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Old 8th May 2019, 07:27   #226
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Default re: Boeing 737 Max crashes and grounding

^^^
Plausible. Certainly seems more reasonable than the alternate 'theory' of 'it wasn't necessary. It is/was no big deal'.

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Sutripta
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Old 8th May 2019, 08:37   #227
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Originally Posted by im_srini View Post
Perhaps, the folks from the industry could help us understand why this is so & what a "Level-D" system is.
.

A level D simulator is currently the most elaborate type of full motion simulator available. It means it has 6 degrees of motion, realistic outside view, realistic sounds, identical flight model to the real plane. All controls, displays etc in the cockpit are true to life and fully functional.

It is a s close to the real McCoy as you can get without leaving the ground. Simulators are also subjected to a certification/approval process. I.e. the manufacturer needs to demonstrates the simulator handles like the real plane.

In the past I have built some 747-400 hours on the Lufthansa and Cargolux, level D sims. It is really impressive how close to reality these things are.

https://en.m.wikipedia.org/wiki/Flight_simulator
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Old 8th May 2019, 09:47   #228
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Originally Posted by im_srini View Post
Came across this recent video about the 737-Max...
While most of the information has already been "outed," it does hint at a reason why the MCAS was driven off of a single sensor.
Apparently, the single-sensor decision was a deliberate one since having a 2 sensor system would've meant mandatory simulator training or "Level-D" training ( 35:20 into the video ).
It appears that a system complex enough, or critical enough, to require redundant inputs would've forced simulator training on the pilots for the Max & Boeing wanted to avoid this at all costs.
Perhaps, the folks from the industry could help us understand why this is so & what a "Level-D" system is.
Thank you for sharing this video. Several videos have been made saying pretty much the same thing but this video by 60 minutes Australia is the most comprehensive and lucid. Jeroen has answered the 'D' training question. Coming to the other question - to best of my knowledge yes a significant change in the way a system works requires a 'D' level training especially as it has to do with flight controls. This is not so much to do with one versus two sensors but more to do with how the machine will behave in unexpected circumstances due to a change in one part of the flight control system.

For folks who have dealt with this otherwise wonderful and customer & vendor-partner friendly company seeing all this happen is very very sad. Compared to Airbus Boeing was a far far better, partner friendly organization to deal with much like the Japanese car companies - they worked with you to build you up. Also their design philosophy made maintenance and defect detection simpler compared to their rival. It takes so very very long to build an institution....

Last edited by V.Narayan : 8th May 2019 at 09:53.
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Old 8th May 2019, 10:28   #229
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Quote:
Originally Posted by V.Narayan View Post
Coming to the other question - to best of my knowledge yes a significant change in the way a system works requires a 'D' level training especially as it has to do with flight controls. This is not so much to do with one versus two sensors but more to do with how the machine will behave in unexpected circumstances due to a change in one part of the flight control system.
...
I have seen some discussion on this where it was suggested that MCAS was considered a secondary flight control. (e.g. flaps, spoilers, slats, trim). As such it would require less strict specifications and testing than the primary flight controls (e.g. rudder, ailerons). Although one could argue that any system that can push the nose down in this way would require extra attention, it might also be a case where Boeing was pushing the envelope on how to interpret the formal (legal) definition of primary versus secondary flight controls.

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Old 8th May 2019, 10:51   #230
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Default re: Boeing 737 Max crashes and grounding

Not sure if this has been discussed. These are from the embedded software point of view on how exhaustive mitigation software should be. Even in my practice of embedded/communication with industrial temperature range of -40 to +80, one encounters myriad number of events that doesn't make sense. In this case according to below links the AoA changed 75 degrees in about a second !

Error handling/mitigation code is huge compared to the actual logic (has its own perils of not being able to show code coverage during testing:( ). We do reboot the systems in case of extreme non-concurring data. Should be really difficult where human lives are involved. But also underlines the skills of pilots that are needed in such extreme cases to fall back on.

https://www.flightradar24.com/blog/w...port-ET302.pdf

http://www.ganssle.com/tem/tem370.html#article4
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Old 8th May 2019, 16:26   #231
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Quote:
Originally Posted by V.Narayan View Post

For folks who have dealt with this otherwise wonderful and customer & vendor-partner friendly company seeing all this happen is very very sad. Compared to Airbus Boeing was a far far better, partner friendly organization to deal with much like the Japanese car companies - they worked with you to build you up. Also their design philosophy made maintenance and defect detection simpler compared to their rival. It takes so very very long to build an institution....
Maybe Boeing thought that the best way to compete with Airbus was to become like Airbus!

