards, or the FAA grant and explain any dispensation, messy. Particularly painful if the FAA agrees a lower standard of training, such that the rest of the world is financially disadvantaged, call lawyers.

Worse still if this openness overflows to disagreements over the technical modifications, currently within the FAA regulatory process, but still subject to multi-agency review ( but not necessarily public comment ?)

Should we expect that there is already a closed-doors agreement between the main regulatory authorities to circumvent most of these issues ?

* world wide 'expert' opinion on creditable human contribution in aircraft with system failure, recognition, reaction time, and performance sufficient to achieve an acceptable level of safety. (Aviation expertise or Human Factors expertise in general ).
Might be a lengthy comment / reply section in the NPA.

rotorwills

22nd Jul 2020, 16:29

Well there is no, and shouldn't ever be, any rush to get the airplane back in the air. This terrible pandemic has some way to go yet. Aviation as we know only too well is going through a really spell and the devastating effect upon all in our industry is sad to behold. We have to prepare for the worst and of course hope for the best.

WillowRun 6-3

22nd Jul 2020, 17:56

The rumour bouncing through my recollection is that a NPRM framework has not been used previously for FSB or JOEB processes. Caveat: I don't know -- but if it had happened before, would it not be the case that the particular airworthiness certification question or set of issues would be known and would be attached, in the pro pilot community, to the basic background about a given type of transport category aircraft or a given derivative model of a type of transport category aircraft?

If I am recalling properly the EASA position publicly has been stated as having a preference for a third AOA input or, as a possibly satisfactory alternative, input of synthetic airspeed. I agree with the assessment that the opportunity for comments by disparate authorities and experts (some of whom might not be actually expert or authoritative) creates a potential for a long and drawn out, and convoluted, process (if that is a correct reading of safetypee's post).

Can't help but wondering if the Special Conditions which were part of the 787 type certification with regard to its use of lithium-ion batteries had been subjected to NPRM for commenters far and wide, what result might have obtained? (That is, on the assumption noted above that the NPRM process for 737 MAX now is a one-off, first-time deal, in Dep't of Transportation/FAA's ongoing efforts to cope with the monumental shooting-in-the-foot by the manufacturer.)

wrench1

22nd Jul 2020, 22:45

The FAA is to use the NPRM process leading to the final rule. How common is it for a FSB Review to be put to NPRM, or published in draft before public comment ? Similarly for the JOEB Validation; unusual ?.
FYI: the NPRM is only for the AD. Since each AD is a new Part 39 regulation (rule) a NPRM is required by law. The rest are admin tasks.

safetypee

23rd Jul 2020, 17:40

WillowRun, thanks.
Maybe a first time; not necessarily mitigating the 'shooting-in-the-foot by the manufacturer', but to demonstrate robust corrective action and restore confidence in the FAA's role in this saga; - because they provided the gun for Boeing.

wrench 1, part 39 appears to relate to the AD process, the implementation of the ruling.
If the content of the AD involves certification aspects, which MCAS does - design and procedures, then your 'admin tasks' are very relevant, if not the central issue. Re FAA press release ' … comment on proposed design changes and crew procedures to mitigate the safety issues identified …'

wrench1

23rd Jul 2020, 19:06

part 39 appears to relate to the AD process, the implementation of the ruling.'
Not quite. The AD process, i.e., the steps required to create an AD, are handled separately by several policies/laws depending on the type of AD. Once the AD is issued it becomes a separate FAA regulation under Part 39. It is as a new regulation that it becomes enforceable by law.
If the content of the AD involves certification aspects, which MCAS does - design and procedures, then your 'admin tasks' are very relevant,
Never said they were not relevant. My point was to separate the NPRM/AD from those admin tasks as they are not related from a regulatory standpoint. Technically, an AD does not affect the certification aspects which are found in Parts 23, 25, 27, 29. The AD corrects an unsafe condition but does not change the certification requirements. That would require a separate process/change of the relevant aircraft certification regulation, i.e., Part 25. Once issued, the AD becomes the legal mechanism for the FAA, and by extension other CAAs, to enforce the required changes to the MAX as stated in the AD. Whether the other CAAs wish to follow the final AD procedures is up to them, however, there are a number of international bi-lateral agreements, etc. that bind certain countries to this process. I expect there will be a considerable amount of public input on this NPRM and will be interesting to read them as the process moves along.

Dave Therhino

23rd Jul 2020, 19:17

To elaborate on what Wrench1 wrote, the law in the US driving this is the Administrative Procedures Act, which requires public notice and opportunity for comment, and requires agencies to address comments received, for all changes to regulations unless there is an emergency as defined in the Act. That includes airworthiness directives issued under 14 CFR part 39. The airplanes are grounded, so there is no emergency from a safety standpoint.

There also is a requirement in the FAA authorization statute for any emergency orders by the FAA Administrator to be followed by a public proceeding as defined in the law, which was not done after the grounding order. The FAA theoretically can't simply rescind or revise the order at this point without holding such a proceeding or they'd be violating that law.

Failure to follow either of these requirements in this case seems likely to invite court challenges by various parties, so I suspect the FAA is going to be careful to follow the law. This is a situation where trying to skip steps may cause additional delay versus following the required steps.

Whenever an AD requires a change in design to be incorporated, both the certification procedures of 14 CFR part 21 (which requires evaluation of compliance with airworthiness standards) and the regulatory promulgation process requirements of 14 CFR part 39 and the Administratve Procedures Act are required to be followed. Normally this is done sequentially, but it can be done in parallel or even in reverse (resulting in ADs that say "fix in a manner acceptable to the FAA"). The design changes to address the issues with the Max are apparently in the late stages of the certification process. It sounds like the FAA's plan is that, once the design changes are approved, the AD process will begin with issuance of an NPRM. The process for promulgating an AD when public notice and opportunity for comment prior to the final rule are provided typically takes at least six months. There are likely to be many comments, so I doubt the process will be faster than that in this case.

WillowRun 6-3

23rd Jul 2020, 19:23

If I understand what safetypee means, then I more than agree - the "administrative" items with regard to the JOEB and FSB outputs are very relevant and potentially quite significant for purposes of restoring the assurance of safety of the airplane. Additionally to these, the Department of Transportation Inspector General (I.G.) report on the certification lapses with this aircraft - the first, according to the I.G., of a number of reports on the lapses - states that public comments will be sought by FAA on another highly relevant reform (a new policy with respect to FAA oversight of the ODA process, taking account of input from an Expert Review Panel mandated by Section 213 of the 2018 FAA Reauthorization Act). And beyond all that, the FAA also is establishing and implementing an Organization Designation Authorization Office, and assuredly the Senate and House Committees in the Congress will have "comments" on that initiative as well.*

On the subject of public comments and/or the NPRM process in a situation the same or substantially similar as the 737 MAX safety crisis, I can think of two somewhat - or maybe quite similar - prior instances to look at. One, the actions taken after a DC-10 (American Airlines Fl. 191) crashed shortly after takeoff from Chicago O'Hare International Airport on May 25, 1979. I haven't yet dug back into the FAA administrative record to examine, that is to research, what specific actions were taken and what exact form or format they took. (Whether official documents and records from 41 years ago have been moved into an internet-accessible form will be an interesting side note - the published court decision in the lawsuit filed by British Caledonian contains a lot of interesting record citations.)

The other instance involved the actions taken after the two Lithium-Ion battery fires on new Boeing 787 aircraft a few years ago (one in Boston, the other in Japan).

In both instances, significant changes were made to the airplanes afterwards, in the case of the Ten, quite substantial, if I recall properly, in terms of hydraulic lines. So if the law was, back then and at the time of the 787 incidents, the same as wrench1 has stated or implied, then the ADs relating to these two prior instances should be relevant. Not necessarily in a sense of relevance for what is happening to get the 737 MAX back into service as such - but in a context of the aviation safety ecosystem, anyway I see these past instances and their administrative law components (as they may exist) as relevant, quite.

*source is the memo from the DOT General Counsel appended to the I.G.'s June 29, 2020 report (which itself is the subject of another thread here).

wrench1

23rd Jul 2020, 20:01

the "administrative" items with regard to the JOEB and FSB outputs are very relevant and potentially quite significant for purposes of restoring the assurance of safety of the airplane.
FYI: While they are relevant, neither the JOEB or FSB carry weight legally to unground the MAX. Both are policy processes (admin) and not regulatory processes (AD). If future changes are needed to the certification regulations, IG issues, etc. in general then those changes will get their own NPRMs. Same as in your DC-10 and 787 examples as the APA/NPRM process has been around since the 1940s. But trying to tie in the JOEB/FSB with the Airworthiness Directive NPRM process is not possible as they follow separate and distinct paths. That doesn't mean the FAA rule-making committee who drafts the MAX NPRM will exclude any finding from any external boards rather the opposite. There is usually a robust, public, discussion during the NPRM process especially with a high-profile subject matter like the MAX. And I have a feeling this NPRM process will be quite the discussion.

