Boeing 737 Max8 Aircraft Crashes and Investigations [Part 8] 24

[Sparweb]

This post is the continuation from this series of previous threads:

thread815-445840
thread815-450258
thread815-452000
thread815-454283
thread815-457125
thread815-461989
thread815-466401

This topic is broken into multiple threads due to the length to be scrolled, and images to load, creating long load times for some users and devices.
If you are NEW to this discussion, please read the above threads prior to posting, to avoid rehashing old discussions.

Thank you everyone for your interest! I have learned a lot from the discussion, too.

Some key references:
Ethiopian CAA preliminary report (Link from Ethiopia is now broken. See link from NTSB Investigations below)

Indonesian National Transportation Safety Committee preliminary report

NTSB Investigations

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

A Boeing 737 Technical Site

Washington Post: When Will Boeing 737 Max Fly Again and More Questions

BBC: Boeing to temporarily halt 737 Max production in January

Pulitzer Prize, For groundbreaking stories that exposed design flaws in the Boeing 737 MAX that led to two deadly crashes and revealed failures in government oversight.

http://www.sparweb.ca

 

[RedSnake]

Thanks Alistair..

What is the modern standards for stall systems?
And did you mean that the "locking" of the column at a stall was original on all 737?

Why I am asking is because the elevator feel computer EFC and the dual feel actuator seems to be able to do there job as they are suppose to, in a good way, which has nothing to do with any "safety", as longs as you do not mix it up with MCAS or Stall warnings etc.

I think it's the Romans they hade swords long before Napoleon, you carry the sword on the left side to be able to pull it with the right hand, then it will be easier to defend yourself if you ride or drive on the left side.
The same thing in a boat, the oar or side rudder is on the right side because most people are right-handed.

In English speaking culture most things in aviation are taken from Maritime to do with naming and ships are always she. I think German its masculine and Russian they always call aircraft he as well.

In Sweden boats are mostly female.
Apparently sailing ships are female but smaller boats can be male or neutrum , tugboats are always male.
And Viking ships, if never so sailing, was he.
The word for them was dragon "drake".
One famous one was "The Long Snake ".

Best Regards A




“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[waross]

My favorite explanation is that in England the Coach driver sat on the right so as to have more room to swing his whip.
This advantage would also apply to the use of weapons.
The same principle applied in America.
The driver sat on the left so that the shotgun guard had better access to his weapons.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Alistair_Heaton]

I don't know what the current certification standard is on stall systems. As such its just a indication system. Its when it gets linked into other things that it explodes in complexity and redundancy.

Napoleon was something to do with driving on the other side I seem to remember. Your right handed explanation is as I remember it.

 

[RedSnake]

Napoleon was something to do with driving on the other side I seem to remember.
Do you mean on the right, right side? ;-)

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

I have driven both it makes no difference to me. When you drive a vehicle that's meant for the other side that's when it gets dangerous in both systems.

http://www.b737.org.uk/stallwarningsys.htm

It seems the stall system and feel system is the same since the 1960's 100.

And the stick shaker is in series so both fire if triggered. All other planes its a dual independent system so if you cancel one side the other continues to work.

 

[RedSnake]

God morning..
Well I been driving in Ireland no major problem other than when you get to a roundabout and there is no traffic, god so confusing.
Not only that you should drive on the wrong side but then you started to think about whether you should drive through the roundabout counterclockwise or clockwise as well.
With traffic around it is just to go with the flow

Best Regards A

PS. Most roads were so narrow that it was not possible to determine whether you were driving on the right or left side.

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Lou Scannon]

I have driven both it makes no difference to me. When you drive a vehicle that's meant for the other side that's when it gets dangerous in both systems.

I fully agree. Talk about engineering failures and disasters. Don't know if it exists elsewhere, but in St. Croix US Virgin Islands, all the cars seem to be LHD (including rental cars), yet driving is on the left side of the road. Nearly had a crackup on the way to the hotel last summer. In fact, a few minutes earlier, on leaving the airport, I kid you not, I had correctly taken the left side of a two lane road and had a truck bearing down on me on my side until it veered off into a side road, leaving me confused as hell until I reached a road with significant traffic giving me a frame of reference.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[RedSnake]

Well after coming back from Ireland I went of the main road one day into the wood to se if I could find some mushrooms, when I was driving out on the main road again where there was no traffic as far as the eye could reach, I thought something felt very strange until I realized that I was driving on the wrong side of the road.

I was with the same thing before Christmas someone had managed to drive off the highway and ended up on the wrong side of the road division there were two lanes going in both directions and came driving towards me in my lane just over a bridge crest it was just undone that it became a frontal collision if they did not turn away.

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[LittleInch]

Lets keep the LHD/RHD thing to a different post eh?

I've asked this before and can't recall the answer, but my understanding is that on the 737, all vintages, the FCC used by MCAS and other functions switches sides after every flight once you power down. And how do you know which one is active?

As in both instances Lion Air and Ethiopian, it seems that in both instances it was the captains side FCC which received bad AoA information and hence everything started going wrong from there on. So on a 50% likelihood this was one of the first holes in the swiss cheese.

Is there / was there a chance to switch FCC in mid flight or is this something that just isn't done or isn't practical? On Airbus because you have three, I presume one with bad data compared to the other two just shuts down and gives you some alarm that it needs fixing later?

Now that the 737 max looks at both FCC or AoA data, to discover an inconsistency does this (only one FCC active) still apply?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[davefitz]

I had thought the british right hand steering was adopted from the railroad engineers side, which in turn may have been adopted from the boat pilot's preferred side. The early US cars might have chosen the left side due to the difficulty of shifting the early transmissions implied the stronger right hand be used to force the tranny into gear.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[moon161]

LI, I think the active FCC switched every reboot, though I'm not a primary source on that.

 

[Alistair_Heaton]

Don't know about Boeing. But there is usually what's call ed a reversion panel which allows you to cycle through the various sensors and data sources.

And it's reasonably easy and we some times swap sides out of choice for nav . You wouldn't normally fiddle with the flight control computers unless told to by a checklist.

 

[RedSnake]

Now that the 737 max looks at both FCC or AoA data, to discover an inconsistency does this (only one FCC active) still apply?

The way, I understand it, is that both AOA sensors are evaluated for the alert "AoA sensors not ok" but this is just an alarm no function.

It was only the active FCC that used its own AoA sensor (just one for the MCAS function) and then evaluated it together with speed and other things to se if there was a stall and if the MCAS was to bee turned on.

I have also been wondering, if it automatically changes FCC every flight was it then reset before the next flight, since it also got the same problem.
But if it hade not been reset it would not have made such a big difference in the end since, flight 3 would probably had crashed if the second one didn't.
Since they did not understand what the problem was.

Best Regards A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

Thankfully the pedals are the same for both. That would really screw with my head. With the driving...

Now you see why I call it a Frankenstein design the 737. It works don't get me wrong. But its an organically grown design so you just can't use any presumption or logic with it. Makes trouble shooting extremely difficult.

If it was proper FBW certification which Boeing moved heaven and earth to avoid having to do then it would be covered. But that would have added 2-3 years and they were already 18 months behind the Neo and would have required more than 30 mins on an Ipad of training.

BTW this is tech pilot and examiner level of system knowledge working out how it all interacts that we are doing here in this discussion. The normal line pilot wouldn't normally go near it or if they are so inclined have the opportunity to brainstorm with like minded individuals and work out what's really going on. And remember that this is just a couple of systems out of 20-40 of similar complexity.

The philosophy of system knowledge required has also changed over the years. They really don't want you to be able to get inventive. They just want you to run the checklists. Jetstream theory course went all the way down to how the fuel controller meters fuel and the various modes the prop functioned in. Q400 not a thing. Its an engine the FADEC deals with the prop and the power you demand it and it will provided it. A220 there it is even more weighted to where the various switches are and not what the switches actually do to the big picture.

 

[Alistair_Heaton]

just for interest

https://uk.yahoo.com/finance/news/boeing-cites-risks-design-newest-230523327.html

Personally I can see their point. But do suspect that the 450 orders for them and nothing in development by Boeing may be a factor.

 

[LittleInch]

Wrap around fuel tanks eh? What can possibly go wrong?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[thebard3]

AH-- That's kind of the management style I'm used to after working for 40+ years. You can make yourself look better by making your peers seem worse.

Brad Waybright

The more you know, the more you know you don't know.

 

[Alistair_Heaton]

The fuel tank stuff is a mess after the accident referred to in the article.

Its again this grandfathering. Boeing stuck with electrical submersed fuel pumps, everyone else went to motive flow pumps 40 years ago...

To be fair it is a valid point although I suspect it might not be as bigger problem to solve as Boeing thinks. The market for them isn't really in FAA airspace anyway.

I suspect its more to do with single type qualification and Boeing having nothing that could even remotely be stretched to do the same job. But it will cut into their wide body markets which already getting hammered for a variety of issues some of which are not Boeings fault.

Being able to send a crew short/medium haul for a number of days and then send them on a ultra long followed by the required days off makes rostering very economical even if it kicks the hell out of the crew. It means the airline can get 20 days work a month out of a crew instead of 10 days doing ULH.

 

[Alistair_Heaton]

Turns out airbus have already got this feature on other aircraft, And many aircraft before have also had it including MD and Boeing.

They have a fix already for another type which is a Kevlar liner bag.

But to note the forum that the comment was made in is one of these regulator peer review processes. Boeing was completely right to highlight the issue.

Anyway saw this but didn't want to start another thread and thought those that would be interested would see it here.

Its a bit personal for me because I ended up stuck in Vilnius for 6 hours while they sorted it all out. And then saw it everyday I was in Tallinn.

But its a good example of a FBW airbus crew machine interaction accident triggered by a technical issue.

https://youtu.be/bo-S3kAInB8

 

[dik]

I guess the 'fat lady hasn't sung', yet. From a recent eMail from Change.Org...

"Dik — Over 346 people lost their lives in two crashes involving the Boeing 737 Max airplane. Years later, experts say that the model is still unsafe for use and countries like China and Norway have banned or are questioning their usage. This petition is calling on the federal government to ban the 737 Max in Canada, and call a public inquiry to find out why the 737 Max was approved in the first place. If you think that the 737 Max should not be used in Canadian airspace, sign today."

Not to worry... the Canadian government doesn't often listen to the people, either...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik