Boeing 737 Max8 Aircraft Crashes and Investigations [Part 6] 17

[Sparweb]

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

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

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

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

 

[IRstuff]

The temperature shifts could also have been due to the reduced thermal loading on the atmosphere. Assuming 43,000 2-hr flights daily with 737 output of 111000 hp results in 25.6 petajoules into the atmosphere every day. The contrails may be doing something as well, but not every plane produces a contrail, although they all dump heat.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[moon161]

The temperature shifts could also have been due to the reduced thermal loading on the atmosphere. Assuming 43,000 2-hr flights daily with 737 output of 111000 hp results in 25.6 petajoules into the atmosphere every day. The contrails may be doing something as well, but not every plane produces a contrail, although they all dump heat.

Yeah, but the assertion is greater night day temperature difference. Does the difference, if any between dailight and night time aviation explain this?

 

[waross]

Alistair;
Do any pilots experience any difficulty changing seats and going fro right hand flying to left hand flying?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

Some do but it's more to do with finding switches with muscle memory.

For years I was qualified in both seats on the Jetstream and it didn't bother me. The q400 I only very occasionally had to go into the RHS as pilot monitoring in the sim during checkes and it was a pain because I had no feel for where the panels were and position of the switches with my left hand.

Everyone is different though.

 

[waross]

Thanks

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

https://www.seattletimes.com/busine...f-boeings-goal-to-win-approval-by-mid-summer/

Well that's the summer season gone for the MAX.

And it seems they have started chasing the dogs tail with finger pointing instead of going after the top bosses.

https://www.seattletimes.com/busine...g-whether-boeing-pilot-knowingly-lied-to-faa/

And the one that really makes me laugh...

https://www.seattletimes.com/busine...n-state-tax-breaks-to-avoid-european-tariffs/

Give up a tax break when you know fine your going to be making 30 billion losses over the next 5 years so won't be paying any tax at all.

Welcome to the 21st century!
Canadian design & assembly with a fair fraction of Asian and Irish manufacturing.

Thanks, it will be good to fly aircraft that are younger than my kid. But its only a plane which I am told is very nice to fly on both automatics and manually. A fair bit of sensible work has been done on he whole human hardware interface and its works well. But these days I am more interested in the roster and quality of life than the hardware. As I said to the FO today different fleet different shade of brown to deal with...

Just have to see what happens with these engines self destructing in the first 300 hours on airframe. You have to take an old engine with you when you go and pick a new one up apparently and take the second new one back with you in the hold.

 

[LittleInch]

Assume you mean this

https://www.flightglobal.com/safety...atest-to-suffer-engine-failure/136723.article

Another software failure?

https://www.skiesmag.com/news/another-engine-failure-on-the-airbus-a220/

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

 

[Alistair_Heaton]

It's not really a software failure although that's apparently the reason that it occurs is due to something in the software that controls the fan. Some sort of 3rd or 4th order resonance is set up in big fan I presume due to the controlling of the blades.

They are working on new firmware and have put various limitations in on the auto thrust and max flight levels. I don't know much about it. I think in a couple of months the new firmware is due to be released.

https://aeronauticsonline.com/software-issue-suspected-as-cause-for-airbus-a220-engine-failures/

This covers as much as I know.



Per say its nothing to do with Airbus or Bombardier its purely an engine certification issue for Pratt & Whitney for PurePower PW1500G engines.

 

[davefitz]

eliminating the washington state tax break ( meant to keep the manufacturing in washington state) also implies Boeing has no financial need to maintain its factories in washington state, and can move production completely out of washington state. Possibly to the land of the current virus issues.

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

 

[dik]

davefitz... because of the military work Boeing does, that might be a little trickier... maybe to Russia?



Dik

 

[Alistair_Heaton]

Boeing is tied to the USA with all its grandfathered models that are imperial sized.

The 787 I believe is metric and is more adaptable to production outside the US.

And Ethiopia has announced that it won't be releasing the final report next month. It will though have an interim report out before the anniversary.

 

[SWComposites]

Nope, 787 uses imperial units. But parts are made all over the world - Italy, Japan, China, Malaysia, etc.

 

[dik]

and likely the lowest tendered price...


Dik

 

[Alistair_Heaton]

Thanks I seem to remember there was some discussions about it about 15 years ago.

There was talk of aviation going the same way as automotive and going metric world wide.

As a matter of interest what components are internationally outsourced?. Even now in the UK its extremely hard to get your hands on machine tools which are geared to produce imperial screw threads.

I believe Boeing has just killed off the robotic riveter program and there was rumours that said robots were metric drives and so were producing a baw hair out tolerances. I can't remember where I was reading about it and fully admit it could be nonsense.

https://www.huffpost.com/entry/a-wing-and-a-prayer-outso_n_811498?

looking at the diagram it looks to be a mish mash of imperial/metric designing. With huge parts with true imperial parts and huge parts with metric conversion imperial parts designed on metric systems and then an imperial conversion factor applied. No wonder they struggled.

