Ethiopian airliner down in Africa

[gums]

Salute!

you are wrong, sky9
There are two vanes.

The problem is the MCAS switches from one to the other upon reset. Had Lion crew MCAS been using the good vane all they would have had would have been unreliable something or other warnings and no flight control interference. And no stick shaker for left seat guy.
I am more scared by what Aloha hints. AoA inputs and who knows what other things for the spoiler What other things on the MAX that we do not know, nor the pilots?

Gums sends.....

[poldek77]

Originally Posted by SLFinAZ

I'd love to know what your background and knowledge base is on this. To date my understanding is that MCAS is trim specific in function and adds incremental trim specific to certain criteria. Taken in a vacuum it's difficult to fathom how this by itself could lead to a loss of control by a qualified aviator. Under what possible circumstances would speed brakes be deployed except during landing??? Or are you confusing speed brakes with the leading edge flaps and slats on the 737?

Most probably not in this case but here it is:

Elevator Jam Landing Assist
This will give limited changes to the vertical flight path from the spoilers to assist the approach and landing if the normal elevator system jams. The control panel is located on the Aft Overhead Panel, even if it is switched on it will only be active when the flaps are 1 or greater. When in use, the spoilers rise to a preset position; they then extend or retract as the elevator column is pushed or pulled to increase or decrease the rate of descent.

(737 MAX - FBW Spoiler System)

[flyingchanges]

Originally Posted by Aloha_KSA

Have we ruled out the Max's FBW spoilers?! IMHO the precipitous and unrecoverable descent would be consistent with un-commanded spoiler deployment.

Nope, it barely descends with full boards...

[SquintyMagoo]

cervo77 asks "How should they know that pulling on the Yoke didn’t stop the trim?"

Shouldn't they hear or notice the trim wheel continuing to turn?

[Airbubba]

The NTSB is sending investigators to France to help with the recorders:

NTSB Sends Additional Investigators to Assist in Ethiopian Investigation

​WASHINGTON (March 14, 2019) —The U.S. National Transportation Safety Board is dispatching three investigators to France Thursday to assist with the downloading and analysis of flight recorders from the Boeing 737 MAX 8 that crashed Sunday near Addis Ababa, Ethiopia.

The NTSB investigators have expertise in recorders, flight crew operations and human factors. The French Bureau d'Enquętes et d'Analyses (BEA) will be downloading the flight data recorder and cockpit voice recorder in support of the Ethiopian investigation.

The investigation is being led by the Ethiopian Aircraft Accident Investigations Bureau in accordance with the standards defined in International Civil Aviation Organization Annex 13. The NTSB appointed an accredited representative to the investigation under the ICAO standards because the airplane was manufactured in the United States. All investigative data regarding the investigation will be released by Ethiopian authorities.

For more information on NTSB participation in foreign investigations go to: https://go.usa.gov/xEswV.

The NTSB investigators dispatched to France will work in coordination with investigators on the ground in Addis Ababa. Those investigators were sent immediately after the accident and have been integral to the efforts underway in Ethiopia. They are being assisted by technical advisers from the Federal Aviation Administration, Boeing and GE/Safran, the manufacturer of the engines.

The NTSB is an independent U.S. federal agency charged with investigating transportation accidents and issuing recommendations to improve safety.

[airman1900]

Originally Posted by Rated De

Precisely, the old Boeing would not need reminding.
Nor would they have lobbied the President to intervene if they were certain the data supported their public rehearsed statements of safety.

The "old Boeing" almost always tries to blame the pilots: USAir Flight 427, September 8, 1994 when Boeing said the pilots stepped on the wrong pedal.
https://www.ntsb.gov/investigations/...s/AAR9901.aspx

And sometimes an investigating agency tries to blame the pilots, especially when the aircraft is made in their country, like the French BEA when they blamed the pilots for American Eagle Flight 4184, October 31, 1994.
https://www.ntsb.gov/investigations/...s/AAR9601.aspx
https://www.ntsb.gov/investigations/...s/AAR9602.aspx

[TBC Retired]

Originally Posted by Rated De

Precisely, the old Boeing would not need reminding.
Nor would they have lobbied the President to intervene if they were certain the data supported their public rehearsed statements of safety.

I'm sure they're burning a lot of midnight oil at Boeing amid constant urging from the CEO on down to fix the problem 'yesterday'. As Trump said, 'Boeing is under great pressure', which is not a good working environment when dealing with critical safety issues. When some of the dust settles, I hope the appropriate people will take a broader look at the Max program. MCAS is far from the only new software on the airplanes. FMC U13 was all about layering Max changes on top of the existing performance algorithms and data that also support the NG and OG models. Entirely new engine performance and thrust management software and data were required for the Max models as well as changes to the performance database which holds the data for all of the OG/NG/Max model/engine/rating combinations, of which there are hundreds of permutations. I sincerely hope that all of the initial problems with keeping all of that separated and straight got ironed out in the end and thoroughly verified. Again, these are things largely transparent to the flight crews and customers, so I'm pretty sure that Boeing wouldn't have 'burdened' them with excess information.

