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moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
I hope you know it's not about new or old code. It's about how well you have tested the code TOGETHER with the other systems. Pilots included! To me it seems like Boeing have skipped many testing procedures in rush of competing with other airliners. They also gave the impression to airline companies that the MCAS is nothing to bother about. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30639 Credit: 53,134,872 RAC: 32 |
I hope you know it's not about new or old code. moomin, you don't test it, you prove it. An important distinction. You test to find human typos. You prove software to show it does what it is supposed to do. It isn't any different than a formal math proof. You can test until the cows come home, but if you don't test the right thing(s) you still have no confidence in the product. You must prove the software to have confidence in it. Let me point you and any other hackers out there to a small little publication you should read. Validation Verification and Testing of Computer Software W. Richards Adrion, Martha A. Branstad, John C. Cherniavsky Library of Congress Catalog Card Number 80-600199 National Bureau of Standards Special Publication 500-75 February 1981 "Programming is an exercise in problem solving. As with any problem solving activity, determination of the validity of the solution is part of the process. This survey discusses testing and analysis techniques that can be used to validate software and to instill confidence in the programming product. Verification throughout the development process is stressed. Specific tools and techniques are described." Oh it is even online today https://www.govinfo.gov/content/pkg/GOVPUB-C13-d8cbebacc4749b5c4284cce1ffb796d1/pdf/GOVPUB-C13-d8cbebacc4749b5c4284cce1ffb796d1.pdf While some of the tools may be dated, the concepts are not. |
moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
moomin, you don't test it, you prove it. An important distinction.LOL:) You can only prove something that you know about. Not things that you don't know about. Hence testing:) Been there, done that:) The problem is not typos (usually the parser take care of that) but setting up a testing scenario Then do the actually testing!!!! Sometimes the code doesn't behave like we system developers think it should do. Don't you have "This cannot happen" in your code? Let me present an example from mine experience. I have developed a program that communicate with a database using SQL. Worked like a charm until one day I got error messages that the date conversion was wrong... WTF! It worked before and every customer that use my program had no problem either. However later one customer called having the same problem. Not everyone. So back to testing. I never find the cause of the error, still haven't. Yes, I checked if we had different system setups and versions. But it seems like there's a god after all:) A week later it worked again without me doing anything or any changes in the setups! From your link to the publication about testing. Still valid but many have forgotten about it or should I say the budget doesn't allow that. At all stages of the lifecycle, software should be testable. To accomplish this it must be understandable. The desired product (the requirements and design) and the actual product (the code) should be represented in a structured, concise, and selfdescriptive manner so that they can be compared. The software must also be measurable, allowing means for actually instrumenting or inserting probes, testing,, and evaluating the product of each stage. |
moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
For some reason I think that Boeing has this problem:) https://www.youtube.com/watch?v=BKorP55Aqvg |
W-K 666 Send message Joined: 18 May 99 Posts: 19048 Credit: 40,757,560 RAC: 67 |
Ryanair to cut flights after 737 Max delays Ryanair has said it will be forced to cut the number of summer flights it operates next year blaming further expected delays before the Boeing 737 Max is allowed to fly again. Analysis: |
ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
Now here is a damning comparison, complete with some carefully forthright wording: YouTube: Boeing Max 8 and the Cirrus Vision jet story - Prof Simon The US aircraft builder 'Cirrus' had a problem with its Angle of Attack sensors... This is is the story of how the USA smallest Jet company, did the right thing and how Boeing did the wrong thing. Thanks to Isabel Goyer - editor Plane and Pilot magazine for this fascinating investigation. Damning indeed... All in our only one world, Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
And here is what it is like when you cannot trim a Boeing 737: YouTube: Boeing 737 Unable to Trim!! Cockpit video (Full flight simulator) ... Why would a crew, potentially, come across problems with trimming the Boeing 737 at higher speeds? What kind of forces are acting on the jack-screw that might have grave implications and what is a "roller coaster manoeuvre"?... Note the comment part way though to an outside operator to "Hit the red button"... (Only works for a flight simulator...) Very hard work! All in our only one world, Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
Is Prof. Simon Holland some kind of authority or expert in aviation? Well he however make sense. Those 737 Max engine changes doesn't work as thought. Back to drawing board and test some more. When fixed? Oh dear... |
Sirius B Send message Joined: 26 Dec 00 Posts: 24879 Credit: 3,081,182 RAC: 7 |
Interesting. While watching the video, on the Up Next section on the right was this... ...The Boeing 787 - Broken dreams Well worth a watch. This was 2014. Scary. |
moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
... Why would a crew, potentially, come across problems with trimming the Boeing 737 at higher speeds? What kind of forces are acting on the jack-screw that might have grave implications and what is a "roller coaster manoeuvre"?...It's very hard work to trim a 737 manually with the trim wheels. It was THREE people trying to do that in the Ethiopian or the Indonesian incident! Boeing 737 Stall Escape manoeuvre, why MAX needs MCAS!! https://youtu.be/aoNOVlxJmow?t=598 |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30639 Credit: 53,134,872 RAC: 32 |