WillowRun 6-3

23rd Jul 2020, 20:14

wrench1, thank you for all the clarifications.

Part of my interest relates to the ongoing Congressional agitation (to put it politely) around matters, and/or issues, concerning modifying, reforming, rebuilding/starting over, the ODA process. While the FAA as regulator deals with its APA obligations (as you point out) the Congress will try to keep up, and also try to envision the next set of problems in the future and define via legislation what could be successful or effective in keeping those problems from occurring, or minimizing them. The various admin actions will get a lot of airtime as part of that . . . and as part of the international commercial issues bound to arise or recur.

At the same time, to anticipate a shortage, let alone absence, of grandstanders on Capitol Hill - and among aviation interest groups and lobbies - would be a bit disappointing. Meaning, to understand separation between AD/NPRM under administrative law, and the comparatively only policy-making admin maneuvers, is a big point.

wrench1

23rd Jul 2020, 20:41

Except the problem with Capitol Hill and aviation is that once the aviation "issue" is out of the news we once again become the red-headed step child and are relegated back to our proverbial room. Once the MAX starts flying again and everybody gets that warm fuzzy I don't expect congress to get immediately involved in any aircraft certification legislation. It will merely get passed off to the DoT to correct, etc., etc. and join the existing list of previous aviation correction issues. Besides I don't think there will be a need for any new transport aircraft variants in the near future. Time will tell.......

safetypee

23rd Jul 2020, 21:43

Thanks for the clarification wrench 1.

For my continuing education, whilst 'neither the JOEB or FSB carry weight legally to unground the MAX', conversely can (or will) the MAX be ungrounded without JOEB and FSB being acceptable for: -

A. The FAA, (legally possible ?), but politically unlikely.

B. Other regulatory authorities; with potential for different standards of modification, procedures, and training, which might be unacceptable to Boeing (cost), and with little benefit to the FAA seeking to improve world standing and restoring the necessary trust in 'certification' being seen to be well done.

Given that that there may be many HF related comments on the JOEB and FSB, and that previously the FAA was short of the necessary expertise, now seeking to recruit many new HF specialists, will the 'new brigade' be sufficiently competent in aviation matters to be able to respond to wide ranging, and probably more knowledgeable worldly views.

Longtimer

23rd Jul 2020, 23:20

wrench1

Along with the virus and the constant press about the failings of the MAX and aviation in general (exposure to the virus), I would sadly bet that it will be many months if not years before everybody will get "warm and fuzzy" about flying in general let alone the MAX .

wrench1

24th Jul 2020, 00:00

For my continuing education, whilst 'neither the JOEB or FSB carry weight legally to unground the MAX', conversely can (or will) the MAX be ungrounded without JOEB and FSB being acceptable for: ....
I think the direction being taken to those questions and the dozens of others out there will be answered when the MAX AD NPRM is posted. And you'll be able to personally read and ask/comment directly to those who are writing the requirements to release the MAX for flight. After the NPRM is posted an online docket is opened that will provide supporting info and provide a place to comment and read previous comments. At some point the NPRM committee will usually respond to the posted comments and either agree or disagree with them while normally providing the reasons why. Considering all the stakeholders involved in this I anticipate most questions will be answered. And since the media update stated "in the near future" they probably have a majority of the NPRM already completed.

CW247

24th Jul 2020, 06:54

So is MCAS still going to rely on a single (often faulty) AoA sensor?

alf5071h

24th Jul 2020, 14:52

Lake, repetitive questions and arguments from endless tech threads. (MCAS could have worked many times, but the crew might not know in normal operation - no AoA failure.)

Take up the technical discussion after the proposed changes are published in the NPRM.
Then we might debate fact not fiction.

PAXboy

24th Jul 2020, 17:28

Lake1952

One of the key restrictions that Boeing was working to was that most carries, notably SouthWest and AA (I sit to be corrected) refused to accept a new 73- that required additional training. They wanted as small a conversion as possible to save money.

As is often the case, saving money in the short term ...

DaveReidUK

24th Jul 2020, 22:29

Since normal activation of MCAS is a normal event, and essentially undistinguishable from an autotrim, it would not have been reported.

There is no such thing as "normal activation" of MCAS, which (by definition) was intended "to provide consistent handling qualities in unusual flight conditions".

Nor is it "undistinguishable from autotrim" - the latter can be arrested by the control column microswitches, MCAS can't.

Also, I guess that MCAS was intentionally tested (and activated) at least in Boeing test flights, and perhaps in certification flights, which would make the statement demonstrably false.

The OP was clearly referring to deployment of MCAS in revenue service, not during certification. There have been no documented instances of the former, other than on the accident aircraft.

_Benjamin_

24th Jul 2020, 23:02

The OP was clearly referring to deployment of MCAS in revenue service, not during certification. There have been no documented instances of the former, other than on the accident aircraft.

How it have been recognised as an event then subsequently documented if pilots were unaware of mcas existence?

Also, where will we see the FAA response to JATR:

Recommendation R3.4: The FAA should review the natural (bare airframe) stalling
characteristics of the B737 MAX to determine if unsafe characteristics exist. If unsafe
characteristics exist, the design of the speed trim system (STS)/MCAS/elevator feel shift
(EFS) should be reviewed for acceptability.

And

Recommendation R3.5: The FAA should review 14 CFR 25.201 (Stall Demonstration)
compliance for the B737 MAX and determine if the flight control augmentation functions
provided by STS/MCAS/EFS constitute a stall identification system.

WillowRun 6-3

25th Jul 2020, 00:48

FAA response to certain parts of JATR . . . .

A very pointedly relevant question! A few suggestions for possible answers:
1) The anticipated NPRM for the AD for modifications (as explained upthread by wrench1) would be an interesting place for FAA to address what it has done about JATR recommendations as well as what it has deferred, rejected or otherwise not acted on. And then the public comments on the NPRM could, at least as a general matter under administrative law, prompt the FAA to modify the AD in more than minor ways. But the JATR recommendations noted by Benjamin's post would have to have been designed into the recertification flight test program already, no? And is it known whether this was done?

2) Relatedly, and also as clarified by wrench1 earlier, the pending JOEB and FSB inputs will yield a report which in turn will be subject to public comment, for administrative purposes. Those groups' reports, and the comments on their work, also could press FAA to address the JATR's recs . . . although again, if the recertification flight test program hasn't already included what JATR recommended, would FAA go back and retest?

3) The FOIA (Freedom of Information Act) lawsuit by the Flyers' Rights group, seeking all the documents provided by Boeing to FAA with regard to recertification, has been plodding along for months. The point of the lawsuit is not mere receipt of documents, though - the explicitly stated purpose of the lawsuit is to obtain those documents so that Flyers' Rights and a kind of "shadow FAA certification experts cadre" it has assembled (which includes famed Capt Sullenberger IIRC) can assess whether FAA has acted properly or not. Which would imply a vehicle to try to intervene via further court action to arrest a flight test and recertification program which has failed to account properly for the JATR's recommendations, and halt the return to service. (I don't speak for the Flyers' Rights group, I'm not involved in their case at all, and this is just an SLF-att'y assessment of what ....*plausibly could* happen.)

Bend alot

25th Jul 2020, 01:21

While FAA can use JATR recommendations as just recommendations - EASA seem clear on what is required for EASE to certify the aircraft in EASA land.

“Aircraft longitudinal stability is subject to airworthiness requirements. Boeing has to demonstrate compliance of the 737 MAX airframe with these requirements. Consequences of failures of systems affecting potentially the aircraft stability need to be assessed using acceptable safety analysis methodology also subject to airworthiness requirements,” EASA said in its published statement.

https://www.aviationtoday.com/2019/09/29/easa-clarifies-position-boeing-737-max-return-service/

Bend alot

25th Jul 2020, 02:28

I find it strange that the re-certification test flights carried out were in the shorter variant -7, that currently zero units have been delivered and small orders.

I find it hard to believe that they did not have a -8 laying around to do these tests with, as the crashed aircraft were both -8 variants.

The original MAX test flights were in a -8 and reported to have an unusually forward C of G.

