Boeing 737 Max8 Aircraft Crashes and Investigations [Part 7] 16

[Sparweb]

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

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

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 is now broken. See PDF download below, 3 MB)

Indonesian National Transportation Safety Committee preliminary report

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

www.sparweb.ca

 

[Alistair_Heaton]

As for the ATR crew that let the machine hit the water. I have zero excuse for that, its mind boggling to myself.

 

[3DDave]

I'm sad to think that the CAAs of many countries around the planet depend on a comment here. Sort of makes my point.

 

[LittleInch]

I assume in your post of 2037 you mean competent instead of compete?

Any way I do wonder here in terms of the mcas fix whether the cure will turn out to be worse than the disease. Turning an aircraft never designed to FBW into a semi FBW is going to result in some unforeseen crash. Either it will freeze or mcas won't become active when it needs to.

Sure this has escalated beyond one issue as people dug more into the design and certification. And some of those fixes would have meant fundamental redesign.

AH is correct. Most punters just want cheap tickets. But if another 737 max falls out the sky because of design issues and it gets highlighted then that could be an unstoppable demand for other aircraft.

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

 

[Alistair_Heaton]

The issue has morphed into something way beyond the original issue.

Hopefully they will release a full list of the eventual changes.

And once it's done then hopefully they will look at the regulation big picture.

To be honest the money involved is small in the aviation scale of things. With the tech work to fix the issues in the design office. It's the change to the dry operating weight which is the biggest issue. And will give a clue to how much has been added.

 

[3DDave]

Another near disaster from Airbus:

https://www.flightglobal.com/safety...collision-avoidance-manoeuvres/139244.article

Lack of human factors studies and failure to allow inputs from one pilot as force feed-back to the other pilot. Seems like a cost savings move to not include haptic feedback to get the pilots on the same page. It's FBW. Yet again, hero pilots triumph over poor systems design.

 

[davefitz]

When one reviews the widely changing quality of posts by a particular poster, it suggests that some posts are being made in the local bar after 6 pints have been consumed.

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

 

[Lou Scannon]

Ouch!

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Sparweb]

AH,
Perhaps when you take a second look at your post from 14 Jul 20 21:01 you might want to edit a little. It's the kind of thing I normally red-flag for deletion. Maybe a warning is appropriate here. I will look in tomorrow to see if it's cleared up. If you need clarification, please read the posting guidelines (link on the bottom of the page).

http://www.sparweb.ca

 

[Alistair_Heaton]

It's deleted and yes number of pints involved.

Personally I do think the fundamental rules of fly by wire need revisiting. With the main controls not connected you get no feel what the other is doing.

We have a very loud dual input sounded if the system see's it. Plus it gets flagged to the safety office via acas. You can kill the otherstick. And the inputs are sum so if one puts full forward in and other full back nothing will happen.

The not following TCAS has been around for years the Swiss DHL and subsequent murder is case in point. It is again an every 6 month exercise. To be honest I don't understand why. The system takes into account performance, It can deal with 8 aircraft at the same time. It gives you green and red bands to nail. If you do everything works. You don't have to think. You don't have to react particular fast either. 45 second to disengage the ap and pitch. The boxes speak to each other and combine the solution to the least aggressive that works giving 300 ft seperation. When you have multiple involved it can get a bit more technical with reversions requiring quicker changes but it's still hit the green band on the vsi and everything works.

The TCAS stuff is none type related but the fbw dual input is common to all side stick types with no connect. To be honest even when connected two pilots fighting over control has always been an issue.

Per say the same thing could happen on multiple different types

 

[LittleInch]

AH - You deleted the wrong one

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

 

[Alistair_Heaton]

Mo and didn't see it, now dealt with thanks.

It should have been more politely worded.

More than fair call getting my knuckles rapped for it.

 

[LittleInch]

I'm still wondering if all these relatively cheap software mods are going to cut it with everyone else. I've not seen mention of any other hardware mods as part of the return to service work.

The base design of the max to fit the bigger engines resulted in a cascade of issues which were downgraded to meet an impossible "no sim training" requirement.

So on the shopping list for (non US) regulators is surely:
1) Stick shaker disconnect / cancel (Canadians want that?)
2) Separate isolation for the stab trim motor for auto controls and manual controls ( i.e. back to the NG)
3) Something that tells the pilots that MCAS is active / in operation and a cancel button
4) Those software mods to stop the thing activating every 5 seconds multiple times
5) Those wiring issues and other things on the long list
6) Does this semi FBW approach (1oo2) actually work or does it open up other failure modes / conflicts




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

 

[Alistair_Heaton]

1 the Canadians are going for it big style with the stick shaker.
2. I believe its taken care of via 2 flight control computers and its on the list of want requires to happen in the next 24 months.
3. They already have the AOA for free no charge and its link to 2.
4.its been stopped one time only activation. What happens to the flight envelope is any ones guess.
5. Nothing said apart from it fixed to within requirements nobody has clue if they have fixed it or not but we suspect they have.
6. I really don't have a f'ing clue, its a Frankenstein setup which is not legal, but it soon will be. And will have been created to allow the 737 Frankenstein to fly. It won't be repeated. economic and political reasons will be the prime mover which is why my bum and my family's will never strap there lily pink or hairy bums in it for a right few years until proved safe. The mother in law can fly in it with no limitations.