On a more serious note I hope some enterprising investigative journalist will look into the organisation of the teams trusted to see the Max through. Did it include (in key decision making posts) people who made Boeing Boeing? Or was the normal caution and conservative attitude of these people considered to be stumbling blocks, and were thus removed from this project. And the Max project essentially handed over to (for want of a better word, at least in my vocabulary) the MBA crowd?

Regards
Sutripta

Last edited by Sutripta : 8th May 2019 at 16:31.
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Old 12th May 2019, 09:43   #232
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https://www.seattletimes.com/busines...shut-off-mcas/

A former Boeing engineer confirms that 737 MAX switches were modified, from the previous models, which affected how the MCAS systems could be disabled.

Last edited by HappyWheels : 12th May 2019 at 09:57.
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Old 28th May 2019, 17:01   #233
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It appears there are some more concerns on the 737, pre-dating the Max:

https://www.moonofalabama.org/2019/0...g-737-ngs.html


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Old 13th June 2019, 08:57   #234
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Things not looking good for the 737 Max fleet; the planes might not fly at least until December. Just goes to highlight the extent to which Boeing cut corners to get the 737 Max off the ground after development.

Quote:
Boeing’s troubled 737 MAX aircraft, which has been grounded since March following two fatal crashes in five months, will be back in the air by December, Bloomberg reported here on Wednesday, citing a top Federal Aviation Administration safety official.

While the FAA is “under a lot of pressure”, the MAX will be returned to service “when we believe it will be safe,” Bloomberg reported, quoting Ali Bahrami, FAA’s associate administrator for aviation safety.
https://www.cnbc.com/2019/06/12/boei...er-report.html
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Old 18th June 2019, 21:04   #235
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IAG orders 200 737 Max 8 - 10 variants! The chap driving the deal is a former 737 pilot.

Sure hope those sensors up front and their interlinking with MCAS at the back is sorted out.

https://www.bbc.com/news/business-48682123
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Old 18th June 2019, 21:15   #236
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The title of this thread gives me bad vibes, each time it pops up on the recently updated page it makes look like another accident.(God forbid)

Mods: can it be renamed to something more appropriate maybe including the flight number? Thanks.
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Old 29th June 2019, 13:52   #237
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Quote:
The Max software -- plagued by issues that could keep the planes grounded months longer after U.S. regulators this week revealed a new flaw -- was developed at a time Boeing was laying off experienced engineers and pressing suppliers to cut costs.

Increasingly, the iconic American planemaker and its subcontractors have relied on temporary workers making as little as $9 an hour to develop and test software, often from countries lacking a deep background in aerospace -- notably India.
Source
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Old 3rd July 2019, 11:52   #238
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Default Re: Boeing 737 Max crashes and grounding

Here is the most detailed explanation of 'how' and 'why' the Ethiopian Airlines Flight 302 crashed within six minutes after takeoff.

Prime cause of the crash is malfunction of Maneuvering Characteristics Augmentation System (MCAS).

I love watching this Flight Channel for detailed explanations regarding aircraft incidents & it also makes me nervous of flying.


Last edited by RM Motorsports : 3rd July 2019 at 11:55.
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Old 6th July 2019, 09:31   #239
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Boeing offers $100 million as compensation to 346 families of MAX accidents

https://www.thehindubusinessline.com...le28279999.ece

Either Boeing is cash starved or their insurance doesn't work or they believe that African and Asian lives matter less. This works out to $ 290k per family. Compared to Asia and Africa it isn't completely off colour but about 2X to 3X below par in my opinion given the circumstances and the cause. In USA in a similar situation the compensation per family would have been multiples higher - $4.5 million is the average for aviation fatalities in USA. Draw your own conclusions. Even China averages $500k per passenger fatality with a per capita income 6 times lower than the US!!

The actual amount can vary due to circumstances. The rules of compensation are governed by the Montreal Convention which has been signed by Ethiopia but not Indonesia. The Convention actually covers Airlines. I do not know if it covers OEMs -I believe not.

Where compensation in USA goes the "McDonnell coffee spilling on the thighs" is a poster child case. A lady won damages of $640k in 1994 (like a little over $ 1 million today) for burning her thighs with coffee from a cup she bought at McDonell's and then placed between her thighs and then tried to drive Duh!!

But American companies ducking when it comes to compensation in Asia-Africa is nothing new. You only need to look at Pan Am 73 hijacking (1986) and Union Carbide gas tragedy in Bhopal (1984)

Last edited by V.Narayan : 6th July 2019 at 09:33.
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Old 6th July 2019, 09:44   #240
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^^^
McDonalds I think.

Also is this what Boeing is offering the families in entirety, or in addition to sums to be decided later, or as sign of remorse but not linked to compensation?

Or maybe Boeing is using PPP (Payment Power Parity!) based on what they pay thirdworld programmers.

Regards
Sutripta

Last edited by Sutripta : 6th July 2019 at 10:10.
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