Dave Therhino

25th Jul 2020, 03:02

If the horizontal stabilizer is the same, and the nacelle aerodynamics and wing are the same, the airplane with the shortest moment arm between the cg and the stabilizer would likely be the worst case airframe configuration for the evaluation of control forces in the approach to stall for compliance with the requirement for the control force to increase in order to increase angle of attack (14 CFR 25.203(a)).

Dave Therhino

25th Jul 2020, 05:04

I was not actually interested in the control force for compliance, more the approach to stall.

I don't know what you mean by the last part of this sentence. Can you clarify it?

MechEngr

25th Jul 2020, 05:09

Bend alot

This does not seem correct. The change in pitch moment is regardless of the length of the aft fuselage. The shorter the aft fuselage the greater the required force to offset the pitch moment change, so the greater the stabilizer movement to generate that force. Consider if the tail was at the rear of the wing but had to compensate for the same pitch moment. The loads would be far higher and require far more deflection to attain.

I don't foresee a large difference in pitch moment vs AoA for the nacelles based on aft-fuselage length so just going with the shortest aft fuselage should represent the worst case for that parameter.

tdracer

25th Jul 2020, 20:35

Agreed - shorter fuselage is always the worst case for engine pitch-up effects due to the reduced moment arm of the tail surfaces.
737 maximum engine ratings are limited on the shorter models for the same reason. I didn't work the NG, but on the 'classic' 737-3/4/500 (tel:737-3/4/500) series, the -300 and -500 models had a physical throttle block to prevent full throttle operation (the engines were common with a common rating). Otherwise under certain conditions, if you firewalled the throttle the engine pitch-up moment could be greater than what the tail surfaces could overcome.

turbidus

26th Jul 2020, 13:45

It is curious a a few test flights...poof...nothing...no information whatsoever...

Matey

26th Jul 2020, 22:33

CW247

The new software compares both AOA sensors, and if a difference of 5.5 degrees is detected then MCAS is deactivated for the remainder of the flight.

OPENDOOR

27th Jul 2020, 11:49

So if both sensors jam at maximum AoA then MCAS kicks in and attempts to apply full nose down horizontal stab trim?:uhoh:

Less Hair

27th Jul 2020, 12:01

AFAIK it's limited to one MCAS-cycle per event. So it won't start to trim over and over again when jammed somehow.

infrequentflyer789

27th Jul 2020, 22:03

Er, no - or at least we can't say it won't do that without much more info.

The previous version didn't in fact trim "over and over again" unless it was "reset" - and then the next trim is for a new event, because it's been reset (if a system has no memory of previous state due to a reset, anything is a new event). If the pilots had known that "all" they had to do was hold the column against one MCAS-cycle of trim and not reset it (not touch the trim), MCAS might not have been as lethal.

Thing is, there has to be a reset, there has to be an end-of-event (even if it's WOW or end-of-flight), and after reset MCAS can trim again. I think I understand why the original reset was done the way it was, working from what has been revealed about the way MCAS was implemented I've tried to put together plausible implementation logic / pseudocode, and if you reset it the way they did (going from published info) you end up with something that is very definitely in the "simple, elegant and wrong" class of solutions. Really simple, really neat, deceptively enticing. I can even see how the post-flight-test changes that made it more lethal may have eluded some reviews, because they could have been done with no actual code changes at all (no logic, just values of constants - data initialization).

What I can't see is how you "fix" the reset problem without introducing a lot more state into the logic, way more aircraft-state inputs, way more complex calculations, and probably orders of magnitude more lines of code. Even then, somewhere, somewhen, there still needs to be a reset, and hiding behind that implementation is the risk of MCAS trimming over and over again. Now I haven't done real time control stuff for decades, nor flying code, there may be a solution that is simple and elegant and right, they may even have found it... but I have a suspicion (especially given the reported problems with it) that MCAS is now a solution that is complex, ugly, and maybe right - but very hard to prove it isn't wrong in some circumstances.

Dave Therhino

28th Jul 2020, 01:02

Reset based on validated AOA returning to the normal nominal flight range, maybe with a time integrator?

Big Pistons Forever

28th Jul 2020, 17:44

It is curious a a few test flights...poof...nothing...no information whatsoever...

Third hand rumor I heard is the only way to get the Max back in the air is a let on some hard stability certification requirements. The FAA is OK going there but other regulators not so much. I am guessing a lot of behind the scenes negotiations happening right now as to the exact wording of the AD......

Ditching Switch

31st Jul 2020, 07:29

Boeing are laying off 19 (out of a total of 24) of their most experienced 737 MAX licensed engineers in Dublin with RTS on the horizon. It strikes me as an incredibly callous commercially driven decision bearing in mind all the regulatory eyes that will be on the project.

On an empathetic level it will be a bitter pill to swallow for the engineers who have no prospects of similar employment in the near future particularly in Ireland. There isn't a job to be had in the sector.

_Benjamin_

31st Jul 2020, 10:26

Sorry to hear that, hopefully the redundancy package softens the blow. What's the situation with other Boeing run 737 max engineering operations? Similar lay offs? Surprised given the alleged return to service as you say.

Ray_Y

31st Jul 2020, 10:43

Because it won't Return To Service in Europe anymore???

Ditching Switch

31st Jul 2020, 11:21

Derisory I am lead to believe in comparison to the industry standard and a mere shadow of what the DAA staff have been offered in their concurrent redundancy procedure.

In relation to your second question, they operate two teams of engineers operating in Dublin and Gatwick respectively under the auspices of an Irish part 145. Only the Irish engineers are being made redundant however.

It seems some engineers are more equal than others.

A terrible time for the industry.

tdracer

31st Jul 2020, 18:33

Ditching
Yesterday Boeing announced a $2.4 Billion loss in the last quarter - adding to the billions they'd already lost last year. Many thousand Boeing employees have already been laid off in the Puget Sound area, with thousands more to come (not to mention the many thousands of employees at the Boeing suppliers that have been let go in the last 12 months). Right now, regardless of the mistakes that were made during the MAX development, Boeing is trying to do what it has to do to simply survive until air traffic recovers.
Yes, it sucks for the people in Dublin, but I doubt the thousands who have lost their job in the Puget Sound will have much sympathy.

kiwi grey

1st Aug 2020, 04:23

Ditching
Yesterday Boeing announced a $2.4 Billion loss in the last quarter - adding to the billions they'd already lost last year.

According to comment on Leeham News (https://leehamnews.com/2020/07/29/boeings-second-quarter-of-2020-cutting-production-as-revenue-halves-due-to-max-grounding-and-covid-19/), it's actually much worse than that.
The chances of either the B787 or the B737MAX programmes reaching their 'accounting block' production targets in the foreseeable future - or indeed ever - are becoming more and more remote each Quarter. However, continued use of Program Accounting allows Boeing to defer recognising and crystallising billions and billions of dollars in losses until the indefinite future, or until the company wants to put Boeing Commercial Aircraft into Chapter 11. My own view is that's at least a 50/50 proposition.