 

[IRstuff]

That's a bit ludicrous; machining tolerance is about the same, regardless of whether the units are metric or US. Mazda actually built transmissions tighter than Ford specs; that was well over 30 years ago.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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faq731-376 forum1529 Entire Forum list

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[Alistair_Heaton]

Not in my experience with oil stuff in Aberdeen. Locally produced on metric machines was always a bawhair out to one side of tolerances which you usually fudged by heat soaking or chilling the part outside or a good coating of green before delivery to get it past the QA inspectors. You did the same thing on a imperial geared lathe and it was spot on and no fudges required. And that's in a country which traditionally did used to work in imperial.

You also have the issue that all the QA gear is metric measure and calibrated and then unit conversion after measurement outside the USA. Although I presume Boeing will have provided all the tooling and QA gear. But after the flap track issue if the producers will actually use it is a different matter especially if it creates a bottle neck.

I think japan went metric in 1950's

UK it was completed in 1980 I think. I certainly wasn't taught imperial in school ever and I was born in 1972 and went to school in 1976. 1989 we weren't taught anything about imperial at Uni.

I am not surprised Mazda could build tighter than ford for the very reason above. There have been extremely few imperial built machine tools built in the last 50 years. And the US automotive industry have now given up even trying and have gone metric. All CNC lathes and mills are metric geared. The errors wrack up at every stage. I believe there are 2 pipe lathes left in Aberdeen now that are imperial geared. And if your fitting something to anything that originated from USA that's the ones you use if you don't want any screw ups.

In theory yes if its within tolerances it should all work but in practise a load of measurements will be slightly out one way and another slightly out the other outside normal distribution curve. Multiple parts over a spread the whole span is outside tolerances or you find jamming occurring at temperature extremes. Bearings get hot and fail early etc etc. Personally I wouldn't go near a split system item. Metric designed and manufactured or Imperial designed and manufactured. Designed imperial and built in a metric machined production no chance and the same the other way not that its an issue because outside the USA there are no imperial machine left outside India and the like. And I know I am not alone in have this view. Luckily its pretty easy to avoid mix race items in most of the world you just don't buy American and there are plenty of options not to.

 

[Lou Scannon]

Interesting discussion about Imperial/customary vs SI/metric. Almost worth a thread on its own.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[LionelHutz]

Ya, really far off base, both in topic and accuracy....

 

[moon161]

I worked for about a year a north american maker of automatic riveting systems, which on the small end would fit several to a sea container and on the large end would fit in several sea containers. I worked mostly drafting 'like this platform or but longer', detailing drawings, and manlift modifications. The systems would locate the work, then clamp, drill, countersink, insert and squeeze a rivet, cut it flush and go on to the next. The patents in the lobby went back to 1927 and pictures I saw of installed systems had operators with mullets, so mid 80's. All the equipment I worked on was imperial units as were boeing spec rivets on the chart, the oversize increments were were fractional, I think +1/32" as well. WKtaylor here has probably forgotten more about aerospace fasners than I'll ever dream of knowing.

 

[Alistair_Heaton]

They have and working with Imperial designed products they work an absolute treat...

Unfortunately for Boeing they went for a swiss automatic riveting system BAltec which of course is as metric as they come.... its failed and they have ditched the project and gone back to manual riveting.

Airbus has something similar using robots on the metric Airbus 330 and it works an absolute treat.

Just look at the tolerance for the metric CNC machines and then look at the tolerances on the imperial you will find that it always goes one way or the other with a metric jump.

I have done a metric to imperial conversion and the other way of analogue machine tools. You basically have to change the whole gear box. The gearing ratios are completely different to get accurate threads.

If everything goes through the same machine shop then you have zero issues. If you do it on a metric machine then stick it in the pipeyard to chill it down to 5 degs C then green it to pass QA then it gets sent to Texas or Gabon to get mated to US produced items after its been used then you need to heat it or freeze it with liquid nitrogen to get it unmated. I have been hearing this nonsense for the last 30 odd years that the two systems can co exist and you can run both side by side. Its only US engineers that continue to claim it can be done. The majority world wide have given up even trying. To be honest its virtually impossible to find imperial tools outside the US. Central Europe if I want a imperial set of spanners I get them of amazon UK. Even the pipe BSP imperial fittings have a imperial thread with a metric nut so you have a female 3/4" connector on one side with a 22mm compression pipe the other. You get a tank connector spiral imperial for a EU produced tank don't bother getting it from the usa because it will leak. Get exactly the same spec part from a EU produced product and it will work no problems. Why because the tank is produced using metric machine tools and so is the connector, Metric produced tank with imperial produced connector equals pissing joint. Which may not happen at time of fitting or pressure testing but only when it heats up or cools down.

I really don't care what units the yanks use but I will stay clear of the product unless I know what its made on. Automotive its now all metric anyway. They eventually gave in and although haven't admitted the issue running both in parallel have just gone metric anyway on the grounds of its cheaper.

If a technician is sent to fix an airbus and is missing a 50mm socket they can get one anywhere in the world locally. If they need 2" socket for Boeing its going to have to be shipped in or what's mostly going to happen is they will use a 50mm spanner and grind a bawhair off one face. Getting something torqued to a book value is just lost to local requirements of home made tools.