Boeing 737 Max8 Aircraft Crashes and Investigations [Part 4] 28

[Sparweb]

This is the continuation from:

thread815-445840
thread815-450258
thread815-452000

This topic is broken into multiple threads due to the long length to be scrolled, and many 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.

My personal point of view, since this falls close to (but not exactly within) my discipline, is the same as that expressed by many other aviation authorities: that there were flaws in an on-board system that should have been caught. We can describe the process that "should have happened" in great detail, but the reason the flaws were allowed to persist is unknown. They are probably too complex to reveal by pure reasoning from our position outside of the agencies involved. Rather, an investigation of the process that led to the error inside these agencies will bring new facts to light, and that process is under way, which will make its results public in due time. It may even reveal flaws in the design process that "should have" produced a reliable system. Every failure is an opportunity to learn - which is the mandate of the agencies that examine these accidents.

Some key references:

Ethiopian CAA preliminary report

Indonesian National Transportation Safety Committee preliminary report

The Boeing 737 Technical Site


No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[3DDave]

Alistair, at least we agree that the pilots did risk the lives of their passenger for the paycheck. There is no evidence they bothered to understand either the AD or the Ethiopian Airlines specific FCOM pages. Also, it may surprise you, accountants don't make decisions about how to run companies. The management does. And the management of Ethiopian Airlines was perfectly happy to take the cash saved by not training their pilots in exchange for the deaths of all those passengers and the crew.

How does a cancer filled company do a successful clean sheet design? Seems like the only other choice was to liquidate the company when it was clear they were diseased people running it instead of building on what worked.

That article - where is the 4 second reaction time requirement spelled out? I see the claim, just nothing to back it. I know that Ethiopian Airline had been given all the info about MCAS that is repeatedly claimed was withheld. It should have been in the manual, but maybe Ethiopian Airline management expected a big payout from a crash? What other motive could ETH have for not passing it to pilots? Or did pilots round bin it as just another piece of junk mail?

Seems like another hit piece as it leaves out every misstep the crew made to ensure the crash happened.

 

[VEBill]

Re. 777 Heathrow "BTW that was also an initial pilot screw up flying too high when it was cold."

I trust that was intended to be gentle sarcasm. Famously, it was the fuel heat exchangers that were redesigned. Tubes a bit too long, preventing the ice from contacting the hot plate.

Report: "[highlight #FCE94F]G-YMMM was operated within the certified operational envelope at all times.[/highlight]"

Edit:

Please take note of the above quotation that is from the report. This contradicts any claim that the pilots were outside the approved operating conditions.

Also, the fuel heat heat exchangers did not perform their basic function. They failed to melt particles of ice, and in fact became clogged with ice. They were not redesigned because they "didn't help"; they were redesigned because they didn't work, and were a menace.

 

[Alistair_Heaton]

There is no evidence that they didn't read the AD. I know for a fact compliance with a written instruction bares very little resemblance to the first attempt of a new procedure in the sim. A bit of paper or 45 min ipad presentation is just not going to cut the mustard for a new critical failure.



The First hole of the cheese was Boeing management cutting corners and pushing through a flawed aircraft because the competition had a flying product released already and they were loosing market share.

The engineers who gave into management pressure to keep their pay checks were the next slice.

The certifiers the next slice etc etc.

The at the very end airline and crew.

Then we ended up with two fatal crashes.

Nobody is going to say the pilots or airlines were blameless in either crash. But all that was required was one hole to be closed in the other multiple slices and two crashes would never have happened.

The heat exchangers did get redesigned after that, but above the tropopause was unusually cold that day below -70 and lower altitude and every other aircraft had descended into warmer air because the fuel was getting too cold on multiple different types. I suspect they were a bit tight on fuel and didn't want to descend. They didn't get any cold fuel ecam messages but the fuel was in minus figures already in China when it was loaded. And to be honest I really wouldn't trust the fuel in china to be of the same quality aka water content as the fuel in Europe, same as when I load it in Africa and a few other places. I carry my own water test kits when I work in those sort of places and have refused a fuel load more than a few times because of water content. Its not mandatory to do this test as a pilot in theory the fuel cert and company QA should ensure its OK, its just my own self preservation SOP.

They had been planned to descend by ops but elected to monitor instead of complying. But it was decided that the design didn't help things so they fixed it. I Think they also did a fair bit of work on if the fuel temp sensor was in the right place and gave a true reading. And I think there was also something about one tank had two hydraulic coolers in it and the other one only had one but as both engines failed I doubt that made any difference. So its not a clear cut engineering issue. We will never know if they followed the flight plan if it would never have happened.