[PaxBritannica]

Boeing 737 Max aircraft grounded 'until May at least'

[MPN11]

As someone has recently posted on another Forum ..

Having TWO new types grounded in the space of 5-6 years is truly appalling by modern standards.

Something is wrong, deep down in the system either at Boeing or the FAA.

[PJ2]

Originally Posted by MPN11

As someone has recently posted on another Forum ..Something is wrong, deep down in the system either at Boeing or the FAA.

This will take an examination of culture at Boeing, particularly before and after 1997 to see the changes. Diane Vaughan examined NASA after the Challenger accident and issued "The Challenger Launch Decision: High Risk Technology, Culture and Deviance at NASA" in 1997, (revised 2016). The examination led to changes but not before Columbia was lost. I believe there is something similar here. Hopefully there is someone with the capacity, time and energy to do so because the question does at least need asking with regard to both organizations, (FAA & Boeing themselves, and also the relationship between the two).

[WHBM]

Originally Posted by MPN11

As someone has recently posted on another Forum ..

Something is wrong, deep down in the system either at Boeing or the FAA.

You can actually find this increasingly with government Regulatory Authorities, in various countries, and with other regulators/augitors, eg for the finance industry.

Time was when the regulators were quite independent, and looked at things with true external oversight. They would need the knowledgeable personnel to work through everything. Then it slowly occurred to them that they might get the industry they were regulating to do certain of their jobs for them, particularly if this lessened their own costs. Instead of checking everything out from the outside, get the industry to bear the cost and write up a description of what they had done, which could then just be signed off. Increasing the industry did all the work, and the Regulator just said "OK then". Of course, they did not then need as many of their own knowledgeable technical staff now, it becomes just admin staff checking that a box ticking exercise has been completed. If they don't know what boxes to ask to be ticked in the first place, well, just ask the industry to devise the list for you ...

[oldoberon]

PJ2 1396
would be good if they could get the same person to do it on FAA then boeing

[WHBM]

Originally Posted by dsc810

...and their customers are exactly the same
They know the low cost cheap flights risk a monumental mess up every now and then that leaves them stranded for XX hours in some ghastly place
But they also just hope the odds work in their favour and its not them that get caught.
Its the same everywhere: people complaining how some corporate is cutting services or not doing it "properly" while the same complainers are busy bodging up their electrics, roof, guttering whatever and hope the next purchaser does not notice.

The airline "customers" are often not those flying at all, but corporate central beancounter staff making bookings for their staff on what is the cheapest fare to the destination, regardless of other considerations. The staff actually flying end up just stuck with the choice. Certain carriers have made a whole market out of this ...

Some corporates are better at this than others. There is a general belief that oil companies, well used to very substantial Due Diligence of their helicopter operators, let this approach go through to the comercial airline bookings for their staff as well, who to use and who not. Others not so much. It's notable that a significant number of the Ethiopian passengers were travelling for a major worldwide organisation, who possibly procure their air tickets centrally.

[Sailvi767]

Originally Posted by SquintyMagoo

cervo77 asks "How should they know that pulling on the Yoke didn’t stop the trim?"

Shouldn't they hear or notice the trim wheel continuing to turn?

Yes.

filler

[DaveReidUK]

Originally Posted by oldoberon

Surely BEA are responsible for recovering data not analysing

The BEA are responsible for whatever they have agreed to do on behalf of the ECAA who are leading the investigation.

I would be amazed if their remit did not include initial analysis of the recovered data. After all, that's what the 'A' in BEA stands for.

[Joejosh999]

Is there an airspeed input component to MCAS ?
http://www.b737.org.uk/mcas.htm
this mentions “at airspeed approaching stall”

I wondered because we know there was likely an UAS situation for ET, so potentially a pitot hardware issue.
If AoA was all that MCAS received , then we’d be looking at possible alpha vane failure as well, therefore we’d have hardware issues with two separate components.

So - could a blocked pitot be another single point of failure? And the AoA was fine?....

[TBC Retired]

Originally Posted by PJ2

This will take an examination of culture at Boeing, particularly before and after 1997 to see the changes. Diane Vaughan examined NASA after the Challenger accident and issued "The Challenger Launch Decision: High Risk Technology, Culture and Deviance at NASA" in 1997, (revised 2016). The examination led to changes but not before Columbia was lost. I believe there is something similar here. Hopefully there is someone with the capacity, time and energy to do so because the question does at least need asking with regard to both organizations, (FAA & Boeing themselves, and also the relationship between the two).