Dave Therhino

3rd Aug 2020, 20:41

737 Max flight control system NPRM has been posted on line by FAA:

https://www.faa.gov/news/updates/?newsId=93206

derjodel

4th Aug 2020, 06:45

To ensure that an erroneous signal from a failed single AOA sensor does not prevent continued safe flight and landing, and specifically that it does not generate erroneous MCAS activation, the FAA proposes to require installation of updated FCC software with revised flight control laws 10 associated with MCAS. These revised flight control laws would use inputs from both AOA sensors to activate MCAS. This is in contrast to the original MCAS design, which relied on data from only one sensor at a time, and allowed repeated MCAS activation as a result of input from a single AOA sensor.
The updated FCC software would also compare the inputs from the two sensors to detect a failed AOA sensor. If the difference between the AOA sensor inputs is above a calculated threshold, 11 the FCC would disable the speed trim system (STS), including its MCAS function, for the remainder of that flight, and provide a corresponding indication of such deactivation on the flight deck.
To ensure that MCAS will not command repeated movements of the horizontal stabilizer, the revised flight control laws would permit only one activation of MCAS per sensed high AOA event. A subsequent activation of MCAS would be possible only after the airplane returns to a low AOA state, below the threshold that would cause MCAS activation.
The updated FCC software would also limit12 the magnitude of any MCAS command to move the horizontal stabilizer, such that the final horizontal stabilizer position (after the MCAS command) would preserve the flightcrew’s ability to control the airplane pitch by using only the control column. The original design allowed MCAS commands to be made without consideration of the horizontal stabilizer position – before or after the MCAS command.
An undesired MCAS activation could prompt the flightcrew to perform a nonnormal procedure. To ensure that after any foreseeable failure of the stabilizer system, safe flight is not dependent on the timeliness of the flightcrew performing a non-normal procedure, the FAA proposes multiple changes.
First, as previously discussed, the flight control laws would be changed to instead use inputs from two AOA sensors for MCAS activation, so that there would not be an undesired MCAS activation due to a single AOA sensor failure that could lead a flightcrew to perform a non-normal procedure.
Second, in the event that MCAS is activated as intended (i.e., during a high AOA event), the updated flight control laws software would limit the number of MCAS activations to one per high AOA event, and limit the magnitude of any single activation so that the flightcrew could maintain pitch control without needing to perform a nonnormal procedure.
The FAA also proposes requiring an additional software update that would alert the flightcrew to a disagreement between the two AOA sensors. This disagreement indicates certain AOA sensor failures or a significant calibration issue. The updated MDS software would implement an AOA DISAGREE alert on all 737 MAX airplanes. Some 737 MAX airplanes were delivered without this alert feature, by error. While the lack of an AOA DISAGREE alert is not an unsafe condition itself, the FAA is proposing to mandate this software update to restore compliance with 14 CFR 25.1301 and because the flightcrew procedures mandated by this AD now rely on this alert to guide flightcrew action. As a result of the changes proposed in this AD, differences between the two AOA sensors greater than a certain threshold13 would cause an AOA DISAGREE alert on the primary flight displays (PFDs).
...
...
As part of the FAA’s review of these design changes, the agency reviewed the entirety of the 737 MAX horizontal stabilizer control system. This review revealed that the physical separation of the horizontal stabilizer trim arm wiring and the horizontal stabilizer trim control wiring does not meet the criteria specified in 14 CFR 25.1707. This design standard was promulgated in 2007 and therefore is part of the certification basis of the 737 MAX but not of previous Boeing Model 737 airplanes. Certain wiring installations must have enough physical separation so that a wiring failure cannot create a hazard. Since design changes must comply with FAA regulations, the FAA proposes to require changes to the wiring installation to meet the required physical separation between the horizontal stabilizer trim arm wiring and the horizontal stabilizer trim control wiring. The FAA proposes this action to bring the airplanes into regulatory compliance.

My question: can MAX be certified with:
a) a single MCAS input per AOA event
b) MCAS limited so that it would preserve the flightcrew’s ability to control the airplane pitch by using only the control column.

In essence, does MAX with these limitations still meet the certification criteria which required MCAS in the first place??

Snyggapa

4th Aug 2020, 07:08

_Benjamin_

4th Aug 2020, 07:51

The FAA seem to suggest it is fine... I think there will be a large number of questions relating to the specifics of the flight handling tests conducted as part of this.

Max Angle

4th Aug 2020, 09:32

Indeed, it seems that the FAA are proposing that it is fine to fly in effect with MCAS disabled (AOA disagree) or crippled (only one activation) - in which case why it there in the first place?Many failures of safety and envelope protection systems result in them being locked out for the rest of the flight following a sensor or computer malfunction, you normally can't dispatch without them but if they fail in flight you continue with appropriate mitigations.

Ray_Y

4th Aug 2020, 10:31

On one hand: This is about basic cert criteria, handling/stability during approach to stall. In former times this had to be ensured by fundamental design no matter what. Now Boeing introduced a gadget to mitigate the issue. If you approached to stall 100 times a flight it would counter 100 times. Now it wouldn't: once an AoA disagree momentarily(!) exceeds a set value, MCAS will be disabled. That's when the plane enters an inherent state of being aerodynamic instable. This can justify "Land nearest suitable".

On the other hand: Compare to stick pusher gadget to mitigate actual stall, which is also used to certify types. What happens if this fails? Is there detection at all? Land nearest if detected?

Ray_Y

4th Aug 2020, 11:05

To ensure that an erroneous signal from a failed single AOA sensor does not prevent continued safe flight and landing, ...

Your quick summary was very helpful. I tried to squeeze it down, then adding more from the FAA proposal.

Like this:

AOA DISAGREE alert on PFD installed by default (activates when more than 10 degrees difference for more than 10 seconds)

Inputs of both AoA sensors processed as source for activating MCAS

AoA disagree exceeding a calculated threshold will inop STS/MCAS for the remainder of the flight
(treshold as function of magnitude of disagreement between AoA sensors and rate of change of the values)
This will activate an indication to crew (STS/MCAS off)

Only one MCAS activation per high AoA event

The magnitude of MCAS stab command will be limited so that the plane thereafter can be controlled by elevator only to climp/level/descend.
The magnitude varies according to parameters such as the airplane’s altitude and airspeed

Not only MCAS related checklist changes

Wiring Changes to comply with current regulation

Maintenance:

AoA prope system test once befor RTS
MEL affected, new MMEL

That completes my overview.

Details I digged out:

WRT checklist changes:Airspeed Unreliable
Runaway Stabilizer
Stabilizer Trim Inoperative
Speed Trim Fail
Stabilizer Out of Trim
AOA Disagree
ALT Disagree
IAS Disagree
I also found the answer to my question "land next suitable" in a proposed new NNC:
Speed Trim Fail (Required by AD 2020-**-**)
The Speed Trim function and MCAS function are inoperative.
Continue normal operation.
Note: The Speed Trim System will not provide stabilizer trim inputs when
deviating from a trimmed airspeed.

...with the background(...)To assist the flightcrew in properly responding to such
an occurrence, a non-normal checklist, called the Speed Trim Fail checklist, would be
added to the AFM. This checklist would be used when the STS and MCAS functions are
inoperative, and inform the flightcrew to continue normal operation. (...)

Protection from aerodynamic instability lost? Continue normal! Even in the notes no addressing of approach to stall issues. Wow. But the document states: checklist proposals may be altered as a result of flight evaluation.

Regarding MEL and Flight Control System, this is suggested:
(1) Dispatch is not permitted with both autopilot systems inoperative.
(2) The autopilot disengage aural warning system must be operative for dispatch.
(3) The STAB OUT OF TRIM light must be operative for dispatch.
(4) The speed trim function must be operative for dispatch. NOTE: This requires both FCCs to be operative for dispatch.
(5) The SPEED TRIM FAIL light must be operative for dispatch.
(6) Dispatch is not permitted with both A/P ENGAGE Command (CMD) Switches (A and B) inoperative.
(7) Dispatch is not permitted with both A/P ENGAGE Command (CMD) switch lights inoperative.
(8) Dispatch is not permitted with both autopilot (A/P) disengage lights inoperative. Dispatch may be made with one A/P disengage light inoperative provided the autopilot disengage aural warning system operates normally.
(9) Dispatch is not permitted with both Control Wheel Autopilot Disengage Switches inoperative. Dispatch may be made with one control wheel autopilot disengage switch inoperative provided the following conditions are met. a) Mode Control Panel autopilot DISENGAGE bar operates normally, b) Autopilot is not used below 1,500 feet AGL, and c) Approach minimums do not require use of autopilot.
(10) Both control wheel trim switch systems must be operative for dispatch.

Mad (Flt) Scientist

4th Aug 2020, 12:25

Many failures of safety and envelope protection systems result in them being locked out for the rest of the flight following a sensor or computer malfunction, you normally can't dispatch without them but if they fail in flight you continue with appropriate mitigations.

Concur, it comes down to the probability of you encountering the conditions the system is protecting against during the balance of the flight.

And note that if the flight indeed could not be completed safely under normal circumstances, you would have to design some kind of backup or alternative - even a "land immediately" type instruction doesn't alter the fact that it will take some period of time to get back on the ground, so you have at least to be able to achieve that minimum "continued safe flight and landing" in any case.

safetypee

4th Aug 2020, 13:28

derjodel, #187.
Q a). Presumably both Boeing and the FAA believe that a single MCAS cycle is sufficient to meet certification requirements for normal operation.
Item 6 page 22 describes the revised logic for further MCAS activation, this assumes appropriate pilot response to the change in stick force - adjusting AoA and re-trimming, as for normal manual flight, before further MCAS input.
However, the assumption of normality might not be so sound during manoeuvring flight, when MCAS AoA trim demand may be higher due to less trimming.
The key aspect appears to depend on comparisons with previous variants; thus in normal operation if a single activation is sufficient to match other 737 handling characteristics ( including range of possible cg ) then there is certification 'equivalence'. Also note that we don't know the extent of, or changes made to the MCAS AoA trigger point, which is described as involving time / magnitude, and previously sensed Mach.

Q b). From the above, a single, normal MCAS trim input would probably not be noticed by pilot, it adjusts the feel of the aircraft in the background.
With failure, MCAS trim input could occur in a situation where stab trim is very powerful and thus a hazard. The chosen point of trim-cutout would have to be a sufficient for the crew to retain control, within certification limits for 'abnormal' stick forces, and then manual trim, again without excessive force.
Equivalence' in abnormal operation; the resultant stability issue is certificated according to in-flight-failures as discussed in previous posts.

These points raise other concerns.

The trim monitor senses abnormal operation by comparing output from the FCCs. Is the detection at the 'box' output, or at the trim servo. If within the FCC, then an electrical short could still result in a trim runaway, which as in previous variants required pilot identification and timely action (challenged as an inappropriate assumption by the MCAS accidents). A hazard is that crews could be less concerned with trim runaway because of the new MCAS protections, and with similar limiting human performance may not react quickly enough. Again equivalence could be the judge; as debated widely in Pprune - trim failure, roller coaster, etc. The wiring changes may also be involved with this.

It is not clear how MCAS would function when disconnecting the AP where MCAS activation was required. Previous descriptions suggested that MCAS did not require stability enhancing trim input ( doesn't depend on stick force ), thus with AP disconnect the pilot may detect a 'jump in control response / stick force before MCAS trim is computed ( time / magnitude ).

Of greater concern is how the 737 autopilot manages AP control overpower. If it is similar to the 767 (re Atlas accident), then manual overpowering input could create a follow-up trim response without opposing MCAS input; i.e. aircraft trims into the turn with increased AoA, worst case trimming into a stall.

WingNut60

4th Aug 2020, 13:30

One might ask also why it took so long to come up with this answer?

derjodel

4th Aug 2020, 17:09

derjodel, #187.
Q a). Presumably both Boeing and the FAA believe that a single MCAS cycle is sufficient to meet certification requirements for normal operation.

A single MCAS cycle with limited input. But the thing is, we know that Boeing test pilots requested to increase MCAS input, right? If memory serves me well, the original input was insufficient.

As for the single cycle... MCAS is triggered at specific AOA, presumably to comply with elevator feel, right? I mean, that was the original story. Now Boeing themselves are saying it's in order to "to enhance the pitch stability of the airplane", which does kinda smell like anti-stall system.

Anyway, let's assume AOA is exceeded (due to nacelle lift), MCAS is triggered, but AOA remains above threshold and even increases due to nacelle lift.. is this now the same event or new event? If AOA newer fell below threshold, it's the same event, right? But then, what's the point? Why have MCAS at all? Unless a single cycle is the magic potion. But if it is, why wasn't it designed as such in the first place. If a single cycle is enough, then surely Boeing is guilty for the two crashes?

Ray_Y

4th Aug 2020, 17:29

derjodel good point. At the end the first stall incident in a MAX will tell - not. There's the stick pusher as final resort (when a stall could be detected)

Ray_Y

4th Aug 2020, 17:36

So will you file comments to the FAA? Which ones? FAA published the NPRM early before it's formally available on regulations.gov: The FAA is posting the NPRM on its website today to enable the public to begin review early.

And it's basically this invitation:

Comments Invited
The FAA invites you to participate in this rulemaking by submitting written comments, data, or views about this proposal. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should submit only one copy of the comments. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2020-0686; Product Identifier 2019-NM-035-AD” at the beginning of your comments.

Big Pistons Forever

4th Aug 2020, 21:29

Is EASA still insisting that the Max demonstrates acceptable high AOA handling characteristics without MCAS? Also what about the inability to move the trim wheel at higher airspeeds. Is the hillbilly roller coaster procedure going to be the only approved method?

I find it amazing that Boeing and the FAA still think it is OK to have an airplane where inside normal operation speed if the main stab trim motor fails or is turned off, the only other way to move the stab is with the manual wheels which can’t be moved by a normal human being unless significant into the out of trim control wheel deflection is applied. This is craziness.

GlobalNav

4th Aug 2020, 23:00

Ethiopian is fully responsible for their crash. .

Ehiopian’s mistake was, unfortunately, buying the airplane. Be assured that EASA, Transport Canada and FAA, including their test pilots and flight control specialists, after significant investigation, consider Boeing and the faulty Max design to be responsible.

safetypee

5th Aug 2020, 12:33

derjodel, # 196

The weakness of your point is the assumption that the nacelles change AoA; they do not. The change is in the relationship between stick force and speed (AoA) - the longitudinal stability.

At constant speed, AoA is increased by moving the stick and pitching the aircraft. Thus with the first high AoA 'event' - trim down, the stick force will increase, providing a force-feel feedback to the pilot. This change encourages the pilot to move the stick forward to reduce stick force and thus reduce AoA ( normal flying technique for speed / AoA change ).
There is a risk that the pilot will accept or even increase stick force - manoeuvring the aircraft to a higher AoA, this is like any other aircraft. MCAS was intended to achieve a similar stick force-to-speed (AoA) relationship the NG; i.e. the Max will feel the same as the NG and still meet the certification requirements even with the larger engines.

The MAX can be stalled, as the NG. One MCAS input might be judged as sufficient to cue pilot awareness of a deceleration / manoeuvre, but never intended to prevent a stall.
The aircraft stall characteristics would be the same with / without MCAS, although without MCAS the potentially lower stick force during recovery could encourage re stalling.

Big Pistons,

The FCCs will now be cross monitored to limit trim failures within a range where manual control is acceptable (13.3).
Non FCC related failures, e.g. stab trim runaway, are not protected - as in the NG, but wiring changes in the MAX reduce the likelihood of failure, the corrective action for which still relies on timely pilot intervention (13.6).

Ray_Y

5th Aug 2020, 13:12

Thus with the first high AoA 'event' - trim down, the stick force will increase, providing a force-feel feedback to the pilot. .
I've read such before, don't remember it was you. If it was for helping the crew with adapted "feel", why didn't Boeing just change the parameters of Elevator Feel Computer (Elev Feel Shift Module) as it was already available on 737NG?

The EFS module increases hydraulic system A pressure to the elevator feel and
centering unit during a stall. This increases forward control column force to
approximately two times normal feel pressure. (...)

I talked to other PRO's, none of them believed that was the goal of MCAS.

safetypee

5th Aug 2020, 14:33

'… why didn't Boeing just change the parameters of Elevator Feel Computer (Elev Feel Shift Module) as it was already available on 737NG?'
I don't know, nor have access to Boeing's thoughts at the time.

There may be clues in the references to the integrated MCAS within the exsisting STS (NG). In terms of speed, adapting the STS would be logical, and when the 'Manoeuvring' requirement was identified - need for AoA and Mach, then the existing 'digital' computation from DADC (air data and AoA input) and FCS / FCC with stab trim output, was more practical for test and development than modifying the 'heavy engineering' at the back of the aircraft.

Ray_Y

5th Aug 2020, 15:33

There may be clues in the references to the integrated MCAS within the exiting STS (NG).
you asked for it, so let's uncover the next feature:

Stall identification and control is enhanced by the yaw damper, the Elevator Feel
Shift (EFS) module and the speed trim system. These three systems work
together to help the pilot identify and prevent further movement into a stall
condition.

(...)

As airspeed decreases towards stall speed, the speed trim system trims the
stabilizer nose down and enables trim above stickshaker AOA. With this trim
schedule the pilot must pull more aft column to stall the aircraft. With the
column aft, the amount of column force increases with the onset of EFS.

Oh, look at this (but not special to the Stall Identification feature):

Conditions for speed trim operation are:
...
5 seconds following release of TRIM switches.
...
Autopilot not engaged.

We're talking of the NG! MCAS 0.5? But at least they told the pilots back then.

WillowRun 6-3

5th Aug 2020, 22:00

SLF attorney reaching into aviation-related law - plus a custom disclaimer of anything like full understanding of the flight control dynamics being discussed.

But as to what Boeing engineering and management cadres might have known, it's true that a federal criminal inquiry still is open and underway, isn't it? And in pre-trial discovery in the direct liability cases as well as a number of related cases, there is a very large amount of factual information yet to be uncovered. The pertinent Committee of the House of Representatives released a not insignificant batch of documents some months ago, but it is hardly the complete picture. So whether Boeing just never thought about a particular flight control situation, or instead and more troubling, thought about it but tried to hide the ball, still is an unknown.

As for the lack of training initiatives by Ethiopia after the Lion Air accident . . . while the factual predicate of that point might be correct, did any of the other 737 MAX customers initiate such training after Lion Air? Again I'm not asserting support for either content of the prelim report or for any specific iteration of how those pilots responded or did not respond - but there's something quite starkly "hindsight, purely" about noting a lack of new training initiated, let alone a grounding by the operater

parkfell

6th Aug 2020, 06:37

Would I be right is saying that the defective MCAS system had activated erroneously on more than one occasion in flight in the US prior to the fatal accidents?

The crews dealt successfully with the situation, and reporting action to the FAA took place?

Bend alot

6th Aug 2020, 06:53

No you would be incorrect.

Only 3 MCAS events are known to have happened, none in the US.

Only one MCAS event was "dealt with successfully" and that was a Lion Air crew.

sky9

6th Aug 2020, 15:29

Someone in the FAA needs to dig out "Handling the Big Jets" by DP Davis, test pilot with the British Air Registration Board in the 1950's and read page 137 and the diagrams on 138 and 9.

The BAC 1-11 ended up with 4 AOA indicators, 2 on each side that operated a stick shaker and stick push to keep it out of a deep stall. Why is the Max restricted to 2 AOA's?

Lake1952

6th Aug 2020, 15:41

Bend alot

It is a widely accepted fact that the MCAS software has NEVER activated in in hundreds of thousand of hours in revenue service EXCEPT IN ERROR. Perhaps that is why at one point the Canadian authorities (perhaps tongue in cheek?) suggested doing away with the software altogether and simply training for the difference in handling, if significant, from previous editions of the B737. .

DaveReidUK

6th Aug 2020, 17:36

sky9

That's the legacy of a decision that was being made around the same time as the 1-11 was entering service.

BDAttitude

6th Aug 2020, 19:32

...it is a widely accepted fact that the MCAS software has NEVER activated in in hundreds of thousand of hours in revenue service EXCEPT...
By whom? Says who? By what evidence?
It doesn't chime, doesn't deploy the RAT, doesn't electrocute the captain. We shall never know ... unless Boeing hid a MCAS activation counter somewhere. Which they have not disclosed.
I don't think it activated often though. But to claim it didnt' activate EXECPT those three incidents is a bit far fetched.

DaveReidUK

6th Aug 2020, 22:26

There are certainly no documented instances of MCAS deployment in regular service operations.

But while it's true that absence of evidence isn't evidence of absence, given that the stated aim of MCAS is/was "to provide consistent handling qualities in unusual flight conditions", I think it's reasonable to expect that we'd have heard by now of any instance where a MAX on a revenue service had entered the flight regime where MCAS would have deployed by design.

turbidus

6th Aug 2020, 23:36

No you would be incorrect.

Only 3 MCAS events are known to have happened, none in the US.

that may not technically correct;

Pilots were not aware of MCAS...therefore, they did not have any idea of the parameters associated with MCAS, or its initiation, or the aircraft response when MCAS initiated...
so when a report was filed, it was simply a FMS issue. They did not know what to call it, the issue was lost in the filing procedure.

In further review, the circumstances the pilots described were MCAS...

There were instances, especially AFTER MCAS was identified, where pilots encountered issues, that reports were being filed...., but again, as an FMS issue as you all are aware, there is no box on the form stating MCAS.

Australopithecus

7th Aug 2020, 02:37

Well how many of those reports were for stabiliser trim runaway? Because a incorrectly activated MCAS could only be handled via the stab trim runaway checklist. An MCAS working as designed could only do so in a dangerously low speed event which itself is reportable.

Bend alot

7th Aug 2020, 07:23

turbidus

None of the reports to the FAA could have been a MCAS event - many had the Auto Pilot on at the time (so not possible), others not a character of MCAS.

All possibles were linked in a early MAX thread.

SLF3

7th Aug 2020, 08:01

This whole thing feels like a fudge.

If you can safely disable MCAS after one actuation, why do you need it in the first place?

If it does not meet the certification standard without MCAS, why is it acceptable to turn it off when the certification standard essentially is looking for a benign and predictable control response across the flight envelope?

Have EASA updated their position on the Max?

There was a suggestion they were going to insist on a retrofit to upgrade to the equivalent of three sensors for AOA from two. Which would mean you would not need to turn it off if a sensor failed, since you could vote 2 oo 3 sensors.

Bend alot

7th Aug 2020, 08:46

This whole thing feels like a fudge.

If you can safely disable MCAS after one actuation, why do you need it in the first place?

More the point why did it's authority need to be increased during initial testing?

I guess a valid question to the FAA as a feedback question.

Peter H

7th Aug 2020, 10:14

Can you clarify something for a SLF with a fallible memory.

I can remember they had to enable MCAS -- with increased authority -- in a different region of the flight envelope. I can't remember them increasing MCAS authority in the original area of the flight envelope.

krismiler

7th Aug 2020, 10:33

The BAC 1-11 ended up with 4 AOA indicators, 2 on each side that operated a stick shaker and stick push to keep it out of a deep stall.

Back in those days, aircraft lacked modern flight envelope protection and on a rear engined "T" tail aircraft such as the BAC 1-11, Trident, B727 etc, if you managed to mishandle it into a deep stall you would more than likely crash. The wing shielded the engines and tailplane from the airflow so the engines stopped and the rudder and elevators became ineffective. The ailerons wouldn't be able to do much at low speed on a stalled wing and you simply sat there in a high nose up attitude, low forward speed and high rate of descent until the aircraft impacted with the ground.

Aircraft with underwing engines weren't nearly as likely to deep stall and the tailplane was less shielded by the wing at high pitch attitudes so control was easier to regain. Obviously any stall was something to be avoided no matter what type the aircraft was.

The regulations of the day took account of the consequences and likely hood of the event occurring and provided for extra protection.

safetypee

7th Aug 2020, 12:59

SLF3, '… safely disable MCAS after one actuation, why do you need it in the first place?'
In part see https://www.pprune.org/showpost.php?p=10853024&postcount=194 and https://www.pprune.org/showpost.php?p=10853787&postcount=201

'… why is it acceptable to turn it off when the certification standard '
There are many safety and certification arguments in regulatory documents; essentially the difference is between normal and abnormal (emergency) operations. MCAS can be compared with requiring two engines, but if one fails then the aircraft must be able to fly and land at a suitable airport.

EASA position; wait and see, particularly if they comment publicly or not on the NPRM.

Reading between the lines; the modifications explained in the NPRM suggest that a compromise (equivalent level of safety) has already been agreed for detecting AoA failures and MCAS inhibition, particularly reducing the pilot's contribution. More info required for ADIRU AoA 'valid' cross monitor and in some circumstances the choice of which AoA to use (valid erroneous data ??).

Similarly, a compromise for manual trim range, but not necessarily all failures for '737' stab trim runaway - but arguments have been made for previous variants and accepted.

One unknown is the view about multiple alerts stemming from a single AoA failure. The NPRM discusses the provision of 'AoA Disagree' to aid diagnosis, but until the new checklist is published the diagnosis is unknown. Also the 'disagree' alert appears to be dual purpose ((MCAS diagnostic at 5 deg, and AoA EFIS indicator 10 deg), which could be misleading.

There is no discussion about continuous stick shake - stall warning, whether to inhibit or not. The weakness is that a single AoA failure can simultaneously disable stall warning and a stability enhancement (MCAS) for increasing stick force high AoA; in this the three AoA argument is valid, but wait for the detail on alternative mechanisms for computing AoA validity (ADIRU). Also note MCAS only required flaps up, and greater focus on speed (which could have errors), but there is a standby system for that - workload argument.

infrequentflyer789

7th Aug 2020, 23:58

More the point why did it's authority need to be increased during initial testing?

I guess a valid question to the FAA as a feedback question.

If my memory serves, MCAS was designed to address an issue in high-speed high-g turns at high AOA, based on wind tunnel tests and simulations. When they did the flight tests with the real aircraft they found similar issue at low-speed and high AOA (and with no g-dependency), which had not been found in wind tunnel or simulation. So they extended MCAS to work in larger area of flight envelope and removed the g threshold so it triggered solely on AOA. Because speed was lower in the new target area, the maximum authority was increased to have the same effect.

Note that:
1. I am not sure if there was also an altitude dependency (which was then removed), some reports mention altitude but they may be mistaken or it may be that the original target area of flight envelope (or target manoeuvre) would only occur at high altitude.
2. I am not definitely sure if authority was increased across the board or only in the new lower-speed areas - I suspect the latter (i.e. the original authority for the original problem was not changed)

Bend alot

8th Aug 2020, 01:11

Yes that is similar to what I recall.

Given the FDR MCAS activation of the crashed aircraft it seems the authority (or motor speed increase) did not change as the aircraft speed increased.

One would assume that the FAA will be having a good look at the low speed high AoA flight envelope area for this certification.

The new MCAS has been given a bit more thought than the original band-aid version, I am sure.