 

[Alistair_Heaton]

BTW its not just a cheap software mod there is poo loads of changes occurring.

Quite how much is not common knowledge. We might get the full changes through me and spar knowing what documents to have a look at from both sides of the divide. The control runs and electrics will not be in the pilot realm. We shall see how open they are about the changes. So far from 6 month's ago since the FAA boss screwed up completely in the sim according to 6th hand reports and went WTF is this. Boeing have been remarkably open apparently.

BTW beer alert... I have had a few sorry spar.

 

[Alistair_Heaton]

But what we do know thought is that the 2 inch thick QRH is here to stay. Finding it and navigating to the right page is what every pilot will have to do. So 27 memory items they will have to find a book behind a seat and have to decided what the hell is going on after doing 12 hours for 7 day in a row.

which over 60 percent of Boeing selected pilots screwed up monumentally. And most of them were not third world. And one of them was the faa director.

So enjoy your flight in a 737 max...

 

[1503-44]

That ain't never gonna happen. Boeing rolled the dice on that design and they were not playing with their own chips. I prefer to do my gambling at the card table rather than at 3500 ft. It's the principle of the thing. This is software defined aircraft. "The die has been cast." Julius Caesar

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[Alistair_Heaton]

its a software design aircraft and operated but its 1960's design. Fudged to meet 1980's standards.

 

[3DDave]

Alistair, all immediately crashed; just shoved the wheel forward and went TOGO thrust at the same time?

Is that the screw up? Not knowing how the trim switch works or how to read the trim dial?

Knowing this only 7th hand, it seems like the Telephone game + conspiracy theory making a story people want to hear, rather that a clear factual record.

I'd believe it if told they missed a step, like disabling the A/P soon enough; in the original software the problem only happens when the A/P is disabled. But I would be mystified if the proper response to an alarm was to nose it over and make it crash, unless one was in a position to cast blame outside the organization they head in an effort to get increased funding.

2) Separate isolation for the stab trim motor for auto controls and manual controls ( i.e. back to the NG)

This is wrong, at least in terms of the crashes. The pilots chose not to trim, so isolation did not matter. They knew the trim switch would override the MCAS inputs; the Lion Air pilot did it dozens of times. The Ethiopian pilots did too. Both crews let the trim error accumulate and the wheel force accumulate and did nothing with the still working trim control to affect it. It would happen just the same with a wiring issue in an NG and the separate switch would make no difference to pilots ignoring the controls and indicators. In fact, Ethiopian re-enable the trim motor and did not adjust the trim, in contravention of the instructions.

There has been no report by anyone that a fault in the NG was safely handled because they were separate and, in the NG, the pilots were trained to shut them both off anyway rather than diagnose the problem in-flight. If there is a problem in the trim switch itself, what good is shutting off just the automatics.

 

[Alistair_Heaton]

Apparently over 60 percent of them ran the wrong check list.

This is a black and white issue. Wrong checklist wrong direction.

Nobody crashed. There were a ew engines shut down that were perfectly serviceable but such is life. All commercial pref A aircraft can fly on one. So its no big deal.

But the main thing is that over 60% of the operators from all nationalities could not diagnose what the hell is wrong with the machine when they were fully rested and geared up for an important sim session. If you can't get it right from those conditions you have zero chance at 4 am body time on day 7. They had zero clue and ran the wrong checklist.

 

[1503-44]

That's it right there. If you can't diagnose what the heck is going, no checklist is going to work. Plus the more checklists you have just increases the chance of selecting the wrong one.

I crashed an ultralight. Actually two and almost 3, but the first is most relevant here. I'll save the other stories for a later date. It was a very high performance type at very low speeds. Furthermore it even had a specially designed Robertson STOL package installed on it. Takeoff speed was 15mph. I took off in a bit of a strong headwind, started climbing at 1000 fpm and when I looked down, I had a negative ground speed. I looked up and there were a lot of clouds. I thought I was in some kind of a climbing, power on stall, because negative GS and 1500 fpm climb really gives one a weird perspective when trying to analyze what was happening. I pulled back power and lowered the stick, but it turned out that I was still too close to ground and landed HARD! OK, really hard. Fortunately with the slow forward AS, headwind and negative GS and my fast reaction time, I still landed on the strip. Point is, if you don't diagnose correctly, even flying within the envelope doesn't work.

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"