777 was the last program I worked on at Boeing where I felt they did everything pretty much as it should be done. "Working Together" was the motto and that meant not just consulting with customers, but coordinating internally by having 'design/build'' teams working with each other all the way rather than emerging from their individual tunnels at the end of the process to find miscommunications and things that didn't work together properly. After that program, Boeing dismantled their traditional design matrix organizations which served as checks and balances on each other, but required lots of staff. Later programs seemed to have lost that magic and each follow-on project was mandated to have a faster and cheaper design/build/test/certify cycle than the previous one. Most of the low hanging wasteful effort was eliminated long ago and it was value added activities that started being cut. I felt that trend culminated on the Max program which kicked off with a misguided dream by program leadership that they might actually be able to eliminate flight testing altogether because prediction methods and computational models were so accurate and mature. Pure hubris. Every program I ever worked on had unanticipated show stoppers which surfaced during flight testing and required panic fixes, yet that basic lesson seemed to have to be constantly relearned.

[Ian W]

Originally Posted by oldoberon

Ian I assume you read all of the narratives.

A few quick points from memory
Pilots not being able to usual scan and see what they are looking for
Pilots not familiar with new displays
Pilots not Knowing what the "Maint" msg means and unable to find it in pilots notes
Pilots not knowing what a particular switch labelled SEL was for.

That is abysmal conversion training (classroom and sim) , abysmal documentation and DANGEROUS

If those points are correct then how were they even flying the aircraft? The airline involved is responsible for ensuring conversion to type and should ensure that the crews are trained and tested. If the Boeing difference and conversion is insufficient then Boeing needs to be told. Then surely simple self preservation if you are put into a new cockpit and cannot 'scan and see what you are looking for' not find switches read displays or know what switches are for.... I would expect that crew to not fly the aircraft. That they did indicates something very very wrong at the airline involved. It seems we are starting to see the impact of the beancounters on flight safety and/or perhaps - if you are right either a gung-ho approach from some crews or an unwillingness to stand above the parapet and say I need more training for this one.

More to the point in both cases the aircraft were in good VFR at low level, speed should be apparent without looking inside so there is a visual cross check, the trim keeps going nose down - so switch off stab trim (AFAIK the switches are in the same place in all 73's) start using the trim wheel and fly manually and visually while PM goes through the various memory items and checklists. We know that this approach works as a Lion Air flight before the crash flight did just that and continued as a normal flight.

[FCeng84]

Originally Posted by Joejosh999

Is there an airspeed input component to MCAS ?
737 MAX - MCAS
this mentions “at airspeed approaching stall”

I wondered because we know there was likely an UAS situation for ET, so potentially a pitot hardware issue.
If AoA was all that MCAS received , then we’d be looking at possible alpha vane failure as well, therefore we’d have hardware issues with two separate components.

So - could a blocked pitot be another single point of failure? And the AoA was fine?....

MCAS activation requires AOA above an activation level that is a function of Mach number. The dependence on Mach is not particularly significant (i.e., errant Mach would not significantly impact the MCAS activation point). The amount of stabilizer motion that MCAS will command is also a function of Mach number. With Mach less than 0.4 MCAS will move the stabilizer as much as 2.5 degrees if AOA exceeds the activation threshold by many degrees. At cruise Mach number the size of the MCAS stabilizer motion increment is less than 1/3rd that at low Mach numbers. The bottom line with regard to the question posed here is that a blocked pitot coupled with healthy AOA data would not cause MCAS to activate unless actual (and thus properly sensed) AOA increased to a level significantly above that for normal operation. If you follow pitch/power guidelines after pitot blockage and detection of unreliable airspeed you will not get MCAS. If you get slow and get to elevated AOA following pitot blockage you are likely to encounter MCAS provide flaps are up and autopilot is not engaged.

[Joejosh999]

Originally Posted by FCeng84

MCAS activation requires AOA above an activation level that is a function of Mach number. The dependence on Mach is not particularly significant (i.e., errant Mach would not significantly impact the MCAS activation point). The amount of stabilizer motion that MCAS will command is also a function of Mach number. With Mach less than 0.4 MCAS will move the stabilizer as much as 2.5 degrees if AOA exceeds the activation threshold by many degrees. At cruise Mach number the size of the MCAS stabilizer motion increment is less than 1/3rd that at low Mach numbers. The bottom line with regard to the question posed here is that a blocked pitot coupled with healthy AOA data would not cause MCAS to activate unless actual (and thus properly sensed) AOA increased to a level significantly above that for normal operation. If you follow pitch/power guidelines after pitot blockage and detection of unreliable airspeed you will not get MCAS. If you get slow and get to elevated AOA following pitot blockage you are likely to encounter MCAS provide flaps are up and autopilot is not engaged.

Thanks for the clarification!

So it’s possible we’ve had hardware failure in two separate components? Pitot and alpha vane?