The 4 second thing seems to be a FAA certification standard we can't find it in any EU regs. There seems to be a lot of noise about it your side of the pond along with some of the other reaction time stuff. Must admit it did make me laugh the first time I saw someone state that if its your average American airline pilot can react in 4 seconds and save the aircraft with Boeings design, that means there is 50% of them out there that wouldn't save the aircraft, how about sex and travel Boeing.

Must admit some of the numbers coming up with predicted reaction times are highly dubious from my own experience. 10 seconds from rapid decompression to hitting 5000ft per min in the decent. After 10 seconds you would have only just got the mask over your head and established coms but not yet finished farting. BTW the A220 has a button you press then it will take you down to 10k or MSA which ever is higher while your putting your mask on.

 

[LittleInch]

3DDave,

I think personally you're going too far here in the desire to blame the pilots.

One thing that always reassures me when I step on board any aircraft is that the person(s) at the front of the bus have an equal desire to arrive in one piece as I do (barring the odd suicidal lunatic).

So to say that they in essence "engineered" the crash is going way too far.

And in essence all pilots take the paycheck and take the risk. I think if most of us knew how many faults were present on aircraft that were still deemed fit to fly then we wouldn't set foot inside them. Is that risking the lives of passengers for a paycheck?? Happens every day. But the airlines would argue those risks are managed and evaluated.

Now there may well be faults in how the AD was transmitted to the pilots, though clearly not helped by the lack of the AOA disagree alarm on those planes, something Boeing knew about but did nothing, and the strange way the AD was written. It's basic tenant which was turn off the electric trim, don't worry you can always manual trim, has been proven to be false. Also it is clear from the article and from our resident pilot here that the runaway trim issue did not occur in isolation and can severely overload the pilots ability to determine what the correct actions are when all sorts of alarms and things are happening with NO SPECIFIC ALARM.

It is clear that there was an overriding aim from Boeing during the design and certification process to avoid requiring retraining of pilots to save their customers money. A noble aim no doubt, but in this case may have gone too far. As numerous articles state, the basic boeing philosophy is to grant the pilot the ultimate control. Hence why normally pulling the control stick back cuts out the automated trim movement. But now it didn't due to the fact MCAS needed to operate in those conditions and they essentially found themselves in a strange place between "manual" flying and FBW.

That the manual backup system now didn't work due to size of the stabiliser increasing and the diameter of the wheel going down, plus a rather fast aircraft is not down to pilot error. That's a design fault. How they fix that will not be a software issue I fear and may be a key issue that is very difficult to solve.




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

 

[Alistair_Heaton]

I wouldn't worry about blaming the pilots to much they do carry a portion of the blame. It's pretty much sop anyway. And if that doesn't work next stop is maintenance.

You get pretty hardened to it after a couple of years working. It's half the skill of being a Captain is covering your arse against the obvious lines when the finger pointing starts. Mostly it's ops issues such as pax offloading and refusing cargo. The flying is easy in comparison.

You will never change the view of pilot haters anyway.

Let's face it our one's comments has triggered the complete re certification of the autopilot disconnect system. Must be 30 odd people and 2 months work and add in the flight test flights plus mods. An easy 10 million I suspect. Mods installation are extra.

They will never acknowledge what the true environment was like when the mcas triggered the three times.like our partners they just think of pilots sitting on there arses drinking tea for a 12 hour shift. Never been on a jumpseat ride in there lives in shite wx.

Btw I am sitting on a beach after having a brake failure this morning....

And I didn't follow the qrh I learned afterwards. No memory items in the qrh for the failure. A read and do checklist for a antiskid caution in the air which doesn't cover it anyway.

You have to love turbo props. Touch down get it into beta touch the brakes and the master caution goes off and the aircraft heads off towards the side of the runway doing 100 knts. Release the brakes slap in 6000 shp full reverse as you give it full oppersite rudder yell your tops and go for the tiller... Start thinking about the emergency hand brake. Sod it we are at 50 knts now. In theory I should cancel reverse now... Sod that I will tell the technicians I busted it. Get a remote stand so didn't need a tug.

Write up in tech log mention about using rev below 50 get laughed at by technicians. Do I know how long it takes to do a runway excursions inspection? Go home after a 12 hour shift finishing at 6am to be met by my 4 year old boy who has a broken favourite toy. Soldering iron out and fix it. Go to bed after being awake for 24 hours at 8am. 2pm awake and go to beach and sit down with a beer and write a reply on this thread.


To be honest I don't even consider this an unusual day apart from I can have a beer because I am off tomorrow after 6 days working. I get 36 hours off then back for another 4 sector day starting with the alarm clock going off at 5 am for another 6 day block. Oh and I got my leave refused next month because of lack of captains.