_Benjamin_

8th Aug 2020, 08:46

One would assume that the FAA will be having a good look at the low speed high AoA flight envelope area for this certification.

In the FAA paperwork submitted, there's a somewhat wishy-washy response to this part of the JATR recommendation. I'm sure this will be commented on in the spirit of their commitment to transparency.

Bend alot

8th Aug 2020, 09:59

It would be some what embarrassing for the FAA should they not.

JATR regulators may be a little flexible for re-certification, one country my go above and beyond to do evaluation tests - Tick Tock.

That could then expose the other regulators cozy relationships or interpretations of regulations for a back scratch later.

High stakes on this - and we see very little to no transparency to date on "the fix" from Boeing or the FAA.

safetypee

8th Aug 2020, 10:51

Infrequent 789,
You appear to misunderstand the effects of 'g' and AoA; or is it memory ;)

The need to change the magnitude of MCAS trim would more likely be an effect of Mach - difficult to replicate in a wind tunnel.
Although described as a trim increase, this could have been a larger value, or an earlier trigger point with an extended duration or change of trim speed.

The aerodynamic intrigue with MCAS is why AoA was required at all. Existing technologies could manage low speed situations ( speed trim ), and Mach trim at higher speed. The Max modifications appear to be similar to the military 'Leading Edge Extension' which involves AoA and vortex management, but implemented with full FBY technology.

The initial, single MCAS trim input is variable; modified system: -

"The MCAS flight control law becomes active when the airplane exceeds an AOA threshold that varies depending on Mach (airspeed). If activated by a high AOA, MCAS moves the horizontal stabilizer at a rate of 0.27 degrees per second, which is the same trim rate as Speed Trim with flaps down. The magnitude of the MCAS command is a function of Mach. At higher airspeeds, flight control surfaces are more effective than at lower airspeeds. Therefore, a smaller MCAS command at higher airspeeds has the same effect as a larger MCAS command at lower speeds. At low Mach, when the stabilizer has lower effectiveness, the MCAS command can be up to the maximum of 2.5 degrees of incremental stabilizer movement. The MCAS flight control law is reset after the AOA falls sufficiently below the AOA threshold." Preliminary Summary Page 23

infrequentflyer789

8th Aug 2020, 14:19

Infrequent 789,
You appear to misunderstand the effects of 'g' and AoA; or is it memory ;)

Oh it may well be memory, my aero engineering was a long time ago, my career ended up going in a different direction. I am pretty sure however that there was a (minimum) g threshold for MCAS to activate in the first version, which was later removed to allow MCAS to address the "low-speed high-AOA" problem area discovered in flight tests.

The need to change the magnitude of MCAS trim would more likely be an effect of Mach - difficult to replicate in a wind tunnel.
Although described as a trim increase, this could have been a larger value, or an earlier trigger point with an extended duration or change of trim speed.

Magnitude of trim needed is definitely going to be Mach-dependent, but again there was a change to this (probably to data in a lookup table) as they needed MCAS at lower speeds. My understanding is that it was a trim authority increase by increasing the trim run time, and trim speed didn't change (there are only two speeds for auto and I'm pretty sure it was already using the faster one - that is a hardware change and I don't think they made an MCAS hardware change post-flight-test).

The aerodynamic intrigue with MCAS is why AoA was required at all. Existing technologies could manage low speed situations ( speed trim ), and Mach trim at higher speed. The Max modifications appear to be similar to the military 'Leading Edge Extension' which involves AoA and vortex management, but implemented with full FBY technology.

I think the lift from the engine nacelles is the problem, with pitching moment even worse because the engines are further forward. That lift is probably non-linear with AOA. Not sure why the effect wasn't found in wind tunnel or computer modelling given that they found it at high mach but not low - I doubt my aerodynamics was ever good enough to work that out. I'm also not sure why it isn't needed with flaps when it appears to be needed at same speed without flaps (since it seems it can kick in the minute flaps go up) - again, that may be my aerodynamics lacking.

hec7or

8th Aug 2020, 14:42

I think the lift from the engine nacelles is the problem, with pitching moment even worse because the engines are further forward.

I would also think that stab downforce needed to be increased to counteract the moment arm produced by the fwd position of the engines, but since the flight deck stab trim indication is similar to the NG this must have been done by a hidden re calibration of the stab incidence. This would contribute to a change in pitch characteristics due to the required increased downforce.

wrench1

8th Aug 2020, 15:46

That lift is probably non-linear with AOA.
FYI: it's my understanding, the only non-linear issue the MCAS was designed to correct applied to tactile stick force when the aircraft was at extreme angles of attack at the upper edges of the control envelope. With the engines mounted more forward and up, the aircraft tended to go into rocket mode faster and unload the control forces. As the MCAS was not needed in other flight attitudes it was automatically disabled as with flaps down, etc. There were specific Part 25 certification requirements that required positive linear stick force as the control stick was pulled back up to and throughout stall angles. The MCAS provided increased stick force by moving the stabilizer nose down. There are much better explanations in other threads.

And just as a side note, while it might be just semantics, the proposed AD will only correct known safety related problems and will not "re-certify" the MAX. All MAXs today retain their original certification and remain certified per Part 25. Even if there are new Part 25 certification changes via a separate NPRM, they will not apply backwards to any existing aircraft and will only apply to new model aircraft certifications regardless of manufacturer.

Ray_Y

9th Aug 2020, 17:28

The NPRM is online now and open for commenting
https://www.regulations.gov/document?D=FAA-2020-0686-0001

(And I filed a comment)

tdracer

9th Aug 2020, 18:48

Not sure why the effect wasn't found in wind tunnel or computer modelling given that they found it at high mach but not low - I doubt my aerodynamics was ever good enough to work that out. I'm also not sure why it isn't needed with flaps when it appears to be needed at same speed without flaps (since it seems it can kick in the minute flaps go up) - again, that may be my aerodynamics lacking.

This could be an artifact of the wind tunnels they use. I haven't been involved in wind tunnel testing in decades - so this may be obsolete information - but at least when I was involved, Boeing didn't really have a good low speed wind tunnel. The primary wind tunnel was the "BTWT" - Boeing Transonic Wind Tunnel - which was really good from about Mach 0.6 to nearly 1.0. The have a real low speed wind tunnel in Philly - with moving ground plane capabilities (at least when I was involved it was used for reverser testing) - but it's only good up to maybe 180 knots. That left a big gap in capability between ~Mach 0.3 and 0.6. When we were doing the 767 way back when, they rented the University of Washington tunnel to cover that gap - but even then there were complaints that UW equipment wasn't completely up to snuff...
As noted, it's been a long time since I was involved so this could be completely obsolete - but if not it might explain why they didn't see the low speed effects on the MAX until they got to flight test.

Peter H

9th Aug 2020, 21:18

... I'm also not sure why it isn't needed with flaps when it appears to be needed at same speed without flaps (since it seems it can kick in the minute flaps go up) - again, that may be my aerodynamics lacking

I remember reading that using the flaps extended the slats which changed the airflow at the front of the wing ...

Gotit:
In https://leehamnews.com/2019/09/27/bj...-wire-part-10/ (https://leehamnews.com/2019/09/27/bjorns-corner-fly-by-steel-or-electrical-wire-part-10/)
MCAS is not active on the 737 MAX when flaps are deployed. This is because when flaps are out the slats are out as well and these
diminish the disturbance to the pitch moment curve from the larger and further forward-higher slung engine nacelles.

gums

11th Aug 2020, 04:21

The Max modifications appear to be similar to the military 'Leading Edge Extension' which involves AoA and vortex management, but implemented with full FBY technology.

Excuse me, but I do not think the MCAS does anything close to what the LEX configurations did for the fighters since the 70's. Nor was it intended to do so. Good item for the Tech Log.

Secondly, the fighter LEX configurations provide good directional stability and keep the main wing providing useable lift at higher AoA than previous configurations WITHOUT FBW FLIGHT CONTROL SYSTEMS. Gasp! I am constantly amused by how many folks still have trouble uderstanding what FBW does and the various implementations - e.g. full FBW with zero mechanical or hydraulic anything like the Viper and Raptor and Stubbie, or hybrid systems as the early Hornets had and likely even the latest Super Bugs. Dunno about the Tiffie or Russian planes.

From everything I read about MCAS, and its evolution, the primary independent variables were AoA and mach and flaps/gear position. Upon flight tests, several aspects of the kludge were changed. But the biggest sin was implementing such a system without informing the pilots, and not even the reliance upon a single sensor and the repeated activation a few seconds after using the trim switches on the yoke.

DirtyProp

11th Aug 2020, 05:29

Oh dear....

‘Don’t rock the boat with Boeing.’ In survey, FAA employees who monitor airplane makers report feeling pressured.
https://www.chicagotribune.com/business/ct-biz-faa-boeing-oversight-survey-20200810-ycgctlw6szfu5pukxnh5vrah2e-story.html?outputType=amp

BDAttitude

11th Aug 2020, 06:13

Ali is still doing fine @FAA. What would you expect.

568

11th Aug 2020, 06:49

TD,
Always appreciate your valid comments.
Many believe that the Boeing Company will provide world class R&D for new designs etc.
If the wind tunnel tests were made available/rented at the UW, then this indicates that R&D wasn't a part of current budget, hardly a "world class" Company?

etudiant

11th Aug 2020, 09:15

Think Boeing has always used outside tunnels as well as their own, tunnels are pretty widely shared between industry and academia, as well as internationally.
Their role has been taken in part as well by numerical simulation, so overall tunnel use is probably well down from even 20 years ago.

keesje

11th Aug 2020, 09:40

I would like to see all congress people, committees and industry executives that pressured the FAA to reform and streamline on aircraft certification projects in the 2010-2019 period to demonstrate accountability. .

Boeing took the lead on embedding the FAA:
https://thehill.com/policy/transportation/319723-boeing-urges-congress-to-streamline-aircraft-certification-process

and the rest of the industry was very supportive:
https://docs.google.com/viewerng/viewer?url=https://www.aia-aerospace.org/wp-content/uploads/2016/09/AIA_SMC_Letter_Sept2017_v3.pdf&hl=en

Looking back, everybody sees oversight was lost. Boeing was self certifying and changed product rules (aggressive grandfathering of design & requirements was back on the table) after being removed by the FAA earlier on. https://www.flightglobal.com/faa-rules-kill-grandfather-rights-in-usa-and-europe-/32615.article. But apparently they changed their minds after the 787 Dreamliner development. and certification.

My point is everybody was pushing & supporting delegation, kpi driven streamlining and keeping EASA at arms length. To improve competitiveness of the national airspace industry. Which proved driven by short term profit maximization (stock value, buy backs, dividends, executive bonuses) .

Google logged everything for us over the last 10 years. People changed their mind, but it is clear what happened.

Less Hair

11th Aug 2020, 10:06

Boeing used and uses Farnborough for low speed plus others. The point is to use wind tunnels over and over again to get to know their characteristics. Over time you can compare the results between your other programs. It doesn't matter if a company owns everything. Low speed is the most complex part and - like noise - one of the hardest to simulate in the computer. Big manufacturers test globally in wind tunnels.

safetypee

11th Aug 2020, 13:23

gums
' I do not think the MCAS does anything close to what the LEX configurations did for the fighters since the 70's. Nor was it intended to do so.'

'LEX' similarity was used to describe the problem; an anticipated outcome of the design, but which warranted a 'military style' solution.
In previous 737 variants the aerodynamic changes were managed with simple speed and Mach corrections (STS, Mach trim).
However, the Max engine / nacelles resulted in aerodynamic effects (similar to LEX) which required mitigation involving several parameters; - speed, Mach, and AoA, where the combination, and apparent non-linearity warranted high integrity computation, detailed system assessment, and validated assumptions.
Boeing chose to use single sensor, single path computation, and simplified certification; - hindsight defines history, and that which must be learnt.

The Tech Log plea is noted; however the subject is part of a complex system of aerodynamics, design, engineering, certification, communication, etc. If individual aspects are discussed in isolation, influencing interconnections could be overlooked.
In this area, dual monitored AoA as part of the modification to inhibit the effects of failures might be easy to understand and certificate. However, the additional computation which can apparently identify the better AoA input of a 'failed' dual input is harder to understand without more detailed description ("valid erroneous" data - 6.1.3). Such computation might not be not perfect, but good enough; all of this requires further technical explanation, test results, proof of concept, and certification acceptability.

Yes LEX chines interact with directional stab; some early Russian aircraft changed nose cones until they found one that did not depart - slice (SETP conference - SU 27 briefing, question re 'cobra' manoeuvre for airshows), nowadays FBW is much better.

Longtimer

21st Aug 2020, 16:00

Transport Canada test flight scheduled.

https://www.reuters.com/article/us-boeing-737max-canada-idUSKBN25G223

sablatnic

21st Aug 2020, 17:38

I wonder, wouldn't it have been faster and cheaper just to fit the thing with a blue ring radar?

WillowRun 6-3

28th Aug 2020, 12:52

https://www.easa.europa.eu/newsroom-and-events/news/easa-schedules-its-flight-tests-boeing-737-max

COLOGNE, August 27, 2020 - The European Union Aviation Safety Agency (EASA) has been working steadily, in close cooperation with the FAA and Boeing, to return the Boeing 737 MAX aircraft to service as soon as possible, but only once it is convinced it is safe.

While Boeing still has some final actions to close off, EASA judges the overall maturity of the re-design process is now sufficient to proceed to flight tests. These are a prerequisite for the European agency to approve the aircraft’s new design.

EASA has been working with the FAA and Boeing to schedule its flight tests, a process which has been hindered by COVID-19 travel restrictions between Europe and the United States.

The parties have now reached agreement that EASA’s flight tests will take place in Vancouver, Canada in the week commencing September 7, 2020.

Simulator tests will take place in the previous week (from Sept 1, 2020) in London Gatwick in the United Kingdom. The Joint Operations Evaluation Board (JOEB), will also take place in Gatwick, in the week beginning September 14, 2020.

[end quote]

Less Hair

28th Aug 2020, 13:23

What actions has Boeing to close off?

WillowRun 6-3

28th Aug 2020, 13:44

Don't know - saw the EASA notice only.

_Benjamin_

28th Aug 2020, 15:04

If I had to take a guess it would be relating to the outstanding AoA integrity issue that Patrick Ky referred to in his EASA presentation "the four conditions that must be met before return to service". Therefore assume that EASA is waiting on Boeing's plan to get a 3rd or equivalent AoA sensor input into the system architecture.

I imagine that hell would have had to have frozen over before Boeing will commit to it. Hope they prove me wrong.

megan

29th Aug 2020, 03:22

However, the Max engine / nacelles resulted in aerodynamic effects (similar to LEX) which required mitigation involving several parametersDon't lose sight of the fact that hanging the CFM on the -300 and subsequent required the installation of the STS to overcome the very same issue that MAX presented with its still larger nacelle. Boeing patent here

https://patents.google.com/patent/US4676460A/en

Pilot DAR

29th Aug 2020, 13:10

While Boeing still has some final actions to close off,

This important consideration deserves a little more attention than Boeing and the FAA are enabling. One of two situations exists before an aircraft is presented for design approval evaluation - either it conforms to a defined design (that for which approval is being sought), or it does not. If the aircraft has some "final actions to close off", is it appropriate for Boeing to present it for evaluation, and approval? Sure, there may be developmental test flying, we all agree what that is, but if the plane is being presented for certification flight testing, it should be 100% compliant with the design configuration for which approval is sought.

I believe that EASA and the other international authorities are aware that Boeing and the FAA may have the cart before the horse a little with the MAX recertification, and are asserting that correct process be followed. After all, it was an apparent breakdown of the certification process which got them here in the first place! The certification testing process usually requires that the applicant present a completed "Declaration of Conformity" report, to certify to the authority that what is being presented for test conforms entirely to the design for which approval is sought. I hope that Boeing has had the courtesy to the authorities to complete the process in the intended order of operations.

Big Pistons Forever

29th Aug 2020, 21:10

The “what” in certification standards is black and white, the “how” in terms of how the aircraft meets that certification standard has many shades of grey. Rumour I am hearing is that with the new MCAS lite, the airplane can’t meet the certification standard in all circumstances, all though it is close to compliance. The FAA has apparently approved it anyway on the basis that sometime in the future there will be a third synthetic AOA input added.

EASA has indicated that they have not decided if they will accept this work around. The future of the MAX and maybe the company is hanging on the EASA flight test program in September.....

GlobalNav

30th Aug 2020, 15:58

I don’t think it takes as long to add the necessary redundancy as it does for Boeing to conclude they must. The authorities should hold fast until the latter becomes reality. Forget about work-arounds and promises of changes to come. Compliance is compliance, and no partiality should be allowed, Taxpayer speaking!

Drc40

31st Aug 2020, 20:28

Pilot DAR

This times 1000%! Boeing is trying to get away with “we’ll address this later, take our word for it” crap. There should be no approval with a contingency for “final action”. Do it now, then get your approval. Simple. Why do they even chose this route after being through so much? Bloody nonsense.