Now here is a damning comparison, complete with some carefully forthright wording:Well, since the video shows two entirely different designs for AoA sensors and does not in any way address why the sensors fail, about all this really says is Boeing is a big enough company to bully the FAA. The question remains, did Boeing also bully every other country's flight certification people? |
W-K 666 Send message Joined: 18 May 99 Posts: 19048 Credit: 40,757,560 RAC: 67 |
Now here is a damning comparison, complete with some carefully forthright wording:Well, since the video shows two entirely different designs for AoA sensors and does not in any way address why the sensors fail, about all this really says is Boeing is a big enough company to bully the FAA. The question remains, did Boeing also bully every other country's flight certification people? Up until the second 737Max crash, just about every country accepted the FAA's decisions and for Airbus they accept the EASA decisions. It's just too expensive and time consuming to do otherwise. This time it looks, from here, that the FAA followed the rest of the world in grounding the 737Max, after being told to by Trump. |
Sirius B Send message Joined: 26 Dec 00 Posts: 24879 Credit: 3,081,182 RAC: 7 |
Comments from the workers at Boeing's South Carolina plant says it all. "They are built to sell not fly". Of those asked the question: Will you fly on one? 2/3 said no. |
j mercer Send message Joined: 3 Jun 99 Posts: 2422 Credit: 12,323,733 RAC: 1 |
The workers just as guilty as management for criminal neglect with that post. ... |
ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
A few years ago Boeing were using members of the 8x86 family supported by DSPs from various manufacturers with some particular functions being handled by a Motorola chip. I guess they may have moved away from these in recent years, but probably stick with the i86 family. In addition there are quite a number of FPGA type chips in use. One small snippet on the web for what the Flight Control Computer CPU is... It is an Intel 80286. That is mentioned in the Wikipedia list of what is being 'fixed' for the Boeing 737 Max. All in our only one world, Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
Is this an indication of what I assume to be the callously cold cruel calculations of the 'Boeing Bean-counters'? Families 'cheated of Boeing crash compensation' Relatives of people killed in the Boeing 737 Max crash in Indonesia last year have been cheated out of compensation, their lawyers say. ... many families were persuaded to sign forms preventing them from taking legal action. BBC Panorama has discovered that other relatives signed similar agreements after two other crashes, stopping them from suing Boeing in the US courts... ... Within weeks, relatives were offered compensation by insurance lawyers. To access the money, families had to sign agreements that would prevent them from taking legal action against Boeing or the airline, Lion Air... ... They will get compensation of just under £74,000 ($92,000) each... How cheap is that?! No wonder safety and good design was seen to be 'too expensive'? Legalized murder?... All in our only one world, Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
Richard Haselgrove Send message Joined: 4 Jul 99 Posts: 14650 Credit: 200,643,578 RAC: 874 |
How convenient that Boeing had such forms readily available for them to sign. |
rob smith Send message Joined: 7 Mar 03 Posts: 22190 Credit: 416,307,556 RAC: 380 |
WOW - a 286. Little surprise then that it is getting overloaded.... Talk of input lags and the like makes me want to ask what the processor cycle(loop) time is (not the CPU clock frequency). There is a lot of re-engineering required to increase the clock frequency and not upset the cycle loop timing which is going to be pretty critical on that processor- it's not just a case of twiddling the clock, tweaking the voltages, but the memory (RAM, ROM etc) will, at least need to be reviewed, and probably replaced - and that might mean a new board - which is what I guess Boeing were trying to avoid doing by sticking with the old FCC hardware. There are a lot of lessons to be gained from this episode - not the least "think of the consequences before not after". Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
moomin Send message Joined: 21 Oct 17 Posts: 6204 Credit: 38,420 RAC: 0 |
One small snippet on the web for what the Flight Control Computer CPU is... It is an Intel 80286.I can't see any mentioning of Intel 80286 in that link. However I find this link. https://www.moonofalabama.org/2019/06/boeings-software-fix-for-the-737-max-problem-overwhelms-the-planes-computer.html The 737 uses only one FCC at a time and the Speed Trim System (STS), of which MCAS is a part, runs only on one of that Flight Computer's two internal processors.Computer overload... Sounds like Apollo 11 LEM program error "1202"... Boeing's latest announced time frame for bringing the grounded 737 MAX planes back into the air is "mid December". In view of this new problem one is inclined to ask "which year?" |
rob smith Send message Joined: 7 Mar 03 Posts: 22190 Credit: 416,307,556 RAC: 380 |
I can't see any mentioning of Intel 80286 in that link. About half way down, in the middle of the section titled "Flight control data processing issue" Although the test pilot ultimately recovered control, the system was slow to respond to the proper runaway stabilizer checklist steps, due to an 80286[353] microprocessor being overwhelmed with data Actually the next part of the same section is pretty damming: The FAA characterized the slow responsiveness as "catastrophic", whereas Boeing initially classified it as "major". The solution appears to consist in rerouting data across multiple chips. Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
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