Now should the OEMs design for the average well rested pilot. Or for the minimum skilled pilot who has been working 10 hour shifts for the last 6 days?.

I would like to think I am not anywhere near the minimum skilled label. But the state of my underpants after this mornings adrenaline burst could have been done without. Don't worry they weren't brown just a bit damp with sweat and the seat cover needed extracted after I cancelled reverse.

To be honest sorting out a surface mounted usb port was quite therapeutic before going to sleep.

Now I think a second pint is in order.

 

[LittleInch]

Hmmm,

Sounds like an interesting landing...
Why the 50 knots limit? I've been in turbo props that have reversed to get maximum take off length in the past.

The flight crew working times do seem high sometimes and it has turned up a few times on ACI. how you factor for that in a design environment is an interesting thought - double reaction time?

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

 

[Alistair_Heaton]

Mate just read your edit I utterly love I am blaming the command choices and you are blaming the engineering.

That's the way the system should work for ensuring safety. No finger pointing at others. If everyone says it's our fault we will work to minimise the chances of it ever happening again. Your risk is decreased by multiple factors.


The utter pish of finger pointing and trying to target one specific group as the culprates will have no where near the same benefits.

 

[Alistair_Heaton]

50 knts is because of the composite props and recirculation of crap off the ground basically eating them. Its to try and limit delamination. They are a 1/4 mil each I think for the q.

If you are sliding towards a follow me car at 10 knts you use it. You just tell the techs and within 10 flights they run a ultra sound over them and see if they have delaminated apparently.

A normal landing for me with a 28 ton q and 2000 meters of black I don't need brakes or reverse.

The q400 is stupidly over powered. I have never done a mtop take off ever evenin the SIM.

The Jetstream with dowry or Macaulay props made out of metal there was zero limitations. We used to reverse off stand. Had a complete brake failure including emergency brakes due shuttle valve jamming going into Plymouth UK which is 1600 meters in a Jetstream which has a school 300 meters off the end of the runway with a 100 ft drop. I hit full reverse and by the time I had sorted my shit outin my head after 1000 meters of runway used we were reversing back up the runway. It was pure overload I hadn't cancelled it. The ground handlers all thought I was showing off.

 

[LittleInch]

Makes sense.

BTW I'm a London based pipeline engineer, (If you click on a persons handle they sometimes have extra information on their profile and somewhere you can hover over and it lets you know their location) but I follow these sorts of threads to broaden my knowledge of things. My family only let me watch ACI when they're out...

Been on a few hairy flights to Sumburgh in my time and used to love jumping out of aircraft for fun, mainly turbo props with the odd piston and the very occasional jet or ballon or chopper. I fly a fair bit on business so am always interested in why some of the buggers fall out of the sky, always hoping it never happens to me. I do carry a smoke hood with me now on flights - seen too many disasters where people died because they couldn't see/ breathe. Gets the odd strange look at security, but no ones stopped me yet. Whether it would work god only knows but it makes me feel safer.

enjoy your beer.

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

 

[Alistair_Heaton]

I used to fly for Highland airways into sum delivering the Sunday sport in truely shite wx.


When I was doing my failed PhD my supervisor was Donald Mackenzie at Strathclyde and Tommy Grey.

Born in ABZ and dad a radiation protection advisor

Saw my first industrial fatality in an oil yard in ABZ when I was 15 years old. I went under the lorry Axel's and the other guy tried to run away. He got splatted I shat my pants...

 

[Alistair_Heaton]

btw I personally think these sort of threads are useful for all flavours of engineers.

If my comments make you think even once about how the operators can f up and abuse your design and you protect against it then. I will be an extremely happy ex fea nonlinear now captain ex practicing engineer.

Although I have just installed a dogs bollocks heatpump heating and cooling system in my farm and thanks to my engineering skills I have avoided having an extremely crap system installed. Also just put through the drawings to a roof truss manufacturer for frames for the barn with two tons of solar panels on the roof.

And apparently I talk sense to the spanner monkeys. So the qualifications are not wasted. Still have a copy of ansys on the computer and k-pipe. I recon I could still write 90% of an ansys input deck without ever booting it.

 

[dgallup]

Boeing shares rise as company hires for 737 MAX work

Boeing announced plans to hire hundreds of temporary workers to help roll out the 737 Max aircraft once it is FAA approved, which is likely to happen before Thanksgiving.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[Sparweb]

THIS THREAD IS CLOSED.

Please continue the discussion at the new thread:
thread815-457125

Thank you everyone for this enjoyable discussion.
This topic is being broken into multiple threads due to the length to be scrolled and many images to load, creating long load times for some users and devices.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF